Underlying mechanisms of ovarian cancer risk reduction after tubal ligation

Contraceptive strategies for reducing the risk of reproductive cancers

Reproductive cancers, encompassing various malignancies like endometrial, ovarian, cervical cancer, and gestational trophoblastic neoplasia, pose a significant global health burden. Understanding their patterns is vital for effective prevention and management. Contraceptives show a protective effect against some of these cancers. This clinical guidance document aims to elucidate the disease burden of reproductive cancers and the evidence supporting contraceptive methods in prevention and management. Regional disparities in incidence and mortality highlight the urgent need for targeted interventions, particularly in low-resource settings. Healthcare providers must weigh individual risk profiles and medical eligibility criteria when discussing contraceptive options. Enhanced health literacy through direct patient education is essential for leveraging low-cost behavioral interventions to mitigate reproductive cancer risks.

Risk of ovarian cancer after salpingectomy and tubal ligation: Prospects on histology and time since the procedure

OBJECTIVE

Recent theories propose that most epithelial ovarian cancer (EOC), depending on histological type, originate from other gynecological tissues and involve the ovary secondarily. According to these theories, any protective effect of salpingectomy and tubal ligation may vary by histological type. The study aim was to examine the association between salpingectomy and tubal ligation, respectively, and risk of EOC, with a focus on associations specific for histological types.

METHODS

We identified EOC cases and matching controls in national registries and gathered information on surgical procedures and potential confounders. Conditional logistic regression was used to estimate odds ratio (OR) with 95% confidence interval (CI) of EOC related to salpingectomy and tubal ligation, respectively, overall and stratified by histological type. Furthermore, we investigated the association according to timing of the procedures.

RESULTS

Our study comprised 16,822 EOC cases. Each case was matched with 40 controls. There was an overall EOC risk reduction after unilateral (OR = 0.73; 95% CI: 0.60-0.87) and bilateral salpingectomy (OR = 0.46; 95% CI: 0.31-0.67). A slight risk reduction was seen among women with previous tubal ligation (OR = 0.91; 95% CI: 0.83-0.99). For salpingectomy, the risk reduction increased with increasing time since the surgical procedure and was only present among women younger than 50 years at salpingectomy. Unilateral and bilateral salpingectomy was associated with a risk reduction for most histological types.

CONCLUSION

The association between previous salpingectomy and reduced risk of several histological subtypes of EOC supports the suggested theories about the site of origin of EOC and may be of clinical importance.

Hysterectomy With and Without Oophorectomy, Tubal Ligation, and Risk of Cardiovascular Disease in the Nurses' Health Study II

Background: Hysterectomy, oophorectomy, and tubal ligation are common surgical procedures. The literature regarding cardiovascular disease (CVD) risk after these surgeries has focused on oophorectomy with limited research on hysterectomy or tubal ligation. Materials and Methods: Participants in the Nurses' Health Study II (n = 116,429) were followed from 1989 to 2017. Self-reported gynecologic surgery was categorized as follows: no surgery, hysterectomy alone, hysterectomy with unilateral oophorectomy, and hysterectomy with bilateral oophorectomy. We separately investigated tubal ligation alone. The primary outcome was CVD based on medical-record confirmed fatal and nonfatal myocardial infarction, fatal coronary heart disease, or fatal and nonfatal stroke. Our secondary outcome expanded CVD to include coronary revascularization (coronary artery bypass graft surgery, angioplasty, stent placement). Cox proportional hazard models were used to calculate hazard ratios (HR) and 95% confidence intervals (CIs) and were adjusted a priori for confounding factors. We investigated differences by age at surgery (≤50, >50) and menopausal hormone therapy usage. Results: At baseline, participants were on average, 34 years old. During 2,899,787 person-years, we observed 1,864 cases of CVD. Hysterectomy in combination with any oophorectomy was associated with a greater risk of CVD in multivariable-adjusted models (HR hysterectomy with unilateral oophorectomy:1.40 [95% CI: 1.08-1.82]; HR hysterectomy with bilateral oophorectomy:1.27 [1.07-1.51]). Hysterectomy alone, hysterectomy with oophorectomy, and tubal ligation were also associated with an increased risk of combined CVD and coronary revascularization (HR hysterectomy alone: 1.19 [95% CI: 1.02-1.39]; HR hysterectomy with unilateral oophorectomy: 1.29 [1.01-1.64]; HR hysterectomy with bilateral oophorectomy: 1.22 [1.04-1.43]; HR tubal ligation: 1.16 [1.06-1.28]). The association between hysterectomy/oophorectomy and CVD and coronary revascularization risk varied by age at gynecologic surgery, with the strongest association among women who had surgery before age 50 years. Conclusion: Our findings suggest that hysterectomy, alone or in combination with oophorectomy, as well as tubal ligation, may be associated with an increased risk of CVD and coronary revascularization. These findings extend previous research finding that oophorectomy is associated with CVD.

