Comparative study of ovarian cancer histopathology by registry pathologists and referral pathologists: a study by the Gilda Radner Familial Ovarian Cancer Registry

Pathology of Ovarian Cancer: Recent Insights Unveiling Opportunities in Prevention

Ovarian carcinomas were formerly referred to as "surface epithelial carcinomas," reflecting the belief that they all arise from the ovarian surface epithelium. It is now appreciated that most ovarian carcinomas originate from either fallopian tube or endometriotic epithelium, and how we approach prevention will thus differ between histotypes. The 5 histotypes of ovarian carcinoma (high-grade serous, clear cell, endometrioid, mucinous, and low-grade serous, in descending order of frequency) can be reproducibly diagnosed, and are distinct disease entities, differing with respect to genetic risk factors, molecular events during oncogenesis, patterns of spread, and response to chemotherapy.

Lymph node ratio has prognostic value related to the number of positive lymph nodes in patients with vulvar cancer

AIM

We investigated the value of the number of positive lymph nodes (PLNs) and lymph node ratio (LNR) on survival of vulvar cancer patients.

METHODS

A total of 2332 patients with vulvar squamous cell carcinoma were included from the SEER program.

RESULTS

In multivariate analysis, the number of PLNs and LNR were independent prognostic indictors of survival outcomes, a higher number of PLNs and a higher LNR had poorer survival outcomes. An LNR >0.2 was associated with poor survival outcomes according to the number of PLNs.

CONCLUSION

The LNR has prognostic value related to the number of PLNs and may allow a more accurate determination of the lymph node status of vulvar cancer patients.

Trends in the incidence of serous fallopian tube, ovarian, and peritoneal cancer in the US

OBJECTIVE

To identify the trends in incidence of serous fallopian tube, ovarian, and peritoneal epithelial cancers in the United States.

METHODS

Data was obtained from United States Cancer Statistics (USCS) from 2001 to 2014. All incidences are per 100,000 women. Analyses were performed using SEER*Stat and Joinpoint regression programs.

RESULTS

Of the 146,470 patients with serous cancers, 9381 (6.4%) were fallopian tube, 121,418 (82.9%) were ovarian, and 15,671 (10.7%) were primary peritoneal. The study period was divided from 2001 to 2005, 2006-2010, and 2011-2014, and there was an increase in fallopian tube incidence from 0.19 to 0.35 to 0.63, with a corresponding decrease in ovarian incidence from 5.31 to 5.08 to 4.86. There was no significant change in peritoneal cancers from 0.64 to 0.69 to 0.62. The age-specific peak incidence of fallopian tube cancer was younger at age 70-74, compared to ovarian and peritoneal cancer at age 75-79. Further, the incidence of serous fallopian tube cancer was highest in Whites at 0.42, compared to Blacks at 0.24, Hispanics at 0.27, and Asians at 0.28.

CONCLUSION

From 2001 to 2014, the diagnosis of serous fallopian tube cancer increased fourfold with a corresponding decrease in ovarian cancer. The peak incidence of tubal cancer was 70-74years with an increased incidence in Whites.

The Molecular Analysis of Breast Cancer Utilizing Targeted Nanoparticle Based Ultrasound Contrast Agents

This study was structured to challenge the hypothesis that nano-sized particulates could be molecularly targeted and bound to the prognostic and predictive HER-2/neu cell membrane receptor to elicit detectable changes in ultrasound response from human breast cancer cells. SKBR-3 human breast cancer cells were enlisted to test the efficacy of the particle conjugation strategy used in this study and ultimately, to provide conclusive remarks regarding the validity of the stated hypothesis. A characterization-mode ultrasound (CMUS) system was used to apply a continuum mechanics based, two-step inversion algorithm to reconstruct the mechanical material properties of four cell/agarose test conditions upon three independent test samples. The four test conditions include: Herceptin® conjugated iron oxide nanoparticles bound to cells (HER-con), Herceptin® bound to cells (HER), iso-type matched antibody conjugated iron oxide nanoparticles bound to cells (ISO-con), and Cold Flow Buffer mixed with agarose (CFB). The statistical analysis of these ultrasound results supported the ability to differentiate between HER-2/neu positive SKBR-3 cells that have been successfully tagged with Herceptin® conjugated iron oxide particles to those that have not demonstrated particle binding. These findings serve as promising proof-of-concept data for the development of a quantitative histopathologic evaluation tool directed towards both in situ and in vivo applications. The ultimate goal of this research is to exploit the molecular expression of the HER-2/neu protein to offer rapid, quantitative ultrasound information concerning the malignancy rating of human breast tissue employing tumor targeting nanoparticle based ultrasound contrast agents. When fully developed, this could potentially help 32,000–63,000 women efficiently find their proper treatment strategy to fight and win their battle against breast cancer.

