Uterine Corpus Cancer Research Articles

Cancer-associated retinopathy in a patient with synchronous fallopian tubal and uterine corpus cancers

Background: Cancer-associated retinopathy (CAR) is a paraneoplastic syndrome that significantly diminishes the quality of life of patients. Case Report: A 53-year-old woman with a history of glaucoma, cataract, and cerebral infarction was diagnosed with synchronous FIGO Stage IVB fallopian tubal cancer and Stage IA uterine corpus cancer. She complained of acute low vision and ring scotoma during the examination. Although her visual acuity was 25/20 in both eyes, and neither fundoscopy nor brain CT showed any abnormalities, electroretinography recorded no responses. Anti-recoverin antibodies were detected in her serum, and both fallopian tubal, and endometrial malignant cells expressed recoverin. These malignant tumours caused CAR. Although surgical debulking and chemotherapy reduced the size of the tumours, her low vision progressively worsened and anti-recoverin antibodies were still detected in her serum. Conclusion: The authors treated a rare case of CAR with synchronous fallopian tubal and endometrial cancer. This rare paraneoplastic syndrome should be considered during the differential diagnosis of ophthalmological symptoms in patients with malignant disease, as well as in the gynaecological field.

Uterine Corpus Malignancies in Appalachia Kentucky: Incidence, Survival, and Related Health Disparities.

Uterine cancer is the nation's most common gynecologic malignancy, but it is understudied in the geographically and socioeconomically diverse state of Kentucky (KY). Our aim was to assess the frequency, distribution, and survival of uterine corpus malignancies in KY, and specifically the differences between Appalachia (AP) and non-Appalachia (NAP) KY. This population-based cohort study used Surveillance, Epidemiology, and End Results data and the Kentucky Cancer Registry to study uterine corpus malignancy between January 1, 2000 and December 31, 2014. The analysis looked at the incidence between diagnoses in AP and NAP. The evaluation criteria included tumor histology (type I, type II, sarcoma, and mixed uterine malignancy), age, race, smoking status, stage at diagnosis, insurance status, and county of residence at diagnosis. The overall age-adjusted incidence rate and survival are similar for US and KY populations; however, histologic types and distribution differ. Compared with the United States, the incidence of corpus cancers in KY is higher for type I (P = 0.03), but lower for type II (P = 0.003), sarcoma (P = 0.006), and mixed (P < 0.001). AP KY has a higher incidence of type I (P < 0.0001) and mixed malignancy (P = 0.04), younger age at diagnosis (P < 0.0001), larger non-Hispanic white population (P < 0.0001), fewer smokers (P = 0.002), and more uninsured and Medicaid recipients (P < 0.0001) compared with NAP KY. The hazard ratio for death is similar in AP and NAP KY (0.896; 95% confidence interval 0.795-1.009). Type I and mixed uterine corpus cancers have a higher age-adjusted incidence and a younger age at diagnosis in AP compared with NAP KY.

Secondary Breast, Ovarian, and Uterine Cancers After Colorectal Cancer: A Nationwide Population-Based Cohort Study in Korea.

The risk of a second primary cancer has increased along with the increasing life expectancies of colorectal cancer survivors. We aimed to evaluate the incidence rate and risk factors of breast and gynecological (ovarian, uterine cervix/corpus) cancers among female colorectal cancer survivors. This is a retrospective population-based cohort study. This study used data from the National Health Insurance Corporation of Korea. Each patient with colorectal cancer diagnosed from 2007 to 2012 was followed until 2015 and compared with age-matched women without colorectal cancer at a 1:5 ratio. The primary outcome was de novo breast/gynecological cancer. Patients with available medical checkup data were included in an additional analysis. We analyzed 56,682 patients with colorectal cancer and 288,119 age-matched noncolorectal cancer controls. The risk of breast/gynecological cancer was higher among patients with colorectal cancer than among controls (HR, 2.91; p < 0.001). The association with colorectal cancer was the highest for ovarian cancer (HR, 6.72), followed by uterine corpus cancer (HR, 3.99), cervical cancer (HR, 2.82), and breast cancer (HR, 1.85). This association remained consistent in the subgroup analysis of medical checkup data (14,190 patients with colorectal cancer, 71,933 controls). Among patients with colorectal cancer, those aged <55 years had a higher risk of breast/gynecological cancers than those aged >55 years (HR, 3.51 vs 2.59), and those with dyslipidemia had a higher risk of breast cancer than those without dyslipidemia (HR, 2.66 vs 2.06). This was a retrospective, population-based study. A prospectively designed study is needed to validate our conclusions. Compared with the general population, patients with colorectal cancer carry a higher risk of developing secondary breast, ovarian, and uterine cancers. See Video Abstract at http://links.lww.com/DCR/A731.

