Assisted Reproductive Technology and the Incidence of Ovarian Cancer: A Meta-Analysis

Live birth is not the only relevant outcome in research assessing assisted reproductive technology

In assisted reproductive technology (ART) research, live birth has been generally accepted as an important outcome, if not the most important one. However, it has been reported inconsistently in the literature and solely focusing on live birth can lead to misinterpretation of research findings. In this review, we provide an overview on the definitions of live birth, including various denominators and numerators use. We present a series of real clinical examples in ART research to demonstrate the impact of variations in live birth on research findings and the importance of other outcomes, including multiple pregnancy, pregnancy loss, time to pregnancy leading to live birth, other short and long term maternal and offspring health outcomes and cost effectiveness measures. We suggest that outcome choices in ART research should be tailored for the research questions. A holistic outcome assessment beyond live birth would provide a full picture to address research questions in ART in terms of effectiveness and safety, and thus facilitate evidence-based decision making.

Ovulation induction drug and ovarian cancer: an updated systematic review and meta-analysis

OBJECTIVE

To explore the association between ovulation induction drugs and ovarian cancer.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Women without ovarian cancer who ever or never underwent ovarian induction.

INTERVENTION(S)

An extensive electronic search of the following databases was performed: PubMed, EMBASE, MEDLINE, Google Scholar, Cochrane Library and CNKI, from inception until January 2022. A total of 34 studies fulfilled our inclusion criteria and were included in the final meta-analysis. The odds ratio (OR) and random-effects model were used to estimate the pooled effects. The Newcastle-Ottawa Scale was used to assess the quality of included studies. Funnel plots and Egger tests were used to assess publication bias.

MAIN OUTCOMES

New diagnosed borderline ovarian tumor (BOT) and invasive ovarian cancer (IOC) between ovulation induction (OI) group and control (CT) group considering fertility outcome, OI cycles and specific OI drugs.

RESULTS

Primarily, there was no significant difference in the incidence of IOC and BOT between the OI and CT groups. Secondly, OI treatment did not increase the risk of IOC and BOT in the multiparous women, nor did it increase the risk of IOC in the nulliparous women. However, the risk of BOT appeared to be higher in nulliparous women treated with OI treatment. Thirdly, among women exposed to OI, the risk of IOC and BOT was higher in nulliparous women than in multiparous women. Fourthly, the risk of IOC did not increase with increasing OI cycles. Lastly, exposure to specific OI drugs also did not contribute to the risk of IOC and BOT.

CONCLUSION

Overall, OI treatment did not increase the risk of IOC and BOT in most women, regardless of OI drug type and OI cycle. However, nulliparous women treated with OI showed a higher risk of ovarian cancer, necessitating their rigorous monitoring and ongoing follow-up.

Hospitalizations up to 8 years following delivery in assisted reproductive technology-treated and subfertile women

OBJECTIVE

To investigate hospitalizations up to 8 years after live birth among women who used assisted reproductive technology (ART) or who were subfertile compared with women who conceived naturally.

DESIGN

Retrospective cohort.

SETTING

Deliveries among privately insured women aged ≥18 years between 2004 and 2017 from Massachusetts state vital records were linked to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System and hospital observational/inpatient stays.

PATIENT(S)

We compared patients with ART, medically assisted reproduction (MAR), and unassisted subfertile (USF) delivery with those with fertile delivery.

INTERVENTION(S)

NA.

MAIN OUTCOME MEASURE(S)

Postdelivery hospitalization information was derived from the International Classification of Diseases codes for discharges and combined by type. The relative risks and 95% confidence intervals (CIs) of hospitalization for up to the first 8 years postdelivery were modeled.

RESULT(S)

Among 492,515 deliveries, 5.6% used ART, 1.6% used MAR, and 1.8% were USF. Compared with fertile deliveries, deliveries that used ART or MAR or were USF were more likely to have hospital utilization (inpatient or observational stay) for any reason for up to 8 years of follow-up (USF, adjusted relative risk [aRR], 1.18 [95% CI, 1.12-1.25]; MAR, aRR, 1.20 [1.13-1.27]; and ART, aRR, 1.29 [1.25-1.34]). Assisted reproductive technology deliveries had an increased risk of hospitalization for conditions of the cardiovascular system (aRR, 1.31 [95% CI, 1.20-1.41]), overweight/obesity (aRR, 1.30 [1.17-1.44]), diabetes (aRR, 1.25 [1.05-1.49]), reproductive tract (aRR, 1.62 [1.47-1.79]), digestive tract (aRR, 1.39 [1.30-1.49]), thyroid (aRR, 2.02 [1.80-2.26]), respiratory system (aRR, 1.13 [1.03-1.24]), and cancer (aRR, 1.40 [1.18-1.65]) up to 8 years after delivery. Deliveries with MAR and subfertility had similar patterns of hospitalization as ART deliveries.

CONCLUSION(S)

Women who conceived through fertility treatment or experienced subfertility were at increased risk of subsequent hospitalization resulting from a variety of chronic and acute conditions.

Subfertility, use of fertility treatments and BRCA mutation status and the risk of ovarian cancer

PURPOSE

The objective of the study is to evaluate the possible association between history of subfertility, fertility treatments, BRCA mutations and the risk of ovarian cancer.

METHODS

This Israeli National Case-Control study included 1269 consecutive ovarian cancer cases and 2111 individually matched healthy controls. All participants were interviewed and molecular analysis of BRCA mutations were performed to 896 cases. The main outcome measure was reported history of subfertility and exposure to fertility treatments.

RESULTS

The rate of reported subfertility was 15.1% and 14.3% in ovarian cancer cases and controls, respectively. However, subfertility was more prevalent in cases with borderline ovarian cancer (but not for invasive ovarian cancer cases) than controls. Multivariate conditional logistic regression revealed that the risk of borderline ovarian cancer was elevated in both women treated for subfertility and those that were not treated for subfertility, (OR = 1.74; 95% CI 0.9-3.36 and OR = 1.79; 95% CI 0.98-3.26, respectively). In non-carriers of BRCA1/2 mutations, fertility treatments were associated with a decreased risk of invasive ovarian cancer while a significant increased risk of borderline ovarian cancer was observed (OR = 2.92, 95%CI 1.67-5.10).

CONCLUSIONS

Reported subfertility and exposure to fertility treatments were associated with borderline but not with invasive ovarian tumors. This association was more prominent in women who are non-carriers of a BRCA mutation.

Fertility treatment and cancers-the eternal conundrum: a systematic review and meta-analysis

STUDY QUESTION

Does fertility treatment (FT) significantly increase the incidence of breast, ovarian, endometrial or cervical cancer?

SUMMARY ANSWER

Overall, FT does not significantly increase the incidence of breast, ovarian or endometrial cancer and may even reduce the incidence of cervical cancer.

