By Billy Candra 
Cambridge, UK – A landmark study conducted by researchers at the University of Cambridge has provided compelling evidence that bilateral salpingo-oophorectomy (BSO), the surgical removal of the ovaries and fallopian tubes, is associated with a substantial reduction in the risk of early death among women diagnosed with breast cancer who carry specific BRCA1 and BRCA2 genetic variants. Crucially, the extensive analysis also found that this life-extending procedure does not lead to an increased risk of serious long-term side-effects, such as heart disease, stroke, or depression, challenging previous general population findings. The findings, published today in The Lancet Oncology, are set to significantly impact clinical guidelines and patient counselling for this high-risk population.
Understanding BRCA Mutations and Elevated Cancer Risk
The BRCA1 and BRCA2 genes are well-known tumor suppressor genes, playing a critical role in repairing damaged DNA and maintaining the stability of a cell’s genetic material. When these genes are mutated, they lose their ability to function correctly, significantly increasing an individual’s lifetime risk of developing certain cancers, most notably breast and ovarian cancer. Approximately 1 in 400 people in the general population carry a harmful BRCA mutation, though this prevalence is higher in certain ethnic groups, such as Ashkenazi Jewish individuals, where it can be as high as 1 in 40.
For women inheriting a harmful BRCA1 mutation, the lifetime risk of developing breast cancer can be as high as 72% by age 80, compared to about 13% in the general population. The risk of ovarian cancer is also dramatically elevated, reaching between 39% and 44%. Similarly, BRCA2 mutation carriers face a breast cancer risk of up to 69% and an ovarian cancer risk of 11% to 17%. These figures underscore the profound impact of these genetic variants on an individual’s cancer susceptibility, driving the need for proactive risk management strategies.
The Prophylactic Approach: Bilateral Salpingo-Oophorectomy (BSO)
Given these elevated risks, medical guidelines have long recommended prophylactic surgeries for BRCA carriers. For ovarian cancer, BSO has emerged as the most effective preventative measure. The procedure involves the removal of both ovaries and fallopian tubes, which are the primary sites for ovarian cancer development and the source of most ovarian cancers. For BRCA1 carriers, BSO is typically recommended between the ages of 35 and 40, while for BRCA2 carriers, the recommendation is between 40 and 45. This timing aims to balance the reduction in cancer risk with the onset of premature menopause, which is an unavoidable consequence of ovarian removal.
Previous research has already established the efficacy of BSO in preventing ovarian cancer, demonstrating an impressive 80% reduction in risk among BRCA-positive women. However, despite this clear benefit, concerns have persisted regarding the broader health implications of early menopause induced by BSO. The sudden cessation of ovarian hormone production, primarily oestrogen, can lead to a range of menopausal symptoms, including hot flashes, sleep disturbances, mood changes, and potential long-term effects on bone density and cardiovascular health. For women who have already been diagnosed with breast cancer, the situation is further complicated, as hormone replacement therapy (HRT), often used to manage menopausal symptoms, may be contraindicated due to concerns about potentially stimulating breast cancer recurrence. Consequently, the overall impact of BSO on the long-term health and survival of BRCA-positive women with a prior history of breast cancer remained a critical area of uncertainty.
The Cambridge Study: A Breakthrough in Long-Term Outcomes
Addressing this crucial knowledge gap, a team of researchers at the University of Cambridge embarked on the first large-scale study of its kind to investigate the long-term outcomes of BSO specifically in BRCA1 and BRCA2 pathogenic variant (PV) carriers who had previously been diagnosed with breast cancer. The study’s innovative methodology bypassed the ethical impossibility of conducting a randomized controlled trial (RCT)—the ‘gold standard’ for evaluating treatments—in this context. An RCT would have required assigning some high-risk women to a control group without BSO, knowingly placing them at substantially greater risk of developing ovarian cancer, which would be unethical.
Instead, the Cambridge team, in collaboration with the National Disease Registration Service (NDRS) in NHS England, leveraged the immense power of electronic health records and data from NHS genetic testing laboratories. This extensive dataset, meticulously collected and curated by NDRS, allowed researchers to examine the real-world, long-term health trajectories of thousands of women. The study cohort comprised 3,400 women carrying one of the cancer-causing BRCA1 or BRCA2 variants, with approximately 1,700 women for each variant. Within this group, around 850 BRCA1 carriers and 1,000 BRCA2 carriers had undergone BSO surgery. The median follow-up period for the study was 5.5 years, providing robust insights into the procedure’s long-term effects.
Key Findings: Survival and Secondary Cancer Reduction
The results of the Cambridge study were profoundly reassuring and clinically significant. The researchers found that women who underwent BSO were approximately half as likely to die from cancer or any other cause over the follow-up period compared to those who did not have the surgery. This translates to a remarkable 50% reduction in overall mortality.
Delving deeper, the study revealed nuanced differences between the two genetic variants. The reduction in mortality was more pronounced in BRCA2 carriers, experiencing a 56% reduction in early death, compared to a 38% reduction for BRCA1 carriers. While the precise reasons for this differential benefit require further investigation, it highlights the importance of distinguishing between the specific genetic mutations when counselling patients.
Beyond overall survival, the study also demonstrated a significant reduction in the risk of developing a second primary cancer. Women who underwent BSO were found to be at around a 40% lower risk of developing an additional cancer. This finding is particularly impactful for breast cancer survivors, who already face an elevated risk of subsequent cancers due due to their genetic predisposition. While the research team acknowledges the inherent limitations of observational studies in definitively proving causality, they contend that the strength and consistency of the evidence strongly point towards BSO being the cause of these observed benefits.
