Utilization and Awareness of Japanese General Rules of Clinical and Pathological Recording of Cancers Among Japanese Pathologists: A Nationwide Questionnaire Survey

ABSTRACT

The Japanese General Rules of Clinical and Pathological Reporting of Cancers (Kiyaku) are unique standardized systems for cancer handling and documentation used by professionals involved in cancer care in Japan. The Japanese Society of Pathology (JSP) conducted a questionnaire survey among practicing pathologists regarding the utilization and awareness of Kiyaku. We analyzed 1083 valid responses, representing 22.4% of the JSP members and 33.8% of the board‐certified pathologists. Kiyaku, with > 90% latest‐edition ownership, covered approximately 90% of all cancers in Japan. The timing of the implementation of the new editions varied not only across institutions but also among individuals in each institution. Among department directors, 46.1% reported implementing new editions at their discretion without prior notice. Item‐level responses were collected for the stomach, lung, and breast as representative Kiyaku; histological classification and descriptive symbols were widely considered useful and frequently used across the three cancers, whereas biopsy‐related items in the lung and breast were used less frequently. In conclusion, Kiyaku is broadly embedded in daily practice and facilitates standardized cancer documentation in Japan, although several challenges remain. The JSP should clearly articulate the purpose of Kiyaku and promote coordinated adoption to standardize its use in pathology practice.

This study examines the current use of the Japanese General Rules for Clinical and Pathological Recording of Cancers (Kiyaku) among Japanese pathologists. Ownership and use of Kiyaku are widespread, while their implementation varies across institutions, and coordination within pathology departments, between pathology and clinical departments, and across hospitals nationwide remains insufficient. These findings indicate that harmonization and standardized reporting practices are needed to further enhance consistency and overall quality of cancer pathology reporting nationwide.

Abbreviations

BCOP

board‐certified oral pathologist certified by the Japanese Society of Pathology

BCP

board‐certified pathologist certified by the Japanese Society of Pathology

ICCR

International Collaboration on Cancer Reporting

JSP

Japanese Society of Pathology

Kiyaku

Japanese General Rules of Clinical and Pathological Recording of Cancers

LIS

laboratory information system

PR

pathology resident

1. Introduction

The Japanese General Rules of Clinical and Pathological Reporting of Cancers, commonly referred to as “Kiyaku” in Japanese, have played a pivotal role in the standardization of cancer diagnosis, pathological reporting, and cancer registration in Japan for several decades [1, 2, 3].

The earliest Kiyaku was the Japanese General Rules for Gastric Cancer, which was first published in 1962 by the Japanese Gastric Cancer Association [4]. Since then, most organ‐specific Kiyaku have been published and revised solely by relevant societies in accordance with advances in cancer diagnosis and treatment, whereas a minority have been developed in collaboration with the Japanese Society of Pathology (JSP) and/or the Japan Radiological Society [5, 6, 7, 8]. The Japanese General Rules for Breast Cancer is currently in its 19th edition, representing the most frequently updated Kiyaku [8].

Unlike tumor classification systems, such as the World Health Organization (WHO) tumour classification [9], staging systems, such as the Union for International Cancer Control (UICC)‐TNM [10], and structured pathology reporting systems, such as the College of American Pathologists cancer protocols and International Collaboration on Cancer Reporting (ICCR) data sets [11], Kiyaku provide a comprehensive framework for describing and standardizing the clinical, radiological, surgical, and pathological documentation of each cancer site. Importantly, Kiyaku are not merely pathology‐oriented tumor classifications or reporting templates; rather, they are consensus‐based multidisciplinary standards that define tumor entities and terminology, standardize specimen handling and reporting formats, and specify approaches for staging, evaluating treatment response, and performing survival analyses [5, 6, 7, 8]. In Japan, routine medical record entries for most cancers are documented in accordance with the relevant Kiyaku. Hospital‐based and organ‐specific cancer registries, which form the basis of real‐world cancer data studies in Japan, are established by accurately extracting and registering cancer‐related information documented using Kiyaku's terminology [12, 13, 14, 15].

Pathologists are routinely required to diagnose and report various malignancies in clinical practice in Japan. For this purpose, Kiyaku serves as a concise yet comprehensive reference that supports standardized reporting in the daily practice of Japanese pathologists. The JSP has been exploring ways to incorporate the Kiyaku and ICCR data sets to facilitate the international use of Japanese cancer data [3, 11].

