Could an addition to routine pelvic surgery help protect women from ovarian cancer?
Every year, countless women undergo routine hysterectomies and tubal ligations, at least 60,000 in Canada alone. What if these women could reap some protection against ovarian cancer at the same time?
That question has been driving Canadian gynaecologic oncologist Dianne Miller and her colleagues, as they’ve watched and contributed to research that’s isolated the fallopian tubes as the source of some common ovarian cancers. The problem is that traditional surgical techniques leave behind a portion of the tube, most significantly the part nearest the ovary that’s been linked to those early cancers, according to Miller.
During the typical removal of the uterus during a hysterectomy, she explains, “it was just simpler to cut the tube near the uterus as opposed to cutting it near the ovary. There was never any thought that went into it. It was just the way that the operation was done.”
As for tubal ligations – or getting the tubes “tied” – several approaches have been used, such as cutting or clipping the tubes to stop an egg from reaching the uterus. But a portion is left behind. The idea was to make reversal more feasible if the woman later had second thoughts, but now such women usually pursue in vitro fertilisation, Miller says.
So in the autumn of 2010, Miller and her Vancouver colleagues launched a massive ovarian cancer prevention project in British Columbia, encouraging physicians to take out the entire tubes instead. The educational campaign quickly gained traction.
By 2011, 35 per cent of women having hysterectomies were getting their tubes (but not their ovaries) out along with the uterus, compared with just 7 per cent two years previously. That same year, 33 per cent of sterilisations involved complete tube removal compared with 0.3 per cent in 2009.
Meanwhile, US-based gynaecologic oncologist Christine Holschneider has embarked on a similar albeit smaller effort at the Olive View–UCLA Medical Center in Los Angeles, educating gynaecologists there about the surgical alternative to hysterectomy. “Occasionally it is technically very difficult because the fallopian tube is scarred to the bowel or something like that,” she says. “But in most cases, it’s achievable.”
The shift in practice at the California hospital has also been quick, with 77 per cent of hysterectomy patients getting their tubes out during the first six months of 2012, compared with 3 per cent in 2009. And patients embrace the concept, eager to take any step that could reduce their risk of ovarian cancer, Holschneider says.
The alternative technique doesn’t add much time, just 16 minutes to a roughly two-hour hysterectomy, according to the British Columbia data. Neither does it increase surgical risks, including time spent in the hospital or the need for a blood transfusion.
Compared with women who carry a BRCA mutation, the risk of ovarian cancer in the average woman is far lower – just one out of every 100 women will ever be diagnosed. Yet the malignancy is a scary one, as it’s difficult to catch before it’s spread beyond the ovary. Despite best efforts to date, Miller says, “everything that anybody has even remotely looked at for screening doesn’t work”.
One outstanding concern is whether removing the tubes has any impact on future ovary function, such as affecting the blood supply to them. Although there’s no indication so far, that’s being monitored by the Canadian researchers, Miller says. “You have to be very sure that there’s not some hidden harm,” she says. The most significant question, of course, is: will it work?
It will take some years to find out, as women tend to get these pelvic surgeries in their mid-30s to mid-40s and the risk of ovarian cancer doesn’t escalate until 15 to 20 years later, Miller says. By as early as 2020, she predicts, any reduction in ovarian cancer rates should become visible.
“We feel very strongly that it’s going to work,” she says. “It’s really just a matter of how much it’s going to work. What will be the degree of benefit, and will there be any harms?”