Adherence to national guidelines for colorectal, breast, and cervical cancer screenings in Japanese workplaces: a survey-based classification of enterprises’ practices into “overscreening,” “underscreening,” and “guideline-adherence screening”

Abstract

Background

Workplace cancer screening programs are determined as part of an employee’s benefits package and health checkups are perceived positively. However, the current status of workplace cancer screening programs in Japan is unavailable. This study aimed to assess the adherence to national guidelines for colorectal, breast, and cervical cancer screenings in the workplace among Japanese enterprises and identify factors associated with excessive or inadequate screenings.

Methods

A cross-sectional study design was employed. Data were obtained from a survey conducted by the “Corporate Action to Promote Cancer Control” between November and December 2022 among registered partner enterprises in Japan. The survey included questions on background characteristics, cancer screening practices, and intervention approaches. The analysis included 432 enterprises that provided complete responses regarding colorectal, breast, and cervical cancer screenings.

Results

The guideline-adherence rates for colorectal, breast, and cervical cancer screenings in the workplace were 12.7%, 3.0%, and 8.8%, respectively. Enterprises had lower adherence to screening guidelines than local governments. Colorectal (70.8%) and breast (67.1%) cancer screenings were predominantly categorized as “overscreening” and cervical (60.6%) cancer screening, as “underscreening.” Factors such as enterprise scale, health insurance associations, and the number of interventional approaches were significantly associated with increased “overscreening” (101–1000: β = 0.13, p = 0.01; ≥ 1000: β = 0.17, p < 0.01; health insurance association: β = 0.23, p < 0.01; and approaches: β = 0.42, p < 0.01) and reduced “underscreening” (101–1000: β = -0.13, p = 0.01; ≥ 1000: β = -0.17, p < 0.01; health insurance association: β = -0.18, p < 0.01; and approaches: β = -0.48, p < 0.01).

Conclusion

Adherence to national guidelines for colorectal, breast, and cervical cancer screenings in the workplace was suboptimal among Japanese enterprises. Therefore, appropriate cancer screening measures and interventions to ensure guideline adherence and optimization of screening benefits while minimizing potential harms should be expeditiously implemented.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-024-19775-1.

Background

Globally, cancer is the leading cause of mortality [1]. In Japan, cancer-related deaths have been the leading cause of mortality since 1981, and the age-adjusted incidence rate has exhibited an upward trend [2]. Other high-income countries have either stable or declining trends in major cancers including colorectal, breast, and cervical cancers [1, 3]. Japan advocates five cancer screening programs for gastric, lung, colorectal, breast, and cervical cancers [4]. Gastric cancer mortality rates have demonstrated a downward trend, whereas colorectal, breast, and cervical cancer mortality rates have remained unchanged [4, 5]. Population-based screening for colorectal, breast, and cervical cancers is used worldwide to effectively reduce mortality [6]. However, the cancer screening participation rates in Japan are lower than that in other high-income nations, with colorectal, breast, and cervical cancers having a participation rate of < 50% [7, 8].

In Japan, health checkups are legally mandated, and nearly all individuals undergo regular checkups comprising tests including chest radiographs, blood pressure measurements, anemia evaluation, and electrocardiograms [9]. Despite the ambiguous efficacy of health checkups, many individuals believe in their effectiveness [10, 11]. However, standardized nationwide cancer screening programs for the general population are yet to be established in Japan. Cancer screening is either population-based or opportunistic. Population-based screening is known to reduce targeted cancer-related mortalities, whereas opportunistic screening—despite insufficient evidence—is considered acceptable for individual decision-making [12]. Local governments conduct cancer screening programs under the Health Promotion Act, and approximately half of the population undergo screening in their workplaces [13]. Japanese human resource management, characterized by familism and paternalism, often extends to health-related responsibilities of employees [14]. Consequently, workplace cancer screening programs emerged as a proactive measure in response to the comparably high incidence of cancer among employees. The details of workplace cancer screening programs are determined as part of an employee’s benefits package and while population-based screening is recommended, this type of opportunistic screening is also considered acceptable [12, 13]. Local governments and enterprises do not always comply with the population-based approach in screening types, eligibilities, and intervals [9]. Reportedly, 85% of local governments provided screening programs beyond the Ministry of Health, Labour, and Welfare’s (MHLW) recommendations [15]. The Organization for Economic Co-operation and Development (OECD) has criticized Japan for not reviewing all health checkups, including cancer screening, because non-recommended screening may lead to potential harm including duplicate examinations, waste, overdiagnosis, and unnecessary injuries [9]. Although the current status of cancer screening programs in local governments is documented, data regarding workplace cancer screening specifics are unavailable.

