Association of Reproductive Factors, Oral Contraceptive Use and Selected Lifestyle Factors with the Risk of Ovarian Borderline Tumors: A Danish Case-control Study

Anatomic Distribution of Benign Ovarian Tumors in Perimenopausal and Postmenopausal Women

Introduction We aim to report the histotypes and reassess the anatomic distribution of benign ovarian tumors in perimenopausal and postmenopausal women. Methods Medical and pathology reports of women with histologically confirmed benign ovarian pathology were investigated. Data were collected, retrospectively between 2000 and 2020, and analyzed from perimenopausal and postmenopausal women with benign ovarian tumors, after bilateral salpingo-oophorectomy (BSO) with or without total abdominal hysterectomy (TAH). The ovarian masses histology and the distribution of locations were further evaluated. Results The total sample consisted of 1,355 women with benign ovarian tumors; 929 (68.6%) of the perimenopausal and 426 (31.4%) of the postmenopausal age. A dermoid cyst was prominent in the right ovary (52.8%), compared to the left side (41%) (p<0.01). Conversely, in patients with endometriomas and cysts of Morgagni, the observed proportion was more prominent in the left-sided ovary (61.8% vs 27%; p<0.001 and 52.3% vs 36.4%; p<0.01, respectively). Moreover, in the perimenopausal women, we mostly detected endometrioma (18.3%), dermoid cyst (15.5%) and cyst of Morgagni (4%) compared to postmenopausal women, where serous cysts (29.8%) and ovarian fibroids (8%) were the most common tumors. Conclusions Benign ovarian tumors are frequently seen in perimenopausal women and most histotypes present anatomical differences between the left and right ovaries. Serous cysts, followed by paraovarian, dermoid cysts and endometrioma present the commonest ovarian benign masses. Gynecologists should pay special attention to adnexal tumors in the postmenopausal period to choose the right operating setting for women at risk for ovarian cancer.

Nanotechnology-Based Nucleic Acid Vaccines for Treatment of Ovarian Cancer

Anticancer vaccines represent a promising approach for effective treatment of cancer and along with recent advantages of nucleic acid-based vaccines for other diseases form a prospective and potentially efficacious direction of the research, development and clinical applications. Despite the ongoing several clinical trials of mRNA vaccines for the treatment of various types of cancer, to-date no cancer vaccines were approved by the US Food and Drug Administration. The present review analyzes and summarizes major approaches for treating of different forms of ovarian cancer including mRNA-based vaccines as well as nanotechnology-based approaches for their delivery.

The preventive effect of breastfeeding against ovarian cancer in BRCA1 and BRCA2 mutation carriers: A systematic review and meta-analysis

OBJECTIVE

A recent study showed that even a few months of breastfeeding is associated with a significant decrease in the risk of ovarian cancer in the general population. This study aimed to perform a systematic review and meta-analysis to determine the significance of the length of the breastfeeding period on ovarian cancer risk in BRCA1/2 mutation carriers.

METHODS

PubMed, EMBASE, and Cochrane databases were searched up to June 1, 2021. We included case-control and cohort studies that contained information on breastfeeding and the risk of ovarian cancer in BRCA1/2 mutation carriers. Odds ratios (OR) were meta-analytically pooled using a fixed-effects model.dd RESULTS: Five studies, including one cohort study and four case-control studies, were included in this meta-analysis. Of the 14,601 BRCA1/2 mutation carriers, the overall pooled OR of ever having performed breastfeeding in patients who had ovarian cancer was 0.767 (95% confidence interval [CI], 0.688-0.856) and 0.817 (95% CI, 0.650-1.028) for patients with BRCA1 and BRCA2 mutation, respectively. Breastfeeding for >1 year acted as a protective factor in both BRCA1 [OR: 0.787 (95% CI, 0.682-0.907)] and BRCA2 [OR: 0.567 (95% CI, 0.400-0.802)] mutation carriers. No significant heterogeneity was present (I2 = 0%), and the funnel plot was also properly distributed, showing no publication bias.

CONCLUSIONS

Breastfeeding is a preventive, modifiable factor for ovarian cancer in BRCA1/2 mutation carriers. Ever having performed breastfeeding was significantly preventive for ovarian cancer in the BRCA1 mutation carriers, however a period of 1 year or more of breastfeeding is required for a reduced ovarian cancer risk in BRCA2 mutation carriers.

Borderline ovarian tumors in Denmark 1997-2018: Time trends in incidence by histology, age and educational level

INTRODUCTION

After some decades with an increasing incidence of borderline ovarian tumors, more recent studies have observed that the incidence rate seems to be leveling off or declining. In this study, we describe the incidence of borderline ovarian tumors in Denmark 1997-2018 by histology, age at diagnosis and educational level.

MATERIAL AND METHODS

All borderline ovarian tumors registered in the Danish Pathology Registry during 1997-2018 were identified and individual-level educational information was retrieved from nationwide registers. Age-standardized incidence rates were estimated according to histology, age at diagnosis and educational level. To investigate incidence trends over time, the average annual percentage change and corresponding 95% confidence intervals (CIs) were estimated using Poisson regression.