An exceptional case of degenerative endometriosis of the uterine torus

There are less than ten cases of deep endometriosis degeneration in the literature. The duration of endometriosis, the ovarian stimulation, the perimenopause and the obesity exposes the woman to an increased risk of endometriosis degeneration.

Risk-Reducing Options for High-Grade Serous Gynecologic Malignancy in BRCA1/2

Ovarian cancer (OC) is the leading cause of death among women with gynecologic malignancy. Breast Cancer Susceptibility Gene 1 (BRCA 1) and Breast Cancer Susceptibility Gene 2 (BRCA 2) germline mutations confer an estimated 20 to 40 times increased risk of OC when compared to the general population. The majority of BRCA-associated OC is identified in the late stage, and no effective screening method has been proven to reduce mortality. Several pharmacologic and surgical options exist for risk-reduction of gynecologic malignancy in BRCA 1/2 mutation carriers. This review summarizes up-to-date research on pharmacologic risk-reducing interventions, including the oral contraceptive pill, acetylsalicylic acid/nonsteroidal anti inflammatory drugs (ASA/NSAID) therapy, and denosumab, and surgical risk-reducing interventions, including risk-reducing bilateral salpingo-oophorectomy, salpingectomy with delayed oophorectomy, and hysterectomy at the time of risk-reducing bilateral salpingo-oophorectomy.

What are the mechanisms of action of the different contraceptive methods to reduce the risk of ovarian cancer?

OBJECTIVE

Ovarian cancer (OvCa) is the deadliest gynaecologic malignancy. Knowing that OvCa, as a disease, has different origins has allowed us to relate them to the mechanisms of action of different contraceptive methods with the aim of evaluating the possibility of their use in reducing risk.

STUDY DESIGN

This commentary review article will instead focus on the recent findings on the role of contraceptive methods in preventing of OvCa.

RESULTS

Combined hormonal contraceptive (CHC) use is an effective method of chemoprevention for OvCa in the general population and in women with genetic disorders. Salpingectomy, better than tubal ligation, should be offered for ovarian/tubal/peritoneal cancer prevention. Progestogen-only methods can decrease the risk of OvCa via reduced menstrual bleeding and by changes in the hormonal environment that surrounds the ovary. IUDs of any type, through different mechanisms, decrease the risk of OvCa. Barrier methods prevent the passage of germs into the tubes and ovaries and the inflammatory state they produce.

CONCLUSIONS

Most contraceptive methods have a mechanism of action that may favour a reduction in the risk of OvCa. The theories of incessant ovulation, retrograde menstruation, and that the fallopian tubes are the site of origin of a proportion of high-grade serous OvCa, have led to the recommendation that anovulatory methods, those that decrease menstrual bleeding, and those that blocked tubes, or even better, 'opportunistic salpingectomy' are a current approach to prevent OvCa in the population general and, above all, in the population at risk.

Repeated hyperstimulation affects the ultrastructure of mouse fallopian tube epithelium

Controlled ovarian hyperstimulation (COH) is routinary used in assisted reproductive technologies (ARTs) to increase the yields of mature oocytes. The possibility that patients with a history of failures or poor-responders may develop side-effects following these treatments is still debated. Epidemiological studies reported controversial results about pregnancy outcome and the risk of developing gynecological cancers. By using a mouse model, here we compared the ultrastructural features of fallopian tubes (FTs) obtained from mice undergoing or not (control, CTR) four (4R) and eight (8R) rounds of gonadotropin stimulation. Although the morphological characteristics of oviductal layers seemed unaffected by repeated treatments, dose-response ultrastructural alterations in the ampulla appeared in the 4R group and even more in the 8R group. The targets were oviductal ciliated (CCs) and non-ciliated (NCCs) cells, which showed damaged mitochondria and glycogen accumulations in the cytoplasm. The drastic reduction of CCs, evident after 4R, was supported by the absence of cilia. After 8R, glycogen granules were significantly reduced and massive degeneration of mitochondria, which appeared swollen and/or vacuolated, occurred in NCCs. Moreover, disintegrated mitochondria were found at the periphery of mitophagic vacuoles with evident signs of cristolysis. The morphometric analysis evidenced a significant increase in the density and frequency of damaged mitochondria after 4R and 8R. The absence of cilia, necessary to sustain oviductal transport of oocytes, spermatozoa and embryos, may originate from either mitochondrial dysfunction or glycogen consumption. These results suggest that repeated COH treatments could induce alterations impairing fertilization and embryo transport toward the uterus.

