Recent advances in the understanding of the pathogenesis of serous carcinoma: the concept of low- and high-grade disease and the role of the fallopian tube

Recurrence Rate and Associated Factors of Primary Fallopian Tube Carcinoma in the South of Vietnam

Objectives

This study aimed to determine the recurrence rate and related risk factors of primary fallopian tube cancer (PFTC).

Materials and Methods

We conducted a retrospective study of 47 patients with histopathological diagnosis of PFTC treated at Tu Du Hospital between January 1, 2015, and July 31, 2022. The cumulative recurrence rate was estimated using the life table method, and recurrence-associated factors were determined using the Log-rank test and Cox proportional hazard model.

Results

The median follow-up period was 40 months (range, 7-96 months). Eight patients (17.0%) experienced recurrence. The cumulative recurrence rate of PFTC patients at 12 months was 4.4% (95% confidence interval [95% CI]: 1.12-16.45), at 24 months was 9.1% (95% CI: 3.52-22.5), at 36 months was 14.9% (95% CI: 6.92-30.41), at 48 months was 19.3% (95% CI: 9.35-37.24), and at 60 months was 25.7% (95% CI: 12.68-47.88). A higher recurrence rate was significantly associated with elevated pretreatment CA 125 level (<35 U/mL vs. ≥35 U/mL, hazards ratio [HR] = 36.9, 95% CI: 1.47-921.37), advanced FIGO stages (Stage I-II vs. stages III, HR = 6.61, 95% CI: 1.18-36.93), and suboptimal debulking surgery (residual disease ≤1 cm vs. residual disease >1 cm, HR = 7.52, 95% CI: 1.47-38.49).

Conclusion

The overall recurrence rate of PFTC patients in Southern Vietnam was 17.0%. Appropriate follow-up strategies for patients with high-risk factors are needed for early detection and management of recurrence.

The incidence of occult ovarian neoplasia and cancer in BRCA1/2 mutation carriers after the bilateral prophylactic salpingo-oophorectomy (PBSO): A single-center prospective study

BACKGROUND

Due to ineffective ovarian cancer (OC) screening programs, prophylactic bilateral salpingo-oophorectomy (PBSO) is suggested for BRCA1/2 genes mutation carriers. The reported incidence of clinically occult neoplasia and OC detected during PBSO varies widely (2-17 %), reflecting differences in studies design.

OBJECTIVE

We aimed to prospectively evaluate the incidence of occult neoplasia in specimens collected during PBSO performed in a single tertiary center and to determine the effectiveness of this procedure in BRCA1/2 mutation carriers.

STUDY DESIGN

Between January 2010 and October 2016 a total of 564 new germline BRCA1/2 mutation positive women were identified and 71 carriers underwent laparoscopic PBSO. Patients were prospectively followed-up after the surgery and data on operation, age, complications, histological reports and BRCA1/2 gene mutation types were collected and analyzed.

RESULTS

Serous tubal intraepithelial carcinoma (STIC) was diagnosed in 7 (9.85 %) and OC in 4 (5.6 %) women (one advanced (FIGO IIIC) and 3 early (FIGO IA/C) stages); total incidence 15.5 %. Women's mean age at the time of surgery was 46.5 years. The mean age of women diagnosed with STIC and OC was 45.9 years (42-64). The mean follow up time for women being diagnosed with OC/STIC was 3.72 years; no recurrence was observed. The median time to perform laparoscopic PBSO was 43 min. (ranging from 25 to 65 min.), no surgical complications occurred during this operation. Interestingly, we found statistically significant (P = 0.0105) enrichment of STIC lesions in BRCA1 c.4035delA (an established Baltic founder mutation) carriers group.

CONCLUSION

The incidence of pathological findings in BRCA1/2 mutation carries after PBSO is sufficiently high and our prospective study data supports PBSO as the most effective measure for reducing the risk of OC in BRCA1/2 mutation carriers. A novel finding of the enrichment of STIC lesions in BRCA1 c.4035delA carriers may show important biological differences in OC tumorigenesis between different BRCA1 mutations, which warrant further investigations.