O3-2-2 - Efficacy and safety of nivolumab in patients with uterine cervical cancer, uterine corpus cancer, or soft-tissue sarcoma

O3-2-2 - Efficacy and safety of nivolumab in patients with uterine cervical cancer, uterine corpus cancer, or soft-tissue sarcoma

Radiation Risks of Uterine Cancer in Atomic Bomb Survivors: 1958-2009.

BackgroundIonizing radiation is known to be capable of causing cancer of many organs, but its relationship with uterine cancer has not been well characterized.MethodsWe studied incidence of uterine cancer during 1958–2009 among 62 534 female atomic bomb survivors. Using Poisson regression analysis, we fitted excess relative risk (ERR) models to uterine cancer rates adjusted for several lifestyle and reproductive factors. Person-years at risk were also adjusted for the probability of prior hysterectomy, because it could affect the subsequent risk of uterine cancer. We assessed the modifying effect of age and other factors on the radiation risk. For analysis of the modifying effect of age at radiation exposure around menarche, we compared the radiation risk for several exposure-age categories as well as using parametric models.ResultsThere were 224 uterine corpus cancers and 982 cervical cancers. We found a significant association between radiation dose and risk of corpus cancer (ERR per Gray [ERR/Gy] = 0.73, 95% confidence interval [CI] = 0.03 to 1.87) but not for cervical cancer (ERR/Gy = 0.00, 95% CI = −0.22 to 0.31). For corpus cancer, we found statistically significant heterogeneity in ERR/Gy by age (Pheterogeneity = .001) with elevated risk for women exposed to radiation between ages 11 and 15 years (ERR/Gy = 4.10, 95% CI = 1.47 to 8.42) and no indication of a radiation effect for exposures before or after this exposure-age range.ConclusionsThe current data suggest that uterine corpus is especially sensitive to the carcinogenic effect of radiation exposure occurring during the mid-pubertal period preceding menarche. There is little evidence for a radiation effect on cervical cancer risk.

Highlights of This Issue

Uterine corpus cancer is the most common invasive gynecologic cancer among United States women, and incidence of the epithelial type, endometrial cancer, is rapidly increasing. In this new article type, Felix and Brinton summarize the literature related to etiology, disparities, early detection, and survivorship of endometrial cancer, with a focus on progress that has been made and avenues for future research. The authors suggest that future research should be directed at reducing the prevalence of modifiable risk factors and identifying risk factors for aggressive endometrial cancer subtypes, particularly among black women.Recent evidence suggests that the incidence of colorectal cancer among younger adults (under 50 years at diagnosis) is increasing, but data on incidence trends across racial/ethnic groups are limited. Using California Cancer Registry data, Ellis and colleagues examined trends in incidence of colorectal cancer among detailed racial/ethnic groups (non-Hispanic white, non-Hispanic black, Hispanic, and 7 Asian American groups) by age and stage over the 25-year period of 1990 to 2014. The authors found increases in the incidence of early onset colorectal cancer in most racial/ethnic groups in California. These finding may have implications for revisiting screening guidelines in the United States.This study by Bergin and colleagues is the first to examine if delayed pathways to diagnosis and treatment contribute to rural–urban survival disparities seen in colorectal cancer, but not breast cancer. Survey data from patients in Victoria, Australia, their primary care physician and specialist, and cancer registry data were analyzed using quantile regression. Six intervals from first symptom or screening test to treatment were examined. Rural residence was associated with longer total intervals for colorectal cancer, but not breast cancer, with most disparities in the time from presentation to diagnosis. Pathways research such as this can identify where policy interventions should be targeted to reduce cancer disparities.Cancer screening and survival rates in the Medicaid population are lower than in the privately insured population. Slater and colleagues conducted a population-based randomized controlled trial among all individuals enrolled in Minnesota's Medicaid program overdue for breast and/or colorectal cancer screening. The intervention – direct mail, a $20 incentive, and patient navigation – led to significantly higher screening in treatment versus control subjects (ORs of 1.30 and 1.12 for mammography and colonoscopy, respectively). Whereas this approach increased cancer screening in a Medicaid population, it may also have broader application for reaching individuals who remain outside the health care system despite having health insurance.