Hysterectomy and unilateral salpingectomy associate with a higher risk of subsequent ovarian cancer: A population-based cohort study in Taiwan

Studies on the relationship between gynecologic surgery and subsequent ovarian cancer have been carried out in limited Western ethnic groups. We aim to evaluate whether receiving hysterectomy and/or salpingectomy associated with ovarian cancer risk in Taiwan.From the Taiwan National Health Insurance Research Database, we identified a gynecologic surgery cohort consisting of women who had newly received hysterectomy (N = 181,151), salpingectomy (N = 45,410) or both hysterectomy and salpingectomy (N = 11,875) in 2000 to 2013. A comparison cohort of 953,744 women was randomly selected from women without the surgeries, frequency-matched by age and index date of the surgery case. They were followed up to identify subsequent ovarian cancer by the end of 2013.The overall ovarian cancer incidence was 4.4-fold greater in the gynecologic surgery cohort than in the comparison cohort (41.5 vs 9.43 per 10 person-years) with an adjusted hazard ratio of 3.86 (95% confidence interval = 2.56-5.84). Women with both hysterectomy and salpingectomy had the highest incidence and followed by women with hysterectomy or salpingectomy (52.5, 45.5, or 23.3 per 10 person-years, respectively). No ovarian cancer was noted in the subgroup with bilateral salpingectomies.We conclude that women with gynecologic surgery of hysterectomy and/or salpingectomy are at an increased risk of developing ovarian cancer, particularly among women who have had other gynecologic comorbidity. Women with gynecologic surgery and comorbidity deserve greater attention to prevent and screen for ovarian cancer.

Contraception options for patients with known hereditary risk for ovarian cancer

For patients with a known hereditary risk of ovarian cancer, primary prevention typically is accomplished through prophylactic bilateral salpingo-oophorectomy. However, some patients may wish to preserve fertility or delay menopause and its associated comorbidities. This article discusses appropriate methods of contraception for these patients.

Tubal Ligation and Age at Natural Menopause

OBJECTIVE

To determine the effect of tubal ligation on age at natural menopause, as a marker of long-term ovarian function.

METHODS

Three preexisting population-based cohorts were included in this cross-sectional study. Data from each cohort was analyzed separately. The cohorts were restricted to women who never smoked and had reached natural menopause, without prior hysterectomy or oophorectomy. The following variables were collected: race, age at menarche, age at menopause, history of hysterectomy or oophorectomy, gravidity and parity, tobacco use, and ever use of hormonal contraception. The type of tubal ligation and age at tubal ligation were manually abstracted in cohort 1. For cohorts 2 and 3, history of tubal ligation was obtained from an institutional form, completed by patient report. The primary outcome, age at natural menopause, was compared between the two groups (those with and without a history of tubal ligation).

RESULTS

Inclusion criteria was met by 555 women from cohort 1, 1,816 women from cohort 2, and 1,534 women from cohort 3. Baseline characteristics did not differ between cohorts. The percentage with tubal ligation was the same in all cohorts: 26.0%, 25.5%, and 25.0%, respectively. Women with a tubal ligation were more likely to have had at least one pregnancy and to have used hormonal contraception compared with women without a tubal ligation. There was no significant difference in age at natural menopause in women who underwent tubal ligation (50.1, 49.9, 50.0 years, respectively) compared with those who did not (50.7, 49.6, 50.0 years, respectively). The type of tubal ligation (cohort 1 only) had no effect on age at menopause.

CONCLUSIONS

Tubal ligation did not affect age at natural menopause in the three large cohorts included in this study.

Ovarian cancer in the world: epidemiology and risk factors

Aim: Ovarian cancer is one of the most common gynecologic cancers that has the highest mortality rate. Considering the fact that knowledge on the incidence, mortality of ovarian cancer, as well as its risk factors is necessary for planning and preventing complications, this study was conducted with the aim of examining the epidemiology and risk factors of ovarian cancer in the world.

Materials and methods: In order to access the articles, Medline, Web of Science Core Collection, and Scopus databases were searched from their start to the year 2018. Full-text, English observational studies that referred to various aspects of ovarian cancer were included in the study.