Despite their widespread use in Japan, little is known about how Kiyaku are applied consistently across institutions and organ systems. The Kiyaku Committee of the JSP conducted a questionnaire survey of pathologists engaged in routine diagnostic practice in Japan. This study aimed to assess the availability and awareness of Kiyaku among pathologists in Japan.

2. Materials and Methods

2.1. Questionnaire Design

The questionnaire survey was designed by the Survey Working Group (N.T., R. W., I. I., T. T.), formed within the Kiyaku Committee of the JSP. The full questionnaire remains accessible online [16] and is also available as Supporting Information: S1.

The survey targeted all JSP members engaged in routine pathological diagnoses in Japan. In this study, pathologists certified by the JSP were hereafter referred to as BCPs, and board‐certified oral pathologists were hereafter referred to as BCOPs. “Pathology residents (PRs)” referred to residents registered with the JSP who were undergoing training for board certification in pathology. Responses were collected over a 4‐week period, beginning in late August 2024. During the survey period, announcements were made through the JSP mailing list, pathology‐related academic society mailing lists, and the official X (formerly Twitter) accounts of the JSP.

2.2. Survey Contents

The questionnaire consisted of the following components, presented in a fixed order: respondent demographics (professional qualification, type and size of primary workplace, and institutional position within the pathology department); questions related to three major cancer types (gastric, lung, and breast cancers) [6, 8, 17, 18], including ownership of the latest editions of the relevant Kiyaku, perceived usefulness of individual sections, frequency of consultation during diagnosis, and frequency of reporting specific items; and questions regarding ownership of other organ‐specific Kiyaku, sources of updated information, funding for acquisition, and strategies for implementing new editions. Because it was not feasible to conduct a detailed survey of all Kiyaku, three major cancer types were selected as representative organ‐specific Kiyaku. Institutional centralization was relatively low for gastric cancer and high for lung and breast cancers [17]. For each organ‐specific Kiyaku, respondents were asked whether the Kiyaku were purchased at their own expense or by their institutions and whether they were the latest edition, an older edition, or not owned.

Questions were also addressed regarding the integration between the pathology laboratory information system (LIS) and Kiyaku‐based reporting items at respondents' institutions and familiarity with and use of ICCR data sets [11].

An optional free‐text comment section was included to allow respondents to share their opinions on Kiyaku in general. As these comments were qualitative and not suitable for systematic analysis, they were not included in the results of this study, except for the number of comments and the total number of characters.

2.3. Statistical Analyses

Descriptive statistics were used for most analyses. For selected categorical variables, comparisons were performed using the χ ² test. A p‐value < 0.05 was considered statistically significant.

2.4. Consent for Data Analysis and Publication

Consent for data analysis and publication was obtained from all respondents, and only responses from consenting participants were included in the analysis.

3. Results

3.1. Respondents

In total, 1092 responses were received. After excluding three responses that declined aggregation and six responses from individuals not currently engaged in pathological diagnosis, 1083 responses were included in the analysis (Table 1a). One response from a PR who provided predominantly “do not know” responses was included.

Table 1a.

Respondent characteristics of the Kiyaku utilization survey (n = 1083).

Item	n	%
No. of JSP members	4836
Total responses	1092	22.6%
Valid analyzed responses	1083	22.4%
Professional qualification		%
All BCPs in the JSP	2754
Respondent BCPs	931	33.8%
All BCOPs in the JSP	171
Respondent BCOPs	43	25.1%
All PRs	500
Respondent PRs	106	21.2%
Other categories	3
Position		%
Director of pathology department	425	39.2%
Full‐time staff pathologist (non‐director)	490	45.2%
Part‐time pathologist	141	13.0%
Others/unspecified	27	2.5%
Primary workplace for pathological diagnosis
Designated cancer care hospital (non‐university)	437	40.4%
University hospital	385	35.5%
Other hospitals	190	17.5%
University pathology department or research institute (non‐hospital)	29	2.7%
Pathology practice clinic	12	1.1%
Commercial clinical laboratory/others	30	2.8%
Hospital size (beds)
≥ 400 beds	736	68.0%
200–399 beds	253	23.4%
20–199 beds	39	3.6%
0–19 beds/pathology practice clinic/commercial laboratory center	41	3.8%
Do not know	14	1.3%
Number of full‐time pathologists at the primary workplace
0	22	2.0%
1	245	22.6%
2	213	19.7%
3	133	12.9%
4	73	6.7%
5	56	5.2%
6	46	4.2%
≥ 7	287	26.5%
Do not know	8	0.7%

Note: BCPs, board‐certified pathologists certified by the Japanese Society of Pathology (JSP); BCOPs, board‐certified oral pathologists by the JSP; PRs, pathology residents—residents registered with the JSP who were undergoing training for board certification in pathology. “Other hospitals” indicate hospitals other than designated cancer care hospitals and university hospitals. “University pathology department or research institute (non‐hospital)” indicates non‐hospital university pathology departments or pathology units in research institutes, excluding university hospital pathology departments.