Life Cycle Assessment of an On-Road Dynamic Charging Infrastructure

On road dynamic charging represents a possible solution for the electrification of the transport sector and eventually, for its decarbonisation. However, only a few studies have evaluated the environmental impact of this technology. A detailed life cycle assessment (LCA) of charging infrastructure is missing. This study is a life cycle assessment of the construction and maintenance of an electrified road (e-road) equipped with dynamic wireless power transfer technology (DWPT). The data from an e-road tested in a test site in Susa (Italy) have been adapted for motorway applications. The results show the relevance of wireless power transfer components compared to traditional components and materials. The wireless power transfer (WPT) component production in fact accounts for more than 70% of the impacts in the climate change category, even though it represents less than 1% weight. Maintenance is the phase with the highest impact due to the structural features of the e-road. However, there is considerable uncertainty about this value which still requires further refinement when more data from e-road monitoring are available.

Pathogenesis, Genetics, and Genomics of Non-High Grade Serous Ovarian Cancers

The 5 main non-high grade serous epithelial ovarian cancers (clear cell, low grade endometrioid, low grade serous, mucinous, and carcinosarcoma) are discrete in terms of their pathogenesis, molecular biology, and treatment sensitivity. This article reviews the current understanding of their pathogenesis and molecular biology, highlighting areas of uncertainty where future research efforts should be focused.

Management Strategies for the Ovaries at the Time of Hysterectomy for Benign Disease

Gynecologists performing hysterectomy for benign disease must universally counsel women about ovarian management. The beneficial effect of elective bilateral salpingo-oophorectomy (BSO) on incident ovarian and breast cancer and elimination of need for subsequent adnexal surgery must be weighed against the risks of ovarian hormone withdrawal. Ovarian conservation rates have increased significantly over the past 15 years. In postmenopausal women, however, BSO can reduce ovarian and breast cancer rates without an adverse impact on coronary heart disease, sexual dysfunction, hip fractures, or cognitive function.

Incidence and Characteristics of Unsuspected Neoplasia Discovered in High-Risk Women Undergoing Risk Reductive Bilateral Salpingooophorectomy

OBJECTIVE

Risk reducing salpingooophorectomy is recommended to women with a BReast CAncer susceptibility gene (BRCA) 1 or 2 germline mutation to reduce the risk of ovarian cancer. The incidence of unsuspected neoplasia varies in the literature. The purpose of this study was to identify the rate of unsuspected neoplasia in a high-risk Australian population, discuss their management, and assess the clinical outcome.

METHOD

This is a retrospective review of all women undergoing risk reductive salpingooophorectomy between January 2006 and December 2014. The medical, operative, and pathology results were reviewed. The specimens were assessed using the Sectioning and Extensively Examining the Fimbriated End protocol to the fallopian tube, and the ovary was also examined using 2 to 3 mm sectioning.

RESULTS

During the study period, 138 patients underwent risk-reducing salpingooophorectomy for a known BRCA 1 or 2 germline mutation or a high-risk personal or family history of ovarian cancer. Five patients with neoplasia were identified, 2 with invasive tubal carcinoma and 3 with serous tubal intraepithelial carcinoma (STIC), giving an overall incidence of 3.62%. Invasive tubal carcinoma occurred in 1 woman with a BRCA 1 mutation and 1 woman with a BRCA 2 mutation. The incidence of carcinoma in women with either a BRCA 1 or 2 germline mutation was subsequently 2.78%. STIC occurred in 2 women with a BRCA 1 germline mutation and 1 woman carrying a BRCA 2 germline mutation. The incidence of STIC in women with either a BRCA 1 or 2 germline mutation was subsequently 4.17%. Of the patients with STIC, all 3 remain disease free at an average follow-up period of 79.33 months.

CONCLUSIONS

In this retrospective review, we found the incidence of neoplasia within a high-risk Australian population undergoing risk-reducing bilateral salpingo-oophorectomy to be 3.62%. The incidence of STIC was 2.17%. During our follow-up period, all patients with STIC remained disease free.

Low-grade serous ovarian cancer: A review

Epithelial ovarian cancers can be divided into the more common, aggressive type II cancers and the less common, slow-growing type I cancers. Under this model, serous ovarian carcinomas can be subdivided into high-grade (type II) and low-grade (type I) tumours. The two-tier system for grading serous ovarian carcinomas is superior to more detailed grading systems in terms of predicting survival. Low-grade serous carcinomas typically present in young women and have a relatively good prognosis, despite being resistant to chemotherapy. Low-grade serous cancers have a high prevalence of KRAS and BRAF mutations, but a low prevalence of TP53 mutations (which are characteristic of high-grade serous cancers). Among women with low-grade serous ovarian cancer, the presence of a KRAS/BRAF mutation is a favorable prognostic factor. Studies of the mitogen-activated protein kinase (MAPK) inhibitor in low-grade serous ovarian cancer suggest that identifying MAPK mutations might eventually be useful in guiding treatment.

