By Billy Candra 
Women diagnosed with breast cancer who carry particular BRCA1 and BRCA2 genetic variants are offered surgery to remove the ovaries and fallopian tubes, a procedure proven to dramatically reduce their risk of ovarian cancer. Now, groundbreaking research from the University of Cambridge has revealed that this intervention, known as bilateral salpingo-oophorectomy (BSO), is also associated with a substantial reduction in the risk of early death among these women, without introducing serious long-term side effects. Published in The Lancet Oncology, this large-scale study offers crucial evidence reinforcing the life-saving benefits of BSO, particularly for those with a prior history of breast cancer where the overall impact of such surgery has remained less clear.
Understanding the Genetic Link: BRCA Mutations and Cancer Risk
The BRCA1 and BRCA2 genes are critical components of the human DNA repair system. When these genes are mutated or altered, they lose their ability to effectively repair damaged DNA, increasing an individual’s susceptibility to developing certain cancers, most notably breast and ovarian cancers. These mutations are relatively rare in the general population, affecting about 1 in 400 to 1 in 800 people, but they significantly elevate lifetime cancer risks. For women carrying a BRCA1 mutation, the lifetime risk of breast cancer can be as high as 45-85%, and ovarian cancer risk ranges from 39-46%. For BRCA2 carriers, the breast cancer risk is similarly elevated (40-85%), with an ovarian cancer risk of 11-20%. These figures represent a stark contrast to the general population’s lifetime risks, which are approximately 13% for breast cancer and less than 2% for ovarian cancer.
The discovery of the BRCA genes in the mid-1990s marked a pivotal moment in cancer prevention and personalized medicine. Prior to this, risk assessment was largely based on family history, but the identification of specific genetic markers allowed for a more precise understanding of individual predisposition. This knowledge quickly led to the development of tailored risk management strategies, including increased surveillance, chemoprevention, and prophylactic surgeries. For women at extremely high risk of ovarian cancer due to BRCA mutations, the recommendation for BSO emerged as a powerful preventative measure.
The Prophylactic Approach: Benefits and Lingering Questions
Prophylactic bilateral salpingo-oophorectomy involves the surgical removal of both ovaries and fallopian tubes. For BRCA1 and BRCA2 carriers, this procedure is typically recommended at a relatively early age: between 35 and 40 years for BRCA1 carriers, and 40 to 45 years for BRCA2 carriers, after childbearing is complete. Previous research had firmly established BSO’s efficacy in preventing ovarian cancer, demonstrating an approximately 80% reduction in risk among these high-risk women. Given the aggressive nature of ovarian cancer, which is often diagnosed at advanced stages due to a lack of early symptoms, this reduction is profoundly significant. The vast majority of ovarian cancers are epithelial ovarian cancers, which are difficult to detect early and have a low five-year survival rate of around 48% when diagnosed at later stages, underscoring the importance of prevention.
Despite the clear benefit in ovarian cancer prevention, BSO introduces a significant physiological change: immediate surgical menopause. The ovaries are the body’s primary source of estrogen, and their removal abruptly halts hormone production. This sudden hormonal deprivation can trigger a cascade of menopausal symptoms, including hot flashes, night sweats, vaginal dryness, mood swings, and sleep disturbances. Beyond these immediate discomforts, there have been concerns about potential long-term health consequences associated with early menopause, such as an increased risk of cardiovascular disease, osteoporosis, and cognitive decline. These concerns are particularly amplified for women with a history of breast cancer. For many breast cancer survivors, hormone replacement therapy (HRT), which could alleviate menopausal symptoms and potentially mitigate long-term health risks, is often contraindicated due to its potential to fuel estrogen-sensitive breast cancer recurrence. Consequently, the overall impact of BSO in BRCA1 and BRCA2 carriers with a prior history of breast cancer, especially regarding overall survival and the development of other diseases, has remained a critical area of uncertainty.
Overcoming Research Hurdles: A Novel Study Design
Traditionally, the "gold standard" for evaluating the efficacy and safety of medical interventions is a randomized controlled trial (RCT). In an RCT, participants are randomly assigned to either receive the intervention (e.g., BSO) or a control (e.g., watchful waiting). However, conducting an RCT for BSO in women carrying BRCA1 and BRCA2 variants would be ethically untenable. Randomly assigning women at extremely high risk of a lethal cancer to a control group that would forgo a proven preventative surgery would expose them to substantially greater and unacceptable risks of developing ovarian cancer.
To circumvent this ethical dilemma and provide much-needed evidence, a dedicated team at the University of Cambridge, in collaboration with the National Disease Registration Service (NDRS) in NHS England, employed an innovative research approach. They leveraged the power of electronic health records and comprehensive data from NHS genetic testing laboratories, meticulously collected and curated by NDRS. This allowed them to conduct a large-scale, observational study to examine the long-term outcomes of BSO among BRCA1 and BRCA2 pathogenic variant (PV) carriers who had already been diagnosed with breast cancer. This methodology offered a real-world perspective on the procedure’s impact, drawing from a vast and representative patient population.