Cancer Progress and Priorities: Uterine Cancer.

This article is featured in Highlights of This Issue, [p. 983][1] Uterine corpus cancer is the most common invasive gynecologic cancer among U.S. women. Studies of endometrial cancers, which comprise approximately 90% of all uterine cancers, have identified numerous risk factors, many of which

Risk of subsequent myeloid neoplasms after radiotherapy treatment for a solid cancer among adults in the United States, 2000–2014

Although increased risk of acute myeloid leukemia (AML) has been observed after chemotherapy and radiotherapy, less is known about radiotherapy-related risks of specific AML subtypes and other specific myeloid neoplasms. We used the US population-based cancer registry data to evaluate risk of myeloid neoplasms among three cohorts of cancer survivors initially treated with radiotherapy only. We included 1-year survivors of first primary thyroid (radioiodine only, stages I-IV; N = 49 879), prostate (excluding stage IV; N = 237 439), or uterine corpus cancers (stage I-II; N = 16 208) diagnosed during 2000-2013. We calculated standardized incidence ratios (SIRs) and excess absolute risks (EARs). Thyroid cancer survivors had significantly elevated risks of total AML (SIR = 2.77, 95% CI: 1.99-3.76), AML with cytogenetic abnormalities (SIR = 3.90, 95% CI: 1.57-8.04), AML with myelodysplasia-related changes (SIR = 2.87, 95% CI: 1.05-6.25), and BCR-ABL1-positive chronic myelogenous leukemia (CML) (SIR = 5.38, 95% CI: 2.58-9.89). Irradiated prostate and uterine corpus cancer survivors were at elevated risk for total AML (SIR = 1.14, 95% CI: 1.03-1.27 and SIR = 1.77, 95% CI: 1.01-2.87, respectively), AML with cytogenetic abnormalities (SIR = 2.52, 95% CI: 1.84-3.37 and SIR = 7.21, 95% CI: 2.34-16.83, respectively), and acute promyelocytic leukemia (SIR = 3.20, 95% CI: 2.20-4.49 and SIR = 8.88, 95% CI: 2.42-22.73, respectively). In addition, prostate cancer survivors were at increased risk of BCR-ABL1-positive CML (SIR = 2.11, 95% CI: 1.52-2.85). Our findings support the importance of diagnostic precision in myeloid neoplasm classification since susceptibility following radiotherapy may vary by myeloid neoplasm subtype, thereby informing risk/benefit discussions in first primary cancer treatment.

Efficacy and safety of nivolumab (Nivo) in patients (pts) with advanced or recurrent uterine cervical or corpus cancers.

5594Background: Recent advances in immuno-oncology provide evidence for the efficacy of PD-1/PD-L1 blockade therapy for a variety of cancers. However, the clinical activity of Nivo, an anti-PD-1 mo...

The bidirectional association among female hormone-related cancers: breast, ovary, and uterine corpus.

Breast, ovarian, and uterine corpus cancers are common female cancers and categorized as hormone‐related diseases. Previous studies reported a unidirectional relationship for each cancer, but few studied the reciprocal association in the same cohort. A population‐based study was carried out in Taiwan to test the hypothesis that there are pairwise bidirectional associations among these cancers. Using the same cohort of 110,112 cases with primary female cancers including uterine corpus cancer (11,146 cases), ovarian cancer (12,139 cases), or breast cancer (86,827 cases) from the Taiwan Cancer Registry from 1979 to 2008, the pairwise risks of second cancer among uterine corpus, ovary, and breast cancer cases were evaluated by standardized incidence ratios (SIRs) and the corresponding 95% confidence intervals (CIs) to quantify the excess of second malignancies. A reciprocal relationship was found for these three female cancers, particularly most prominent between uterine and ovarian cancers, followed by breast and uterine cancers as well as breast and ovarian cancers. The overall risk of second cancers was highest within the first 5 years after the diagnosis of primary cancer. The bidirectional relationships suggest common risk factors among these three female cancers. This is the largest cohort study to focus on the bidirectional associations among hormone‐related cancers in Asian women, and these results could aid in the development of early prevention strategies and follow‐up surveillance programs.