WHAT IS KNOWN ALREADY

Infertility affects more than 14% of couples. Infertility and nulliparity are established risk factors for endometrial, ovarian and breast cancer, yet the association with FT is more contentious.

STUDY DESIGN, SIZE, DURATION

A literature search was carried out using Cochrane Library, EMBASE, Medline and Google Scholar up to December 2019. Peer-reviewed studies stating cancer incidence (breast, ovarian, endometrial or cervical) in FT and no-FT groups were identified. Out of 128 studies identified, 29 retrospective studies fulfilled the criteria and were included (n = 21 070 337).

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the final meta-analysis, 29 studies were included: breast (n = 19), ovarian (n = 19), endometrial (n = 15) and cervical (n = 13), 17 studies involved multiple cancer types and so were included in each individual cancer meta-analysis. Primary outcome of interest was cancer incidence (breast, ovarian, endometrial and cervical) in FT and no-FT groups. Secondary outcome was cancer incidence according to specific fertility drug exposure. Odds ratio (OR) and random effects model were used to demonstrate treatment effect and calculate pooled treatment effect, respectively. A meta-regression and eight sub-group analyses were performed to assess the impact of the following variables, maternal age, infertility, study size, outliers and specific FT sub-types, on cancer incidence.

MAIN RESULTS AND THE ROLE OF CHANCE

Cervical cancer incidence was significantly lower in the FT group compared with the no-FT group: OR 0.68 (95% CI 0.46-0.99). The incidences of breast (OR 0.86; 95% CI 0.73-1.01) and endometrial (OR 1.28; 95% CI 0.92-1.79) cancers were not found to be significantly different between the FT and no-FT groups. Whilst overall ovarian cancer incidence was not significantly different between the FT and no-FT groups (OR 1.19; 95% CI 0.98-1.46), separate analysis of borderline ovarian tumours (BOT) revealed a significant association (OR 1.69; 95% CI 1.27-2.25). In further sub-group analyses, ovarian cancer incidence was shown to be significantly higher in the IVF (OR 1.32; 95% CI 1.03-1.69) and clomiphene citrate (CC) treatment group (OR 1.40; 95% CI 1.10-1.77), respectively when compared with the no-FT group. Conversely, the incidences of breast (OR 0.75; 95% CI 0.61-0.92) and cervical cancer (OR 0.58; 95% CI 0.38-0.89) were significantly lower in the IVF treatment sub-group compared to the no-FT group.

LIMITATIONS, REASONS FOR CAUTION

The large, varied dataset spanning a wide study period introduced significant clinical heterogeneity. Thus, results have to be interpreted with an element of caution. Exclusion of non-English citations, unpublished work and abstracts, in order to ensure data accuracy and reliability was maintained, may have introduced a degree of selection bias.

WIDER IMPLICATIONS OF THE FINDINGS

The results for breast, ovarian, endometrial and cervical cancer are reassuring, in line with previously published meta-analyses for individual cancers but the association between IVF and CC treatment and an increase in ovarian cancer incidence requires additional work to understand the potential mechanism driving this association. In particular, focusing on (i) discriminating specific treatments effects from an inherent risk of malignancy; (ii) differential risk profiles among specific patient sub-groups (refractory treatment and obesity); and (iii) understanding the impact of FT outcomes on cancer incidence.

STUDY FUNDING/COMPETING INTEREST(S)

This study did not receive any funding. The authors have no financial, personal, intellectual and professional conflicts of interest to declare.

PROSPERO REGISTRATION NUMBER

CRD42019153404.

Obesity aggravates COVID-19: An updated systematic review and meta-analysis

This review aimed to evaluate the impact of obesity on the onset, exacerbation, and mortality of coronavirus disease 2019 (COVID‐19); and compare the effects of different degrees of obesity. PubMed, EMBASE, and Web of Science were searched to find articles published between December 1, 2019, and July 27, 2020. Only observational studies with specific obesity definition were included. Literature screening and data extraction were conducted simultaneously by two researchers. A random‐effects model was used to merge the effect quantity. Sensitivity analysis, subgroup analysis, and meta‐regression analysis were used to deal with the heterogeneity among studies. Forty‐one studies with 219,543 subjects and 115,635 COVID‐19 patients were included. Subjects with obesity were more likely to have positive SARS‐CoV‐2 test results (OR = 1.50; 95% CI: 1.37–1.63, I² = 69.2%); COVID‐19 patients with obesity had a higher incidence of hospitalization (OR = 1.54, 95% CI: 1.33–1.78, I² = 60.9%); hospitalized COVID‐19 patients with obesity had a higher incidence of intensive care unit admission (OR = 1.48, 95% CI: 1.24–1.77, I² = 67.5%), invasive mechanical ventilation (OR = 1.47, 95% CI: 1.31–1.65, I² = 18.8%), and in‐hospital mortality (OR = 1.14, 95% CI: 1.04–1.26, I² = 74.4%). A higher degree of obesity also indicated a higher risk of almost all of the above events. The region may be one of the causes of heterogeneity. Obesity could promote the occurrence of the whole course of COVID‐19. A higher degree of obesity may predict a higher risk. Further basic and clinical therapeutic research needs to be strengthened.

Infertility and ovarian cancer risk: Evidence from nine prospective cohort studies

Epidemiological studies have investigated the relationship between infertility and the risk of ovarian cancer (OC); however, the results have been inconsistent. We therefore conducted the first meta-analysis to update and quantify the aforementioned association based on prospective cohort studies. Studies were identified by searching PubMed, EMBASE and Web of Science databases up to January 8, 2020. We extracted data from the studies and performed quality assessments. Summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Publication bias, and subgroup, meta-regression and sensitivity analyses were also conducted. Nine prospective cohort studies with a total of 10 383 OC cases and 6 278 830 participants were included in the present study. The summary RR of the association between infertility and the risk of OC was 1.51 (95% CI: 1.35-1.69), with low heterogeneity. Positive associations were observed in most subgroup analyses stratified by predefined factors, including region, duration of follow-up, study quality, causes of infertility, invasiveness of OC, infertility treatment status and adjustment of potential confounding parameters. No significant publication bias was detected. Our findings suggest that infertility in women were associated with an increased risk of OC.

Risk of ovarian cancer in women treated with ovarian stimulating drugs for infertility

BACKGROUND

This is an updated version of the original Cochrane Review published in the Cochrane Library in 2013 (Issue 8) on the risk of ovarian cancer in women using infertility drugs when compared to the general population or to infertile women not treated. The link between fertility drugs and ovarian cancer remains controversial.

OBJECTIVES

To evaluate the risk of invasive ovarian cancer and borderline ovarian tumours in women treated with ovarian stimulating drugs for subfertility.

SEARCH METHODS

The original review included published and unpublished observational studies from 1990 to February 2013. For this update, we extended the searches from February 2013 to November 2018; we evaluated the quality of the included studies and judged the certainty of evidence by using the GRADE approach. We have reported the results in a Summary of findings table to present effect sizes across all outcome types.

