Abstract
Background & Objective
Thyroid cancer is among the most common endocrine cancers, and its incidence in our country is in progress over the past decades. This aggravates the necessity to evaluate the changes in thyroid cancer.
Materials & methods
Through accessing the information of the records of all patients with a diagnosis of thyroid cancer between 1996 and 2017, the present study was conducted at Baqiyatallah Hospital (Tehran, Iran) according to scientific criteria. After the diagnosis, most of them also underwent surgery and were evaluated in terms of the rate of the involvement and the type of thyroid cancer, and the pathology report was recorded in their records. Information about the intended patients such as age, gender, pathologic type of cancer, associated with the patient (except thyroid cancer), and history of radiation to the patient were recorded in a standard form and subjected to statistical analysis. Demographic changes and pathological manifestations of cancers in the two decades (1997–2007) and (2007–2017) were compared. But comparisons have been made over five years.
Results
The incidence of thyroid cancer, especially papillary thyroid cancer type, was increasing at an early age, and the incidence of tumor size measuring 2–4 cm was rising. But the incidence of tumor sizes less than one centimeter declined. The amount of vascular and capsule involvement was about 3 times, and lymph node involvement was nearly 2 times. The increasing incidence of 2–4 cm tumor size in the age group of 20–50 years was more than other age groups.
Conclusion
The incidence of thyroid cancer was increasing at an early age, and the enhancement of papillary thyroid type was higher than other types. As well as, in this study, it was found that the incidence of 2–4 cm tumor sizes was rising.
Keywords: Thyroid Cancer, Demographic, Pathologic, Hospital
Introduction
Thyroid cancer accounts for the majority of endocrine cancers, and the number of cases is increasing worldwide likely due to increased recognition more than a real increment of the disease. Most thyroid cancer types respond well to conventional treatment consisting of surgery and radioactive iodine (RAI) therapy [1, 2].
Thyroid cancer annually includes about 1% of new cancer diagnoses in the United States. Thyroid malignancies are divided into papillary thyroid cancer (PTC) (80%), follicular thyroid cancer (FTC) (10%), medullary thyroid cancer (MTC) (5–10%), anaplastic thyroid cancer (ATC) (1–2%), primary thyroid lymphoma (PTL) (rare), and primary thyroid sarcoma (PTS) [3]. Papillary thyroid cancer (also sometimes called papillary thyroid carcinoma) is the most common type of thyroid malignancy, making up almost 80% of thyroid cancers. Papillary thyroid cancer is a slow-growing tumor formed of follicular cells producing thyroglobulin, sensitive to Thyroid-stimulating Hormone (TSH), and iodine-consuming [4, 5]. Follicular thyroid cancer (FTC) is the second most common thyroid malignancy and accounts for about 10% of thyroid cancers [6, 7]. Medullary thyroid cancer (MTC) accounts for almost 5% of all thyroid cancers. These tumors stem from parafollicular cells (C cells) in the thyroid gland. Anaplastic thyroid cancer (ATC) accounts for 1.6% of all thyroid cancers, however, it has the most aggressive malignant behavior among other thyroid cancers [8, 9]. Primary lymphoma of the thyroid gland includes approximately 2–5% of all thyroid malignancies. Most thyroid lymphomas are non-cellular tumors. Hodgkin’s lymphoma (HL), Burkitt’s cell lymphoma (BL), and T cell lymphoma have also been reported [10, 11].The rate of sarcomas that arise in the thyroid gland is low. They are aggressive tumors that are most likely caused by stromal or vascular tissue in the lymph nodes. Most sarcomas do not react to chemotherapy. Recurrence in sarcomas is widespread [12–14].
Thyroid cancer often appears as a single, painless nodule in the thyroid. The key to the treatment of thyroid cancers is the diagnosis of malignant disease from benign diseases, based on which the need for more aggressive intervention in patients is identified, and patients are followed up through it. History investigation, physical examination, laboratory evaluation, and fine-needle aspiration (FNA) are critical in the evaluation of thyroid nodules. Moreover, imaging studies can be employed in some cases [3]. In a study carried out by Chen et al. on 30,766 cases over 17 years in the United States, it was found that the incidence of thyroid cancer in the study population represented a incidence rate of about twice. Furthermore, it was found that the incidence rate of developing cancer in women was much more than men. The study revealed that the prevalence of tumors with a size of less than 3 cm was rapidly in progress [14]. In this regard, this study aimed to evaluate the demographic characteristics and pathological manifestations of thyroid cancer in patients referred to Baqiyatallah Hospital (Tehran, Iran) during the past two decades (1997–2017).