Survival differences in women with serous tubal, ovarian, peritoneal, and uterine carcinomas

OBJECTIVE

The fallopian tube has been implicated as the primary origin of pelvic serous cancers. We proposed to determine the survival outcomes of serous tubal, ovarian, peritoneal, and uterine cancer patients.

STUDY DESIGN

Data were obtained from the National Cancer Institute between 2004 and 2009. Kaplan-Meier and Cox proportional hazards models were used for analysis.

RESULTS

Of 12,336 high-grade serous cancer patients, 563 were tubal (TC), 8560 ovarian (OC), 1037 primary peritoneal (PPC), and 2176 uterine cancer (USC). The median ages of these patients were 63 vs 62 vs 67 vs 68 years, respectively. The majority were white (89% vs 88% vs 91% vs 74%). The overall 5 year, disease-specific survival was 37%. The survivals of those with TC, OC, PPC, and USC were 50%, 37%, 26%, and 40% (P < .01). There was no detailed staging on PPC cancers. Adjusted for stage, the survival of those with stage I, II, III, and IV TC were 73%, 62%, 44%, and 22% (P < .01), OC were 83%, 64%, 34%, and 15% (P < .01), and USC were 88%, 72%, 55%, and 17% (P < .01). On multivariate analysis, younger age, white race, earlier stage, and tubal origin were independent predictors for improved survival.

CONCLUSION

In advanced-staged serous cancer patients, tubal cancer patients have better survivals compared with ovarian, peritoneal, and uterine cancer.

Influence of Gynecologic Oncologists on the Survival of Patients With Endometrial Cancer

Purpose

Despite a lack of evidence for survival benefit, the American College of Obstetrics and Gynecology has recommendations for referral to gynecologic oncologists for the treatment of endometrial cancer. Therefore, we propose to determine the influence of gynecologic oncologists on the treatment and survival of patients with endometrial cancer.

Patients and Methods

Data were obtained from Medicare and Surveillance, Epidemiology, and End Results (SEER) databases from 1988 to 2005. Kaplan-Meier and Cox proportional hazard methods were used for analyses.

Results

Of 18,338 women, 21.4% received care from gynecologic oncologists (group A) while 78.6% were treated by others (group B). Women in group A were older (age > 71 years: 49.6% v 44%; P < .001), had more lymph nodes (> 16) removed (22% v 17%; P < .001), presented with more advanced (stages III to IV) cancers (21.9% v 14.6%; P < .001), had higher-grade tumors (P < .001), and were more likely to receive chemotherapy for advanced disease (22.6% v 12.4%; P < .001). In those with stages II to IV disease, the 5-year disease-specific survival (DSS) of group A was 79% versus 73% in group B (P = .001). Moreover, in advanced-stage (III to IV) disease, group A had 5-year DSS of 72% versus 64% in group B (P < .001). However, no association with DSS was identified in stage I cancers. On multivariable analysis, younger age, early stage, lower grade, and treatment by gynecologic oncologists were independent prognostic factors for improved survival.

Conclusion

Patients with endometrial cancer treated by gynecologic oncologists were more likely to undergo staging surgery and receive adjuvant chemotherapy for advanced disease. Care provided by gynecologic oncologists improved the survival of those with high-risk cancers.

Epidemiological evaluation of concordance between initial diagnosis and central pathology review in a comprehensive and prospective series of sarcoma patients in the Rhone-Alpes region

Background

Sarcomas are rare malignant tumors. Accurate initial histological diagnosis is essential for adequate management. We prospectively assessed the medical management of all patients diagnosed with sarcoma in a European region over a one-year period to identify the quantity of first diagnosis compared to central expert review (CER).

Methods

Histological data of all patients diagnosed with sarcoma in Rhone-Alpes between March 2005 and Feb 2006 were collected. Primary diagnoses were systematically compared with second opinion from regional and national experts.

Results

Of 448 patients included, 366 (82%) matched the inclusion criteria and were analyzed. Of these, 199 (54%) had full concordance between primary diagnosis and second opinion (the first pathologist and the expert reached identical conclusions), 97 (27%) had partial concordance (identical diagnosis of conjonctive tumor but different grade or subtype), and 70 (19%) had complete discordance (different histological type or invalidation of the diagnosis of sarcoma). The major discrepancies were related to histological grade (n = 68, 19%), histological type (n = 39, 11%), subtype (n = 17, 5%), and grade plus subtype or grade plus histological type (n = 43, 12%).