A survival analysis comparing women with ovarian low-grade serous carcinoma to those with high-grade histology

Ovarian low-grade serous carcinoma (LGSC) and high-grade serous carcinoma have distinct molecular profiles, clinical behaviors, and treatment responses. The survival advantage for patients with low-grade carcinoma compared with patients with high-grade histology remains controversial. We retrospectively reviewed the medical charts of 381 patients with ovarian serous carcinoma at Peking Union Medical College Hospital from 2007 to 2010. Patients were classified into two groups according to MD Anderson two-tier system: 35 (9.2%) cases with LGSC and 346 with high-grade serous carcinoma. Patients with low-grade serous ovarian cancer had a significantly younger age at diagnosis (46 versus 56 years, P=0.046), and their median progression-free survival (PFS) and overall survival values were 35.0 and 54.0 months, respectively. A multivariate analysis showed that, for serous ovarian cancer, the histological grade was a significant prognostic factor for PFS but not for overall survival (P=0.022 and P=0.0566, respectively). When stratified by the existence of a residual disease, patients with low-grade disease who underwent cytoreductive surgery without macroscopic residual disease (>1 cm) had a significantly improved median PFS time (36.0 months) compared with that of patients with high-grade carcinoma who received optimal cytoreductive surgery (16.0 months, P=0.017). Conversely, patients with low-grade and high-grade carcinoma who were left with macroscopic residue (>1 cm) experienced a similarly shorter median PFS (10.0 and 13.0 months, respectively, P=0.871). The International Federation of Gynecology and Obstetrics stage and residual disease were significant prognostic factors of low-grade carcinoma, while positive ascites was associated with a worse PFS value. Our data showed that LGSC is a different entity from high-grade carcinoma and that LGSC was associated with improved PFS after optimal cytoreductive surgery but not suboptimal operation.

Ovarian carcinoma histotype determination is highly reproducible, and is improved through the use of immunohistochemistry

AIMS

To assess the variation in ovarian carcinoma type diagnosis among gynaecological pathologists from Nordic countries, and whether a rationally designed panel of immunohistochemical markers could improve diagnostic reproducibility.

METHODS AND RESULTS

Eight pathologists from four countries (Sweden, Denmark, Norway, and Finland) received an educational lecture on the diagnosis of ovarian carcinoma type. All tumour-containing slides from 54 ovarian carcinoma cases were independently reviewed by the participants, who: (i) determined type purely on the basis of histology; (ii) indicated whether they would apply immunohistochemistry in their routine practice; and (iii) determined type after reviewing the staining results. The results for six markers (WT1, p53, p16, HNF-1β, ARID1A, and progesterone receptor) were determined for all 54 cases, by staining of a tissue microarray. The median concordance with central review diagnosis was 86%, and significantly improved to 90% with the incorporation of immunostaining results (P = 0.0002). The median interobserver agreement was 78%, and significantly improved to 85% with the incorporation of immunostaining results (P = 0.0002).

CONCLUSIONS

Use of the immunostaining results significantly improved both diagnostic accuracy and interobserver agreement. These results indicate that ovarian carcinoma type can be reliably diagnosed by pathologists from different countries, and also demonstrate that immunohistochemistry has an important role in improving diagnostic accuracy and agreement between pathologists.

Outcome of unexpected adnexal neoplasia discovered during risk reduction salpingo-oophorectomy in women with germ-line BRCA1 or BRCA2 mutations

OBJECTIVE

This study computed the risk of clinically silent adnexal neoplasia in women with germ-line BRCA1 or BRCA2 mutations (BRCA(m+)) and determined recurrence risk.

METHODS

We analyzed risk reduction salpingo-oophorectomies (RRSOs) from 349 BRCA(m+) women processed by the SEE-FIM protocol and addressed recurrence rates for 29 neoplasms from three institutions.