SELECTION CRITERIA

In the original review and in this update, we searched for randomised controlled trials (RCTs) and non-randomised studies and case series including more than 30 participants.

DATA COLLECTION AND ANALYSIS

At least two review authors independently conducted eligibility and 'Risk of bias' assessments and extracted data. We grouped studies based on the fertility drug used for two outcomes: borderline ovarian tumours and invasive ovarian cancer. We conducted no meta-analyses due to expected methodological and clinical heterogeneity.

MAIN RESULTS

We included 13 case-control and 24 cohort studies (an additional nine new cohort and two case-control studies), which included a total of 4,684,724 women.Two cohort studies reported an increased incidence of invasive ovarian cancer in exposed subfertile women compared with unexposed women. One reported a standardised incidence ratio (SIR) of 1.19 (95% confidence interval (CI) 0.54 to 2.25) based on 17 cancer cases. The other cohort study reported a hazard ratio (HR) of 1.93 (95% CI 1.18 to 3.18), and this risk was increased in women remaining nulligravid after using clomiphene citrate (HR 2.49, 95% CI 1.30 to 4.78) versus multiparous women (HR 1.52, 95% CI 0.67 to 3.42) (very low-certainty evidence). The slight increase in ovarian cancer risk among women having between one and three cycles of in vitro fertilisation (IVF) was reported, but this was not clinically significant (P = 0.18). There was no increase in risk of invasive ovarian cancer after use of infertility drugs in women with the BRCA mutation according to one cohort and one case-control study. The certainty of evidence as assessed using GRADE was very low.For borderline ovarian tumours, one cohort study reported increased risk in exposed women with an SIR of 3.61 (95% CI 1.45 to 7.44), and this risk was greater after treatment with clomiphene citrate (SIR 7.47, 95% CI 1.54 to 21.83) based on 12 cases. In another cohort study, the risk of a borderline ovarian tumour was increased, with an HR of 4.23 (95% CI 1.25 to 14.33), for subfertile women treated with IVF compared with a non-IVF-treated group with more than one year of follow-up. A large cohort reported increased risk of borderline ovarian tumours, with HR of 2.46 (95% CI 1.20 to 5.04), and this was based on 17 cases. A significant increase in serous borderline ovarian tumours was reported in one cohort study after the use of progesterone for more than four cycles (risk ratio (RR) 2.63, 95% CI 1.04 to 6.64). A case-control study reported increased risk after clomiphene citrate was taken, with an SIR of 2.5 (95% CI 1.3 to 4.5) based on 11 cases, and another reported an increase especially after human menopausal gonadotrophin was taken (odds ratio (OR) 9.38, 95% CI 1.66 to 52.08). Another study estimated an increased risk of borderline ovarian tumour, but this estimation was based on four cases with no control reporting use of fertility drugs. The certainty of evidence as assessed using GRADE was very low.However, although some studies suggested a slight increase in risks of ovarian cancer and borderline ovarian tumour, none provided moderate- or high-certainty evidence, as summarised in the GRADE tables.

AUTHORS' CONCLUSIONS

Since the last version of this review, only a few new relevant studies have provided additional findings with supporting evidence to suggest that infertility drugs may increase the risk of ovarian cancer slightly in subfertile women treated with infertility drugs when compared to the general population or to subfertile women not treated. The risk is slightly higher in nulliparous than in multiparous women treated with infertility drugs, and for borderline ovarian tumours. However, few studies have been conducted, the number of cancers is very small, and information on the dose or type of fertility drugs used is insufficient.

Fertility drugs and cancer: a guideline

Methodological limitations in studying the association between the use of fertility drugs and cancer include the inherent increased risk of cancer in women who never conceive, the low incidence of most of these cancers, and that the age of diagnosis of cancer typically is many years after fertility drug use. Based on available data, there does not appear to be a meaningful increased risk of invasive ovarian cancer, breast cancer, or endometrial cancer following the use of fertility drugs. Several studies have shown a small increased risk of borderline ovarian tumors; however, there is insufficient consistent evidence that a particular fertility drug increases the risk of borderline ovarian tumors, and any absolute risk is small. Given the available literature, patients should be counseled that infertile women may be at an increased risk of invasive ovarian, endometrial, and breast cancer; however, use of fertility drugs does not appear to increase this risk.

Does ovarian stimulation for IVF increase gynaecological cancer risk? A systematic review and meta-analysis

The aim of this study was to evaluate whether ovarian stimulation for IVF increases the risk of gynaecological cancer, including ovarian, endometrial, cervical and breast cancers, as an independent risk factor. A systematic review and meta-analysis was conducted. Clinical trials that examined the association between ovarian stimulation for IVF and gynaecologic cancers were included. The outcomes of interest were incidence rate of gynaecologic cancers. Twelve cohort studies with 178,396 women exposed to IVF were included; 10 studies were used to analyse ovarian (167,640 women) and breast (151,702 women) cancers, and six studies were identified in the analysis of endometrial (116,672 women) and cervical cancer (114,799 women). Among these studies, 175 ovarian, 48 endometrial, 502 cervical and 866 cases of breast cancer were reported. The meta-analysis found no significant association between ovarian stimulation for IVF and increased ovarian, endometrial, cervical and breast cancer risk (odds ratio [OR] 1.06, 95% confidence interval [CI] 0.85 to 1.32; OR 0.97, 95% CI 0.58 to 1.63; OR 0.43, 95% CI 0.30 to 0.60; OR 0.69, 95% CI 0.63 to 0.76, respectively). Ovarian stimulation for IVF, therefore, does not increase the gynaecologic cancer risk, whether hormone-dependent endometrial and breast cancer or non-hormone-dependent ovarian and cervical cancer.

Predictors of Driving Ability Following Stroke: A Systematic Review

BACKGROUND AND PURPOSE

The objective of this review is to identify the most consistent predictors of driving ability post stroke.

METHOD

A computerized search of numerous databases from 1966 forward was completed. Measured outcomes included voluntary driving cessation or results of on-road driving evaluation. Studies were evaluated using the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

17 eligible studies were identified. The most useful screening tests were tests assessing cognitive abilities. These included the Trail Making A and B tests, the Rey-Osterreith Complex Figure Design, and the Useful Field of View Test.

CONCLUSION

Cognitive tests that assess multiple cognitive domains relevant to driving appear to have the best reproducibility in predicting fitness to drive in stroke patients.

Fertility drugs, reproductive strategies and ovarian cancer risk

Several adverse effects have been related to infertility treatments, such as cancer development. In particular, the relationship between infertility, reproductive strategies, and risk of gynecological cancers has aroused much interest in recent years. The evaluation of cancer risk among women treated for infertility is very complex, mainly because of many factors that can contribute to occurrence of cancer in these patients (including parity status). This article addresses the possible association between the use of fertility treatments and the risk of ovarian cancer, through a scrupulous search of the literature published thus far in this field. Our principal objective was to give more conclusive answers on the question whether the use of fertility drug significantly increases ovarian cancer risk. Our analysis focused on the different types of drugs and different treatment schedules used. This study provides additional insights regarding the long-term relationships between fertility drugs and risk of ovarian cancer.