Results: In total, 125 articles that had been published during the years 1925–2018 were entered into the study. Ovarian cancer is the seventh most common cancer among women. Increased risk factors of cancer have led to an upward trend in the incidence of cancer around the world. In 2018, 4.4% of entire cancer-related mortality among women was attributed to ovarian cancer. Although the incidence of cancer is higher among high Human Development Index (HDI) countries, the trend of mortality rate tends to be reversing. Various factors affect the occurrence of ovarian cancer, from which genetic factor are among the most important ones. Pregnancy, lactation, and oral contraceptive pills play a role in reducing the risk of this disease.

Conclusion: This study provides significant evidence about ovarian cancer. Considering the heavy burden of ovarian cancer on women's health, preventive measures as well as health education and early detection in high risk groups of women are highly recommended. Although some risk factors cannot be changed, a focus on preventable risk factors may reduce the risk of ovarian cancer. More studies are needed to explore the role of unclear risk factors in ovarian cancer occurrence.

Evaluation of lysophosphatidic acid in vaginal fluid as a biomarker for ovarian cancer: A pilot study

There remains a need to differentiate between women with a benign or a malignant adnexal mass prior to surgery. As part of an ongoing evaluation of vaginal fluid compounds as potential tumor biomarkers we evaluated whether vaginal lysophosphatidic acid (LPA) predicted the subsequent diagnosis of a malignant adnexal mass. In this prospective pilot study vaginal fluid was obtained from 100 post-menopausal women referred for evaluation of a suspicious adnexal mass and tested for LPA by ELISA. Clinical data and serum CA125 results were obtained only after completion of all laboratory testing. Twenty eight of the women were subsequently diagnosed with an ovarian malignancy, four had a borderline tumor and 68 had a benign diagnosis. Among women with a malignant ovarian mass, 11 (39.3%) had an endometrioid adenocarcinoma +/− Clear cell tumor components, 6 (21.4%) had a high grade serous carcinoma, 3 (10.7%) had a mucinous tumor, 2 each (7.1%) had a malignant mixed mesodermal or a granulosa tumor and 1 each (3.6%) had a Clear cell tumor, a mixed cell tumor, leimyosarcoma or metastatic adrenal tumor. Compared to the median vaginal LPA level in women with benign lesions (1.5 μM), LPA was significantly elevated only in women with endometrioid ovarian cancer (7.9 μM) (p = 0.0137). Of the 6 endometrioid tumors in which values for both plasma CA125 and vaginal LPA were available 5 were positive only for LPA while one was only CA125 positive. Detection of LPA in vaginal secretions may be of value for the noninvasive diagnosis of endometrioid ovarian malignancies in post-menopausal women.

Case for a role of the microbiome in gynecologic cancers: Clinician's perspective

In this review, we aimed to provide insight into the microbiome and its association with endometrial and ovarian cancer and their risk factors. We reviewed the literature focusing on the relationship between the microbiome and cancer, as well as the relationship between gynecologic diseases and cancers. The human body contains different kinds of microorganisms in various body parts, which is termed the microbiome. The number of microorganisms that live in and on the human body is greater than that of the human germ and somatic cells by 10-fold. The relationship between a human and their microbiome is complex; it is also one of the most important components of homeostasis. Impairment of microbiome-host homeostasis has been associated with obesity, several cancers, preterm labor, inflammatory and allergic conditions and neurodevelopmental disorders. Direct and strong causal relationships have been established for several cancers and microorganisms, such as gastric lymphoma and Helicobacter pylori infection. Interestingly, eradication of the infectious agents has also been shown to be therapeutic. The association between cancer and the microbiome, however, is more complicated than a 1 bacteria-1 cancer model, and a shift in a healthy microbiome can result in various cancers via inflammation, change in microenvironment or DNA-damaging toxins. The human microbiome is an integral part of homeostasis. Understanding the mechanisms that cause dysbiosis will enable us to elucidate the pathways that result in malignancy and investigate new treatment modalities.

Tubal ligation and ovarian cancer risk in African American women

PURPOSE

Tubal ligation has been associated with reduced risk of epithelial ovarian cancer (EOC) in studies of primarily white women, but less is known about the association in African American (AA) women. We sought to evaluate the associations among 597 invasive ovarian cancer cases and 742 controls of AA descent recruited from the African American Cancer Epidemiology Study, a population-based case-control study in 11 geographical areas in the US.

METHODS

Multivariable logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for potentially confounding factors.

