Liquid Biopsy beats CA125

The Impact of Liquid Biopsy in Advanced Ovarian Cancer Care

https://tinyurl.com/5dy6escn

For some time, the presence of circulating tumour DNA (ctDNA) has been shown as a useful marker for many cancers including breast and colon. Testing for ctDNA is readily available by a polymerase chain reaction (PCR), the use of which became commonplace during the Covid pandemic.

Previous studies have shown ctDNA to be present in ovarian cancer. This study looks at whether using ctDNA liquid biopsy improves the management of the cancer, by confirming adequate surgery and earlier detection of recurrence.

Currently the standard marker of active disease is the cancer antigen CA125. There are problems with this in that there is a significant time lag, with persisting elevation of test scores for CA125 after treatment, and delay in a rise to mark recurrence.

ctDNA does clear rapidly from the circulation after complete clearance of cancer, making it a good indicator of adequate surgery, which remains the most significant factor for long survival. Also, in this small group of women (22), ctDNA increase after recurrence was detected several months earlier than CA125 elevation or changes in imaging.

There is a logistic issue due to cost and access, but the use of ctDNA liquid biopsy does offer some promise of improved management for ovarian cancer.

Is there a “gut feeling” for OC?

Ovarian cancer symptoms in pre-clinical invasive epithelial ovarian cancer – An exploratory analysis nested within the UK Collaborative Trial of Ovarian Cancer Screening 

https://tinyurl.com/2nj7cv48

Ovarian cancer is hard to diagnose, no screening test has so far been shown to be effective. Because of this difficulty women are advised to look out for subtle changes thought to be predictors of later disease. These include bowel symptoms such as bloating, dyspepsia and altered bowel habit.

It seems that this advice is intuitive rather than objective, this study aims to use the mass of data from the UKCTOCS trial to determine the importance of such advice.

UKCTOCS was a huge trial over 15 years involving more than 200000 women which ultimately failed to show any increase in survival from ovarian cancer when an array of screening tests was used. As part of the information sought at commencement the women were asked about bowel symptoms. 

Of the 202 women who were actively screened and developed ovarian cancer, 35% had previously described bowel symptoms. For the non-screened 874 women who developed ovarian cancer, only 9% had previously described bowel symptoms.

It seems that once again there is no accurate discriminator for ovarian cancer outside the known high-risk groups. Some caution when interpreting these results should be exercised,as this is use of data for a purpose other than originally intended.

Is there a reason for BRCA?

Conditional loss of Brca1 in oocytes causes reduced litter size, ovarian reserve depletion and impaired oocyte in vitro maturation with advanced reproductive age in mice

https://tinyurl.com/5cdrru74

Darwin’s theory of evolution includes the concept that a mutation persists because of biological advantage. Meaning that there must be some benefit for women who carry the BRCA mutation.

This fundamental research, using mice who have BRCA knockout (mutation), looked at the fertility and fecundity for these mice compared to non BRCA affected mice. No change in fertility was observed with normal follicle production and fertile lifespan.

However, the size of the litter with fewer infant mice was shown to be significantly smaller for mice which are BRCA positive.

This finding suggests a possible advantage, fewer offspring may mean better maternal care and more likely survival. 

Anti-ageing not all good

Common drug could extend women's fertility by as much as 5 years

https://tinyurl.com/ycyzc6ej

There is much research currently looking at anti-ageing drugs. One such is Rapamycin; this is an immunosuppressant drug currently used to prevent transplant rejection. There is experimental evidence that Rapamycin extends the lifecycle of mice and fruit flies. This has led to a trial using Rapamycin to extend ovarian function.

Results from the study suggest that fertility could be prolonged by up to 5 years. 

This raises the important question as to whether the risk for ovarian cancer will be increased for these women. This risk increases in proportion to the number of menstrual cycles.Ovarian cancer incidence has been decreasing as a side effect of hormonal contraception, which decreases the number of menstrual cycles.

As is often the case, the benefits of one course of action may be offset by unexpected consequences. It seems wise to proceed with caution.

Surprise benefit

Breast cancer after ovarian cancer in BRCA1 and BRCA2 pathogenic variant heterozygotes: Lower rates for 5 years post chemotherapy

https://tinyurl.com/5fm8d9um

For women who have had successful treatment of ovarian cancer it may seem logical to undergo risk reduction surgery to prevent breast cancer as a second primary disease, especially women who carry the BRCA mutation. This review suggests that such surgery may not be urgent due to associated benefits from current cancer therapy.

Retrospective analysis of the incidence of breast cancer after ovarian cancer was collected for women from the UK who had shown the presence of BRCA mutation and compared to a control group known to be BRCA positive but without ovarian cancer.

Results from the survey showed that in the 10- year period following diagnosis of ovarian cancer there is a lower likelihood of breast cancer, this is more for BRCA1 mutations that BRCA2. It is speculated that this reduction is a beneficial side effect of chemotherapy for ovarian cancer. Those women who have early- stage ovarian cancer who do not receive chemo show no similar reduction of breast cancer risk.