Materials & methods
In this study, all patients (1099 patients) who were diagnosed with thyroid cancer between 1997 and 2017 at Baqiyatallah Hospital (Tehran, Iran) and their information were available in the file system, were studied. The study was performed on specimens of thyroid cancer that have undergone surgery and have a definite pathological response. These patients were subjected to the diagnosis of thyroid cancer before referral to the clinic and after clinical examination and palpation of the mass and nodule using thyroid scan and FNA according to scientific criteria, and most of them underwent thyroid surgery (total thyroidectomy or thyroid lobectomy) after the diagnosis. Then, in terms of the rate of the involvement and the type of thyroid cancer, the patients underwent clinical therapy, including treatment with radioactive iodine (I131), to remove thyroid cancer residual tissue, and the pathologic report of the biopsy specimens was recorded in the patient’s record. The information considered in this study such as the age of patient’s involvement, patient’s gender, pathological type of PTC FTC cancers, etc.
The demographic changes and pathological manifestations of cancers during the years (1997–2017) were compared, and the results were presented scientifically. Patients’ information was extracted through the records available in the archive and recorded in the prepared forms.
After collection, the data were entered into SPSS 20 software. The frequency percentage for qualitative variables and mean and standard deviation for quantitative variables were reported. T-test and chi-squared (CHI 2) test and correlation evaluation test was used for analyzing the data.
Results
Demographic data of patients: The number of patients participating in the study was 1099 people, of whom 757 cases (68.9٪) were female, and 342 cases (31.1%) were male. The mean age of women was 37.2 years and the mean age of men was 42.4 years.
Determining age changes in the incidence of thyroid cancer
The mean age of papillary thyroid cancer (PTC) in the first 5 years (1997–2002) was 54.2 years and reached 37.3 years at the end of 20 years of follow-up.
As well as, the mean age of follicular thyroid cancer (FTC), with an 11-year decline, had the highest rate of age reduction in developing cancer after PTC. The medullary thyroid cancer (MTC) has reached from a mean age of 63 years to a mean age of 55 years. The mean age of anaplastic thyroid cancer (ATC) had no significant change and declined for four years (Table 1).
Table 1.
Age changes in the incidence of types of thyroid cancer
| Study time (by year) | The average age of PTC (by year) | The average age of FTC (by year) | The average age of MTC (by year) | The average age of Anaplastic (by year) |
|---|---|---|---|---|
| (1997–2002) | 54.2 ± 7.8 | 55.5 ± 8.3 | 56.1 ± 5.04 | 65.2 ± 9.6 |
| (2002–2007) | 54.67 ± 5.32 | 67.5 ± 51.81 | 51.52 ± 5.84 | 62.3 ± 8.68 |
| (2007–2012) | 50.48 ± 7.57 | 47.5 ± 4.23 | 48.08 ± 6.1 | 62.4 ± 6.27 |
| (2012–2017) | 37.3 ± 4.34 | 45.4 ± 5.1 | 47.4 ± 7.2 | 61.47 ± 4.36 |
| P value | <0.0001 | <0.0001 | <0.0001 |
Papillary thyroid cancer = PTC, Medullary thyroid cancer = MTC, and Follicular.
thyroid cancer = FTCوanaplastic thyroid cancer.
Determining changes in the gender of thyroid cancer incidence: In the first five years, among men with cancer, 60% with PTC, 22% with FTC, 12% with MTC, and 6.1% with anaplastic were, respectively. At the end of the fourth five years, the rate of afflicting to PTC has increased by about 13%. This type of cancer also grew in women at the end of the fourth five years, but the incidence rate was less than that of the men. The prevalence of FTC declined by 10% at the end of the fourth five years in the male gender, but the prevalence of FTC had no change in the female gender. Furthermore, the prevalence of MTC and anaplastic had no significant changes. There was no significant relationship between gender and affliction to the types of cancer, but there was a significant difference between gender and general affliction to thyroid cancer. Thyroid cancer was more prevalent in females, and its pattern had no significant change over the last few years (Table 2).
Table 2.