The analyzed cohort (n = 1083) represented 22.4% of all JSP members at the time of the survey. Among the 1083 respondents, 974 (90.0%) were board‐certified pathologists and 931 (86.0%) were BCPs, corresponding to 33.8% of all BCPs in the JSP. The response rate was significantly higher for BCPs than for BCOPs (25.1%, χ ² test, p = 0.0246 < 0.05) and PRs (21.2%, χ ² test, p < 0.001) (Table 1a).

Regarding their primary workplace for pathological diagnosis, respondents worked at designated cancer care hospitals appointed by the Ministry of Health, Labour and Welfare of Japan or by prefectures (non‐university hospitals) (40.4%), university hospital pathology departments (35.5%), and other hospitals (17.5%). Most respondents worked in mid‐to‐large hospitals with ≥ 200 beds (91.3%).

Of the respondents, 425 (39.2%) were directors of pathology departments. Their workplaces included designated cancer care hospitals (52.2%), university hospital pathology departments (18.1%), and other hospitals (26.8%) (Table 1b).

Table 1b.

Breakdown of responses from department directors (n = 425).

Primary workplace for pathological diagnosis	n	%
Designated cancer care hospital (non‐university)	222	52.2%
University hospital	77	18.1%
Other hospitals	114	26.8%
University pathology department or research institute (non‐hospital)	2	0.5%
Pathology practice clinic	7	1.6%
Commercial clinical laboratory/others	3	0.7%
Hospital size of primary workplace (beds)	n	%
≥ 400 beds	233	54.8%
200–399 beds	163	38.4%
20–199 beds	20	4.7%
0–19 beds/pathology practice clinic/commercial clinical laboratory	9	2.1%
Number of full‐time pathologists per facility	n	%
1	188	44.2%
2	110	25.9%
3	47	11.1%
4	21	4.9%
5	10	2.4%
6	8	1.9%
≥ 7	41	9.6%

Note: Values represent n (%) of department‐director respondents (n = 425). “Other hospitals” indicates hospitals other than designated cancer care hospitals and university hospitals. “University pathology department or research institute (non‐hospital)” indicates non‐hospital university pathology departments or pathology units in research institutes, excluding university hospital pathology departments.

Full‐time staff pathologists not serving as department directors, part‐time pathologists, and others accounted for 490 (45.2%), 141 (13.0%), and 27 (2.5%) respondents, respectively.

3.2. Utilization of the Latest Kiyaku Editions

Most respondents reported that Kiyaku were purchased using individual research accounts or institutional funds (998/1083, 92.2%).

Among the 26 organ‐specific Kiyaku, 17 were owned by > 90% of the respondents in their latest editions. The most commonly used classification in its latest edition was the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma (1054/1083, 97.3%) [7]. The major cancer types surveyed were stomach (94.4%), lung (91.7%), and breast (93.6%) cancers (Table 2).

Table 2.

Summary of self‐reported ownership of the latest edition of organ‐specific Kiyaku according to organ site.

	All respondents n = 1083		Department directors n = 425
Organ site	Owning latest edition	%	Owning latest edition	%
Colorectum	1054	97.3%	419	98.6%
Esophagus	1049	96.9%	417	98.1%
Pancreas	1045	96.5%	415	97.6%
Biliary tract	1043	96.3%	414	97.4%
Uterine corpus	1042	96.2%	411	96.7%
Liver	1040	96.0%	411	96.7%
Prostate	1040	96.0%	408	96.0%
Uterine cervix	1040	96.0%	410	96.5%
Kidney	1037	95.8%	411	96.7%
Renopelvis, ureter, bladder	1036	95.7%	410	96.5%
Ovary, fallopian tube	1030	95.1%	402	94.6%
Thyroid	1028	94.9%	407	95.8%
Head and neck	1026	94.7%	398	93.6%
Stomach	1022	94.4%	403	94.8%
Breast	1014	93.6%	400	94.1%
Lung	993	91.7%	391	92.0%
Testis	977	90.2%	385	90.6%
Brain	973	89.8%	371	87.3%
Oral cavity	955	88.2%	355	83.5%
Soft tissue	903	83.4%	352	82.8%
Skin	899	83.0%	338	79.5%
Mesothelioma	876	80.9%	347	81.6%
Mediastinum	847	78.2%	318	74.8%
Adrenal gland	821	75.8%	320	75.3%
Bone	811	74.9%	313	73.6%
Trophoblastic disease	749	69.2%	296	69.6%
Hematopoietic	709	65.5%	270	63.5%
Japanese cancer staging manual	490	45.2%	188	44.2%