RESULTS

We identified 3927 women with borderline ovarian tumors during the study period, of which 1997 (50.9%) were serous and 1743 (44.4%) were mucinous. The age-standardized incidence rate of serous borderline ovarian tumors did not change significantly over calendar time (average annual percentage change = -0.13, 95% confidence interval [CI] -1.13 to 0.88). For mucinous tumors, the age-standardized incidence rate was also relatively stable during the first half of the study period, followed by a decrease from 2.56 to 1.25 per 100 000 person-years between 2007-2011 and 2017-2018. Over the entire study period, the incidence rate of mucinous borderline tumors declined on average by 2.91% (95% CI -4.24 to -1.51) per year. The incidence of both types of borderline ovarian tumors seemed to be highest among women with a low educational level. Over calendar time, the incidence of mucinous tumors decreased in all educational groups, whereas the incidence of serous tumors decreased exclusively in women with a high educational level. Time trends did not differ markedly by age at diagnosis.

CONCLUSIONS

In Denmark, the incidence of serous borderline ovarian tumors was stable during 1997-2018, whereas the incidence of mucinous borderline ovarian tumors decreased. The incidence rates of both types of borderline ovarian tumors tended to be highest among women with a low educational level throughout the study period.

Association Between Breastfeeding and Ovarian Cancer Risk

Importance

Breastfeeding has been associated with a reduced risk of epithelial ovarian cancer in multiple studies, but others showed no association. Whether risk reduction extends beyond that provided by pregnancy alone or differs by histotype is unclear. Furthermore, the observed associations between duration and timing of breastfeeding with ovarian cancer risk have been inconsistent.

Objective

To determine the association between breastfeeding (ie, ever/never, duration, timing) and ovarian cancer risk overall and by histotype.

Design, Setting, and Participants

A pooled analysis of parous women with ovarian cancer and controls from 13 case-control studies participating in the Ovarian Cancer Association Consortium was performed. Odds ratios (ORs) and 95% CIs of the overall association were calculated using multivariable logistic regression and polytomous logistic regression for histotype-specific associations. All data were collected from individual sites from November 1989 to December 2009, and analysis took place from September 2017 to July 2019.

Exposures

Data on breastfeeding history, including duration per child breastfed, age at first and last breastfeeding, and years since last breastfeeding were collected by questionnaire or interview and was harmonized across studies.

Main Outcomes and Measures

Diagnosis of epithelial ovarian cancer.

Results

A total of 9973 women with ovarian cancer (mean [SD] age, 57.4 [11.1] years) and 13 843 controls (mean [SD] age, 56.4 [11.7] years) were included. Breastfeeding was associated with a 24% lower risk of invasive ovarian cancer (odds ratio [OR], 0.76; 95% CI, 0.71-0.80). Independent of parity, ever having breastfed was associated with reduction in risk of all invasive ovarian cancers, particularly high-grade serous and endometrioid cancers. For a single breastfeeding episode, mean breastfeeding duration of 1 to 3 months was associated with 18% lower risk (OR, 0.82; 95% CI, 0.76-0.88), and breastfeeding for 12 or more months was associated with a 34% lower risk (OR, 0.66; 95% CI, 0.58-0.75). More recent breastfeeding was associated with a reduction in risk (OR, 0.56; 95% CI, 0.47-0.66 for <10 years) that persisted for decades (OR, 0.83; 95% CI, 0.77-0.90 for ≥30 years; P for trend = .02).

Conclusions and Relevance

Breastfeeding is associated with a significant decrease in risk of ovarian cancer overall and for the high-grade serous subtype, the most lethal type of ovarian cancer. The findings suggest that breastfeeding is a potentially modifiable factor that may lower risk of ovarian cancer independent of pregnancy alone.

[Borderline Ovarian Tumours: CNGOFS Guidelines for Clinical Practice - Hormonal Contraception and MHT/HRT after Borderline Ovarian Tumour]

Contraceptive options and menopause management are frequent clinical issues among women previously treated for a borderline ovarian tumour (BOT).

OBJECTIVES

To synthesize knowledge on BOT and risk related to hormonal contraception and to menopausal hormone therapy (MHT), and to propose recommendations on contraception and MHT after BOT treatment.

METHODS

Systematic review of the literature about hormonal contraception and BOT and on MHT and BOT was conducted on PubMed/Medline and the Cochrane Library.

RESULTS

There are no data concerning hormonal contraception after BOT. Current or previous oral contraception is associated with a trend towards decreased risk of serous BOT. Mucinous BOT risk is not or slightly decreased by oral contraception. Hormonal contraception is thus not contraindicated in women previously treated for a BOT (grade C). MHT is associated with a trend towards increased risk of serous BOT. No relation was found between MHT and risk of mucinous BOT. Serous BOTs with high-risk histological criteria (micropapillary pattern, stromal microinvasion or peritoneal implants) are at high-risk of invasive potentially hormone-sensitive recurrence. Hence, caution is needed in the decisions of using MHT after serous BOT with one of these high-risk histological criteria, and MHT should be discussed on a case to case basis. MHT can be prescribed without restriction in women previously treated for mucinous and serous BOT without high-risk histological criteria (grade C).