Conclusions

Over 45% of first histological diagnoses were modified at second reading, possibly resulting in different treatment decisions. Systematic second expert opinion improves the quality of diagnosis and possibly the management of patients.

Complex segregation analysis of pedigrees from the Gilda Radner Familial Ovarian Cancer Registry reveals evidence for mendelian dominant inheritance

BACKGROUND

Familial component is estimated to account for about 10% of ovarian cancer. However, the mode of inheritance of ovarian cancer remains poorly understood. The goal of this study was to investigate the inheritance model that best fits the observed transmission pattern of ovarian cancer among 7669 members of 1919 pedigrees ascertained through probands from the Gilda Radner Familial Ovarian Cancer Registry at Roswell Park Cancer Institute, Buffalo, New York.

METHODOLOGY/PRINCIPAL FINDINGS

Using the Statistical Analysis for Genetic Epidemiology program, we carried out complex segregation analyses of ovarian cancer affection status by fitting different genetic hypothesis-based regressive multivariate logistic models. We evaluated the likelihood of sporadic, major gene, environmental, general, and six types of Mendelian models. Under each hypothesized model, we also estimated the susceptibility allele frequency, transmission probabilities for the susceptibility allele, baseline susceptibility and estimates of familial association. Comparisons between models were carried out using either maximum likelihood ratio test in the case of hierarchical models, or Akaike information criterion for non-nested models. When assessed against sporadic model without familial association, the model with both parent-offspring and sib-sib residual association could not be rejected. Likewise, the Mendelian dominant model that included familial residual association provided the best-fitting for the inheritance of ovarian cancer. The estimated disease allele frequency in the dominant model was 0.21.

CONCLUSIONS/SIGNIFICANCE

This report provides support for a genetic role in susceptibility to ovarian cancer with a major autosomal dominant component. This model does not preclude the possibility of polygenic inheritance of combined effects of multiple low penetrance susceptibility alleles segregating dominantly.

Do clear cell ovarian carcinomas have poorer prognosis compared to other epithelial cell types? A study of 1411 clear cell ovarian cancers

OBJECTIVE

To compare the clinico-pathologic characteristics and survival of women with clear cell versus other epithelial ovarian cancers.

METHODS

Data were obtained from the Surveillance, Epidemiology and End Results Program between 1988 and 2001 and analyzed using Kaplan-Meier and Cox proportional hazards models.

RESULTS

Of 28,082 women with epithelial ovarian cancer, 1411 (5%) had clear cell, 13,835 (49.3%) papillary serous, 3655 (13%) endometrioid, 2711 (9.7%) mucinous, and 6470 (23%) had unspecified histologies. The median age of overall patients was 64 years; with clear cell patients presenting at younger age (55 years). The proportion of clear cell histology was significantly higher in Asians versus Whites, Blacks, and others (11.1% versus 4.8%, 3.1%, and 5.5%; p<0.001). Clear cell carcinoma is more likely to be diagnosed at early-stage (67.3%) compared to 19.2% in serous, 61.6% endometrioid, and 61.3% in mucinous carcinomas (p<0.005). Retroperitoneal lymph node metastases were found in 13.6% of serous carcinomas, 7.9% clear cell, 7.3% endometrioid, and 3.8% of mucinous (p<0.001). Adjusted for stage, the 5-year disease-specific survival of patients with clear cell carcinoma is worse compared to serous: 85.3% vs. 86.4% for stage I, 60.3% vs. 66.4% stage II, 31.5% vs. 35.0% stage III, and 17.5% vs. 22.2% for stage IV, respectively (p<0.001). On multivariate analysis, age, stage, grade, histology, and surgical treatment were independent predictors of disease-specific survival.

CONCLUSIONS

Our data suggest that women with clear cell ovarian cancer present at a younger age, are more likely to be Asian, and have a poorer prognosis compared to serous cancers.

Trends in demographic and clinical characteristics in women diagnosed with corpus cancer and their potential impact on the increasing number of deaths

OBJECTIVE

The purpose of this study was to determine factors responsible for the increasing number of deaths from corpus cancer over three time periods.

STUDY DESIGN

Data were collected from the Surveillance, Epidemiology and End Results database from 1988-2001. Kaplan-Meier and Cox proportional hazards regression analyses were performed.