Note: For the stomach, breast, and lung, the values were derived from detailed organ‐specific questions; therefore, the question set differed from that used for other organ sites. The Japanese Cancer Staging Manual refers to a cross‐cutting staging manual used across 22 organ sites [1].

Cancer sites with < 90% latest‐edition ownership tended to include Kiyaku with older publication years, such as skin cancer (published in 2010), mediastinal tumors (in 2009), malignant bone tumors (in 2015), trophoblastic disease (in 2011), and hematopoietic tumors (in 2010). Other Kiyaku, including those for brain tumors (in 2023), malignant soft tissue tumors (in 2023), mesotheliomas (in 2018), and adrenal tumors (in 2015) also showed < 90% ownership, likely reflecting relatively rare cancers with higher institutional centralization. The ownership rate of the Japanese Cancer Staging Manual, a Kiyaku jointly developed by the Japan Society of Clinical Oncology and the JSP and used across 22 organ sites, was 45.2% (Table 2). When ownership rates were compared between department directors and non‐directors, the chi‐square test showed statistically significant differences (p < 0.05) for several organ sites. However, the absolute differences in percentages were small (data not shown).

3.3. Sources of Information on Kiyaku Updates

The respondents reported diverse sources to obtain information on the new editions. The utilization of Kiyaku‐net remained limited (32.5% for department directors and 35.5% for non‐directors) as did the use of the website of Kanehara & Co. Ltd., a Japanese publisher through which all Kiyaku editions are distributed, except those for urological tumors (39.5%) (Table 3).

Table 3.

Routes for obtaining information on Kiyaku updates (multiple responses allowed).

Sources of information on kiyaku updates	Department directors (n = 425)		Non‐directors (n = 664)
	n	%	n	%
Information from acquaintances/found at bookstores	257	60.5%	306	46.5%
Kanehara/publisher website	216	50.8%	212	32.2%
Kiyaku‐net	138	32.5%	232	35.3%
Notifications from clinical departments	56	13.2%	76	11.6%
Do not particularly keep track***	28	6.6%	138	21.0%
Scientific meetings	23	5.4%	38	5.8%
Social media (X/Facebook)/online retailer websites (e.g., Amazon)	19	4.5%	36	5.5%

^***The proportion selecting “Do not particularly keep track” was significantly higher among non‐directors (n = 658) than among department directors (n = 425) (χ ² test, p < 0.001).

In contrast, many respondents reported informal routes, such as information from acquaintances or discovering updates at physical bookstores (52.0% for department directors and 46.5% for non‐directors) (Table 3).

Non‐directors were significantly more likely than department directors to answer “do not particularly keep track” of updates (138/658, 21.0% vs. 28/425, 6.6%) (Table 3).

3.4. Information Sharing When Implementing New Editions

Regarding pre‐implementation coordination for adopting a new edition, 115 (27.1%) of the 425 department directors reported coordinating within the pathology department and 86 (20.2%) coordinating between clinical and pathology departments, whereas 196 (46.1%) reported implementing new editions at their own discretion, without preliminary consultation or notice to other staff within their institutions (Table 4a). When restricted to facilities with two or more full‐time pathologists, the proportion of department directors implementing new editions without consultation decreased to 34.0%, but remained substantial (Table 4b).

Table 4.