Gender changes in the incidence of thyroid cancer over the last two decades; papillary thyroid cancer = PTC, Medullary thyroid cancer = MTC, and Follicular thyroid cancer = FTC
| Years | PTC | FTC | MTC | Anaplastic | ||||
|---|---|---|---|---|---|---|---|---|
| Gender | Male | Female | Male | Female | Male | Female | Male | Female |
| (1997–2002) | 37.4 | 62.6 | 55.2 | 44.8 | 40.3 | 59.7 | 30.2 | 69.8 |
| (2002–2007) | 39.3 | 60.7 | 50.6 | 49.4 | 37 | 63 | 32.6 | 67.44 |
| (2007–2012) | 35 | 65 | 44.3 | 55.7 | 44.9 | 55.1 | 29 | 71 |
| (2012–2017) | 40 | 60 | 41.5 | 58.5 | 50.2 | 49.8 | 37.6 | 62.4 |
| P value | 0.8 | <0.05 | 0.84 | 0.92 | ||||
Pathological changes in the types of thyroid cancer: In the first 5 years from 1997 to 2002, the highest prevalence was related to PTC with 60.7%, and FTC with 19.3%, MTC with 14%, and anaplastic with 6% were placed, respectively. At the end of the fourth five years, PTC had the highest increase with a prevalence of about 69.1%, and other types of cancers dropped, but their reduction was not significant (Charts 1 and 2).
Chart 1.
Pathological changes of FTC and PTC cancers over the past two decades; papillary thyroid cancer = PTC, Medullary thyroid cancer = MTC and Follicular thyroid cancer = FTC
Chart 2.
Pathological changes of Anaplastic and MTC cancers over the past two decades; papillary thyroid cancer = PTC, Medullary thyroid cancer = MTC and Follicular thyroid cancer = FTC
Determining the relationship between gender and tumor size in a specified time interval
The rate of increased incidence of tumors with sizes of 2 to 4 cm in males was significantly more than that of females, and there was a significant difference (P < 0.05) in the increased incidence of this size. In tumors less than 1 cm, there was also a significant difference (P < 0.05) in both groups, and the rate of decreased incidence was significantly higher in females. In other cases, there was no significant difference in tumor size changes between the two gender groups (Table 3).
Table 3.
Determining the relationship between gender and tumor size in a specified time interval
| Size/Gender | Less than 1 cm | 1–2 cm | 2–4 cm | More than 4 cm | ||||
|---|---|---|---|---|---|---|---|---|
| Male | Female | Male | Female | Male | Female | Male | Female | |
| (1997–2002) | 14.1% | 25.3% | 10.1% | 19.4% | 5.7% | 17.8% | 2.3% | 5.3% |
| (2002–2007) | 13.4% | 20.8% | 16.3% | 18.1% | 9.3% | 19.7% | 4.7% | 13.2% |
| (2007–2012) | 13.2% | 20.1% | 10.8% | 16.9% | 12.1% | 19.3% | 2.6% | 6.1% |
| (2012–2017) | 10.9% | 15.6% | 12.5% | 13.1% | 16.8% | 24.1% | 3.2% | 7.67% |
| P | <0.05 | 0.58 | <0.05 | 0 < 0.05 | ||||
Determining the relationship between age and tumor size in a specified time interval
In the age group of 50 to 80 years, tumors with a size of 2 to 4 cm increased. In the age group of 20 to 50 years, tumors with a size of 2 to 4 cm reached from the incidence of 3.3% to 18.5%. The rate of increased incidence of 2 to 4 cm size in the age group of 20 to 50 years was significantly (P < 0.05) higher than the other age group (Tables 4 and 5).
Table 4.
Determining the relationship between age and tumor size in the specified time interval (less than 1 cm and between 1 and 2 cm)
| Size | Less than 1 cm | 1–2 cm | ||
|---|---|---|---|---|
| Age | 20 to 50 years | 50 to 80 years | 20 to 50 years | 50 to 80 years |
| (1997–2002) | 3% | 35.7% | 2.3% | 27.4% |
| (2002–2007) | 5% | 29% | 3% | 19.8% |
| (2007–2012) | 10.1% | 21.4% | 7.8% | 14.5% |
| (2012–2017) | 15.4% | 16.6% | 12.3% | 13.8% |
| P value | <0.05 | 0.68 | ||
Table 5.