RESULTS

Nineteen neoplasms (5.4%) were identified at one institution, 9.2% of BRCA1 and 3.4% of BRCA2 mutation-positive women. Fourteen had a high-grade tubal intraepithelial neoplasm (HGTIN, 74%). Mean age (54.4) was higher than the BRCA(m+) cohort without neoplasia (47.8) and frequency increased with age (p < 0.001). Twenty-nine BRCA(m+) patients with neoplasia from three institutions were followed for a median of 5 years (1-8 years.). One of 11 with HGTIN alone (9%) recurred at 4 years, in contrast to 3 of 18 with invasion or involvement of other sites (16.7%). All but two are currently alive. Among the 29 patients in the three institution cohort, mean ages for HGTIN and advanced disease were 49.2 and 57.7 (p = 0.027).

CONCLUSIONS

Adnexal neoplasia is present in 5-6% of RRSOs, is more common in women with BRCA1 mutations, and recurs in 9% of women with HGTIN alone. The lag in time from diagnosis of the HGTIN to pelvic recurrence (4 years) and differences in mean age between HGTIN and advanced disease (8.5 years) suggest an interval of several years from the onset of HGTIN until pelvic cancer develops. However, some neoplasms occur in the absence of HGTIN.

Precursors and pathogenesis of ovarian carcinoma

The ultimate goal of defining cancer specific precursors is to facilitate early detection and intervention before the development of invasive malignancy. Unlike other malignancies involving the female genital tract such as cervical or endometrial carcinomas, precursor lesions of ovarian carcinomas have not been well characterised, resulting in a failure to develop effective screening programs. Recent clinicopathological and molecular studies have provided new insight into the origin and pathogenesis of ovarian carcinomas. It has been shown that ovarian cancer is comprised of different tumour types differing not only in morphology, but also in pathogenesis, molecular alterations and clinical progression. A dualistic model of ovarian carcinogenesis has been proposed. Type I tumours which include low grade serous, low grade endometrioid, clear cell, mucinous carcinomas and Brenner tumours, are generally indolent and tend to be genetically stable, although clear cell carcinoma would probably belong to an intermediate category. They demonstrate a step-wise progression from a benign precursor such as a benign to borderline tumour or endometriosis and are characterised by genetic aberrations targeting specific cell signalling pathways. Type II tumours comprise high grade serous, high grade endometrioid, and undifferentiated carcinomas as well as malignant mixed mesodermal tumours. They are clinically aggressive and exhibit high genetic instability with frequent p53 mutations. Mounting evidence suggests that many high grade serous carcinomas originate from the epithelium of the distal fallopian tube, and that serous tubal intraepithelial carcinoma (STIC) represents the putative precursor of these neoplasms. Low grade serous carcinomas arise via transformation of benign and borderline serous tumours, thought to be derived from inclusion cysts originating from the ovarian surface or tubal epithelium. Recently it has been suggested that papillary tubal hyperplasia may be a putative precursor lesion for serous borderline tumours. Both endometrioid and clear cell carcinomas develop from endometriosis, via alterations affecting different genetic pathways. The origin of mucinous and transitional cell neoplasms is not well characterised, although new data suggest a possible origin from transitional cell nests present at the tubal-mesothelial junction. Likewise, the pathogenesis of carcinosarcomas is also not well established because of their rarity but there is accumulating evidence that the carcinomatous component determines the course of the disease and gives rise to the malignant mesenchymal component. This review discusses recent developments in the pathogenesis of ovarian carcinoma, with particular emphasis on the putative precursor lesions that give rise to the major histological subtypes. Recognition of these lesions is not only important in improving the understanding of ovarian carcinogenesis, but it will also influence our approach to prevent, detect and treat these tumours.

Ovarian cancer incidence trends in relation to changing patterns of menopausal hormone therapy use in the United States

PURPOSE

After a report from the Women's Health Initiative (WHI) in 2002, a precipitous decline in menopausal hormonal therapy (MHT) use in the United States was linked to a decline in breast cancer incidence rates. Given that MHT use is also associated with increased ovarian cancer risk, we tested whether ovarian cancer incidence rates changed after 2002.

METHODS

Using the North American Association of Central Cancer Registries database (1995 to 2008; N = 171,142 incident ovarian cancers), we applied standard analytic approaches and age-period-cohort (APC) models to estimate ovarian cancer incidence rate changes before (1995 to 2002) and after (2003 to 2008) the WHI report.