RESULTS

An inverse association between tubal ligation and EOC was observed that was not statistically significant (OR 0.88, 95% CI 0.68-1.14). However, an inverse association with EOC risk was observed among women who had a tubal ligation at age 35 years or older (OR 0.64; 95% CI 0.41-0.98), but not among those who had a tubal ligation before age 35 (OR 0.98; 95% CI 0.74-1.29) (p for interaction = 0.08). The association also varied considerably by tumor subtype. A strong inverse association was observed for endometrioid tumors (OR 0.31, 95% CI 0.14-0.70), whereas associations with mucinous (OR 0.87, 95% CI 0.36-2.12) and serous (OR 0.94, 95% CI 0.71-1.24) tumors were weaker and not statistically significant. A statistically non-significant positive association for clear cell tumors (OR 1.84, 95% CI 0.58-5.82) was based on a low number of cases.

CONCLUSIONS

Our findings show that tubal ligation may confer a reduced risk for EOC among AA women that is comparable to the associations that have been previously observed in primarily white populations.

The association between reproductive and hormonal factors and ovarian cancer by estrogen-α and progesterone receptor status

OBJECTIVE

We assessed the association between reproductive and hormonal factors and ovarian cancer incidence characterized by estrogen receptor-α (ERα) and progesterone receptor (PR) status.

METHODS

Tissue microarrays were used to assess ERα and PR expression among 197 Nurses' Health Study (NHS), 42 NHSII and 76 New England Case-Control Study (NECC) ovarian cancer cases. NHS/NHSII cases were matched to up to 4 controls (n=954) on diagnosis date and birth year. NECC controls (n=725) were frequency matched on age. Cases were considered receptor positive if ≥1% of tumor cells stained positive. Associations by ERα and PR status were assessed using polytomous logistic regression. p-Value for heterogeneity was calculated using a likelihood ratio test.

RESULTS

45% of ovarian tumors were PR(+), 78% were ERα(+) and 45% were ERα(+)/PR(+), while 22% were ERα(-)/PR(-). Postmenopausal status was associated with an increased risk of PR(-) tumors (OR: 2.07; 95%CI: 1.15-3.75; p-heterogeneity=0.01) and age at natural menopause was inversely associated with PR(-) tumors (OR, per 5years: 0.77; 95%CI: 0.61-0.96; p-het=0.01). Increasing duration of postmenopause was differentially associated by PR status (p-het=0.0009). Number of children and tubal ligation were more strongly associated with ERα(-) versus ERα(+) tumors (p-het=0.002 and 0.05, respectively). No differential associations were observed for oral contraceptive or hormone therapy use.

CONCLUSIONS

Postmenopausal women have an increased risk of developing PR(-) ovarian tumors compared to premenopausal women. The associations observed for ovarian cancer differ from those seen for breast cancer suggesting that the biology for tumor development through ERα and PR pathways may differ.

Tubal ligation and ovarian cancer risk in a large cohort: Substantial variation by histological type

Histopathological and molecular studies suggest that different histological subtypes (histotypes) of ovarian cancer have different aetiologies. Few studies have been large enough to explore reliably the effect of tubal ligation (sterilization), which has been associated with a reduced overall risk of ovarian cancer, on different tumour histotypes. In a prospective study of 1.1 million UK women without prior cancer or bilateral oophorectomy, 8,035 ovarian cancers occurred during mean follow-up of 13.8 years. Using a Cox proportional hazards model, we estimated adjusted relative risks of ovarian cancer associated with tubal ligation. Overall, there was substantial heterogeneity in tumour risk associated with tubal ligation for the four main histotypes, serous, endometrioid, mucinous and clear cell (heterogeneity: p < 0.0001). For serous tumours, the most common histotype (n = 3,515), risks differed significantly between high-grade (RR: 0.77, 95% CI: 0.67-0.89) and low-grade tumours (RR: 1.13, 95% CI: 0.89-1.42); heterogeneity: p = 0.007. Relative risks were almost halved for endometrioid (n = 690, RR: 0.54, 95% CI: 0.43-0.69) and clear cell tumours (n = 401, RR: 0.55, 95% CI: 0.39-0.77), but there was no association between tubal ligation and mucinous tumours (n = 836, RR: 0.99, 95% CI: 0.84-1.18). For the main tumour histotypes we found little variation of risk by timing of tubal ligation. The significant differences by tumour histotype are unlikely to be due to confounding and are consistent with hypotheses that high-grade and low-grade serous tumours have different origins, and that some endometrioid and clear cell tumours might arise from cells and/or carcinogens travelling through the fallopian tubes.