Ovarian cancer: risk factors, treatment and management

Ovarian cancer is the fifth most common cancer affecting women in the UK today, with associated statistics illustrating a steadily increasing rate, particularly in women aged 65 and over (Cancer Research UK, 2013). There are no recognised preventative measures and no effective screening tool. Although evidence suggests that the majority of women experience a variety of non-specific symptoms in the year before diagnosis, the disease it is not commonly recognised until an advanced stage, leading to increased mortality and morbidity. This highlights the need to raise awareness among health professionals and women as a whole, as early recognition undoubtedly improves ovarian cancer survival. Best clinical practice in the UK for the recognition and initial management of ovarian cancer is provided by the National Institute for Health and Care Excellence (NICE). Clinical guideline CG 122 (NICE, 2011) and quality standard QS 18 (NICE, 2012) use relevant clinical evidence to define high-quality care standards for ovarian cancer management. Accurate staging of ovarian cancer is essential to the provision of individualised care and management. However, there is currently no single test that provides a reliable indicator of ovarian malignancy. At present, risk-of-malignancy scores are calculated by serum cancer antigen 125 (CA 125) levels, ultrasound score and menopausal status. These are widely used to identify women who are at high risk and require referral to a specialised gynaecological oncology service. Women diagnosed with ovarian cancer require information and support. The clinical nurse specialist acts as a key worker, providing communication, support and holistic care throughout a woman's cancer journey. The value of this role cannot be underestimated. Surgery followed by platinum-based chemotherapy is the usual standard treatment pathway, although individualised assessment and management may deviate from it. Early disease may be successfully treated with surgery alone; advanced disease may require complex management and treatment. New treatments such as bevacizumab show promise of improving ovarian cancer outcomes.

Potential increased risk of cancer from commonly used medications: an umbrella review of meta-analyses

Several commonly used medications have been associated with increased cancer risk in the literature. Here, we evaluated the strength and consistency of these claims in published meta-analyses. We carried out an umbrella review of 74 meta-analysis articles addressing the association of commonly used medications (antidiabetics, antihyperlipidemics, antihypertensives, antirheumatics, drugs for osteoporosis, and others) with cancer risk where at least one meta-analysis in the medication class included some data from randomized trials. Overall, 51 articles found no statistically significant differences, 13 found some decreased cancer risk, and 11 found some increased risk (one reported both increased and decreased risks). The 11 meta-analyses that found some increased risks reported 16 increased risk estimates, of which 5 pertained to overall cancer and 11 to site-specific cancer. Six of the 16 estimates were derived from randomized trials and 10 from observational data. Estimates of increased risk were strongly inversely correlated with the amount of evidence (number of cancer cases) (Spearman's correlation coefficient = -0.77, P < 0.001). In 4 of the 16 topics, another meta-analysis existed that was larger (n = 2) or included better controlled data (n = 2) and in all 4 cases there was no statistically significantly increased risk of malignancy. No medication or class had substantial and consistent evidence for increased risk of malignancy. However, for most medications we cannot exclude small risks or risks in population subsets. Such risks are unlikely to be possible to document robustly unless very large, collaborative studies with standardized analyses and no selective reporting are carried out.

Risk of ovarian cancer in women treated with ovarian stimulating drugs for infertility

BACKGROUND

The use of assisted reproductive techniques is increasing, but the possible link between fertility drugs and ovarian cancer remains controversial.

OBJECTIVES

To evaluate the risk of ovarian cancer in women treated with ovulation stimulating drugs for subfertility.

SEARCH METHODS

We searched for published and unpublished observational studies from 1990 to February 2013. The following databases were used: the Cochrane Gynaecological Cancer Collaborative Review Group's Trial Register, Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 1, MEDLINE (to February week 4 2013), EMBASE (to 2013 week 09) and databases of conference abstracts. We also scanned reference lists of retrieved articles. The search was not restricted by language of publication.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs) and non-randomised studies, and case series including more than 30 participants, reporting on women with exposure to ovarian stimulating drugs for treatment of subfertility and histologically confirmed borderline or invasive ovarian cancer.

DATA COLLECTION AND ANALYSIS

At least two review authors independently conducted eligibility and 'Risk of bias' assessment, and extracted data. We grouped studies based on the fertility drug used for two outcomes: borderline ovarian tumours and invasive ovarian cancer. We expressed findings as adjusted odds ratio (OR), risk ratio (RR), hazard ratio (HR) or crude OR if adjusted values were not reported and standardised incidence ratio (SIR) where reported. We conducted no meta-analyses due to expected methodological and clinical heterogeneity.

MAIN RESULTS

We included 11 case-control studies and 14 cohort studies, which included a total of 182,972 women.Seven cohort studies showed no evidence of an increased risk of invasive ovarian cancer in subfertile women treated with any drug compared with untreated subfertile women. Seven case-control studies showed no evidence of an increased risk, compared with control women of a similar age. Two cohort studies reported an increased incidence of invasive ovarian cancer in subfertile women treated with any fertility drug compared with the general population. One of these reported a SIR of 5.0 (95% confidence interval (CI) 1.0 to 15), based on three cancer cases, and a decreased risk when cancer cases diagnosed within one year of treatment were excluded from the analysis(SIR 1.67, 95% CI 0.02 to 9.27). The other cohort study reported an OR of 2.09 (95% CI 1.39 to 3.12), based on 26 cases.For borderline ovarian tumours, exposure to any fertility drug was associated with a two to three-fold increased risk in two case-control studies. One case-control study reported an OR of 28 (95% CI 1.5 to 516), which was based on only four cases. In one cohort study, there was more than a two-fold increase in the incidence of borderline tumours compared with the general population (SIR 2.6, 95% CI 1.4 to 4.6) and in another the risk of a borderline ovarian tumour was HR 4.23 (95% CI 1.25 to 14.33) for subfertile women treated with in vitro fertilisation (IVF) compared with a non-IVF treated group with more than one year of follow-up.There was no evidence of an increased risk in women exposed to clomiphene alone or clomiphene plus gonadotrophin, compared with unexposed women. One case-control study reported an increased risk in users of human menopausal gonadotrophin (HMG)(OR 9.4, 95% CI 1.7 to 52). However, this estimate is based on only six cases with a history of HMG use.

AUTHORS' CONCLUSIONS

We found no convincing evidence of an increase in the risk of invasive ovarian tumours with fertility drug treatment. There may be an increased risk of borderline ovarian tumours in subfertile women treated with IVF. Studies showing an increase in the risk of ovarian cancer had a high overall risk of bias, due to retrospective study design, lack of accounting for potential confounding and estimates based on a small number of cases. More studies at low risk of bias are needed.