CONCLUSION

Hormonal contraception can be used after BOT. The histological characteristics of the tumour must be taken into account when deciding on the use of HRT/THM.

[Borderline Ovarian Tumours: CNGOF Guidelines for Clinical Practice - Epidemiological Aspects and Risk Factors]

The incidence (rate/100,000) of BOT gradually increases with age from 15-19 years of age and peaks at nearly 4.5 cases/100,000 for the 55-59 year age group (NP3). In the presence of a benign ovarian mass, the standardized risk ratio of serous and mucinous BOT is 1.69, (95% CI 1.39-2.03) and 1.75, (95% CI 1.45-2.10), respectively (NP2). At diagnosis, a median age of diagnosis of OFA is 46 years, unilateral forms (79.7% of cases) are predominant compared to cancers (45.3%) (<0.001) and FIGO I stages represent nearly 63.7% of cases (NP3). The 5-year survival rates for FIGO I, II, III, IV stages are: 99.7% (95% CI: 96.2-100%), 99.6% (95% CI: 92.6-100%), 95.3% (95% CI: 91.8-97.4%), 77.1% (95% CI: 58.0-88.3%), respectively (NP3). Survivors at 5 years for serous and mucinous tumours are 99.7% (95% CI: 99.2-99.9%), 98.5% (95% CI: 96.9-99.3%), respectively (NP3). An epidemiological association exists between personal BOT risk and: (1) a familial history of BOT/certain cancers (pancreas, lung, bone, leukemia) (NP3), (2) a personal history of benign ovarian cyst (NP2), (3) a personal history of pelvic inflammatory disease (IGH), (4) the use of intrauterine device levonorgestrel (NP3), (5) the use of oral contraceptive pills (NP3), (6) multiparity (NP3), (7) hormone replacement therapy (NP3), (8) high consumption of coumestrol (NP4), (9) medical treatment of infertility with progesterone (NP3), (10) non-steroidal anti-inflammatory drug (NSAID). An epidemiological association exists between previous/actual tabacco consumption and the risk of mucinous ovarian BOT (NP2). Relative risk (RR) varies between 2.2 and 2.7, however the relationship is not necessarily a causal one. An epidemiological association exists between overweight/obesity and the risk of serous BOT (NP2). RR varies between 1.2 to 1.8. The high Vitamin D was inversely associated to the risk of serous BOT (NP4). The risk of mucinous BOT was lowered with paracetamol use (OR=0.77; 95% CI: 0.60-0.98) (NP3). However, the relationship between these factors and BOT is not necessarily a causal one and no screening modality can be proposed in the general population (gradeC).

Association between Cigarette Smoking and Histotype-Specific Epithelial Ovarian Cancer: A Review of Epidemiologic Studies

Many studies have demonstrated that smoking can influence ovarian cancer risk and survival; however, the number of studies investigating this relationship according to histologic subtypes is limited. We conducted a review of epidemiologic research that assessed the role of smoking on ovarian cancer risk and survival after diagnosis, specifically capturing studies that discerned between various histologic subtypes of this disease. In the majority of studies, current smoking was associated with increased risk of mucinous cancer. There was also evidence of a decreased risk of clear cell and endometrioid histotypes. No significant association was observed between cigarette smoking and serous cancer. In the studies investigating the relationship between smoking and survival, all the studies reported an increased risk of mortality associated with smoking. Smoking appeared to be a risk factor for both ovarian cancer risk and mortality. Future studies need to investigate further a potential link between smoking and ovarian cancer by having a better assessment of exposure to smoking and having a larger number of participants with the ability to detect associations within rare histotypes.

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.

Parity, infertility, oral contraceptives, and hormone replacement therapy and the risk of ovarian serous borderline tumors: A nationwide case-control study

OBJECTIVE

Few studies have examined the risk of an ovarian serous borderline tumor (SBT) associated with parity, infertility, oral contraceptives (OCs), or hormone replacement therapy (HRT), which was the study aim.

METHODS

This nationwide case-control study included all women with an SBT diagnosis in Denmark, 1978-2002. SBTs were confirmed by centralized expert pathology review. For each case, 15 age-matched female controls were randomly selected using risk-set sampling. Cases and controls with previous cancer (except for non-melanoma skin cancer) and controls with bilateral oophorectomy or salpingo-oophorectomy were excluded. Conditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We found a strongly decreased risk of SBTs among parous women which decreased with increasing number of children (p<0.01). Older age at first birth also decreased the SBT risk (p=0.03). An increased SBT risk was associated with infertility (OR=3.31; 95% CI: 2.44-4.49), which was present both among parous and nulliparous women. HRT use increased the SBT risk (OR=1.32; 95% CI: 1.02-1.72), whereas OC use decreased the risk (OR=0.40; 95% CI: 0.26-0.62).

CONCLUSIONS

Our nationwide study with expert histopathologic review of all SBTs showed that parity, infertility, use of HRT, and use of OCs, respectively, were strongly associated with the risk of SBTs. This is the first study to report a strong and significantly decreased SBT risk associated with OC use and a significantly increased risk with infertility, and HRT use. This supports that SBTs and serous ovarian cancer share similar risk factors.