Feasibility of laparoscopic surgery for obese patients with uterine corpus cancer

Feasibility of laparoscopic surgery for obese patients with uterine corpus cancer

Major clinical research advances in gynecologic cancer in 2017.

In 2017, 10 topics were selected as major clinical research advances in gynecologic oncology. For cervical cancer, efficacy and safety analysis results of a 9-valent human papillomavirus (HPV) vaccine and long-term impact of reduced dose of quadrivalent vaccine were updated. Brief introduction of KEYNOTE trials of pembrolizumab, a monoclonal antibody that blocks the interaction between programmed death (PD)-1 and its ligands, PD-L1 and PD-L2, followed. Tailored surveillance programs for gynecologic cancer related with Lynch syndrome and update on sentinel lymph node mapping were reviewed for uterine corpus cancer. For ovarian cancer, 5 topics were selected including poly(ADP-ribose) polymerases inhibitors and immunotherapy. The other potential practice changers covered in this review were lymphadenectomy in advanced disease, secondary cytoreductive surgery in recurrent disease, weekly dose-dense regimen for first-line chemotherapy, incorporation of bevacizumab maintenance in platinum-sensitive recurrent disease, and effect of platinum-free interval prolongation. Conflicting opinions of academic societies on periodic pelvic examination were introduced in conjunction with relevant literature review. For the field of radiation oncology, results of 2 big trials, The Postoperative Radiation Therapy in Endometrial Carcinoma-3 and Gynecologic Oncology Group-258, for endometrial cancer and recent advance in high-dose-rate brachytherapy for cervical cancer were reported. Topics for breast cancer covered adjuvant capecitabine after preoperative chemotherapy, adjuvant pertuzumab and trastuzumab in early human epidermal growth factor receptor 2-positive disease, olaparib for metastatic cancer in patients with a germline BRCA mutation, 20-year risks of recurrence after stopping endocrine therapy at 5 years, and contemporary hormonal contraception and the risk of breast cancer.

A case of uterine corpus cancer with definitive staging after laparoscopic surgery, and preliminary diagnosis based on endometrial cytology

A case of uterine corpus cancer with definitive staging after laparoscopic surgery, and preliminary diagnosis based on endometrial cytology

Trends of Gynecological Cancers in Turkey: Toward Europe or Asia?

The aim of this study was to evaluate nationwide gynecological cancer trends in Turkey. National cancer registry data (2009-2013) of Turkish Ministry of Health were evaluated. Ovarian, cervical, endometrial, vulvar, vaginal, and tubal cancers are evaluated with respect to age of diagnosis, incidence rates within years, stage, histological distributions, and mortality rates. Data were collected from active cancer registry centers, which increased from 23% in 2009 to 47.5% coverage of the whole population by 2012, and mortality data (2010-2015) were obtained from the Turkish Statistical Institute. A total of 16,023 gynecological cancers were evaluated among 116,940 female patients with cancer (13.7%). Average incidence for gynecological cancers was 22.7 of 100,000, representing 8437 total new cases annually. Incidence changes within time were not statistically significant, when evaluated for each tumor type. Estimated risk of gynecological cancer development before the age of 80 years was 3.08% (95% confidence interval, 3.07-3.09). The most common gynecological cancers were uterine corpus cancers, which were followed by ovarian and cervical carcinomas. Ovarian and uterine cancer incidences were closer to European levels rather than Asian countries, whereas cervical cancer incidence was extremely low. Gynecological cancers constituted an important fraction of cancer-related mortality in women by comprising approximately 10.35% of cancer-related deaths. Mortality rates due to gynecological cancers did not show a statistically significant increase within years. This is the first national cancer registry report to be published for gynecological cancers by the Turkish Governmental Department. As a result, Turkish gynecological cancer epidemiological data were consistent with the data obtained from European and developed countries rather than Asian countries, except for cervical cancer incidence, which is extremely low.