Chinese herbal medicine for infertility with anovulation: a systematic review

The aim of this systematic review is to assess the effectiveness and safety of Chinese herbal medicine (CHM) in treatment of anovulation and infertility in women. Eight (8) databases were extensively retrieved. The Chinese electronic databases included VIP Information, CMCC, and CNKI. The English electronic databases included AMED, CINAHL, Cochrane Library, Embase, and MEDLINE(®). Randomized controlled trials using CHM as intervention were included in the study selection. The quality of studies was assessed by the Jadad scale and the criteria referred to Cochrane reviewers' handbook. The efficacy of CHM treatment for infertility with anovulation was evaluated by meta-analysis. There were 692 articles retrieved according to the search strategy, and 1659 participants were involved in the 15 studies that satisfied the selection criteria. All the included trials were done in China. Meta-analysis indicated that CHM significantly increased the pregnancy rate (odds ratio [OR] 3.12, 95% confidence interval [CI] 2.50-3.88) and reduced the miscarriage rate (OR 0.2, 95% CI 0.10-0.41) compared to clomiphene. In addition, CHM also increased the ovulation rate (OR 1.55, 95% CI 1.06-2.25) and improved the cervical mucus score (OR 3.82, 95% CI 1.78-8.21) compared to clomiphene, while there were no significant difference between CHM and clomiphene combined with other medicine. CHM is effective in treating infertility with anovulation. Also, no significant adverse effects were identified for the use of CHM from the studies included in this review. However, owing to the low quality of the studies investigated, more randomized controlled trials are needed before evidence-based recommendation regarding the effectiveness and safety of CHM in the management of infertility with anovulation can be provided.

Ovarian epithelial tumors and reproductive factors: a systematic review

PURPOSE

The aim of this systematic review is to summarize the current knowledge about the etiology and pathogenesis of borderline tumors ovarian cancer with special emphasis on the role of endocrine treatments and reproductive factors to establish a foundation for future studies.

METHODS

We performed a systematic review on the relation between ovarian epithelial tumors (OET) and reproductive factors using the keywords: ovarian cancer, ovarian tumor, ovarian borderline tumor, age at menarche, age at menopause, parity, infertility, PCO syndrome, oral contraception, menopausal hormone therapy, fertility treatment. Totally, 3,290 abstracts were scanned for their relevance in this publication and 127 were finally included.

RESULTS

The incidence of ovarian epithelial cancer and ovarian borderline tumors is influenced by certain reproductive factors. The strongest protective effects are conferred by parity and use of oral contraceptive pills. Recent molecular biologic and histopathologic studies prove that OET represent a diverse group of tumors, each histologic type with a different genetic background. This is at least partly reflected in epidemiologic and clinical studies showing different risk modulating effects of reproductive factors and endocrine therapies on OET.

CONCLUSIONS

The etiology and pathogenesis of ovarian cancer are still not fully understood. None of the so far proposed hypothesis on the development of OET can fully account for the epidemiologic and clinical findings in the context of reproductive factors and OET development. Further research approaches are warranted and need to put more weight on the clinical and genetical diversity of OET to yield a more detailed insight into their pathogenesis.

Are infertility treatments a potential risk factor for cancer development? Perspective of 30 years of follow-up

The aim of the present study was to evaluate the possible risk for cancer development in infertile women with over 30 years of follow-up. Cancer development was assessed through linkage with the National Cancer Registry updated to 31 December 2005 in a cohort of 2431 women who were treated for infertility at the Sheba Medical Center in Israel during the period 1964-1974 and contributed more than 84,000 women years of follow-up. Standardized incidence ratios (SIR) were calculated between the observed cancer cases and the expected cancer rates in the general population. The mean age at the end of follow-up was 62.7 years. Eighteen cases of ovarian cancer were observed as compared to 18.1 expected (SIR = 1.0; 95% CI = 0.59-1.57). For breast cancer, 153 cases were observed as compared to 131.9 expected (SIR = 1.16; 95% CI = 0.98-1.36), and for endometrial cancer, 30 cases were observed as compared to 17.8 expected cases (SIR = 1.69; 95% CI = 1.14-2.41). No excess risk associated with exposure to gonadotropins was observed. Infertility was found to be associated with significant increased risk for endometrial cancer and borderline increased risk for breast cancer. Ovarian cancer risk was not found to be elevated. No significant excess risk was associated with treatment with ovulation induction.

Endometrioid ovarian carcinoma in a woman with a history of infertility and multiple in-vitro fertilization treatment cycles

Ovarian cancer is rarely diagnosed during assisted reproduction. Several case-control and cohort studies have described its incidence within the infertile population well after the assisted reproductive process. We present a case of endometrioid adenocarcinoma that developed during the ovarian stimulation process and show corresponding ultrasound images of its development.

Benefits and risks of ovarian function and reproduction for cancer development and prevention

Ovarian function and menstrual cycle disturbances, pregnancy, and reproductive medicine procedures can either increase gynecological cancer risk or prevent cancer development. For ovarian cancer development, there are two hypotheses, which are connected with ovulation and gonadotropin secretion. Most of the ovarian cancers seem to be derived from displaced ovarian surfice epithelial cells. One year of ovulatory cycles increases the ovarian cancer risk by 6%. Ovulation between 22 and 29 years of age causes the highest risk increase per year. In contrast, progesterone or progestins appear to create protection. Lifestyle can affect or modify ovarian cancer risk. Breast cancer risk is very much related to age of menarche and menopause, pregnancy, and breast feeding. All of which are related to ovarian function and progestogenic impact that translates either into breast cancer risk increase or decrease. This is modified by body mass index, physical activity, and lifestyle in general. The risk of endometrial cancer is most closely related to endogenous progesterone during the menstrual cycle and pregnancy or by exogenous progestogens as in oral contraceptives. These effects are progestogen dose and time dependent. Endometrial cancer risk can also be increased by estrogen-producing tumors or long-term estrogen treatment.

Ovarian stimulation: is there a long-term risk for ovarian, breast and endometrial cancer?

Adverse effects have been related to infertility treatments. Infertility in general, and female infertility in particular, is a well established risk factor for cancer development, especially ovarian, breast and endometrial cancer. This article addresses the possible association between infertility and cancer development, with an emphasis on the influence of infertility treatments, through a meticulous search of the literature published thus far. While results regarding the possible association of infertility, ovulation induction medications and invasive ovarian cancer show no increased risk and are reassuring, results for increased risk for breast cancer and endometrial cancer following exposure to ovarian stimulation medications are inconclusive. Larger population studies with longer periods of follow-up and better adjustment for confounding factors are needed.