Increased risk of borderline ovarian tumors in women with a history of pelvic inflammatory disease: A nationwide population-based cohort study

OBJECTIVE

Some studies suggest that pelvic inflammatory disease (PID) is a potential risk factor for ovarian cancer. However, only few studies have investigated the association between PID and risk of borderline ovarian tumors. We conducted a population-based cohort study to investigate the association between PID and risk of borderline ovarian tumors.

METHODS

Using various nationwide Danish registries we identified all women in Denmark during 1978-2012, who were born during 1940-1970 (n=1,318,925). Of these, 81,263 women were diagnosed with PID in the study period, and 2736 women had a borderline ovarian tumor (1290 serous and 1344 mucinous). Hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between PID and risk of borderline tumors were estimated using Cox regression models with adjustment for potential confounders.

RESULTS

A history of PID was associated with an increased risk of borderline ovarian tumors (HR=1.39; 95% CI: 1.19-1.61). However, histotype-specific analyses revealed significant variation in risk as PID was only associated with an increased risk of serous borderline tumors (HR=1.85; 95% CI: 1.52-2.24), but not with mucinous borderline tumors (HR=1.06; 95% CI: 0.83-1.35).

CONCLUSIONS

PID is associated with an increased risk of serous borderline tumors. Further research on the potential underlying biological mechanisms and on the identification of the subset of women with PID who are at increased risk of serous borderline tumors is warranted.

Breastfeeding and maternal health outcomes: a systematic review and meta-analysis

AIM

To evaluate the effect of breastfeeding on long-term (breast carcinoma, ovarian carcinoma, osteoporosis and type 2 diabetes mellitus) and short-term (lactational amenorrhoea, postpartum depression, postpartum weight change) maternal health outcomes.

METHODS

A systematic literature search was conducted in PubMed, Cochrane Library and CABI databases. Outcome estimates of odds ratios or relative risks or standardised mean differences were pooled. In cases of heterogeneity, subgroup analysis and meta-regression were explored.

RESULTS

Breastfeeding >12 months was associated with reduced risk of breast and ovarian carcinoma by 26% and 37%, respectively. No conclusive evidence of an association between breastfeeding and bone mineral density was found. Breastfeeding was associated with 32% lower risk of type 2 diabetes. Exclusive breastfeeding and predominant breastfeeding were associated with longer duration of amenorrhoea. Shorter duration of breastfeeding was associated with higher risk of postpartum depression. Evidence suggesting an association of breastfeeding with postpartum weight change was lacking.

CONCLUSION

This review supports the hypothesis that breastfeeding is protective against breast and ovarian carcinoma, and exclusive breastfeeding and predominant breastfeeding increase the duration of lactational amenorrhoea. There is evidence that breastfeeding reduces the risk of type 2 diabetes. However, an association between breastfeeding and bone mineral density or maternal depression or postpartum weight change was not evident.

Breastfeeding and ovarian cancer risk: a systematic review and meta-analysis of 40 epidemiological studies

The present systematic review and meta-analysis was conducted to assess any association between breastfeeding and the risk of ovarian cancer. A systematic search of published studies was performed in PUBMED and EMBASE and by reviewing reference lists from retrieved articles through March 2013. Data extraction was conducted independently by two authors. Pooled relative risk ratios were calculated using random-effect models. Totals of 5 cohort studies and 35 case-control studies including 17,139 women with ovarian cancer showed a 30% reduced risk of ovarian cancer when comparing the women who had breastfed with those who had never breastfed (pooled RR = 0.70, 95% CI: 0.64-0.76; p = 0.00), with significant heterogeneity in the studies (p = 0.00; I2 = 76.29%). A significant decreasd in risk of epithelial ovarian cancer was also observed (pooled RR = 0.68, 95% CI: 0.61-0.76). When the participants were restricted to only parous women, there was a slightly attenuated but still significant risk reduction of ovarian cancer (pooled RR = 0.76, 95% CI: 0.69-0.83). For total breastfeeding duration, the pooled RRs in the < 6 months, 6-12 months and > 12 months of breastfeeding subgroups were 0.85 (95% CI: 0.77-0.93), 0.73 (95% CI: 0.65-0.82) and 0.64 (95%CI: 0.56-0.73), respectively. Meta-regression of total breastfeeding duration indicated an increasing linear trend of risk reduction of ovarian cancer with the increasing total breastfeeding duration (p = 0.00). Breastfeeding was inversely associated with the risk of ovarian cancer, especially long-term breastfeeding duration that demonstrated a stronger protective effect.

Breastfeeding and ovarian cancer risk: a meta-analysis of epidemiologic studies

BACKGROUND

Epidemiologic studies have yielded inconsistent findings between breastfeeding and epithelial ovarian cancer (EOC) risk.

OBJECTIVE

We performed a meta-analysis to summarize available evidence of the association between breastfeeding and breastfeeding duration and EOC risk from published cohort and case-control studies.

DESIGN

Relevant published studies were identified by a search of MEDLINE through December 2012. Two authors (T-TG and Q-JW) independently performed the eligibility evaluation and data abstraction. Study-specific RRs from individual studies were pooled by using a random-effects model, and heterogeneity and publication-bias analyses were conducted.