[Is endometriosis a precancerous lesion? Perspectives and clinical implications]

Epidemiological studies have shown a relationship between endometriosis and clear cell/endometrioid ovarian cancers (named "Endometriosis Associated Ovarian Cancer" or EAOC). The recent discovery of signaling pathways (especially the SWI/SNF and PI3K/AKT/mTOR pathways) that linked endometriosis and EAOC could lead to the development of specific biomarkers as ARID1A to screen benign to premalignant endometriosis and to new targeted treatment. Moreover, the better understanding of the pathogenesis of the epithelial ovarian cancer arising from the Fallopian tube could allow new early prevention strategies that will be described in this review.

Update on permanent contraception options for women

PURPOSE OF REVIEW

Permanent methods are the most commonly used contraceptive options worldwide. Even with the increase in popularity and accessibility of long-acting reversible methods, there remains high demand for permanent options, especially among women in developing countries.

RECENT FINDINGS

Traditional methods of permanent contraception, such as postpartum tubal ligation and interval surgical tubal occlusion or electrocautery by mini-laparotomy or laparoscopy are well tolerated and highly effective. Bilateral total salpingectomy for ovarian cancer risk reduction is currently being investigated. Hysteroscopic tubal occlusion reduces or eliminates the need for anesthesia, but requires surgical training and specialized equipment. Alternative permanent contraception methods are being explored including immediately effective hysteroscopic methods, and nonsurgical permanent contraception methods that have the potential to improve access and reduce cost.

SUMMARY

Permanent contraception methods are an important part of the contraceptive methods mix designed to meet the needs of women who have completed desired family size or wish never to become pregnant. Current surgical approaches to permanent contraception are well tolerated and highly effective. The development of a highly effective nonsurgical approach could simplify the provision of permanent contraception.

Tubal Ligation Induces Quiescence in the Epithelia of the Fallopian Tube Fimbria

Tubal ligation keeps the fimbriated end of the fallopian tube intact while interrupting the conduit for sperm and egg between the uterus and ovary. Tubal ligation is associated with an approximately 20% decreased risk of high-grade serous ovarian cancers, which mounting evidence suggests arise from the distal fallopian tube epithelium. We postulated that biological changes at the epithelial cellular level of the distal fallopian tube may account for the surgical procedure's observed risk reduction. We compared the histology, presence of epithelial progenitors (basally located CD44-positive cells), and degree of epithelial proliferation (Ki67-positive cells) of distal fallopian tube from 10 patients with previous tubal ligation and 10 age-matched patients with uncut fallopian tubes. A significantly reduced population of proliferating epithelial progenitors (basally located CD44/Ki67 dual-positive cells) was detected in the tubal ligated specimens (P = .0002). To functionally assess the effect of tubal ligation, a murine model was utilized to compare the growth capacity of distal fallopian tube epithelial cells isolated from either ligated or sham-operated tubal epithelia. Murine fallopian tube epithelial cells isolated after tubal ligation showed a significantly reduced capacity to grow organoids in culture compared to sham-operated controls (P = .002). The findings of this study show that tubal ligation is associated with a reduced presence and decreased proliferation of progenitor cells in the distal fallopian tube epithelium. These compositional and functional changes suggest that tubal ligation induces quiescence of distal fallopian tube epithelial cells.

Society of Gynecologic Oncology recommendations for the prevention of ovarian cancer

Mortality from ovarian cancer may be dramatically reduced with the implementation of attainable prevention strategies. The new understanding of the cells of origin and the molecular etiology of ovarian cancer warrants a strong recommendation to the public and health care providers. This document discusses potential prevention strategies, which include 1) oral contraceptive use, 2) tubal sterilization, 3) risk-reducing salpingo-oophorectomy in women at high hereditary risk of breast and ovarian cancer, 4) genetic counseling and testing for women with ovarian cancer and other high-risk families, and 5) salpingectomy after childbearing is complete (at the time of elective pelvic surgeries, at the time of hysterectomy, and as an alternative to tubal ligation). The Society of Gynecologic Oncology has determined that recent scientific breakthroughs warrant a new summary of the progress toward the prevention of ovarian cancer. This review is intended to emphasize the importance of the fallopian tubes as a potential source of high-grade serous cancer in women with and without known genetic mutations in addition to the use of oral contraceptive pills to reduce the risk of ovarian cancer.