Information‐sharing scope when implementing new editions of Kiyaku.

a)All facilities
Pre‐implementation coordination	Department directors (n = 425)		Non‐directors (n = 664)
	n	%	n	%
No coordination without consultationa	196	46.1%	261	39.3%
Coordinate within the pathology department	115	27.1%	155	23.3%
Coordinate between clinical departments and pathology	86	20.2%	145	21.8%
Coordinate with clinical departments only	18	4.2%	2	0.3%
Do not know/unsure	7	1.6%	98	14.8%***
Etc. including “depends on Kiyaku”	3	0.7%	3	0.5%

b)Facilities with two or more full‐time pathologists
Pre‐implementation coordination	Department directors (n = 247)		Non‐directors (n = 582)
	n	%	n	%
Coordinate within the pathology department	100	40.5%***	143	23.2%***
No coordination without consultationb	84	34.0%	213	36.6%
Coordinate between clinical departments and pathology	53	21.5%	135	23.2%
Do not know/unsure	6	2.4%***	87	14.9%***
Etc. including “depends on Kiyaku”	3	1.2%	3	0.5%
Coordinate with clinical departments only	1	0.4%	1	0.2%

^a Implementing new editions at their own discretion, without preliminary consultation or notice to other staff in their institutions. The proportion answering “Do not know/unsure” was significantly higher among non‐directors than among department directors (χ ² test, p < 0.001). Significance marker: ***p < 0.001.

^b Implementing new editions at their own discretion, without preliminary consultation or notice to other staff in their institutions. Among respondents from facilities with two or more pathologists, department directors were significantly more likely to report coordination within the pathology department than non‐directors, whereas “Do not know/unsure” responses were significantly more frequent among non‐directors than among department directors (χ ² test, both p < 0.001). Significance marker: ***p < 0.001.

“Do not know/unsure” responses were far more frequent among non‐directors (98/664, 14.8%) than among department directors (7/425, 1.6%) (Table 4a).

A similar pattern was observed when the analysis was restricted to respondents from facilities with two or more full‐time pathologists: department directors more frequently reported coordination within the pathology department than non‐directors (40.5% vs. 23.2%), whereas “Do not know/unsure” responses remained substantially more common among non‐directors than among directors (14.9% vs. 2.4%) (Table 4b).

3.5. Timing of Adoption

As most Kiyaku do not specify a clear official start date, the reported adoption timing was heterogeneous. The most common response was “immediately after obtaining the new edition or as soon as possible” (598, 55.2%), followed by “no specific rule” (234, 21.6%), and “after an appropriate interval” (194, 17.9%). Only four (0.4%) respondents uniformly adopted the new edition from January 1.

3.6. Comparison Among Kiyaku of the Three Major Cancer Types (Stomach, Lung, and Breast)

Overall, Kiyaku ownership was high for the three major cancer types (Table 2).

Histological classification sections were rated as useful across gastric, lung, and breast cancers (86.2%, 79.6%, and 80.3%, respectively) and were frequently included in pathology reports (82.6%, 84.1%, and 77.4%, respectively) (Tables 5, 6, and 7a). Similarly, the standardized descriptive symbols used for surgical specimen reporting were consistently perceived as useful and were frequently recorded across all three organ sites (Tables 5, 6, and 7b).

Table 5.

Summary of item‐level responses regarding the Gastric Cancer Kiyaku.

a) Items rated as useful and items frequently checked during diagnosis
	Usefula		Frequently checkedb
Item	n	%	n	%
Definition of the primary tumor site	717	66.2%	118	10.9%
Handling of surgical resection specimens (grossing)	773	71.4%	75	6.9%
Handling of endoscopic resection specimens (e.g., ESD grossing)	750	69.3%	73	6.7%
Macroscopic classification	796	73.5%	129	11.9%
Depth of invasion	933	86.1%	496	45.8%
Stage (Kiyaku)	827	76.4%	406	37.5%
Lymph node metastasis description	879	81.2%	516	47.6%
Definition of resection margins and residual tumor	761	70.3%	99	9.1%
Checklist of pathological reporting items	923	85.2%	612	56.5%
Histological diagnostic criteria and terminology	934	86.2%	358	33.1%
Pattern of invasion and lymphovascular invasion	769	71.0%	140	12.9%
Histological response criteria for chemo/radiotherapy	780	72.0%	419	38.7%
Gastric biopsy group classification	771	71.2%	100	9.2%
Histology photographs of tumors	860	79.4%	276	25.5%
None	28	2.6%	82	7.6%

b) Items frequently included in pathology reports
Item	n	%
Descriptive symbols (e.g., Ly, V, INFa)	956	88.3%
Histological diagnostic terminology	895	82.6%
Biopsy group classification	798	73.7%
Kiyaku stage	777	71.7%
Histological response grading (grades 0–3)	625	57.7%
Symbols for gastric subsites	602	55.6%
None	39	3.6%

^a Items rated as useful.

^b Items frequently checked by respondent pathologists during diagnosis.

Table 6.