The “Corporate Action to Promote Cancer Control” (hereinafter Corporate Action), a project commissioned by the MHLW, was established in 2009 to enhance cancer awareness among employees [16, 17]. The project conducts regular surveys on cancer control measures targeting registered enterprises (hereinafter Partner Enterprises) [17]. Registration for participation in the Corporate Action is cost-free, and it offers cancer education materials (pamphlets, books, and e-learning modules) and cancer education courses facilitated by cancer specialists and cancer survivors. As of March 2021, 4,065 enterprises, employing approximately eight million individuals, are registered [17]. Approximately 50–100 enterprises continue to register for the program every month, demonstrating their commitment to cancer control [17].

This study focuses on screening for colorectal, breast, and cervical cancers that are insufficiently addressed. Workplace screening for these cancers often adhere to an opportunistic approach, which can result in diminished benefits or even harm if screening is under- or overutilized [13]. This study aims to assess whether workplace screening for colorectal, breast, and cervical cancers adhere to national guidelines. Additionally, it aims to identify the characteristics of enterprises that exhibit either over- or under-utilization of cancer screening practices and to gather insights and provide recommendations for implementing appropriate cancer screening measures in the future.

Methods

Study design

This cross-sectional study was conducted by the Corporate Action among the Partner Enterprises in Japan between November and December 2022. Ethical approval for this study was granted by the Institutional Review Board for Clinical Research, Tokai University (22R046).

Study participants

Enterprises that responded to the survey and agreed to undergo evaluation for academic purposes and whose actual screening practices for colorectal, breast, and cervical cancers could be comprehended via the flowcharts illustrated in Figs. 1 and 2 were included in the study.

Fig. 1.

a Flowchart of colorectal cancer screening (enterprises). b Flowchart of breast cancer screening (enterprises). c Flowchart of cervical cancer screening (enterprises)

Fig. 2.

a Flowchart of colorectal cancer screening (local governments). b Flowchart of breast cancer screening (local governments). c Flowchart of cervical cancer screening (local governments)

The project secretariat notified the 2,550 contactable Partner Enterprises about the survey and received 1,017 responses. After excluding 192 enterprises, which did not consent to the study, and 393 enterprises, which provided incomplete responses for each cancer screening content (screening items, frequency, or starting age), 432 enterprises were included in the final analysis.

Survey methods

The Corporate Action surveyed the Partner Enterprises to assess the current status of cancer screening participation rates, efforts to promote cancer control, and support for working employees with cancer. The project secretariat emailed the Partner Enterprises, requesting their participation in the survey. The contact person of each enterprise checked the survey’s purpose and outline on the project’s website. Enterprises that responded to the survey later received an individualized “advice report.” Depending on the survey results, the enterprises were eligible to receive an “MHLW Award” and an “Excellent Enterprise Award for Cancer Control.” In this context, the enterprises were asked if they consented to the usage of their responses for academic purposes other than the aforementioned purpose. Only enterprises that consented were included in the analysis. Before the completion of the survey, the project secretariat sent reminders to non-responding enterprises to enhance the response rate.

The survey comprised 80 questions on the following: “basic characteristics of the enterprise,” “conducted cancer screenings,” “their details,” “screening participation rates,” “interventional approaches to increase participation,” “support systems for balancing cancer treatment and work,” and “collaborations with medical institutions.” We utilized the responses related to the "basic characteristics of the enterprise," "conducted cancer screenings," "their details," and "interventional approaches to increase participation" in our analysis.