RESULTS

Five prospective and 30 case-control studies were included in this analysis. The pooled RR for ever compared with never breastfeeding was 0.76 (95% CI: 0.69, 0.83), with moderate heterogeneity (Q = 69.4, P < 0.001, I(2) = 55.3%). Risk of EOC decreased by 8% for every 5-mo increase in the duration of breastfeeding (RR: 0.92; 95% CI: 0.90, 0.95). The risk reduction was similar for borderline and invasive EOC and was consistent within case-control and cohort studies.

CONCLUSIONS

Results of this meta-analysis support the hypothesis that ever breastfeeding and a longer duration of breastfeeding are associated with lower risks of EOC. Additional research is warranted to focus on the association with cancer grade and histologic subtypes of EOC.

Cigarette smoking and risk of ovarian cancer: a pooled analysis of 21 case-control studies

PURPOSE

The majority of previous studies have observed an increased risk of mucinous ovarian tumors associated with cigarette smoking, but the association with other histological types is unclear. In a large pooled analysis, we examined the risk of epithelial ovarian cancer associated with multiple measures of cigarette smoking with a focus on characterizing risks according to tumor behavior and histology.

METHODS

We used data from 21 case-control studies of ovarian cancer (19,066 controls, 11,972 invasive and 2,752 borderline cases). Study-specific odds ratios (OR) and 95 % confidence intervals (CI) were obtained from logistic regression models and combined into a pooled odds ratio using a random effects model.

RESULTS

Current cigarette smoking increased the risk of invasive mucinous (OR = 1.31; 95 % CI: 1.03-1.65) and borderline mucinous ovarian tumors (OR = 1.83; 95 % CI: 1.39-2.41), while former smoking increased the risk of borderline serous ovarian tumors (OR = 1.30; 95 % CI: 1.12-1.50). For these histological types, consistent dose-response associations were observed. No convincing associations between smoking and risk of invasive serous and endometrioid ovarian cancer were observed, while our results provided some evidence of a decreased risk of invasive clear cell ovarian cancer.

CONCLUSIONS

Our results revealed marked differences in the risk profiles of histological types of ovarian cancer with regard to cigarette smoking, although the magnitude of the observed associations was modest. Our findings, which may reflect different etiologies of the histological types, add to the fact that ovarian cancer is a heterogeneous disease.

Pelvic inflammatory disease and risk of invasive ovarian cancer and ovarian borderline tumors

PURPOSE

The aim of the study was to examine the potential association between a history of pelvic inflammatory disease (PID) and risk of epithelial ovarian cancer or ovarian borderline tumors.

METHODS

In a population-based case-control study in Denmark, we included 554 women with invasive ovarian cancer, 202 with ovarian borderline tumors, and 1,564 controls aged 35-79 years. The analyses were performed in multiple logistic regression models.

RESULTS

We found a significantly increased risk of ovarian borderline tumors among women with a history of PID (OR = 1.50; 95% CI 1.08-2.08) but no apparent association between PID and risk of invasive ovarian cancer (OR = 0.83; 95% CI 0.65-1.05). We found no effect of age at time of first PID or time since first PID on the risk for either condition.

CONCLUSION

Our results suggest that a history of PID is associated with an increased risk of ovarian borderline tumors, which may support the hypothesis that inflammation is an etiological factor. The lack of an association between previous PID and invasive ovarian cancer may indicate an etiological difference between ovarian borderline tumors and invasive ovarian cancer. However, an important limitation of the study is the use of self-reported PID.

Tubal ligation and risk of ovarian cancer subtypes: a pooled analysis of case-control studies

BACKGROUND

Tubal ligation is a protective factor for ovarian cancer, but it is unknown whether this protection extends to all invasive histological subtypes or borderline tumors. We undertook an international collaborative study to examine the association between tubal ligation and ovarian cancer subtypes.

METHODS

We pooled primary data from 13 population-based case-control studies, including 10,157 patients with ovarian cancer (7942 invasive; 2215 borderline) and 13,904 control women. Invasive cases were analysed by histological type, grade and stage, and borderline cases were analysed by histological type. Pooled odds ratios were estimated using conditional logistic regression to match on site, race/ethnicity and age categories, and to adjust for age, oral contraceptive use duration and number of full-term births.

RESULTS

Tubal ligation was associated with significantly reduced risks of invasive serous (OR, 0.81; 95% CI, 0.74-0.89; P < 0.001), endometrioid (OR, 0.48; 95% CI, 0.40-0.59; P < 0.001), clear cell (OR, 0.52; 95% CI, 0.40-0.67; P < 0.001) and mucinous (OR, 0.68; 95% CI, 0.52-0.89; P = 0.005) cancers. The magnitude of risk reduction was significantly greater for invasive endometrioid (P < 0.0001) and clear cell (P = 0.0018) than for serous cancer. No significant associations were found with borderline serous or mucinous tumours.