Determining the relationship between age and tumor size in the specified time interval (between 2 and 4 cm and more than 4 cm)
| Size | 2–4 cm | More than 4 cm | ||
|---|---|---|---|---|
| Age | 20 to 50 years | 50 to 80 years | 20 to 50 years | 50 to 80 years |
| (1997–2002) | 3.3% | 19.3% | 0.3% | 7.7% |
| (2002–2007) | 9.1% | 20.3% | 3% | 9.1% |
| (2007–2012) | 10.4% | 21.1% | 3.2% | 6.7% |
| (2012–2017) | 18.5% | 24.4% | 5.3% | 5.2% |
| P value | <0.05 | 0.91 | ||
Determining the changes in tumor size
In the first 5 to 10 years, the highest incidence of tumor size was related to the tumors with a size of less than 1 cm, and then the tumors with a size of 2 to 4 cm were in the next rank. At the end of the second decade, tumors with a size of 2 to 4 cm had the highest increase in incidence. The rate of this increase was 1.5 times. Tumors with a size of more than 4 cm had no significant change in the rate of incidence. Tumors with a size of 1 to 2 cm had also increase in incidence (Chart 3).
Chart 3.
Changes in tumor size
Frequency of vascular involvement, capsule involvement, lymph node involvement
The rate of vascular involvement in the first 5 and 10 years was 9% and 12%, respectively, which reached 25% at the end of the second 10 years by a 3-fold increase. In the case of capsule involvement, we also faced an approximately three-fold increase, reaching from the prevalence of 9% to 24%. In lymph node involvement, we observed the incidence from 8.6% to 18.7% that the involvement of lymph nodes doubled (Chart 4).
Chart 4.
Frequency of vascular involvement, capsule involvement, lymph node involvement
Discussion
In this study, the incidence rate of tumors with a size of 2 to 4 cm was in progress, and the incidence rate of tumors with a size of less than 1 cm reduced. In a study conducted by Chen et al. on 30,766 cases over 17 years in the United States, it was found that the incidence of thyroid cancer in the study population represented a incidence rate of about twice. It was also determined that the incidence rate of cancer incidence in women was much more than that of men. The study revealed that the incidence of tumors with a size of less than 3 cm was rapidly progressing. This study was in line with the results of our study. However, the incidence rate of tumors with a size of less than 1 cm in our study was decreasing [14].In our study, we observed the incidence rate of thyroid cancer in recent years with the priority of papillary cancers. The slope (incidence) of papillary thyroid cancer incidence rate was higher in men than in women. Moreover, the incidence of cancer in women was higher. In the study performed by Kilfoy et al. from 1980 to 2009, it was found that the thyroid cancer incidence exhibited 35% incidence rate in males and a 31% incidence rate in females; however, most of the incidence rates in women were related to tumors with more malignant manifestations. Whereas in men, tumors with smaller size and better prognosis led to this increased incidence. The results of this study were consistent with the results of our study and confirmed it [15].
In this study, the highest rate of increase in cancer was in the age range of 30 to 50 years. The highest rate of increase was associated with the papillary thyroid cancer, and then follicular thyroid cancer increased that the results of our study were consistent with the results of the following study. In a study carried out by Gabriella Pellegriti et al. between 1999 and 2008 on 230,000 people with thyroid cancer to determine changes in the incidence and causes of thyroid cancer worldwide, it was found that the thyroid cancer incidence rate in women and men increased that more share of the increase can be attributed to women over 55 years of age. In contrast, increasing incidence occurred in men with a mild slope. It was also found that the largest share in this increase, in terms of the type of cancer, was associated with papillary thyroid cancers [16].
In the present study, the mean age of patients developing thyroid cancer was 38.4 years in all patients, where the mean age of thyroid cancer affliction in women and men was 37.2 and 42.4 years, respectively. In examinations conducted by Larijani et al. in Iran between 1980 and 1994 on 1177 patients with thyroid cancer referred to four Amir A’lam, Shariati, Imam Khomeini, and Sina Hospitals located in Tehran, it was found that the mean age of women and men with thyroid cancer was 41.1 and 45.8 years, respectively. The reason for this difference was because our study was performed over the recent ten-year study period from 2007 to 2017 and compared with the period from 1997 to 2007. Furthermore, the highest rate of tumors associated with papillary tumors (about 80%), and the lowest rate of tumors related to medullary thyroid cancer (4.1%). The most clinical presentation of tumors was neck mass (68%) and then dysphagia (9%), indicating the similarity of our results with this study [17].