Featured cancer screenings and their contents

Among the recommended screenings for gastric, lung, colorectal, breast, and cervical cancers, gastric cancer screening is uncommon except in Japan and Korea [9, 18]. Similarly, lung cancer screening using chest radiographs, regardless of smoking history, is uncommon outside Japan [9, 19]. The present study specifically focused on colorectal, breast, and cervical cancer screenings, which are implemented worldwide. The Japanese guidelines for each screening program by specific items, eligible age groups, and frequency of examination are as follows [4, 13]:

• Colorectal cancer screening: Medical interview and fecal occult blood test, age ≥40 years, conducted annually.

• Breast cancer screening: Medical interview and mammography (in combination with palpation is acceptable), age ≥40 years, conducted biennially.

• Cervical cancer screening: Medical interview, and visual, cytological, and internal examination of the cervix; age ≥20 years; conducted biennially.

Characteristics of the partner enterprises

The Partner Enterprises were classified into three categories based on the Japanese standard industrial classification, excepting health insurance companies and unclassifiable enterprises, as follows: blue-collar, white-collar, and service industries. Blue-collar industry included agriculture/forestry/fishing, construction, manufacturing, transport, and postal services; the service industry included wholesale, retail trade, accommodations, eating, drinking, living-related, amusement, and other services; and white-collar industry included information, communications, real estate, goods rental, medical, healthcare, welfare, education, and learning support [20].

Definitions and description of materials

The United States Centers for Disease Control and Prevention recommends five interventions to improve cancer screening participation rates: small media, reducing structural barriers (times and locations), reducing client out-of-pocket costs, and client reminders were included [21–24].

Flowcharts describing the actual screenings were developed, which outlined the items, age groups, and frequencies for each type of cancer (Figs. 1 and 2). This study focused on the enterprises’ official policies regarding the details of cancer screenings. This approach was taken to evaluate the adherence of enterprise policies to these guidelines, independent of individual employee screening behaviors.

The definitions of the categories, “underscreening,” “guideline-adherent screening,” and “overscreening,” are as follows:

• “Underscreening”: Insufficient screening items, older starting age, and lower frequency.

• “Guideline-adherent screening”: Screening items, starting age, and frequency were consistent with recommended guidelines.

• “Overscreening”: Additional screening items, younger starting age, and higher frequency.

Questions about medical interviews and visual examinations were excluded because the enterprises, presumably, could not comprehend their actual implementation. These physical examinations are often omitted [4].

Comparison of cancer screening provided by the partner enterprises and local governments

The MHLW annually conducts the “Survey on cancer screening practices in local governments” which surveys and reports on cancer screenings provided by local governments [25]. Raw data from the 2021 survey was obtained through an application to the MHLW. The aforementioned flowcharts were employed to compare local governments’ screening status. We compared enterprise-provided screenings and local government screenings to understand the broad context of cancer screening practices in Japan.

Statistical analysis

The guideline-adherence rates of screening for the three cancers between the enterprises and local governments were compared using the Chi-squared test. Multiple regression analysis was used to identify factors that led to “underscreening” and “overscreening” in the workplace. The dependent variables were the sum of “underscreening,” “guideline-adherent screening,” and “overscreening,” with possible values ranging from zero to three, and the independent variables were the number of employees, types of industries, and number of interventional approaches. For example, an enterprise classified as "overscreening" for colorectal and breast cancer screenings and "underscreening" for cervical cancer screening would have a total count of 1 for "underscreening," 2 for "overscreening," and 0 for "guideline-adherent screening" in the regression analysis. This approach allowed us to identify the characteristics of enterprises with a tendency towards multiple overscreening or underscreening practices. In the multiple regression analysis, forced entry was employed to simultaneously include all predictor variables into the regression model, regardless of their individual significance. The regression coefficient for the actual impact per unit change, and the standardized regression coefficient for comparison across different variables on a common scale, are presented. All analyses were performed using the R ver. 4.2.0 statistical software, with a significance level set at 5%.