Addressing Concerns: Absence of Adverse Long-Term Effects
One of the most critical aspects of the Cambridge study was its investigation into potential unintended consequences of BSO-induced early menopause. Previous studies in the general population have sometimes suggested an association between surgical menopause and an increased risk of conditions such as heart disease, stroke, and depression. These concerns have historically contributed to hesitancy among both patients and clinicians regarding BSO, especially in the absence of clear long-term survival data.
The Cambridge researchers meticulously examined these outcomes and, importantly, found no link between BSO and an increased risk of heart disease, stroke, or depression in their cohort of BRCA-mutated breast cancer survivors. This finding provides substantial reassurance, suggesting that for this specific high-risk group, the benefits of BSO in preventing cancer and improving survival are not offset by an elevated risk of other major chronic health issues. This distinction from general population studies may be attributable to the unique genetic predisposition of BRCA carriers, or perhaps to other factors related to their overall health management.
Expert Perspectives and Clinical Significance
Hend Hassan, a PhD student at the Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, and Wolfson College, Cambridge, and the first author of the study, articulated the significance of these findings: "We’ve always known that removing the ovaries and fallopian tubes dramatically reduces the risk of ovarian cancer. However, a significant question mark has lingered over the potential unintended consequences stemming from the sudden onset of menopause that this procedure causes. Our research offers profound reassurance, showing that for women with a personal history of breast cancer and a BRCA mutation, this procedure delivers clear benefits in terms of extended survival and a lower risk of developing other cancers, all without the adverse side effects such as heart conditions or depression that had been a concern."
Professor Antonis Antoniou, from the Department of Public Health and Primary Care and the study’s senior author, emphasized the direct clinical utility of the research: "Our findings will be absolutely crucial for counselling women with cancer linked to one of the BRCA1 and BRCA2 variants. They empower these women to make truly informed decisions about whether or not to opt for this life-changing operation, with a much clearer understanding of the comprehensive benefits."
These expert opinions underscore the immediate impact the study is expected to have on clinical practice. Genetic counselors and oncologists will now have robust, data-driven evidence to present to patients, helping them navigate complex decisions about prophylactic surgery with greater confidence. The study provides a powerful argument for BSO as a comprehensive risk-reducing strategy, extending beyond just ovarian cancer prevention to significantly improve overall survival and reduce the burden of secondary cancers.
The Challenge of Health Equity and Access
While the benefits of BSO are now more clearly defined, the study also brought to light a concerning disparity in its uptake. The researchers observed that most women undergoing BSO in their cohort were white. Black and Asian women were found to be approximately half as likely to undergo BSO compared to white women. Furthermore, women residing in less deprived areas were more likely to have the procedure than those in the most-deprived categories.
These findings highlight significant issues of health equity and access within the healthcare system. Hend Hassan stressed the urgency of addressing these disparities: "Given the clear and substantial benefits this procedure provides for at-risk women, it is deeply concerning that certain groups of women are less likely to undergo it. We have a critical need to understand the underlying reasons for these disparities—whether they stem from awareness gaps, cultural factors, access barriers, or biases in healthcare provision—and then to actively encourage uptake among these underserved women."
Understanding and rectifying these disparities will require multi-faceted approaches, including targeted outreach programs, culturally sensitive education, improved access to genetic counselling and surgical services, and addressing socio-economic barriers that may impede healthcare decisions. Ensuring equitable access to life-saving prophylactic surgeries is a paramount public health goal.
Methodological Innovation and the Power of Real-World Data
Professor Antoniou also lauded the methodological approach, stating, "The study also highlights the power of exceptional NHS datasets in driving impactful, clinically relevant research." The successful execution of this study without an RCT underscores the growing importance of real-world evidence (RWE) in medical research. In situations where traditional randomized trials are ethically or practically unfeasible, leveraging comprehensive electronic health records and national disease registries can provide invaluable insights into treatment effectiveness and patient outcomes. The collaboration between the University of Cambridge and the National Disease Registration Service serves as a powerful model for future research, demonstrating how large-scale, population-level data can accelerate our understanding of complex health interventions.
This approach is particularly pertinent in the era of personalized medicine, where interventions are tailored to an individual’s genetic profile. As genetic testing becomes more widespread and our understanding of genetic predispositions deepens, the ability to rapidly analyze outcomes from real-world clinical practice will be essential for refining guidelines and optimizing patient care.
Broader Implications for Cancer Research and Patient Care
The research was made possible through significant funding from Cancer Research UK, with additional support from the National Institute for Health and Care Research (NIHR) Cambridge Biomedical Research Centre. This institutional backing underscores the strategic importance of this type of research in the ongoing fight against cancer.
Looking ahead, the University of Cambridge and Addenbrooke’s Charitable Trust (ACT) are actively fundraising for a new hospital, the Cambridge Cancer Research Hospital. This ambitious project, a partnership with Cambridge University Hospitals NHS Foundation Trust, aims to transform cancer diagnosis and treatment for patients across the East of England. The research generated by studies like this one, demonstrating clear clinical benefits from prophylactic interventions, will directly inform the practices and priorities within such advanced facilities, ultimately improving outcomes for cancer patients not only in the UK but globally. The findings from this study are a testament to the continuous drive for evidence-based medicine and the commitment to improving the lives of individuals at high risk of cancer.
Future Directions and Ongoing Research
While the Cambridge study provides groundbreaking reassurance regarding BSO, future research will continue to build upon these findings. Further investigation into the differential benefits observed between BRCA1 and BRCA2 carriers could lead to even more personalized risk management strategies. Additionally, understanding the specific barriers contributing to disparities in BSO uptake among different demographic groups will be crucial for developing effective interventions to ensure equitable access to this life-saving procedure. As genetic technologies evolve and our understanding of cancer risk grows, studies like this pave the way for a future where proactive, evidence-based interventions can significantly reduce the burden of hereditary cancers.