Summary of item‐level responses regarding the Lung Cancer Kiyaku.

a) Items rated as useful and items frequently checked during diagnosis
	Usefula		Frequently checkedb
Item	n	%	n	%
TNM classification	854	78.9%	762	70.4%
Surgical reporting guidelines	421	38.9%	167	15.4%
Principles of histological classification	785	72.5%	444	41.0%
Biopsy diagnosis criteria	670	61.9%	320	29.5%
Grossing manual	505	46.6%	85	7.8%
Histological diagnostic criteria and terminology	862	79.6%	620	57.2%
Pathology reporting guidance on describing pathological findings	947	87.4%	788	72.8%
Cytology reporting and diagnostic criteria	420	38.8%	113	10.4%
Histological response criteria for primary lung tumors	593	54.8%	262	24.2%
None	35	3.2%	56	5.2%

b) Items frequently included in pathology reports
Item	n	%
Descriptive symbols (e.g., pl, pm, Ly)	932	86.1%
Histological diagnostic terminology	911	84.1%
TNM classification	853	78.8%
Histological response grading	465	42.9%
Biopsy diagnostic terminology/criteria	444	41.0%
Subsite symbols	428	39.5%
None	43	4.0%

^a Items rated as useful.

^b Items frequently checked during diagnosis.

Table 7.

Summary of item‐level responses regarding the Breast Cancer Kiyaku.

a) Items rated as useful and items frequently checked during diagnosis
	Usefula		Frequently checkedb
Item	n	%	n	%
Clinical description of the tumor site and size	381	35.2%	134	12.4%
Description of treatment	312	28.8%	83	7.7%
Histological diagnostic criteria and terminology	870	80.3%	598	55.2%
Atlas/figures	615	56.8%	296	27.3%
Comparison of WHO and Kiyaku classifications	595	54.9%	289	26.7%
Sectioning method for resection specimens	591	54.6%	142	13.1%
Pathological stage classification	827	76.4%	649	59.9%
Margin assessment	637	58.8%	269	24.8%
Histological handling and reporting of resection specimens/Kiyaku grade classification	832	76.8%	648	59.8%
Cytology reporting format	336	31.0%	78	7.2%
Core needle biopsy reporting format	499	46.1%	183	16.9%
Histological response grading	721	66.6%	520	48.0%
None	54	5.0%	77	7.1%

b) Items frequently included in pathology reports
Item	n	%
Descriptive symbols (e.g., Ly, V)	841	77.7%
Histological diagnostic terminology	838	77.4%
Kiyaku tumor grade classification	774	71.5%
Histological response grading (grades 0–3)	690	63.7%
Biopsy diagnostic terminology/criteria	494	45.6%
Core needle biopsy reporting format	416	38.4%
Cytology reporting format	255	23.5%
None	53	4.9%

^a Items rated as useful.

^b Items frequently checked during diagnosis.

In contrast, respondents reported checking Kiyaku to confirm the histological diagnostic criteria and terminology more often for lung and breast cancers (57.2% and 55.2%, respectively) than for gastric cancer (33.1%) (Tables 5, 6, 7).

Biopsy‐related items showed lower utilization in lung and breast cancers, whereas the biopsy group classification in gastric cancer was rated as useful by 71.2% of respondents and reported by 73.7%. In lung and breast cancers, the corresponding rates of perceived usefulness and reporting were lower (lung: 61.9% and 41.0%; breast: 46.1% and 38.4%, respectively), and the breast cytology reporting format was used by only 23.5% of respondents.

3.7. Laboratory Information System Integration, International Collaboration on Cancer Reporting, and Free Comments

Only 223 of the 1083 respondents (20.6%) reported that their facility's LIS was configured with Kiyaku‐based item lists as an input‐assist function, allowing users to enter Kiyaku items directly within the LIS. Similar proportions were reported in analyses restricted to department directors (17.9%, 76/425), with a slightly higher proportion in facilities with ≥ 400 beds (19.7%, 46/233) than in those with < 400 beds (15.6%, 30/192).

Awareness of the ICCR was limited; only 78 (7.2%) respondents reported knowing it well and 303 (30.0%) reported knowing it to some extent, whereas 322 (29.7%) were not very familiar and 380 (35.1%) were hardly or not at all familiar with the ICCR. Even among respondents who reported knowing the ICCR well (n = 78), 33 (42.3%) reported not using ICCR templates at all, and 17 (21.8%) reported using them only for a few items in a limited number of organs. Comprehensive use remained rare, with only 12 (15.4%) reporting use for most organs (n = 9) or all organs (n = 3).