Results

Table 1 lists the characteristics of the Partner Enterprises. Among them, 40% had more than 1,000 employees, and 28.5% were blue-collar industries. The implementation rates for cancer screening were 88.7%, 77.1%, and 75.2% for colorectal, breast, and cervical cancers, respectively. The most common interventional approach was “reducing client out-of-pocket costs” (86.8%), and each enterprise implemented an average of 3.4 approaches.

Table 1.

Enterprises' characteristics

	Total enterprises
	(N = 432)
	N	%
Number of employees
< 100	146	34.0%
101 – 1000	111	25.8%
≥ 1000	173	40.2%
Industry
Blue-collar industry	123	28.5%
White-collar industry	114	26.4%
Service industry	69	16.0%
Health insurance association	118	27.3%
Unclassifiable	8	1.9%
Implementation of cancer screening
Colorectal cancer
Yes	383	88.7%
No / Unanswered	49	11.3%
Breast cancer
Yes	333	77.1%
No / Unanswered	99	22.9%
Cervical cancer
Yes	325	75.2%
No / Unanswered	107	24.8%
Interventional approaches to increase cancer screening uptake rates
Small media
Yes	184	42.6%
No	248	57.4%
Reducing structural barriers (times)
Yes	236	54.6%
No	196	45.4%
Reducing structural barriers (locations)
Yes	340	78.7%
No	92	21.3%
Reducing client out-of-pocket costs
Yes	375	86.8%
No	57	13.2%
Client reminders
Yes	337	78.0%
No	95	22.0%

Figure 1 illustrates the flowchart of the Partner Enterprises. Colorectal (68.1%) and breast (46.3%) cancer screenings were categorized as “overscreening” because of a younger starting age (≤ 39 years), while cervical cancer screenings (30.8%) were classified as “underscreening” because of an older starting age (≥ 21 years). Figure 2 illustrates the flowchart of local governments. In 2021, more than 99% of the 1,737 municipalities performed screening for each cancer. Approximately 20–36% of these were categorized as “underscreening” primarily because some governments targeted only a portion of the eligible population (colorectal: 99.7% [350/351], breast: 99.5% [618/621], and cervical: 98.3% [534/543]). The starting ages for the screenings were more often guideline-adherent in local governments (colorectal: 79.9% [1,098/1,374], breast: 86.7% [961/1,108], and cervical: 98.4% [1,169/1,188]) compared with that in the enterprises.

Table 2 summarizes the flowcharts. The enterprises (colorectal: 12.7%, breast: 3.0%, and cervical: 8.8%) were less likely to adhere to the guidelines than local governments (colorectal: 62.3%, breast: 11.6%, and cervical: 32.0%). Colorectal (70.8%) and breast (67.1%) cancer screenings in enterprises were predominantly categorized as “overscreening” and cervical cancer screening (60.6%), as “underscreening.”

Table 2.

Summary of the guideline-adherence distribution

	Total enterprises		Local governments (as reference)
	(N = 432)		(N = 1737)
	N	%	N	%	p value
Colorectal cancer screening					< 0.01
Underscreening	71	16.4%	363	20.9%
Guideline-adherent screening	55	12.7%	1083	62.3%
Overscreening	306	70.8%	291	16.8%
Breast cancer screening					< 0.01
Underscreening	129	29.9%	664	38.2%
Guideline-adherent screening	13	3.0%	202	11.6%
Overscreening	290	67.1%	871	50.1%
Cervical cancer screening					< 0.01
Underscreening	262	60.6%	596	34.3%
Guideline-adherent screening	38	8.8%	556	32.0%
Overscreening	132	30.6%	585	33.7%

The category of "Underscreening" encompasses enterprises classified as "No screening," "Unanswered," and "Underscreening"

Table 3 presents the association between guideline adherence and the characteristics of the enterprises. A larger scale of the enterprise, health insurance associations, and a greater number of interventional approaches significantly were related to reduced “underscreening” (101–1000: β = -0.13, p = 0.01; ≥ 1000: β = -0.17, p < 0.01; health insurance association: β = -0.18, p < 0.01; and approaches: β = -0.48, p < 0.01), and increased “overscreening” (101–1000: β = 0.13, p = 0.01; ≥ 1000: β = 0.17, p < 0.01; health insurance association: β = 0.23, p < 0.01; and approaches: β = 0.42, p < 0.01). A slight trend toward increased “guideline-adherent screening” was observed as enterprises expanded their approaches (β = 0.11, p = 0.03).