RESULTS

Among women age ≥ 50 years, age-standardized ovarian cancer incidence declined by 0.8% per year (95% CI, -1.8% to -0.5% per year) before the WHI announcement; after the WHI report, the rate declined by 2.4% per year (95% CI, -2.5% to -2.2% per year). APC models confirmed an accelerated decline in ovarian cancer incidence after the WHI report, adjusted for age and birth cohort effects. This sudden change was notable among women most likely to have used MHT (ie, women age 50 to 69 years, white women, and residents of regions with highest MHT prescription frequency). The largest changes were found for the endometrioid histologic subtype.

CONCLUSION

After a marked reduction in MHT use around 2002, ovarian cancer incidence rates demonstrated an accelerated decline, with the largest changes for endometrioid carcinomas. This strong temporal association, although not proving a causal role of hormones in ovarian carcinogenesis, suggests that future analytic research supporting cancer control efforts should clarify the role of hormonal exposures on the development and behavior of subtypes of ovarian cancer.

Long term follow up of BRCA1 and BRCA2 mutation carriers with unsuspected neoplasia identified at risk reducing salpingo-oophorectomy

OBJECTIVES

The reported incidence of neoplasia identified at the time of risk-reducing salpingo-oophorectomy (RRSO) in germline BRCA1/2 mutation carriers ranges from 4 to 12% but long-term outcomes have not been described. We evaluated recurrence and survival outcomes of mutation carriers with neoplastic lesions identified at RRSO.

METHODS

We identified BRCA1/2 mutation carriers with neoplasia at RRSO at three institutions. Data was collected on clinical variables, adjuvant treatment and follow-up.

RESULTS

We identified 32 mutation carriers with invasive carcinomas (n=15) or high-grade intraepithelial neoplasia (n=17) that were not suspected prior to surgery. 26 occurred in BRCA1 and 6 in BRCA2 mutation carriers. Median and mean age for carcinomas were 50 years and 49.3 respectively, significantly younger than for intraepithelial neoplasm, median 53 years, and mean 55 years (p=0.04). For the 15 invasive carcinomas, median follow up was 88 months (range 45-172 months), 7 recurred (47%), median time to recurrence was 32.5 months and 3 have died of disease; 1 additional patient died of breast cancer. Overall survival was 73%, disease specific overall survival was 80% and disease free survival was 66%. For the 17 high-grade intraepithelial neoplasms, median follow up was 80 months (range 40-150), 4 were treated with chemotherapy. One recurred at 43 months and is currently not on therapy with a normal CA125, 16 months later. All patients with noninvasive neoplasia are alive.

CONCLUSIONS

BRCA1 and BRCA2 mutation carriers with unsuspected invasive carcinoma at RRSO have a relatively high rate of recurrence despite predominantly early stage, small volume disease. High-grade intraepithelial neoplasms rarely recur as carcinoma and may not require adjuvant chemotherapy.

Identification of multiple pathways involved in the malignant transformation of endometriosis (Review)

The association between endometriosis and malignant transformation has often been described in the medical literature. A search was conducted between 1966 and 2010 through the English language literature (online Medline PubMed database) using the keywords endometriosis combined with malignant transformation. The search revealed an increase in reports describing endometriosis and malignancy. Approximately 1.0% of women with endometriosis have lesions that undergo malignant transformation. The malignant processes that are associated with endometriosis may be classified into three groups: i) epithelial ovarian cancers (endometrioid adenocarcinoma and clear cell carcinoma), ii) other Müllerian-type tumors, including Müllerian-type mucinous borderline tumor and serous borderline tumor and iii) sarcomas such as adenosarcoma and endometrial stromal sarcoma in the female pelvic cavity. Persistent oxidative stress induced by endometriosis-dependent hemorrhage may be associated with carcinogenesis. In conclusion, the malignant transformation of endometriosis has multiple pathways of development and may share a common pathogenic mechanism; iron-induced oxidative stress derived from repeated hemorrhage.