RESULTS

Of 48,510 women with corpus cancer, there was an increase in the proportion of patients dying from advanced cancers (52.1% to 56.0% to 68.8%; P < .001), grade 3 disease (47.5% to 53.3% to 60.6%; P < .001), serous tumors (14.3% to 18.4% to 16.6%; P < .001), and sarcomas (19.1% to 20.4% to 27.2%; P < .001) over time. On multivariate analysis, older age, African American race, lack of primary staging procedures, advanced-stage, high-grade, and non-endometrioid histology were independent prognostic factors for worse survival.

CONCLUSION

Our data suggest that the increase in mortality in women with corpus cancer over the last 14 years may be related to an increased rate of advanced-stage cancers and high-risk histologies.

Contribution ofBRCA1andBRCA2mutations to inherited ovarian cancer

A total of 283 epithelial ovarian cancer families from the United Kingdom (UK) and the United States (US) were screened for coding sequence changes and large genomic alterations (rearrangements and deletions) in the BRCA1 and BRCA2 genes. Deleterious BRCA1 mutations were identified in 104 families (37%) and BRCA2 mutations in 25 families (9%). Of the 104 BRCA1 mutations, 12 were large genomic alterations; thus this type of change represented 12% of all BRCA1 mutations. Six families carried a previously described exon 13 duplication, known to be a UK founder mutation. The remaining six BRCA1 genomic alterations were previously unreported and comprised five deletions and an amplification of exon 15. One of the 25 BRCA2 mutations identified was a large genomic deletion of exons 19-20. The prevalence of BRCA1/2 mutations correlated with the extent of ovarian and breast cancer in families. Of 37 families containing more than two ovarian cancer cases and at least one breast cancer case with diagnosis at less than 60 years of age, 30 (81%) had a BRCA1/2 mutation. The mutation prevalence was appreciably less in families without breast cancer; mutations were found in only 38 out of 141 families (27%) containing two ovarian cancer cases only, and in 37 out of 59 families (63%) containing three or more ovarian cancer cases. These data indicate that BRCA1 and BRCA2 are the major susceptibility genes for ovarian cancer but that other susceptibility genes may exist. Finally, it is likely that these data will be of clinical importance for individuals in families with a history of epithelial ovarian cancer, in providing accurate estimates of their disease risks.

Prognostic factors responsible for survival in sex cord stromal tumors of the ovary—An analysis of 376 women

OBJECTIVE

To evaluate prognostic factors that impact on the survival of women with ovarian sex cord stromal tumors (SCST).

METHODS

Data including age at diagnosis, stage, histology, grade, treatment, and survival were extracted from the 1988-2001 Surveillance, Epidemiology, and End Results Program. Kaplan-Meier and Cox proportional hazards analyses were used to determine the predictors for survival.

RESULTS

376 women (median age: 51) with ovarian sex cord stromal cell tumors were identified, including 339 with granulosa cell and 37 with Sertoli-Leydig cell tumors. 265 (71%) patients had stage I, 39 (10%) stage II, 40 (11%) stage III, and 32 (8%) had stage IV disease. Women with stage I-II disease had a 5-year disease-specific survival of 95% compared to 59% in those with stage III-IV cancers (p<0.001). Patients<or=50 years had a survival advantage over those>50 years (93% vs. 84%, p<0.001). This age-associated survival advantage was observed for early (97% vs. 92%, p=0.003), but not for advanced-staged (68% vs. 53%, p=0.09) patients. 110 patients with stage I-II disease underwent conservative surgery without hysterectomy. The survival for this group was similar to patients who underwent a standard surgery including a hysterectomy (94.8% and 94.9%, p=0.38). On multivariate analysis, age<or=50 (p=0.001) and early-stage disease (p<0.001) remained significant prognostic factor for improved survival.

CONCLUSIONS

Younger age and early-stage disease are important predictors for improved survival in patients with ovarian sex cord stromal tumors. Conservative surgical treatment for early-staged patients wishing to retain fertility appears to be a safe alternative.

The benefit of adjuvant radiation therapy in single-node-positive squamous cell vulvar carcinoma

OBJECTIVE

To determine if adjuvant radiotherapy improves the survival of women with invasive squamous cell carcinoma of the vulva involving one inguinal node.

METHODS

Demographic, pathologic, and treatment information was obtained on patients with vulvar cancers from the Surveillance, Epidemiology, and End Results database between 1988 and 2001. Kaplan-Meier estimates and Cox-proportional hazards model were used for analyses.