CONCLUSIONS

We found that the protective effects of tubal ligation on ovarian cancer risk were subtype-specific. These findings provide insights into distinct aetiologies of ovarian cancer subtypes and mechanisms underlying the protective effects of tubal ligation.

Ovarian cancer risk is reduced by prolonged lactation: a case-control study in southern China

BACKGROUND

Ovarian cancer is an important neoplasm that is difficult to diagnose and treat; therefore, prevention is the preferable strategy. Growing evidence indicates a protective effect of breastfeeding on ovarian cancer risk.

OBJECTIVE

The objective was to investigate the association between lactation and the risk of ovarian cancer among southern Chinese women.

DESIGN

A case-control study was undertaken in Guangzhou, Guangdong Province, between August 2006 and July 2008. A validated and reliable questionnaire was used to obtain information on the months of lactation and number of children breastfed in a sample of 493 incident ovarian cancer patients and 472 hospital-based controls (mean age: 59 y). Logistic regression analyses were performed to assess the association between breastfeeding and the risk of ovarian cancer.

RESULTS

Significant inverse dose-response relations were found for both duration of lactation and the number of children breastfed. The adjusted ORs were 0.09 (95% CI: 0.04, 0.19) for women with ≥31 mo of total lactation and those with ≤10 mo of lactation and 0.38 (95% CI: 0.27, 0.55) for women with ≥3 children breastfed compared with those with one child breastfed.

CONCLUSION

Prolonged lactation is associated with a lower risk of ovarian cancer in parous Chinese women.

Recent alcohol consumption and risk of incident ovarian carcinoma: a pooled analysis of 5,342 cases and 10,358 controls from the Ovarian Cancer Association Consortium

BACKGROUND

Studies evaluating the association between alcohol intake and ovarian carcinoma (OC) are inconsistent. Because OC and ovarian borderline tumor histologic types differ genetically, molecularly and clinically, large numbers are needed to estimate risk associations.

METHODS

We pooled data from 12 case-control studies in the Ovarian Cancer Association Consortium comprising 5,342 OC cases, 1,455 borderline tumors and 10,358 controls with quantitative information on recent alcohol intake to estimate odds ratios (OR) and 95% confidence intervals (CI) according to frequencies of average daily intakes of beer, wine, liquor and total alcohol.

RESULTS

Total alcohol intake was not associated with all OC: consumption of >3 drinks per day compared to none, OR=0.92, 95% CI=0.76-1.10, P trend=0.27. Among beverage types, a statistically non-significant decreased risk was observed among women who consumed >8 oz/d of wine compared to none (OR=0.83, 95% CI=0.68-1.01, P trend=0.08). This association was more apparent among women with clear cell OC (OR, 0.43; 95% CI, 0.22-0.83; P trend=0.02), although based on only 10 cases and not statistically different from the other histologic types (P value for statistical heterogeneity between histologic types = 0.09). Statistical heterogeneity of the alcohol- and wine-OC associations was seen among three European studies, but not among eight North American studies. No statistically significant associations were observed in separate analyses evaluating risk with borderline tumors of serous or mucinous histology. Smoking status did not significantly modify any of the associations.

CONCLUSIONS

We found no evidence that recent moderate alcohol drinking is associated with increased risk for overall OC, or that variation in risk is associated strongly with specific histologic types. Understanding modifiable causes of these elusive and deadly cancers remains a priority for the research community.

Histologic distribution of borderline ovarian tumors worldwide: a systematic review

Objective

The histologic types of borderline ovarian tumors (BOTs) exhibit striking differences in clinical behavior and prognosis. Yet, there is no information available on the histologic distribution of BOTs according to geographic region. The purpose of this study was to systematically review this issue worldwide.

Methods

A comprehensive search of the literature was conducted using electronic databases. Studies were eligible if BOTs were investigated and the histologic distribution of the data was shown. The studies were grouped by geographic region and totaled by country.

Results

Of 487 potentially relevant studies, 51 met our inclusion criteria, as follows: 8 studies from North America (2 countries); 26 studies from Europe (14 countries); 7 studies from the Middle East (3 countries); and 10 studies from East Asia (5 countries). The histologic distribution of BOTs was considerably different in different parts of the world, but follows specific patterns. In general, serous-type BOTs were the predominantly identified histology in North America, the Middle East, and Europe, while mucinous-type BOTs predominated in East Asia.

Conclusion

Significant geographic variation is evident among BOT histology in different parts of the world. More research is needed to understand this phenomenon.

Diagnosis, treatment, and follow-up of borderline ovarian tumors

Borderline ovarian tumors represent a heterogeneous group of noninvasive tumors of uncertain malignant potential with characteristic histology. They occur in younger women, are present at an early stage, and have a favorable prognosis, but symptomatic recurrence and death may be found as long as 20 years after therapy in some patients. The molecular changes in borderline ovarian tumors indicate linkage of this disease to type I ovarian tumors (low-grade ovarian carcinomas). The pathological stage of disease and subclassification of extraovarian disease into invasive and noninvasive implants, together with the presence of postoperative macroscopic residual disease, appear to be the major predictor of recurrence and survival. However, it should be emphasized that the most important negative prognostic factor for recurrence is just the use of conservative surgery, but without any impact on patient survival because most recurrent diseases are of the borderline type-easily curable and with an excellent prognosis. Borderline tumors are difficult masses to correctly preoperatively diagnose using imaging methods because their macroscopic features may overlap with invasive and benign ovarian tumors. Over the past several decades, surgical therapy has shifted from a radical approach to more conservative treatment; however, oncologic safety must always be balanced. Follow-up is essential using routine ultrasound imaging, with special attention paid to the remaining ovary in conservatively treated patients. Current literature on this topic leads to a number of controversies that will be discussed thoroughly in this article, with the aim to provide recommendations for the clinical management of these patients.