Ovarian cancer risk factors by histologic subtypes in the NIH-AARP Diet and Health Study

Data suggest that risk factors for ovarian carcinoma vary by histologic type, but findings are inconsistent. We prospectively evaluated risk factors by histological subtypes of incident ovarian cancer (n = 849) in a cohort of 169,391 women in the NIH-AARP Diet and Health Study. We constructed Cox models of individual exposures by comparing case subtypes to the entire non-case group and assessed p-heterogeneity in case-case comparisons using serous as the reference category. Substantial risk differences between histologic subtypes were observed for menopausal hormone therapy (MHT) use, oral contraceptive (OC) use, parity and body mass index (p-heterogeneity = 0.01, 0.03, 0.05, 0.03, respectively). MHT users were at increased risk for all histologic subtypes except for mucinous carcinomas, where risk was reduced (relative risk (RR) = 0.37; 95% confidence interval (CI): 0.18, 0.80). OC users were only at significantly decreased risk for serous cancers (RR = 0.69; 95% CI: 0.55, 0.85). Although parity was inversely associated with risk of all subtypes, the RRs ranged from 0.28 (clear cell) to 0.83 (serous). Obesity was a significant risk factor only for endometrioid cancers (RR = 1.64; 95% CI: 1.00, 2.70). Our findings support a link between etiological factors and histological heterogeneity in ovarian carcinoma.

Copy number aberrations in benign serous ovarian tumors: a case for reclassification?

PURPOSE

Serous ovarian carcinomas are the predominant epithelial ovarian cancer subtype and it has been widely believed that some or all of these may arise from precursors derived from the ovarian surface epithelium or fimbriae, although direct molecular evidence for this is limited. This study aimed to conduct copy number (CN) analysis using a series of benign and borderline serous ovarian tumors to identify underlying genomic changes that may be indicative of early events in tumorigenesis.

EXPERIMENTAL DESIGN

High resolution CN analysis was conducted on DNA from the epithelial and fibroblast components of a cohort of benign (N = 39) and borderline (N = 24) serous tumors using the Affymetrix OncoScan assay and SNP6.0 arrays.

RESULTS

CN aberrations were detected in the epithelium of only 2.9% (1 of 35) of serous cystadenomas and cystadenofibromas. In contrast, CN aberrations were detected in the epithelium of 67% (16 of 24) of the serous borderline tumors (SBT). Unexpectedly, CN aberrations were detected in the fibroblasts of 33% (13 of 39) of the benign serous tumors and in 15% (3 of 20) of the SBTs. Of the 16 cases with CN aberrations in the fibroblasts, 12 of these carried a gain of chromosome 12.

CONCLUSIONS

Chromosome 12 trisomy has been previously identified in pure fibromas, supporting the concept that a significant proportion of benign serous tumors are in fact primary fibromas with an associated cystic mass. This is the first high resolution genomic analysis of benign serous ovarian tumors and has shown not only that the majority of benign serous tumors have no genetic evidence of epithelial neoplasia but that a significant proportion may be more accurately classified as primary fibromas.

The 'incessant menstruation' hypothesis: a mechanistic ovarian cancer model with implications for prevention

Serous, endometrioid, clear cell and mucinous histotypes are the most common epithelial ovarian cancer. Most serous cancers appear to originate from precursor lesions at the fimbriated tubal end, whereas most endometrioid and clear cell cancers seem to derive from atypical endometriosis. Data regarding hormonal factors and associated gynaecologic conditions were critically analysed with the objective of defining a carcinogenic model for sporadic epithelial ovarian cancer complying with epidemiologic and pathologic findings. Oral contraceptives and tubal ligation substantially reduce the risk of serous, endometrioid and clear cell subgroups, but have no significant effect on mucinous tumours, which probably follow a different oncogenic pathway. We hypothesize that serous, endometrioid and clear cell cancers share a common pathogenic mechanism, i.e. iron-induced oxidative stress derived from retrograde menstruation. Fimbriae floating in bloody peritoneal fluid are exposed to the action of catalytic iron and to the genotoxic effect of reactive oxygen species, generated from haemolysis of erythrocytes by pelvic macrophages. This would explain the distal site of tubal intraepithelial neoplasia. Collection of blood inside endometriomas would lead to the same type of genotoxic insult on gonadal endometrial implants. This would explain why endometriosis-associated cancers develop much more frequently in the ovary than at extragonadal sites. In women not seeking conception, bilateral salpingectomy could be advised whenever planning surgery for independent indications, thus possibly reducing cancer risk, while preserving ovarian function. The use of oral contraceptives should be favoured for prolonged periods of time, especially in women with endometriosis, a population at doubled risk of gonadal malignancy.