In total, 427 (39.4% of all respondents) optional free‐text comments were submitted (total, 48 579 characters; mean, 113.8 characters per comment), despite requiring manual text entry.

4. Discussion

Although this was a nonmandatory questionnaire with no incentives and was unrelated to board recertification or institutional accreditation, responses were obtained from approximately one‐fifth of all members of the JSP and more than one‐third of the board‐certified pathologists of the JSP (BCPs [33.8%]) (Table 1). In contrast, responses from PRs were limited to 21.2%, indicating that interest in Kiyaku may increase as professional specialization deepens. Notably, despite requiring manual text entry, 427 respondents (39.4% of all participants) provided optional free‐text comments, with a mean length of 113.8 Japanese characters, suggesting that Kiyaku evokes strong opinions among Japanese practicing pathologists.

More than 90% of the respondents reported owning the latest editions of 17 organ‐specific Kiyaku. According to the National Cancer Registry of Japan (2023), these 17 Kiyaku corresponded to 89.2% of invasive cancers in Japan based on ICD‐O topography codes (886 704/993 469) [19], although this estimate excluded certain cancers addressed in these 17 Kiyaku, such as appendiceal and anal cancers described in the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma [7], and included non‐epithelial malignancies not covered by most Kiyaku.

In Japan, most organ‐specific Kiyaku are developed by academic societies, of which most pathologists are not members. We could not find published reports from other countries describing the use of reporting rules under comparable circumstances. Even for reporting rules developed by pathology societies, few studies have examined their utilization at the national level. Torous et al. reported that the electronic Cancer Checklists of the College of American Pathologists (CAP) Cancer Protocols were licensed to approximately 35%–40% of practicing anatomic pathologists in the United States and Canada and to approximately 45% of hospitals with > 400 beds in the United States [14]. Although direct comparisons with other countries are difficult, the high ownership rate of Kiyaku and the strong engagement of Japanese pathologists with these guidelines support confidence in the quality of pathology‐derived cancer information generated in Japan [1, 12, 13, 15].

In contrast, CAP Cancer Protocols are increasingly being implemented as structured reports integrated into LIS [14], whereas only 20.6% of the respondents in our survey reported that their LIS included a Kiyaku‐based reporting format. The limited LIS integration in Japan may hinder the standardization of pathology reports.

The ICCR provides structured reporting templates to standardize pathology reports internationally [3, 11]. This survey showed that the ICCR was not well‐known and that the uptake of ICCR data sets in Japan remains limited, although several symposia and workshops on the ICCR were conducted at the JSP annual meeting. The situation in other countries is not well‐characterized. One Australian report described a nationwide effort and found a utilization rate of 95.7% for pancreatic cancer; however, this finding was limited to a single cancer type [20]. Nevertheless, their use is expected to expand. Given the high ownership rate of Kiyaku in Japan, incorporating ICCR elements into Kiyaku may facilitate the international use of Japanese cancer data, and further efforts in this direction are warranted.

Although Kiyaku‐net, operated by the JSP, provides up‐to‐date information on the progress and schedule of Kiyaku revisions [18], its awareness and utilization are limited. The importance of coordination within pathology and relevant clinical departments before implementing new content and determining the implementation timelines is not well‐recognized. As the parallel use of different Kiyaku editions within the same institution should be avoided, more systematic information sharing and pre‐implementation alignment across the entire pathology team, including laboratory technologists and relevant clinicians, are required.

Our results showed that consultation within the pathology department and with clinical departments regarding the implementation of new Kiyaku editions was insufficient, although it was significantly better in facilities with two or more pathologists (Table 4a,b). Even in such facilities, approximately one‐third of department directors reported initiating adoption without prior consultation. The marked contrast in “Do not know/unsure” responses between department directors and non‐directors (Tables 4a,b) also suggests asymmetric information flow within departments.

A plausible explanation for this limited coordination is that Kiyaku have traditionally been used on an individual basis as cancer reference books rather than as national or institutional reporting standards. In addition, because many Kiyaku editions do not specify an official implementation date, the timing of adoption may naturally depend on when individual pathologists or relevant clinicians obtain a new edition. These factors may have contributed to heterogeneous adoption timing across institutions and individuals without prior consultation.