Tubal ligation and salpingectomy and the risk of epithelial ovarian cancer and borderline ovarian tumors: a nationwide case-control study

OBJECTIVE

According to the recent theories on the ovarian cancer origin, any protective effect of tubal ligation may vary with histologic subtype of ovarian cancer. Furthermore, bilateral salpingectomy may represent an opportunity for surgical prevention of serous ovarian cancer.

DESIGN

Nationwide register-based case-control study.

SETTING

Denmark during 1982-2011.

POPULATION

Cases were all Danish women diagnosed with epithelial ovarian cancer (n = 13 241) or borderline ovarian tumor (n = 3605) in the study period. Age-matched female population controls were randomly selected by risk set sampling. We required that cases and controls have no previous cancer and that controls have no previous bilateral oophorectomy.

METHODS

Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals, adjusting for potential confounders.

MAIN OUTCOME MEASURES

Epithelial ovarian cancer and borderline ovarian tumors stratified according to histology.

RESULTS

Tubal ligation reduced overall epithelial ovarian cancer risk (odds ratios 0.87; 95% confidence interval 0.78-0.98). We observed significant risk variation according to histology (p = 0.003) with the strongest risk reductions associated with endometrioid cancer (odds ratios 0.66; 95% confidence interval 0.47-0.93) and epithelial ovarian cancer of "other" histology (odds ratios 0.60; 95% confidence interval 0.43-0.83). Tubal ligation was not associated with risk of borderline ovarian tumors. Finally, bilateral salpingectomy reduced epithelial ovarian cancer risk by 42% (odds ratios 0.58; 95% confidence interval 0.36-0.95).

CONCLUSIONS

We confirmed that tubal ligation reduces the risk of epithelial ovarian cancer and particularly endometrioid cancer. To our knowledge, this is the first observational publication to report on salpingectomy and ovarian cancer risk and our promising findings warrant further investigation.

Effect of tubal sterilization technique on risk of serous epithelial ovarian and primary peritoneal carcinoma

OBJECTIVE

To determine the effect of excisional tubal sterilization on subsequent development of serous epithelial ovarian cancer (EOC) or primary peritoneal cancer (PPC).

METHODS

We performed a population-based, nested case-control study using the Rochester Epidemiology Project. We identified all patients with a diagnosis of serous EOC or PPC from 1966 through 2009. Each case was age-matched to 2 controls without either diagnosis. Odds ratios (ORs) and corresponding 95% CIs were estimated from conditional logistic regression models. Models were adjusted for prior hysterectomy, prior salpingo-oophorectomy, oral contraceptive use, endometriosis, infertility, gravidity, and parity.

RESULTS

In total, we identified 194 cases of serous EOC and PPC during the study period and matched them with 388 controls (mean [SD] age, 61.4 [15.2] years). Fourteen cases (7.2%) and 46 controls (11.9%) had undergone tubal sterilization. Adjusted risk of serous EOC or PPC was slightly lower after any tubal sterilization (OR, 0.59 [95% CI, 0.29-1.17]; P=.13). The rate of excisional tubal sterilization was lower in cases than controls (2.6% vs 6.4%). Adjusted risk of serous EOC and PPC was decreased by 64% after excisional tubal sterilization (OR, 0.36 [95% CI, 0.13-1.02]; P=.054) compared with those without sterilization or with nonexcisional tubal sterilization.

CONCLUSIONS

We present a population-based investigation of the effects of excisional tubal sterilization on the risk of serous EOC and PPC. Excisional methods may confer greater risk reduction than other sterilization methods.

The role of the fallopian tube in the origin of ovarian cancer

Advanced cases of epithelial ovarian, primary peritoneal, and primary tubal malignancies have a relatively poor prognosis and collectively remain the most deadly of all gynecologic malignancies. Although traditionally thought of as one disease process, ongoing research suggests that there is not 1 single site or cell type from which these cancers arise. A majority of the serous tumors appear to originate from dysplastic lesions in the distal fallopian tube. Therefore, what we have traditionally considered "ovarian" cancer may in fact be tubal in origin. In this article, we will review epithelial ovarian cancer classification and genetics, theories regarding cells of origin with a focus on tubal intraepithelial carcinoma, and implications for prevention and screening.

Preventing ovarian cancer by salpingectomy

This issue of Current Oncology contains four articles1–4 on the subject of the role of bilateral salpingectomy in preventing high-grade serous ovarian carcinoma.[...]

Evolution, ovulation and cancer

Secretions by epithelial cells of the fallopian tube regulate ovulation through conserved pathways, which means that experiments on flies might provide insights into the human reproductive system and, possibly, ovarian cancer.