Table 3.

Multiple regression analysis with "underscreening," "overscreening," and "guideline-adherent screening" as dependent variables, predicted by enterprises' characteristics

		Underscreening									Overscreening									Guideline-adherent screening
		B	S.E	β	p value	95%CI					B	S.E	β	p value	95%CI					B	S.E	β	p value	95%CI
Number of employees
< 100		(reference)									(reference)									(reference)
101 – 1000		-0.29	0.11	-0.13	0.01	[-0.22, -0.04]					0.31	0.11	0.13	0.01	[0.04, 0.23]					-0.02	0.06	-0.02	0.75	[-0.13, 0.09]
≥ 1000		-0.35	0.11	-0.17	< 0.01	[-0.27, -0.06]					0.36	0.12	0.17	< 0.01	[0.06, 0.28]					-0.01	0.07	-0.01	0.9	[-0.13, 0.12]
Industry
Blue-collar industry		(reference)									(reference)									(reference)
White-collar industry		0.04	0.11	0.02	0.7	[-0.08, 0.11]					0.02	0.12	0.01	0.85	[-0.09, 0.11]					-0.06	0.07	-0.06	0.33	[-0.17, 0.06]
Service industry		-0.07	0.12	-0.03	0.58	[-0.11, 0.06]					0.19	0.13	0.07	0.16	[-0.03, 0.16]					-0.12	0.08	-0.08	0.12	[-0.19, 0.02]
Health insurance association		-0.41	0.11	-0.18	< 0.01	[-0.28, -0.08]					0.53	0.12	0.23	< 0.01	[0.12, 0.33]					-0.12	0.07	-0.1	0.09	[-0.23, 0.02]
Unclassifiable		0.24	0.3	0.03	0.42	[-0.05, 0.11]					-0.07	0.32	-0.01	0.83	[-0.09, 0.07]					-0.17	0.18	-0.05	0.34	[-0.14, 0.05]
Numbers of interventional approaches to increase cancer screening uptake rates
		-0.35	0.03	-0.48	< 0.01	[-0.56, -0.4]					0.31	0.03	0.42	< 0.01	[0.33, 0.5]					0.04	0.02	0.11	0.03	[0.01, 0.21]
R2		0.35									0.30									0.02
adjusted. R2		0.34									0.29									0.01

The category of "Underscreening" encompasses enterprises classified as "No screening," "Unanswered," and "Underscreening"

B Regression coefficient, SE Standard Error, β Standardized regression coefficient

Discussion

This study aimed to clarify the actual status of cancer screening provided by Japanese enterprises through a survey conducted by the Corporate Action. Our study contributes to the existing literature by uniquely classifying workplace cancer screening practices into categories of “overscreening,” “guideline-adherent screening,” and “underscreening,” based on the backgrounds of the Partner Enterprises. The guideline-adherent rates for colorectal, breast, and cervical cancers were 12.7%, 3.0%, and 8.8%, respectively, which were unfavorable compared with those provided by the local governments. Additionally, we observed that colorectal and breast cancer screenings could be classified as “overscreening” and cervical cancer screening as “underscreening.” The scale of the enterprises, presence of health insurance associations, and number of interventional approaches were significant factors predicting increased “overscreening” and reduced “underscreening.”

Screening detects diseases before they become symptomatic and helps improve patient outcomes through prompt treatments. However, not all screenings are beneficial [26]. “Overscreening” refers to tests that are performed at lower starting ages or at higher frequencies (shorter intervals) than that recommended by national guidelines. Previous reports have highlighted the occurrence of “overscreening” in colorectal, breast, and cervical cancer screenings, although most of these studies have examined screening from patients’ perspectives [27–30]. A report by the MHLW revealed that health insurance associations provided various programs, such as prostate cancer screening (54.6%), thyroid cancer screening (7.0%), and CEA tumor marker level measurements (21.4%), beyond guideline recommendations [31]. In this study, we defined “overscreening” as initiating screening at least one year earlier than the nationally recommended age. The criteria of “overscreening” might be too strict, however, we believe that our definition is reasonable because it was deliberately chosen to align with the primary objective of our study—assessing compliance with national screening recommendations by companies.