Breast-feeding and risk of epithelial ovarian cancer

PURPOSE

Evidence suggests that breast-feeding may decrease the risk of epithelial ovarian cancer but it is not clear whether there is a relationship with duration of breast-feeding, patterns of breast-feeding, or particular histological subtypes of ovarian cancer. We sought to investigate these issues in detail.

METHODS

Data from participants in a population-based study of ovarian cancer in western Washington State, USA (2002-2007) who had had at least one birth (881 cases and 1,345 controls) were used to assess relations between patterns of breast-feeding and ovarian cancer. Logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Women who ever breast-fed had a 22 % reduction in risk of ovarian cancer compared with those who never breast-fed (OR = 0.78, 95% CI 0.64-0.96) and risk reduction appeared greater with longer durations of feeding per child breast-fed (OR = 0.56, 95% CI 0.32-0.98 for 18 months average duration breast-feeding versus none). Introduction of supplementary feeds did not substantially alter these effects. The overall risk reduction appeared greatest for the endometrioid and clear cell subtypes (OR per month of average breast-feeding per child breast-fed = 0.944, 95% CI 0.903-0.987).

CONCLUSIONS

Among women who have had the opportunity to breast-feed, ever breast-feeding and increasing durations of episodes of breast-feeding for each breast-fed child are associated with a decrease in the risk of ovarian cancer independent of numbers of births, which may be strongest for the endometrioid subtype.

Dietary phytoestrogens and the risk of ovarian cancer in the women's lifestyle and health cohort study

BACKGROUND

Dietary intake of phytoestrogens has been inversely associated to hormone-dependent cancers, such as prostate and breast cancers. Few studies have investigated the association between ovarian cancer and intake of phytoestrogens. We evaluated the associations between intake of phytoestrogens (isoflavonoids/lignans/coumestrol) and fiber (vegetable/cereal) and risk of ovarian cancer.

METHODS

In 1991-1992 a prospective population-based cohort study among Swedish women was conducted, including 47,140 women with complete dietary questionnaire data. During follow-up until December 2007, 163 women developed invasive (n = 117) and borderline (n = 46) ovarian cancers. The median follow-up time was 16 years and total person year was 747,178. Cox proportional hazards models were conducted to estimate multivariate risk ratios, 95% CI for associations with risk of ovarian cancer.

RESULTS

We found no association between intake of phytoestrogens or fiber and overall ovarian cancer risk. In addition, we found no statistically significant association between intake of specific food items rich in phytoestrogens (berries, nuts, beans/soy, and crisp or whole-grain bread) and ovarian cancer risk overall. Fiber and coumestrol was inversely associated with borderline ovarian cancer, but not with invasive ovarian cancer.

CONCLUSIONS

We found no association between intake of phytoestrogens or fiber and overall ovarian cancer risk.

IMPACT

Phytoestrogens do not play a major etiologic role in ovarian cancer, at least among women in this Swedish cohort with low bean/soy intake. However, our results of a difference in the effect of fiber or coumestrol between invasive and borderline ovarian cancer need to be evaluated in larger studies.

Serous and mucinous borderline ovarian tumors: are there real differences between these two entities?

OBJECTIVE

To evaluate the clinical outcome and pathological features of patients with borderline ovarian tumors (BOT) with special emphasis on serous and mucinous histology.

STUDY DESIGN

Medical and anatomopathological records were reviewed in the Gynecological Oncology Department of the Canarian University Hospital between 1990 and 2005. Survival rates were analyzed by using the Kaplan-Meier technique.

RESULTS

The study included 163 patients. Serous tumors corresponded to 68 cases and mucinous tumors to 91 cases. Eighty-nine percent of patients were at FIGO stage I, 1.2% at stage II and 9.8% at stage III. Serous histology was significantly related to the presence of peritoneal implants (22.4% vs 3.6%; p=0.001), positive peritoneal cytology (35.7% vs 8.5%; p=0.001) and bilaterality (27.9% vs 1.1%, p<0.0001). Event-free survival (EFS) rates at 2, 5 and 10 years were 96.7%, 92.7% and 90.5%, respectively, with a mean survival time of 183 months (CI 95% 172-193). Thirteen recurrence cases were found (7.9%) with a mean time to recurrence of 39.6 months (range 4-140). Overall survival (OS) rates at 2, 5 and 10 years were 100%, 96.4% and 93.6%, respectively, with a mean time of 189 months (CI 95% 179-198). Mucinous BOT were associated with significantly lower OS rates than serous BOT (10 years OS: 88.5% vs 98.2%; p=0.01).