Advancing Uterine Cancer Survivorship Among African American Women

BackgroundFew studies have examined health behavior interventions for African American women who are uterine cancer survivors. Black-white differences in uterine cancer survival suggest that there are unmet needs among these survivors. MethodsThis article identifies opportunities to address disparities in uterine corpus cancer survival and quality of life, and thereby to increase uterine cancer survivorship among African American women. ResultsFor cancer survivors, common side effects, lasting for long periods after cancer treatment, include fatigue, loss of strength, lymphedema, and difficulty sleeping. A variety of interventions have been evaluated to address physical and mental health concerns, including exercise and dietary interventions. Considerable information exists about the effectiveness of such interventions for alleviating distress and improving quality of life among cancer survivors, but few studies have focused specifically on African American women with a uterine corpus cancer diagnosis. Research-tested culturally tailored lifestyle interventions are lacking. ConclusionsThere is a need for a better understanding of uterine cancer survivorship among African American women. Additional evaluations of interventions for improving the quality of life and survival of African American uterine cancer survivors are needed.

Trends of Gynecological Cancers in Turkey: Toward Europe or Asia?

The aim of this study was to evaluate nationwide gynecological cancer trends in Turkey. National cancer registry data (2009-2013) of Turkish Ministry of Health were evaluated. Ovarian, cervical, endometrial, vulvar, vaginal, and tubal cancers are evaluated with respect to age of diagnosis, incidence rates within years, stage, histological distributions, and mortality rates. Data were collected from active cancer registry centers, which increased from 23% in 2009 to 47.5% coverage of the whole population by 2012, and mortality data (2010-2015) were obtained from the Turkish Statistical Institute. A total of 16,023 gynecological cancers were evaluated among 116,940 female patients with cancer (13.7%). Average incidence for gynecological cancers was 22.7 of 100,000, representing 8437 total new cases annually. Incidence changes within time were not statistically significant, when evaluated for each tumor type. Estimated risk of gynecological cancer development before the age of 80 years was 3.08% (95% confidence interval, 3.07-3.09). The most common gynecological cancers were uterine corpus cancers, which were followed by ovarian and cervical carcinomas. Ovarian and uterine cancer incidences were closer to European levels rather than Asian countries, whereas cervical cancer incidence was extremely low. Gynecological cancers constituted an important fraction of cancer-related mortality in women by comprising approximately 10.35% of cancer-related deaths. Mortality rates due to gynecological cancers did not show a statistically significant increase within years. This is the first national cancer registry report to be published for gynecological cancers by the Turkish Governmental Department. As a result, Turkish gynecological cancer epidemiological data were consistent with the data obtained from European and developed countries rather than Asian countries, except for cervical cancer incidence, which is extremely low.

A nationwide multi-institutional retrospective study to identify prognostic factors and develop a graded prognostic assessment system for patients with brain metastases from uterine corpus and cervical cancer

BackgroundThe prevalence of brain metastases (BM) from uterine cancer has recently increased because of the improvement of overall survival (OS) of patients with uterine cancer due to its early detection and improved local control as a result of new effective treatments. However, little information is available regarding their clinical characteristics and prognosis, because oncologists have encountered BM from uterine cancer on rare occasions.MethodsRecords from 81 patients with uterine BM were collected from 10 institutes in Japan. These were used in a multi-institutional study to identify prognostic factors and develop a graded prognostic assessment (GPA) for patients with BM from uterine cancer.ResultsMedian OS after the development of BM was 7 months (95% confidence interval, 4 to 10 months). Multivariate analysis revealed that there were survival differences according to the existence of extracranial metastases and number of BM. In the present uterine-GPA, a score of 0 was assigned to those patients with ≥5 BM and extracranial metastasis, a score of 2 was assigned to those patients with one to four BM or without extracranial metastasis, and a score of 4 was assigned to those patients with one to four BM and without extracranial metastasis. The median OS for patients with a uterine-GPA scores of 0, 2, and 4 was 3, 7, and 22 months, respectively. A survival analysis confirmed the presence of statistically significant differences between these groups (p < 0.05). The results were validated by data obtained from the National Report of Brain Tumor Registry of Japan.ConclusionUterine GPA incorporates two simple clinical parameters of high prognostic significance and can be used to predict the expected survival times in patients with BM from uterine cancer. Its use may help in determining an appropriate treatment for individual patients with BM.

Survival of Cancer Patients in Northeast China: Analysis of Sampled Cancers from Population-Based Cancer Registries.