Cancer screening was first introduced in Japan in 1983 under the “Health Serves Law for the Aged” [4]. Initially, screening programs for gastric and cervical cancers were implemented, followed by those for lung, colorectal, and breast cancers. During this period, scientific evidence on the benefits of cancer screening was not widely discussed, and the general belief was that early detection would lead to better outcomes [4]. Thereafter, these programs have been continuously improved, and guidelines have been established [4]. However, guideline development requires a careful benefit-harm balance. The benefits are often emphasized, while the potential harms are overlooked [32]. Moreover, cancer screening is generally viewed favorably by the general population; hence, it is advocated without critical evaluation [33, 34]. A systematic review, which included 15 studies on cancer screening, assessed patient or public expectations of healthcare interventions and found that participants overestimated the benefits and underestimated the harms [35]. In a workplace setting, higher coverage for health checkups is perceived positively because employers invest more in employee benefits [9]. Our study revealed a tendency toward “overscreening,” particularly in workplace colorectal and breast cancer screenings, probably due to an excessive focus on the benefits of cancer screening, which is considered understandable from the Japanese perspective. In both screenings, younger starting ages were identified as a primary factor associated with “overscreening.” Additionally, in breast cancer screening, shorter intervals were observed between screenings, with 66 enterprises conducting annual rather than the recommended biennial screenings (37 enterprises). Conversely, in workplace cervical cancer screening, approximately 60% were categorized as “underscreening.” A quarter of the enterprises did not conduct the screening, and 30% initiated screenings for those aged ≥ 21 years. In breast and cervical cancer screenings, the rate of “no screening” and “unanswered” rate were slightly > 20%, similar to the rates reported by the MHLW in 2022 [36]. The higher starting age for cervical cancer screening may be because most Japanese enterprises do not employ individuals aged ≤ 22 years, commonly the youngest age for university graduates. Regarding screening frequency, 39 enterprises adhered to the recommended biennial screening interval, while 79 enterprises opted for annual screenings, indicating a tendency toward “overscreening,” in terms of frequency.

Compared with enterprises, although a higher proportion of local governments were guideline-adherent, 20–36% of these were categorized as “underscreening” because the recommended screening tests were implemented only for certain segments of the targeted population. If the untargeted populations are considered guideline-adherent, the prevalence of “overscreening” increases to 22.3%, 73.6%, and 49.0% for colorectal, breast, and cervical cancers, respectively. An additional figure file (Figs. 1a, b, and c) illustrates this in more detail (see Additional file 1).

Multiple regression analysis results revealed contrasting tendencies regarding “overscreening” and “underscreening.” Large-scale enterprises often enhance their benefit packages as part of their investment strategies. Health insurance associations, whose primary focus is on providing healthcare services, might exhibit a bias toward overservicing. Notably, our study found that enterprises that displayed an enthusiasm for financial supports, time and location arrangements, and announcements through social media channels were more likely to engage in “overscreening.” Additionally, we have conducted further multiple regression analyses with each initiative treated as an independent variable (see Additional file 2). The results of this analysis revealed that all four variables, except for locations, showed significant correlations with screening tendencies. These findings suggest that cancer screening is often provided as a benefit within the corporate system, and excessive healthcare services are perceived favorably. Proactive measures by enterprises to improve screening participation rates through various interventions are commendable; however, ensuring that “overscreening” beyond the scope of population-based screening guidelines does not occur is equally important.

The MHLW’s fourth “Basic Plan to Promote Cancer Control Programs,” approved by the Cabinet in 2023, stated that the legal status of cancer screenings is considered. This consideration can potentially address the issue of “overscreening” by incorporating guidelines and regulations into the benefit packages offered by enterprises [17]. The OECD countries with cost-free national screening programs have high cancer screening participation rates than countries without national programs, including Japan [9]. Clarifying the legal status of workplace cancer screening might lead to an opportunity to address “overscreening” and improve overall cancer screening participation rates.