Key Findings: Survival Benefits Without Serious Side Effects
The Cambridge team identified a substantial cohort of 3,400 women who carried either a BRCA1 or BRCA2 cancer-causing variant, with approximately 1,700 women for each variant. Within this group, around 850 of the BRCA1 carriers and 1,000 of the BRCA2 carriers had undergone BSO surgery. The results of their meticulous analysis, published today in The Lancet Oncology, are profoundly reassuring and clinically significant.
The study revealed that women who underwent BSO were approximately half as likely to die from cancer or any other cause over the median follow-up period of 5.5 years. This reduction in overall mortality was particularly pronounced in BRCA2 carriers, who experienced a 56% reduction in early death risk, compared to a 38% reduction in BRCA1 carriers. This differential effect warrants further investigation but underscores the procedure’s benefit across both gene mutations. Furthermore, the study found that these women also had about a 40% lower risk of developing a second cancer, a critical outcome for individuals already battling one cancer diagnosis. While the researchers prudently acknowledge that observational studies cannot establish causation with 100% certainty, they assert that the weight of evidence points strongly towards BSO being the driving factor behind these improved survival outcomes.
Crucially, the study also addressed the long-standing concerns regarding potential adverse effects of early menopause induced by BSO. In a significant finding, the researchers found no link between BSO and an increased risk of other long-term outcomes such as heart disease, stroke, or depression. This stands in stark contrast to some previous studies in the general population that have suggested an association between early surgical menopause and an increased risk of these conditions. This finding provides immense reassurance for both patients and clinicians, indicating that the significant survival benefits of BSO are not offset by an increased risk of other major health complications in this specific high-risk population.
Hend Hassan, the first author of the study and a PhD student at the Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, and Wolfson College, Cambridge, articulated the significance of these findings: "We know that removing the ovaries and fallopian tubes dramatically reduces the risk of ovarian cancer, but there’s been a question mark over the potential unintended consequences that might arise from the sudden onset of menopause that this causes. Reassuringly, our research has shown that for women with a personal history of breast cancer, this procedure brings clear benefits in terms of survival and a lower risk of other cancers without the adverse side effects such as heart conditions or depression."
Addressing Health Equity: Disparities in Uptake
Beyond the clinical efficacy, the study also shed light on critical issues of health equity and access to care. The data revealed concerning disparities in the uptake of BSO. Most women undergoing the procedure were white, while Black and Asian women were found to be approximately half as likely to have BSO compared to white women. Furthermore, women residing in less deprived areas were more likely to undergo BSO than those in the most deprived categories.
These findings highlight a pressing need for further investigation into the underlying reasons for these disparities. Potential factors could include socioeconomic barriers, such as lack of adequate insurance coverage, difficulties in taking time off work for appointments and recovery, or challenges in accessing specialized care. Cultural beliefs, varying levels of health literacy, language barriers, and even potential biases in healthcare provider communication could also contribute to unequal access.
Hassan emphasized the gravity of these disparities: "Given the clear benefits that this procedure provides for at-risk women, it’s concerning that some groups of women are less likely to undergo it. We need to understand why this is and encourage uptake among these women." This call to action underscores the importance of equitable access to life-saving preventative measures and suggests a need for targeted outreach and educational initiatives to ensure all eligible women can make informed decisions and receive appropriate care, regardless of their ethnic background or socioeconomic status.
Implications for Clinical Practice and Future Research
The findings of this Cambridge study are poised to have a significant impact on clinical guidelines and patient counseling for women with BRCA1 and BRCA2 mutations, particularly those with a history of breast cancer. Professor Antonis Antoniou, from the Department of Public Health and Primary Care and the study’s senior author, stated, "Our findings will be crucial for counselling women with cancer linked to one of the BRCA1 and BRCA2 variants, allowing them to make informed decisions about whether or not to opt for this operation." This robust evidence provides clinicians with stronger data to discuss the overall survival benefits of BSO, beyond just ovarian cancer prevention, thereby empowering women to make choices aligned with their individual health goals and risk profiles.
The study’s success also serves as a powerful testament to the value of large-scale, real-world data in medical research. Professor Antoniou, who also directs the Cancer Data-Driven Detection programme, added, "The study also highlights the power of exceptional NHS datasets in driving impactful, clinically relevant research." The ability to leverage comprehensive electronic health records and genetic testing data from a national health service has allowed researchers to answer critical questions that would otherwise be unaddressable due to ethical constraints.
While this study provides groundbreaking insights, it also paves the way for future research. Longer-term follow-up studies will be important to confirm these benefits over extended periods and to explore any very late-onset effects. Further research into the specific mechanisms behind the reduction in overall mortality and second cancer risk could yield valuable insights into cancer biology. Moreover, dedicated studies focusing on the experiences and outcomes of diverse patient populations are essential to address the identified health equity gaps and ensure that the benefits of BSO are universally accessible.
The research was made possible through funding from Cancer Research UK, with additional support from the National Institute for Health and Care Research (NIHR) Cambridge Biomedical Research Centre. This collaborative effort exemplifies the critical role of sustained investment in medical research. 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 facility, a partnership with Cambridge University Hospitals NHS Foundation Trust, is envisioned to transform cancer diagnosis and treatment for patients across the East of England. The research conducted within its walls promises to extend its impact far beyond regional boundaries, changing the lives of cancer patients across the UK and globally, building upon the foundational knowledge provided by studies like this one.