RESULTS

Of the 490 patients with stage III, node-positive vulvar cancers, 208 had a single positive inguinal node. The median age of this group was 71 years (range: 29-100). 82.2% of patients were White, 7.2% were Hispanic, 7.7% were Black, 1.4% were Asian, and 1.4% were Others. 91.8% of patients underwent a radical vulvectomy with a unilateral or bilateral inguinal lymphadenectomy. The median number of lymph nodes resected was 13 (range: 1-34). 102 women underwent adjuvant radiotherapy, while 106 did not receive any radiation treatment. Women who received adjuvant radiotherapy had a 5-year disease-specific survival of 77.0% compared to 61.2% in those without radiotherapy (p=0.02). After stratifying the study group based on the extent of lymphadenectomy, we found that radiation treatment improved the survival of those with <or=12 lymph nodes removed (76.6% versus 55.1%, p=0.035). In those with more than 12 nodes resected, radiotherapy increased the survival from 66.7% to 77.3%, though this difference was not statistically significant (p=0.23). In multivariate analysis, younger age (p=0.01) remained as a significant prognostic factor for improved survival; however, adjuvant radiotherapy had a borderline significance (p=0.06).

CONCLUSION

Our data suggest that adjuvant radiotherapy may improve the disease-specific survival of patients with single-node-positive vulvar cancer who underwent a less extensive lymph node resection (<or=12 nodes removed).

Ovarian cancer in younger vs older women: a population-based analysis

To compare the clinico-pathologic prognostic factors and survival of younger vs older women diagnosed with epithelial ovarian cancer. Demographic, clinico-pathologic, treatment, and surgery information were obtained from patients with ovarian cancer from the Surveillance, Epidemiology, and End Results Program from 1988 to 2001 and analysed using Kaplan–Meier estimates. Of 28 165 patients, 400 were <30 years (very young), 11 601 were 30–60 (young), and 16 164 were >60 (older) years of age. Of the very young, young, and older patients, 261 (65.3%), 4664 (40.2%), and 3643 (22.5%) had stage I–II disease, respectively (P<0.001). Across all stages, very young women had a significant survival advantage over the young and older groups with 5-year disease-specific survival estimates at 78.8% vs 58.8 and 35.3%, respectively (P<0.001). This survival difference between the age groups persists even after adjusting for race, stage, grade, and surgical treatment. Reproductive age (16–40 years) women with stage I–II epithelial ovarian cancer who received uterine-sparing procedures had similar survivals compared to those who underwent standard surgery (93.3% vs 91.5%, P=0.26). Younger women with epithelial ovarian cancer have a survival advantage compared to older patients.

Patterns and progress in ovarian cancer over 14 years

OBJECTIVE

To estimate the change in survival rates of women with ovarian cancer during the past 14 years.

METHODS

Women diagnosed with epithelial, germ cell, sarcomas, and sex-cord stromal ovarian tumors were identified from the Surveillance Epidemiology and End Results Database. Demographic and clinicopathologic factors, and survival information were extracted and tested using chi 2 and Kaplan-Meier and Cox regression analyses.

RESULTS

A total of 30,246 women were diagnosed with ovarian cancer, including 26,753 non-clear cell epithelial, 1,411 clear cell, 818 sarcoma, 778 germ cell, and 486 sex-cord stromal tumors. The 5-year disease-specific survival rate across 1988-1992 and 1993-1997 improved from 45.4% to 48.6% (P < .001). The corresponding estimates show increases for non-clear cell epithelial carcinoma from 42.5% to 45.8% (P < .001), and for sarcomas from 33.5% to 38.8% (P = .07). However, improvements were not observed in those with clear cell, 64.3% to 63.9% (P = .82), and sex-cord stromal, 89.7% to 85.7% (P = .18), tumors of the ovary. In multivariable analyses, younger age, early stage, favorable histologic cell types, low-grade tumors, standard surgery, and recent time interval from 1993-1997 were independent prognostic factors for improved survival.

CONCLUSION

In this large population-based study, there has been some improvement in the overall survival of women with ovarian cancers during a 14-year period. However, new treatment strategies are warranted for those with epithelial cancer and sarcomas of the ovary, given their overall poor prognosis. These results from our updated analyses might help to counsel women diagnosed with ovarian cancers.