In this study, the mean age of the patients was 38.4. Besides, the mean age of being afflicted to papillary thyroid cancer, follicular thyroid cancer, medullary thyroid cancer, and anaplastic thyroid cancer was 37.3, 45.4, 47.4, and 61 years, respectively, representing a reduction of the age of being afflicted to types of thyroid cancer, especially papillary thyroid cancer type. In a study conducted by Haghpanah et al. in Iran between 1996 and 2000 on 319 patients, it was found that 75.2% of patients were female and 24.8% were male. In this study, the mean age of the patients was also determined to be 43.38 years. The mean age of patients was 42.90 in papillary thyroid cancer, 45.37 in follicular thyroid cancer, 48.50 in medullary thyroid cancer, and 67.60 in anaplastic thyroid cancer. These results were similar to those of our study [18].
In this study, the incidence of thyroid cancer, particularly papillary thyroid cancer type had a significant increase during the specified time interval. In the study carried out by Pandeya N et al., between 1982 and 2008 on 14,495 cases of thyroid cancer in the Queensland State of Australia, it was found that the incidence rate of thyroid cancer increased from 2.2 cases per 100,000 population in 1982 to 10.6 cases per 100,000 population in 2008. As well as, the increased incidence in subgroups of papillary thyroid cancers was more than other subgroups of thyroid cancer, which was in line with the results of our study on the incidence of thyroid cancer. Moreover, in this study, the relationship between socioeconomic status and thyroid cancer incidence was examined, which did not lead to tangible results, and a clear relationship was not found. In response to the question of whether the increased incidence is due to overdiagnosis of thyroid cancer or not, Pandeya N et al. in this study concluded that overdiagnosis alone could not justify this multiple-fold increase in thyroid cancer, and other factors were likely involved in this increase [19]. In iodine deficient regions, where iodine supplementation has been introduced, increased proportion of papillary histology has been accompanied with decreased numbers of anaplastic types [20].
In this study, the highest increase in the incidence of thyroid cancer was in the group of tumors with a size of 2 to 4 cm, whereas we had a decline in the incidence in the tumors less than 1 cm size. In a study conducted by Enewold et al. between 1980 and 2005 on 48,403 cases of thyroid cancer in the United States based on the ethnicity and race population, it was found that the only thyroid cancer increased among all races living in the United States was papillary thyroid cancer. The increased rate of papillary thyroid cancer incidence during the study period represented an increase by 100% among races of White non-Hispanics and Black females and an increase of 20% to 50% among races of White Hispanics and Asians and Pacific Islanders and Black males. Also, it was found in this study that the highest rate of increasing incidence of thyroid cancer was related to tumors with small size and low stage so that about 50% of this increasing incidence of thyroid cancer was in tumors of less than 1 cm in size and 30% in tumors between 1.1 and 2 cm and 20% in tumors more than 2 cm in size. The results of this study were contrary to the results of our study, indicating the increasing incidence of thyroid cancers with a size of 2 to 4 cm. Furthermore, according to the conclusions of this study, increasing medical surveillance in the community and employing more sensitive diagnostic approaches cannot justify this increased incidence [21].
Conclusion
The incidence of thyroid cancer was increasing at an early age, and the rise of papillary thyroid cancer type was higher than other types. As well as, it was found in this study that the incidence of tumor size of 2 to 4 cm was also on the rise. While the incidence of tumors less than 1 cm in size dropped. One of the causes of the increasing incidence could be attributed to the more accurate diagnostic tools and the increase in specialized centers, and the thyroid cancer overdiagnosis also appeared to be essential in this respect. During the study period, the rate of vascular and capsular involvement approximately increased three times, and the rate of lymph node involvement nearly doubled. One of the important causes of the increased lymph node and capsule involvement in thyroid cancer may be due to the advancement of diagnostic tools and more accurate and updated medical diagnostic methods as well as enhancement of physicians’ skill and experience in this regard. This increase does not merely demonstrate the deteriorating behavior of the tumors, however, the hypothesis for this increase can also be proposed that carrying out further studies is required in this field.
Compliance with ethical standards
Conflict of interest
The authors declared that they have no conflict of interest.
Footnotes
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Contributor Information
Majid Ramezani, Email: dr.ramezani145@gmail.com.
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