Ovarian cancer may be the cancer that women fear the most. In 2018, nearly 300,000 women around the world were diagnosed with ovarian cancer and approximately 180,000 women died as a result of the disease. In England, approximately 6,780 women are diagnosed each year. According to the World Ovarian Cancer Coalition, only 45% of women with ovarian cancer live for five years after diagnosis, as compared with 89% of women with breast cancer.
So what is being done to improve these figures? Rebecca Rennison, director of public affairs and services at Target Ovarian Cancer, explains that women in the UK have often been diagnosed too late for effective treatment because they, and their doctors, do not recognise the symptoms of ovarian cancer.
Symptoms can be difficult to recognise. Some, such as persistent bloating, stomach pain, urinary symptoms, loss of appetite and change in bowel habits, may be confused with other conditions. About 41% of women visit their GPs three times or more before being referred for tests, and 45% wait more than three months to receive their diagnosis. “You need a system that diagnoses a woman with ovarian cancer promptly,” she says.
The earlier a woman with ovarian cancer is diagnosed, the better the prognosis is likely to be. There has been a lot of progress in recent years – 58% of women with ovarian cancer are diagnosed following a referral from their GP, compared with 47% just over 10 years ago.
However, many women are still only diagnosed after emergency treatment at A&E. And for women with advanced ovarian cancer, the disease will recur in approximately 75% of cases. As a result, there is still a high unmet need – many women with ovarian cancer are often diagnosed with advanced stage disease where effective treatments are limited; the disease may not progress from stage 1 to stage 2 to stage 3-4 but may start in the fallopian tube and spread to the abdominal cavity were it is already a stage 3.
Treatment commonly involves surgery and chemotherapy. Radiation therapy is rarely used for the treatment of ovarian/fallopian tube cancer. However, it may be used selectively to treat some women with clear cell ovarian cancer after chemotherapy. Occasionally, it can be an option for treating small, localised recurrent cancer. Over the past few years, some women have also been given drugs called Parp inhibitors after their chemotherapy as a maintenance therapy, but they have not been prescribed for the majority of patients.
Parp (poly-ADP ribose polymerase) is a protein within our cells that helps damaged cells repair themselves. Parp inhibitors work to prevent Parp from repairing cancerous cells, which may lead to those cells dying. These inhibitors are given to some women as maintenance therapy after a course of chemotherapy to delay the time before a potential recurrence. But only a minority of patients have been eligible to take them as initial therapy, mainly the 15% of women who have a gene mutation called BRCA.
According to Axel Hoos, senior vice president, R&D and therapeutic area head of oncology at GSK: “[The use of Parp inhibitors] is highly targeted treatment and the effect in the right patient population can be substantial.” However, until recently, consideration had not been given to whether people without BRCA mutations would still be likely to respond to the treatment; cancer cells with no BRCA gene mutations already have poor repair systems.
“Not enough attention had been given to people without genetic anomalies, or no detectable anomalies, to see if they were still prone to respond [to Parp inhibitors],” Hoos emphasises. A few years ago, only about 15% of patients – those with BRCA mutations – had been considered eligible for Parp inhibitors.
Additional options in ovarian cancer treatment have made Rennison hopeful. “We have seen the new generation of Parp inhibitors coming through, which is really exciting,” she says. It is already clear that women with ovarian cancer are benefiting from Parp inhibitors as maintenance therapy after chemotherapy.
“Many will still experience progression in their disease but obviously the longer women are surviving the better,” Rennison continues. “There have been great advances but we wouldn’t be doing our jobs if we didn’t say there is still a huge amount to be done.”
In the future, Parp inhibitors may be able to be approved for use in the treatment of other cancers. “Further research could open the door for [diseases] such as lung, breast, prostate and pancreatic cancers,” explains Hoos.
Hoos previously worked in other areas of oncology, specifically with immunotherapy. “This is an expanding area of science that can provide dramatic benefits to patients,” says Hoos. “There is no better time to work in oncology than today. There is so much more we can do as researchers that can help patients with cancer.”
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