Fertility drugs and ovarian cancer risk: a critical review of the literature

There is evidence that medications used for ovarian stimulation and in vitro fertilization may be associated with ovarian cancer. In this review, we attempt to describe this relationship according to the most recent epidemiologic data and to present the possible mechanisms on the molecular level that could potentially explain this correlation. Currently there is no proven relationship between any type of ovarian cancer and drugs used for infertility treatment. Overall, infertile women have increased risk for ovarian malignancies. Nulligravidas that received treatment are at increased risk for ovarian malignancy as compared to women that conceived after treatment. More studies with the appropriate statistical power and follow-up time, as well as with better adjustment for confounding factors, which coexist in infertile patients, are required to evaluate accurately the long-term effects of these drugs and procedures.

Short and long-term risks to women who conceive through in vitro fertilization

There are a number of potential risks to women who conceive through in vitro fertilisation (IVF). Among these, ovarian hyperstimulation syndrome and multiple pregnancies are the most serious. Other potential risks include increased levels of anxiety and depression, ovarian torsion, ectopic pregnancy, pre-eclampsia, placenta praevia, placental separation and increased risk of cesarean section. The association between assisted conception and long-term risk of cancer is debatable. The objective of this review is to critically evaluate the current evidence for potential risks to women who conceive through IVF. To assess the relative risk for any condition, a number of factors need to be taken into account including the method used in identifying the study and control group, the women's characteristics and the number of women included in the study. Many conditions such as ectopic pregnancy and pre-eclampsia appear to be commoner in assisted conception than in spontaneous pregnancy. Nevertheless, the increased risk of these conditions is probably related to the woman's subfertility status and/or increased incidence of multiple pregnancy. Currently, all efforts should concentrate on reduction of multiple births from IVF by restricting the number of transferred embryos.

Use of fertility drugs and risk of ovarian cancer: Danish Population Based Cohort Study

OBJECTIVE

To examine the effects of fertility drugs on overall risk of ovarian cancer using data from a large cohort of infertile women.

DESIGN

Population based cohort study.

SETTING

Danish hospitals and private fertility clinics.

PARTICIPANTS

54,362 women with infertility problems referred to all Danish fertility clinics during 1963-98. The median age at first evaluation of infertility was 30 years (range 16-55 years), and the median age at the end of follow-up was 47 (range 18-81) years. Included in the analysis were 156 women with invasive epithelial ovarian cancer (cases) and 1241 subcohort members identified in the cohort during follow-up in 2006.

MAIN OUTCOME MEASURE

Effect of four groups of fertility drugs (gonadotrophins, clomifene citrate, human chorionic gonadotrophin, and gonadotrophin releasing hormone) on overall risk of ovarian cancer after adjustment for potential confounding factors.

RESULTS

Analyses within cohort showed no overall increased risk of ovarian cancer after any use of gonadotrophins (rate ratio 0.83, 95% confidence interval 0.50 to 1.37), clomifene (1.14, 0.79 to 1.64), human chorionic gonadotrophin (0.89, 0.62 to 1.29), or gonadotrophin releasing hormone (0.80, 0.42 to 1.51). Furthermore, no associations were found between all four groups of fertility drugs and number of cycles of use, length of follow-up, or parity.

CONCLUSION

No convincing association was found between use of fertility drugs and risk of ovarian cancer.

Cancer risk after exposure to treatments for ovulation induction

Uncertainty continues as to whether treatments for ovulation induction are associated with increased risk of cancer. The authors conducted a long-term population-based historical cohort study of parous women. A total of 15,030 women in the Jerusalem Perinatal Study who gave birth in 1974-1976 participated in a postpartum survey. Cancer incidence through 2004 was analyzed using Cox's proportional hazards models, controlling for age and other covariates. Women who used drugs to induce ovulation (n = 567) had increased risks of cancer at any site (multivariate hazard ratio (HR) = 1.36, 95% confidence interval (CI): 1.06, 1.74). An increased risk of uterine cancer was found among women treated with ovulation-inducing agents (HR = 3.39, 95% CI: 1.28, 8.97), specifically clomiphene (HR = 4.56, 95% CI: 1.56, 13.34). No association was noted between use of ovulation-inducing agents and ovarian cancer (age-adjusted HR = 0.61, 95% CI: 0.08, 4.42). Ovulation induction was associated with a borderline-significant increased risk of breast cancer (multivariate HR = 1.42, 95% CI: 0.99, 2.05). Increased risks were also observed for malignant melanoma and non-Hodgkin lymphoma. These associations appeared stronger among women who waited more than 1 year to conceive. Additional follow-up studies assessing these associations by drug type, dosage, and duration are needed.

Fertility drugs and risk of ovarian cancer: dispelling the myth

PURPOSE OF REVIEW

Worldwide 50-80 million people suffer from infertility. Assisted reproductive technology has provided a way of overcoming infertility and childlessness. The current article will focus on data linking infertility and its treatment to ovarian cancer.

RECENT FINDINGS

Ovarian cancer risks associated with fertility drug treatment are encouraging, but not decisive. In view of the limited ability to evaluate drug effects on borderline tumors, given their rare occurrence, studies involving patient reports of prior drug exposures have noted an elevated risk of borderline tumors associated with fertility drugs. Nevertheless, the risk of invasive ovarian cancer appears to be restricted to those women who remain childless despite the infertility treatment.

SUMMARY

As long as doubt persists, it might be advisable to reflect on a few clinical recommendations: identify high-risk infertile patients for ovarian cancer, investigate preexisting cancer before fertility treatment, inform patients regarding potential risks, obtain an informed consent, avoid exposure to long periods of ovulation induction cycles that are given before patients are referred for in-vitro fertilization and embryo transfer for women at greater risk and monitor women who have been treated with these drugs, especially those who failed to conceive, regularly and thoroughly.

Maternal morbidity and mortality in in-vitro fertilization

Pregnancies following in-vitro fertilization (IVF) are known to be at increased risk of a number of pregnancy- and delivery-related complications when compared with non-IVF pregnancies. Most of these complications seem to be due to underlying fertility problems. Ovarian stimulation carries a marked risk for two serious conditions - ovarian torsion and ovarian hyperstimulation syndrome - both of which are relatively rare. Although some common pregnancy complications show an up to five times increased risk over non-IVF pregnancies, the absolute frequencies are still low for most of these conditions. However, an increased risk of placenta praevia might be to some extent due to the IVF procedure. No long-terms effects on cancer risk or mortality can be linked to the IVF procedure, although follow-up time is still relatively short.

Pregnancy after in vitro fertilization-intracytoplasmic sperm injection obtained with a modified natural cycle in a BRCA1 mutation carrier

OBJECTIVE

To report a successful pregnancy after a semi-natural IVF cycle for a BRCA1 gene mutation carrier.

DESIGN

Case report.

SETTING

University hospital.

PATIENT(S)

A 26-year-old patient with BRCA1 gene mutation.

INTERVENTION(S)

Semi-natural IVF cycle and intracytoplasmic sperm injection.

MAIN OUTCOME MEASURE(S)

Pregnancy rate.