Tubal sterilization and breast cancer incidence: results from the cancer prevention study II nutrition cohort and meta-analysis

Tubal sterilization is a common form of contraception in the United States and is hypothesized to be associated with a lower risk of breast cancer. However, prior observational studies have reported inconsistent results. We investigated the association between tubal sterilization and breast cancer risk among 77,249 postmenopausal, cancer-free women in the Cancer Prevention Study II (CPS-II) Nutrition Cohort, enrolled in 21 states in the United States during 1992-1993. During 15 years of follow-up through June 30, 2007, 4,084 invasive breast cancer cases were diagnosed. Multivariable Cox proportional hazard regression was used to estimate hazard ratios and 95% confidence intervals. A meta-analysis including the CPS-II Nutrition Cohort results with other published results from 4 case-control studies and 3 prospective studies was conducted to provide a summary estimate for the association between tubal sterilization and breast cancer risk. In the CPS-II Nutrition Cohort, tubal sterilization was not associated with breast cancer incidence (multivariable-adjusted hazard ratio = 1.08, 95% confidence interval: 0.97, 1.20). Associations stratified by year of tubal sterilization, age, and time since surgery were also null. The meta-analysis also found no association between tubal sterilization and breast cancer risk (odds ratio = 0.97, 95% confidence interval: 0.84, 1.09). Tubal sterilization does not appear to be associated with breast cancer risk.

Ovarian cancer risk factors by tumor dominance, a surrogate for cell of origin

Differentiating ovarian tumors based on developmental pathway may further enhance our understanding of the disease. Traditionally, ovarian cancers were thought to arise from the ovarian surface epithelium; however, recent evidence suggests that some tumors originate in the fallopian tube. We classified cases in a population-based case-control study (New England Case-Control [NECC] Study) and two cohort studies (Nurses' Health Study [NHS]/Nurses' Health Study II [NHSII]) by tumor dominance, a proxy for tissue of origin. Dominant tumors (likely ovarian origin) are restricted to one ovary or are at least twice as large on one ovary compared to the other. Ovarian cancer risk factors were evaluated in relation to dominant and nondominant tumors (likely tubal origin) using polytomous logistic regression (NECC) or competing risks Cox models (NHS/NHSII). Results were combined using random-effects meta-analyses. Among 1,771 invasive epithelial ovarian cancer cases, we observed 1,089 tumors with a dominant mass and 682 with no dominant mass. Dominant tumors were more likely to be mucinous, endometrioid or clear cell, whereas nondominant tumors were more likely to be serous. Tubal ligation, two or more births, endometriosis and age were more strongly associated with dominant tumors (rate ratio [RR] = 0.60, 0.83, 1.58 and 1.37, respectively) than nondominant tumors (RR = 1.03, 0.93, 0.84 and 1.14, respectively; p-difference = 0.0001, 0.01, 0.0003 and 0.01, respectively). These data suggest that risk factors for tumors putatively arising from ovarian versus fallopian tube sites may differ; in particular, reproductive factors may be more important for ovarian-derived tumors. As this is the first study to evaluate ovarian cancer risk factors by tumor dominance, these results need to be validated by other studies.

The post-reproductive Fallopian tube: better removed?

Recently, the distal Fallopian tube has attracted considerable attention not only as site of origin for serous cancer in women with BRCA mutations, but also as the anatomical location where the majority of serous ovarian cancers apparently develop. Consequently, the Fallopian tube may be the unique location where early 'ovarian' cancers can be found--which would contradict the long-standing impression that the ovaries and the Fallopian tubes are always simultaneously involved. Based on the dismal prognosis associated with ovarian cancer and our inability to screen for early-stage disease, we discuss the rationale for introducing salpinges-hysterectomy as new clinical standard for women in need of hysterectomy and further weigh the arguments for and against bilateral salpingectomy as a sterilization method. There is no known physiological benefit of retaining the post-reproductive Fallopian tube during hysterectomy or sterilization, especially as this does not affect ovarian hormone production. On the other hand, the consequences associated with a surgical menopause provide a rationale for preserving the ovaries in premenopausal women. Prophylactic removal of the Fallopian tubes during hysterectomy or sterilization would rule out any subsequent tubal pathology, such as hydrosalpinx, which is observed in up to 30% of women after hysterectomy. Moreover, this intervention is likely to offer considerable protection against later tumour development, even if the ovaries are retained. Thus, we recommend that any hysterectomy should be combined with salpingectomy. In addition, women over 35 years of age could also be offered bilateral salpingectomy as means of sterilization.

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.