PurposeThe cancer survival was characterized by following up sampled subgroups of cancer cases from three population-based cancer registries in Northeast China.Materials and MethodsSurvival analysis was used to analyze 6,871 patients, who had one of the 21 most common cancers based on sampling from the population-based cancer registries of three cities in Liaoning Province. All patients were diagnosed between 2000 and 2002 and were followed up to the end of 2007 by active and passive methods. The 5-year age standardized relative survival rates (ASRS) were estimated for all cancers combined and each of the 21 individual cancers.ResultsThe survival status was traced for 80.8% of 8,506 sampled cancer cases. The 5-year ASRS for all 21 cancers combined was 41.5% (95% confidence interval, 40.3 to 42.7), the highest ASRS was observed for thyroid cancer (85.2%), breast cancer (78.9%), uterine corpus cancer (75.9%), and urinary bladder cancer (70.2%); the lowest 5-year ASRS was noted in pancreatic cancer (8.8%), liver cancer (11.0%), esophageal cancer (18.8), and lung cancer (19.6%). The cancer survival rates in Liaoning cities were similar to those of urban areas in mainland China, but significantly lower than those in Hong Kong, Korea, and Japan.ConclusionThe strikingly poor cancer survival rates in three cities of Liaoning Province and in other places in China highlight the need for urgent investment in cancer prevention, early detection, and standardized and centralized treatment.

Incidence and lifetime risk of uterine corpus cancer in Taiwanese women from 1991 to 2010

ObjectiveAlthough uterine corpus cancer has been the most common malignancy of the female genital tract in many countries, the lifetime risk of this cancer has not yet been determined among Taiwanese women. The purpose of the study was to describe the change in incidence and the lifetime risk of uterine corpus cancer over a 20-year period from 1991 to 2010 in Taiwan. Materials and methodsWe conducted a population-based registry study using the released database (available online) from the Taiwan Cancer Registry. ResultsA total of 15,542 women newly diagnosed with uterine corpus cancer were included in this study. The total number of this cancer increased by 5.7-fold from 1991 to 2010. The annual age-specific rate nearly doubled during the past decade (2001–2010) when compared with the previous decade (1991–2000). Incidence rates were highest in women aged 50–59 years, and increasing incidence rates were observed in each age strata starting from 40 years to 85 years and more, after the year 2000. The lifetime risk of being diagnosed with uterine corpus cancer was 0.39% in 1991–1995, 0.54% in 1996–2000, 0.73% in 2001–2005, and 1.12% in 2006–2010 among Taiwanese women. ConclusionAccording to the observed changes in incidence rate, the burden of uterine corpus cancer in the general female population is expected to increase in the near future. From a public-health perspective, care providers should develop strategies for the prevention, early detection, and intervention to reduce the rapidly increasing incidence of uterine corpus cancer in Taiwan.

Enhancement of Uterine Cancer Development after Oocyte Depletion by Juvenile Exposure to Gamma Radiation in Rats: - A Comparative Study on Sensitivity of Damage to Female Reproductive Organs by Radiation between Juvenile and Adulthood Using a Rat Model.

To clarify sensitivities of juvenile exposure to radiation on uterine carcinogenesis, female Donryu rats, a high yield strain of uterine corpus cancer, were exposed to 0.2 and 1.0 Gy of gamma radiation at postnatal day 14. Sequential changes in their reproductive organs and hematology, and the effects on uterine tumor development were compared to those in adult rats exposed to the same doses. Half number of the rats in each group was treated with N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) after the radiation to accelerate the development of uterine cancer. Severe apoptosis and depletion of oocytes in the primordial/primary follicles were immediately induced after juvenile exposure at 1.0 Gy only. The ovaries in rats exposed to 1.0 Gy at juvenile showed severe atrophy characterized by the loss of all types of follicles and a lack of corpora lutea by 2 months of age, and all rats elicited an early onset of persistent estrus corresponding to the atrophy. At the termination of 9 months of age, juvenile 1.0 Gy exposure with ENNG treatment increased the incidence of endometrial adenocarcinoma and the multiplicities of combined endometrial adenocarcinomas and their precancerous lesions. Enhancement of uterine cancer development was not apparent at the same exposure without ENNG. In comet assays, neither 0.2 nor 1.0 Gy juvenile exposure induced direct DNA damage to uteri though the damage was found in the ovary at 1.0 Gy. The present results indicated that juvenile exposure to gamma radiation indirectly enhanced uterine cancer development in rats through direct damage to oocytes resulting in serious atrophy of the ovary accompanying early onset of persistent estrus. The damage to ovary was more sensitive at juvenile than adults. The result in comet assay suggested that direct DNA damage to the uterus by radiation was excluded.