RESULT(S)

A modified natural IVF cycle was performed, resulting in pregnancy and delivery.

CONCLUSION(S)

A modified natural IVF cycle is an effective and safe solution for BRCA1 or BRCA2 mutation gene carrier women with couple infertility.

Gonadotropins and ovarian cancer

Ovarian epithelial cancer (OEC) accounts for 90% of all ovarian cancers and is the leading cause of death from gynecological cancers in North America and Europe. Despite its clinical significance, the factors that regulate the development and progression of ovarian cancer are among the least understood of all major human malignancies. The two gonadotropins, FSH and LH, are key regulators of ovarian cell functions, and the potential role of gonadotropins in the pathogenesis of ovarian cancer is suggested. Ovarian carcinomas have been found to express specific receptors for gonadotropins. The presence of gonadotropins in ovarian tumor fluid suggests the importance of these factors in the transformation and progression of ovarian cancers as well as being prognostic indicators. Functionally, there is evidence showing a direct action of gonadotropins on ovarian tumor cell growth. This review summarizes the key findings and recent advances in our understanding of these peptide hormones in ovarian cancer development and progression and their role in potential future cancer therapy. We will first discuss the supporting evidence and controversies in the "gonadotropin theory" and the use of animal models for exploring the involvement of gonadotropins in the etiology of ovarian cancer. The role of gonadotropins in regulating the proliferation, survival, and metastasis of OEC is next summarized. Relevant data from ovarian surface epithelium, which is widely believed to be the precursor of OEC, are also described. Finally, we will discuss the clinical applications of gonadotropins in ovarian cancer and the recent progress in drug development.

Fertility Drugs and Gynecologic Cancer

Fertility drugs (FD) are spreading worldwide fast and therefore many studies have reviewed the possible association between the use of these drugs and cancer. Since the drugs used for ovulation induction during in vitro fertilization (IVF) like hCG, hMG, rFSH increase the levels of gonadal hormones, concerns have grown regarding the risk of developing cancer in breast, ovary, endometrium, and other target organs. In this review, we discuss a number of different studies published in recent years that show no association between the use of these drugs and most cancers.

Tumour incidence in Swedish women who gave birth following IVF treatment

BACKGROUND

Possible effects on maternal tumour incidence of a full-term pregnancy following IVF treatment with indicated supraphysiologic steroid and peptide hormonal levels in pregnancy remain uncertain.

METHODS

National registries were used to compare incidence of non-invasive and invasive tumour disease in Swedish women with live birth following IVF treatment with women with live birth without IVF.

RESULTS

The study had a mean follow-up period of 6.2 years in the IVF group and 7.8 years in the non-IVF group, and the mean gestation period (s.d.) for IVF and non-IVF group was 271.0 (21.1) days and 278.5 (14.1) days, respectively. In a multivariate Poisson regression analysis, adjusted rate ratios of 0.70 (0.52-0.92) and 0.93 (0.58-1.43) among IVF women were found for the risk of carcinoma in situ (CIS) of the cervix and breast cancer, respectively. When date of conception plus 1 and 3 years were used as start of follow-up, the rate ratios of CIS of the cervix increased to 0.77 (0.57-1.03) and 0.86 (0.60-1.19), respectively, and the corresponding figures for breast cancer decreased to 0.91 (0.58-1.42) and 0.74 (0.40-1.26).

CONCLUSION

Following a relatively short follow-up period, there is little if any increased risk of premenopausal cancer development in women who gave birth after IVF treatment. The women who gave birth after IVF treatment had a decreased incidence of CIS of the cervix and breast cancer, but only the former was statistically significant. However, further studies are necessary to include longer follow-up times.

Preconception care and treatment with assisted reproductive technologies

Couples with fertility problems seeking treatment with assisted reproductive technologies (ART) such as in vitro fertilization should receive preconception counseling on all factors that are provided when counseling patients without fertility problems. Additional counseling should address success rates and possible risks from ART therapies. Success rates from ART are improving, with the highest live birth rates averaging about 40% per cycle among women less than 35 years old. A woman's age lowers the chance of achieving a live birth, as do smoking, obesity, and infertility diagnoses such as hydrosalpinx, uterine leiomyoma, or male factor infertility. Singletons conceived with ART may have lower birth weights. Animal studies suggest that genetic imprinting disorders may be induced by certain embryo culture conditions. The major risk from ovarian stimulation is multiple gestation. About one-third of live-birth deliveries from ART have more than one infant, and twins represent 85% of these multiple-birth children. There are more complications in multiple gestation pregnancies, infants are more likely to be born preterm and with other health problems, and families caring for multiples experience more stress. Transferring fewer embryos per cycle reduces the multiple birth rate from ART, but the patient may have to pay for additional cycles of ART because of a lower likelihood of pregnancy.

Impact of gonadotrophins and steroid hormones on tumour cells derived from borderline ovarian tumours

BACKGROUND

Conservative surgery is currently proposed for young patients with borderline ovarian tumours (BOT). For those experiencing infertility, the question of medically assisted procreation is raised. We have evaluated in vitro the proliferation of cultured BOT cells in response to FSH or estradiol (E(2)).

METHODS

Primary cell cultures were prepared from BOT. The presence of FSH and E(2) receptors was evaluated by immunochemistry. Cultures in vitro were stimulated with FSH (40 and 200 mUI/ml) or E(2) (300 and 2000 pg/ml) for 96 h and proliferation was evaluated with the WST-1 test.

RESULTS

Four primary cultures were obtained that expressed FSH and E(2) receptors to different extents. Growth was generally similar to controls when treated with either FSH or E(2) although 300 pg/ml E(2) caused a significant inhibitory effect on cell proliferation (P = 0.035).

CONCLUSION

No stimulatory effect of FSH or E(2) on cultured BOT cells was found, despite the presence of receptors. Although preliminary, these results suggest that gonadotrophins and E(2) could be used in patients experiencing infertility after conservative surgery.