CONCLUSIONS

Serous tumors present more unfavorable anatomopathological characteristics but are associated with better prognosis than mucinous tumors. If mucinous BOT diagnosis is retained physicians should be aware that their aggressive potential is not negligible.

Epidemiologic correlates of ovarian cortical inclusion cysts (CICs) support a dual precursor pathway to pelvic epithelial cancer

OBJECTIVE

Many ovarian carcinomas are presumed to arise within ovarian cortical inclusion cysts (CICs). This study examined the frequency of ovarian CICs in relation to epidemiologic risk factors in women with BRCA1 and BRCA2 (BRCA+) mutations.

METHODS

BRCA+ women who underwent risk-reducing bilateral salpingo-oophorectomy were studied (n=74). Fifteen demographic variables (e.g., age at time of surgery, age at first birth, age at menopause, body mass index (BMI), gravidity) from a review of the medical records and three pathologic variables (cystic and atretic follicles, corpora lutea) were recorded. Statistical associations were made using T-test or Chi Square analysis and logistic regression analysis for p-trend.

RESULTS

Women whose ovaries contained 7 for more CICs were older at first birth (p=0.034), surgery (p=0.059), menopause (p=0.046) and had a higher BMI (p=0.034) than those with <7 CICs. Regression analysis revealed a significant association between CICs and increasing BMI (p=0.01).

CONCLUSIONS

CICs correlate with greater body mass index, similar to low-grade serous and endometrioid tumors and in contrast to high-grade serous carcinoma and its putative precursor in the fallopian tube. A model is presented for ovarian and tubal pathways to pelvic cancer that are linked to different microscopic precursors with distinct epidemiologic correlates.

Cigarette smoking and risk of epithelial ovarian cancer

BACKGROUND

An increased risk of mucinous ovarian tumors among cigarette smokers has been observed in multiple studies. The association of smoking with other histologic types of ovarian cancer is less clear, but potentially holds greater importance for prevention of disease incidence and mortality.

METHODS

In a population-based study of 812 women with ovarian cancer diagnosed in western Washington State from 2002-2005 and 1,313 controls, we assessed the risk associated with cigarette smoking, with a particular focus on tumor subgroups jointly classified according to the degree of invasiveness and histology. Information was collected through in-person interviews, and logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The incidence of both borderline and invasive mucinous ovarian tumors was increased among women with a history of cigarette smoking (ORs and 95% CIs = 1.8, 1.2-2.9, and 1.8, 0.8-4.3, respectively). Increases in risk of these tumor types were most evident among women with greater smoking duration and pack-years of exposure, and among those who had smoked within the prior 15 years. We noted no clear patterns of risk of serous tumors with duration or pack-years of smoking; however, risk of these tumor types was somewhat elevated among women who had smoked within the previous 15 years (for borderline serous tumors, OR and 95% CI = 1.5, 0.9-2.3; for invasive serous tumors, OR and 95% CI = 1.4, 1.1-1.9). The risk of endometrioid, clear cell, and the remaining histologic types of invasive ovarian cancer was not increased among smokers.

CONCLUSION

In the aggregate, evidence is insufficient to determine whether smoking is linked with risk of serous or other non-mucinous histologic types of ovarian cancer. Studies that employ additional histopathologic and molecular techniques to more accurately delineate subsets of tumors may improve our understanding of the impact of smoking on ovarian cancer risk.

Different Risk Factor Profiles for Mucinous and Nonmucinous Ovarian Cancer: Results from the Danish MALOVA Study

OBJECTIVES

The aim of the study was to examine the overall risk factors for epithelial ovarian cancer and according to histologic subtypes.

MATERIALS AND METHODS

Ovarian cancer cases and controls were recruited from 1995 to 1999, and personal interviews were conducted. A total of 554 cases and 1,564 randomly selected controls were included. The analyses were done using multiple logistic regression models.

RESULTS

The overall risk of ovarian cancer decreased with ever being pregnant [odds ratios (OR), 0.40; 95% confidence intervals (CI), 0.30-0.55], with increasing pregnancies (OR, 0.63; 95% CI, 0.45-0.87 and OR, 0.51; 95% CI, 0.37-0.69 for two and three pregnancies as compared with one), and with older age at first and last pregnancy, respectively. Increasing years of ovulation was a very strong risk factor with a 7% to 8% increase in risk for each year of ovulation. Use of oral contraceptives (OR, 0.67, 95% CI, 0.53-0.85) and longer duration of use were associated with a decreased risk of ovarian cancer. Ever use of hormone replacement therapy increased the overall risk (OR, 1.30; 95% CI, 1.05-1.61). For all those variables, the effect was present for serous tumors, endometrioid tumors, and tumors of other histologies, but not for mucinous tumors. In contrast, current smoking was a risk factor only for mucinous tumors (OR, 1.78; 95% CI, 1.01-3.15) and increasing body mass index tended to increase the risk especially for mucinous and endometrioid tumors.

CONCLUSIONS

We confirmed already known risk factors for ovarian cancer, and we observed significant differences in the risk profiles between mucinous and nonmucinous tumors indicating different etiologies.