Limitations

This study has several limitations. First, the inclusion of respondent Partner Enterprises whose cancer screening contents could be classified may have introduced selection bias. These enterprises may have a higher interest in workplace healthcare and consequently, a tendency to overservice. Additionally, most participants in the analysis were large-scale enterprises, which is not representative of the current situation in Japan, where small and medium-scale enterprises constitute over 99% of all businesses [37]. This difference in sample composition could impact the generalizability of the findings. Notably, in 2020, only approximately half of the Japanese enterprises assumed the cost of cancer screening and provided medical examinations during working hours [36]. However, in this study, most enterprises had systems in place for arranging time (54.6%), location (78.7%), and reducing costs (86.8%) related to cancer screening. Moreover, the final valid response rate among contactable enterprises was 16.9% (432/2,550). This number is not exceptionally high but acceptable, because even a response rate below 10% is common for web surveys [38]. These factors may introduce further selection biases. Second, response accuracy is subject to potential limitations. The cooperative enterprises that voluntarily participated in the survey may have been motivated by the possibility of receiving rewards, such as the “MHLW Award” and the “Excellent Enterprise Award for Cancer Control,” based on their responses. The presence of cancer screening guidelines on the project webpage may have influenced the respondents’ answers. Third, certain examinations, such as colonoscopy and HPV testing for colorectal and cervical cancer screenings, respectively, were not included in the survey. Although the omission of these tests may result in an underestimation of “overscreening” and reduced compliance with guidelines, the flowcharts of the enterprise (Fig. 1a, b, and c) indicated that approximately 90% of the enterprises were already classified before “combined with other screening tests.” Therefore, the impact of this limitation may be minimal. Fourth, the study focused on five specific interventional approaches that improve cancer screening participation rates, while other approaches with unknown effectiveness were not included in the analysis. Although analysis of these five approaches provides valuable insights, the exclusion of other potentially relevant approaches may limit the comprehensiveness of the findings. Fifth, we did not include questions on the age and gender composition of each enterprise. Since the targeted age and gender differ for colorectal, breast, and cervical cancer screening, the composition of the employed population could potentially influence screening practices, and this aspect warrants further investigation in future research. Despite these limitations, this study is valuable because it has assessed the prevalence of “overscreening” and “underscreening” in workplace cancer screening programs and identified factors contributing to non-adherence to screening guidelines. Furthermore, this study illuminated an important aspect of cancer control efforts and provided a foundational basis for further research and interventions in this area.

Conclusions

This study provided insights into the current state of workplace cancer screening in Japan by analyzing data from the “Corporate Action to Promote Cancer Control” survey. A higher prevalence of “overscreening” for colorectal and breast cancer and “underscreening” for cervical cancer was observed in enterprises than in local governments. The adherence to screening guidelines was low, with less than 13% of enterprises conducting guideline-recommended screenings. Factors identified as contributors to “overscreening” include large-scale enterprises, health insurance associations, and the implementation of multiple interventional approaches aimed at improving cancer screening participation rates. “Overscreening” can have adverse effects, such as overdiagnosis and unnecessary harm to individuals; therefore, the government must address the issue of “overscreening” and undertake measures to improve workplace screening systems.

Abbreviations

MHLW

Ministry of Health, Labour, and Welfare

OECD

Organization for Economic Co-operation and Development

Authors’ contributions

Conceptualization: MM, KN; Methodology: MM, MT; Formal analysis and investigation: MM, TM; Writing—original draft preparation: MM; Writing—review and editing: MM, AK, SO; Supervision: KN.

Funding

Not applicable.

Availability of data and materials

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available.

Declarations

Ethics approval and consent to participate

Ethical approval for this study was granted by the Institutional Review Board for Clinical Research, Tokai University (22R046). The research was conducted in accordance with the Declaration of Helsinki. Participants understood the purpose and methods of the study and signed informed consent.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.