Safety of drugs used in assisted reproduction techniques

Infertility may affect one in six couples; however, the development of the assisted reproduction technique (ART) created the opportunity for a large proportion of the infertile population to bear children. Pharmacological agents are routinely used in ART, and new ones are introduced regularly, with the aim of retrieving multiple oocytes to increase the prospect of pregnancy. The combinations of drugs that are used have specific adverse effects, but it is mostly the combined action of more than one agent that causes the greatest concern. The matter is complicated by the suspicion that some techniques in ART, for example intracytoplasmic sperm injection for severe male infertility problems (including azoospermia), may also contribute to the increase in adverse effects, especially congenital malformation. Gonadotropin releasing hormone (GnRH) agonists are widely used in controlled ovarian hyperstimulation. It may give rise to a short period of estradiol withdrawal symptoms and it may also lead to luteal phase deficiency. Similarly GnRHa antagonists, which have been recently introduced to control ovarian hyperstimulation, can lead to luteal phase deficiency and may cause some local injection site reactions. The more pure form of gonadotropin leads to less local injection site reactions and their main adverse effects are associated with the consequences of multiple ovulations. It has been proposed that gonadotropins may be a factor in the increasing risk of ovarian cancer and possibly breast cancer, but this has not been substantiated. Prion infection is another potential hazard, although no cases have been reported. Ovarian hyperstimulation syndrome is a well recognised complication of controlled ovarian hyperstimulation in ART. It is usually a result of recruitment of a large number of ovarian follicles. Efforts to minimise the incidence of this syndrome and its severity are now well developed. Congenital malformations are another possible adverse effect of fertility drugs, but it is more probable that the increase in congenital abnormality that is reported in ART is because of the population studied, i.e. patients already at high risk of congenital malformation, rather than the fertility drugs used or the technique employed. High order multiple pregnancy and its sequela is a well established complication of controlled ovarian hyperstimulation. This could be a result of multiple ovulations or more than one embryo replacement. Reducing the number of embryos transferred can reduce this more serious adverse effect for expectant mothers and for children conceived from ART.

Gonadotropins and ovarian carcinogenesis: a new era of basic research and its clinical implications

The possible relationship between gonadotropins and ovarian carcinoma development has received much attention, and in recent years, great progress has been made in basic and epidemiologic research about this issue. Gonadotropins sensitivity in the ovarian surface epithelium (OSE) and in a subset of ovarian carcinomas has been established in vivo and in vitro. Gonadotropins have been shown to induce various biologic actions in the OSE and ovarian carcinoma cells, such as changes in cell proliferation, apoptosis, cell adhesion, and chemosensitivity. These basic studies strongly suggest that gonadotropins are involved in the development and progression of ovarian carcinoma. In contrast, although earlier studies showed a significant risk of infertility therapy for ovarian carcinoma development, subsequent studies reported only slightly increased or no significant increased risk of gonadotropin stimulation and/or assisted reproductive technologies for ovarian carcinoma development. Therefore, the association between ovarian stimulation and ovarian carcinoma remains controversial. Nevertheless, since development of ovarian carcinoma in infertile women during infertility treatment is a serious concern for gynecologists, this review also covers important points for clinical practice, especially the issue of early detection of ovarian carcinoma.

Burden of disease attributable to obesity and overweight in Korea

OBJECTIVE

To estimate the burden of disease attributable to overweight and obesity using disability-adjusted life-year (DALY) in Korea.

RESEARCH METHODS

Firstly, overweight and obesity-related diseases and their relative risk (RR) were selected by the systematic review. Secondly, population-attributable fractions (PAFs) were computed by using the formula including RR and the prevalence of exposure (Pe) of overweight and obesity. Thirdly, DALYs of overweight and obesity-related diseases in Korea were estimated. Finally, the attributable burden (AB) of diseases due to overweight and obesity was calculated as the sum of the products from multiplying DALYs of overweight and obesity-related diseases by their PAFs.

RESULTS

The disease burden attributable to overweight was 827.1 person years (PYs) overall, 732.6 for men, 922.9 for women per 100,000 persons. The disease burden attributable to obesity was 260.0 PYs overall, 144.2 for men, 377.3 for women. Diabetes attributable to overweight and obesity accounts for highest burden among other diseases in both genders. The disease burden attributable to overweight was 3.2 times higher than that attributable to obesity.

CONCLUSION

Most proportion of disease burden attributable to high body mass index (BMI) occurred among those with only moderately raised levels such as overweight, not the extremes such as obesity. It suggests that population-based, public health intervention rather than high-risk group-focused strategies are more effective to reduce the burden of disease attributable to overweight and obesity in Korea.

Endometriosis associated with Stage IA clear cell ovarian carcinoma in a woman with IVF-ET treatments in the Yale Series

A 42-year-old woman with Stage IA, grade 3 clear cell ovarian carcinoma arising within an endometrioma after multiple ovarian stimulation attempts was a unique case from a total of 900 patients who underwent laparoscopy for infertility and pelvic pain between 1996 and 2002 at Yale University. Her previous treatments included two laparoscopic cystectomies for left ovarian endometriomas and four cycles of IVF-ET that resulted in one miscarriage and two successful pregnancies. Although it has been suggested that controlled ovarian hyperstimulation may predispose to the development of ovarian cancer, more recent studies postulate a protective effect if fertility treatments ultimately result in successful pregnancy. Our unusual case serves as a reminder that clear cell adenocarcinoma may coexist with endometriosis, and that parity does not necessarily protect infertility patients against the development of ovarian cancer.

Induction of ovulation and ovarian cancer: a critical review of the literature

OBJECTIVE

To critically examine the possible association between ovulation-inducing drugs and ovarian cancer.

DESIGN

Medline literature review and cross-reference of published data.

RESULTS(S)

The studies that have adjusted for the effects of confounding factors such as duration of oral contraceptive use and number of pregnancies have noted an increased risk of ovarian cancer among infertile women who remain childless despite long periods of unprotected intercourse. Whether such women are at risk due to the primary basis for their infertility or factors such as ovulation-inducing drugs, has been the subject of several studies. Overall, the findings on ovarian cancer (especially invasive epithelial and non-epithelial) risk associated with fertility drug treatment are reassuring. However, a stronger association between fertility drug use and borderline tumors of the ovary has been observed.

CONCLUSION(S)

Despite the overall reassuring findings of the available studies, there is a need for well-designed clinical trials to understand the possible carcinogenic effects of the ovulation-inducing drugs.

A new ‘publication bias’: the mode of publication

The editor of a medical journal may influence the opinion of his readers by a 'publication bias'. This can be through the choice of an editorial at the front of the journal, tutoring the article, the choice of an author from the Editorial Board and the organization of a press conference accompanying the publication. The publicity from which certain studies benefited in recent years has had a negative effect on doctors' prescriptions and comprehension of the published studies.

Polycystic ovary syndrome and gynecological cancers: is there a link?

Polycystic ovary syndrome [PCOS] is the most common endocrinopathy of women in reproductive age. An association between PCOS and type-1 endometrial cancer has often been reported in the literature. The prolonged anovulation with consequent continued secretion of estrogen unopposed by progesterone may enhance the development and growth of this malignancy, particularly in young women. Hypersecretion of luteinizing hormone [LH], chronic hyperinsulinemia and increased serum insulin-like growth factor [IGF]-I levels may represent risk factors for endometrial cancer. However, data available in the literature do not allow a meta-analysis to be carried out to calculate an estimate of the relative risk of endometrial cancer in women with PCOS. Anecdotal cases of low-grade endometrial stromal sarcoma and carcinosarcoma have been reported in association with prolonged unopposed estrogen stimulation, and in particular with PCOS. A few studies have addressed the possibility of an association between PCOS and epithelial ovarian cancer risk, and the results are conflicting but generally reassuring, and similarly the few available data appear to exclude a strong association between PCOS and breast cancer.