Uterine papillary serous and clear cell carcinomas predict for poorer survival compared to grade 3 endometrioid corpus cancers

To compare the survival of women with uterine papillary serous carcinoma (UPSC) and clear cell carcinoma (CC) to those with grade 3 endometrioid uterine carcinoma (G3EC). Demographic, pathologic, treatment, and survival information were obtained from the Surveillance, Epidemiology, and End Results Program from 1988 to 2001. Data were analysed using Kaplan–Meier and Cox proportional hazards regression methods. Of 4180 women, 1473 had UPSC, 391 had CC, and 2316 had G3EC cancers. Uterine papillary serous carcinoma and CC patients were older (median age: 70 years and 68 vs 66 years, respectively; P<0.0001) and more likely to be black compared to G3EC (15 and 12% vs 7%; P<0.0001). A higher proportion of UPSC and CC patients had stage III–IV disease compared to G3EC patients (52 and 36% vs 29%; P<0.0001). Uterine papillary serous carcinoma, CC and G3EC patients represent 10, 3, and 15% of endometrial cancers but account for 39, 8, and 27% of cancer deaths, respectively. The 5-year disease-specific survivals for women with UPSC, CC and G3EC were 55, 68, and 77%, respectively (P<0.0001). The survival differences between UPSC, CC and G3EC persist after controlling for stage I–II (74, 82, and 86%; P<0.0001) and stage III–IV disease (33, 40, and 54; P<0.0001). On multivariate analysis, more favourable histology (G3EC), younger age, and earlier stage were independent predictors of improved survival. Women with UPSC and CC of the uterus have a significantly poorer prognosis compared to those with G3EC. These findings should be considered in the counselling, treating and designing of future trials for these high-risk patients.

Outcomes of women with metachronous breast and ovarian carcinomas

INTRODUCTION

Women with a history of breast cancer have a significantly increased risk of developing a second primary ovarian cancer and vice versa. We proposed to determine the characteristics and outcomes of women diagnosed with metachronous breast and ovarian cancer.

METHODS

Patients were identified from the Surveillance, Epidemiology, and End Results program database between 1988 and 2001. Kaplan-Meier and Cox proportional hazards regression tests were used to determine survival outcomes.

RESULTS

Of 704 women, 526 developed breast cancer then ovarian cancer (B-O) and 178 developed ovarian cancer then breast cancer (O-B). The mean age at diagnosis of the first cancer in the B-O versus O-B group was 60.3 versus 58.9 years, respectively (P = 0.23). Twenty-five percent of women in the B-O group had stage I-II ovarian cancer versus 63% in the O-B group (P < 0.001). The percentage of those with stage I-II breast cancer was 94% and 91% in the B-O versus O-B group, respectively (P = 0.13). Women in the B-O group had more high grade of ovarian cancer compared to those in the O-B group (P < 0.001). The mean time interval between diagnoses of breast then ovarian versus ovarian then breast cancer was 58 versus 56 months, respectively (P = 0.42).

CONCLUSIONS

In the largest series to date, we found that women diagnosed with ovarian cancer first had significantly more early stage and lower grade ovarian cancers with better survival compared to those with breast cancer followed by ovarian cancer. Since half of the women had their second cancer beyond 5 years, continued surveillance of these high risk patients is recommended.

Histologic types of epithelial ovarian cancer: have they different risk factors?

OBJECTIVES

The histologic types of epithelial ovarian cancer differ in clinical behavior, descriptive epidemiology, and genetic origins. The goals of the current study were to characterize further the relation of histologic-specific ovarian cancer risks to reproductive and lifestyle attributes.

METHODS

The authors conducted a pooled analysis of 10 case-control studies of ovarian cancer in US White women, involving 1834 patients with invasive epithelial ovarian cancer (1067 serous, 254 mucinous, 373 endometrioid, and 140 clear cell) and 7484 control women.

RESULTS

Risks of all four histological types were inversely associated with parity and oral contraceptive use, but the histologic types showed different associations with nonreproductive factors. Unique associations include an inverse relation of serous cancer risk to body mass index, a positive relation of mucinous cancer risk to cigarette smoking, and a weakly positive relation of endometrioid cancer risk to body mass index. Risk of all histologic types was unassociated with age at menarche, age at menopause, a history of infertility, noncontraceptive estrogen use, and alcohol consumption.

CONCLUSIONS

The most important modifiers of ovarian cancer risk (parity and oral contraceptive use) showed similar associations across the histologies. Nevertheless, the unique associations seen for other modifiers support the conjecture that the histologic types of epithelial ovarian cancer have different etiologies, which should be addressed in future investigations of the molecular basis of ovarian cancers and their responses to therapies.