Regarding the timing of adoption, only a limited number of Kiyaku specify explicit starting dates for new editions. Our study showed that the awareness of the need to define such a start date was low among Japanese pathologists. Whether similar patterns exist among cancer care professionals should also be assessed. Given the role of Kiyaku, a clear nationwide start date for new editions would facilitate their consistent implementation. From a practical standpoint, January 1 would be a desirable start date, as in the UICC and AJCC systems. In our survey, only 0.4% of the respondents selected January 1. Kiyaku are often published to coincide with annual meetings of the corresponding academic societies. However, each new edition should be published with sufficient lead time to allow users to obtain it, review the revisions, and update their LIS before implementation.

More than 90% of respondents owned Kiyaku not only for gastric cancer, whose institutional centralization is relatively low, but also for lung and breast cancers, which are more highly centralized [17].

Sections related to tumor histological classification were consistently rated as highly useful and frequently checked for the three cancers, regardless of centralization (Tables 5, 6, and 7a). Descriptive symbols were consistently included in pathology reports (Tables 5, 6, and 7b). In contrast, items related to biopsy diagnosis were rated as useful and commonly reported in gastric cancer (Table 5), whereas their perceived usefulness and reporting frequency were substantially lower in lung and breast cancers (Tables 6 and 7). This does not imply lower quality of the biopsy‐related content of Kiyaku in lung and breast cancers; rather, it is likely related to differences in centralization. The low utilization of the breast cytology reporting format may reflect current practice patterns and warrants reconsideration of the structure of cytology reporting.

These discrepancies in the evaluation and use of individual items in this survey suggest a tendency among Japanese pathologists to be more interested in histological classification terminology and descriptive symbols than in other components of Kiyaku. The order of reporting items was not standardized across the three cancer types [5, 6, 8]. A consistent item sequence is desirable for pathologists using multiple Kiyaku.

Although we did not analyze the free‐text comments in detail in this report, we noted recurring remarks, such as “Kiyaku are unnecessary if WHO classifications and UICC‐TNM are available.” Similar comments were also reported in a previous study [2]. This suggests that the primary purpose of Kiyaku is not sufficiently shared or understood by practitioners.

This study has some limitations because it was based on a voluntary questionnaire survey of JSP members. Selection, self‐report, and recall biases could not be entirely ruled out. In particular, pathologists with greater interest in, familiarity with, or stronger opinions regarding Kiyaku may have been more likely to respond; therefore, the status of awareness, communication, and implementation in non‐responding institutions may differ from that observed in this study. Nevertheless, the substantial sample size provided a useful overview of practicing pathologists in Japan, particularly those working in mid‐ to large‐scale cancer care and university hospitals. The high proportion of department directors (39.2%) and active BCPs and BCOPs (90.0%) among respondents also supports the clinical relevance of the findings. Our results provide a meaningful insight into the status of Kiyaku use in pathological practice in Japan.

5. Conclusion: Kiyaku and the Japanese Society of Pathology

This survey clarified the current status of Kiyaku use in pathological diagnosis and cancer reporting in Japan. Based on these findings, we propose that the JSP clarify the purpose of Kiyaku, provide practical guidance on their use, promote Kiyaku‐net, strengthen awareness of Kiyaku among PRs, and emphasize the need for coordinated nationwide adoption of new editions. The incorporation of ICCR data sets should also be prioritized.

We believe that the JSP should provide other academic societies involved in developing Kiyaku with guidance on matters such as publication timing, implementation date, and the order of items.

Conducting similar surveys among cancer care professionals, particularly radiologists, who face circumstances similar to those of pathologists, would also be desirable.

Author Contributions

Study conception and design: Norihiro Teramoto. Data acquisition and analysis: Norihiro Teramoto. Drafting of the manuscript and tables: Norihiro Teramoto. Study design and manuscript revision: Reiko Watanabe, Ichiro Ito, and Toyonori Tsuzuki.

Funding

The authors have nothing to report.

Ethics Statement

This study was conducted as a questionnaire survey among medical professionals and did not involve patients, clinical interventions or the use of identifiable human data.

Consent

Participation was voluntary, and all respondents provided informed consent prior to analysis and publication. No personally identifiable information was collected (e.g., facility name, prefecture, or age), and only anonymized, aggregated data were reported.

Conflicts of Interest

The authors declare no conflicts of interest.

Institutional Approval

This manuscript was prepared with the approval of the Board of Directors of the Japanese Society of Pathology. In accordance with local regulations and institutional guidance, formal institutional ethics committee approval was not required for this professional practice survey.

Supporting information

Supporting File

Data Availability Statement

Aggregated data supporting the findings of this study are available from the corresponding author upon reasonable request, subject to approval by the Kiyaku Committee board members of the Japanese Society of Pathology.