Marta Crispens, M.D.
Older treatment for ovarian cancer gets new push from NCI
When it comes to treating advanced ovarian cancer, what's old is new again.
With positive results from a phase III clinical trial, the National Cancer Institute recently announced its support for intraperitoneal (IP) chemotherapy for some women with stage III ovarian cancer.
While not a new approach, IP is making a bit of a comeback and helping extend life for patients with advanced ovarian cancer. It involves inserting a catheter directly into the abdomen, allowing higher doses of two common cancer fighters, cisplatin and paclitaxel, to be pumped straight into the peritoneum, the area where ovarian cancer is most likely to spread.
“IP therapy has been around for decades, but it's not been used commonly in treating ovarian cancer because of the toxicity associated with it,” said Marta Crispens, M.D., a gynecological oncologist with the Vanderbilt-Ingram Cancer Center, who uses IP therapy on a case-by-case basis.
In the most recent clinical trials, Crispens said women with advanced ovarian cancer who received IP therapy compared with standard chemotherapy had a 16-month survival advantage.
“When you think about increments of surviving cancer — three, four, six months — those are huge numbers. We get really excited because 16 months is something you never see, or very rarely see,” she said.
Why does this targeted treatment improve survival so dramatically? Crispens said it could be the direct exposure of the tumor to the chemotherapy drugs, but it could also be the high doses IP therapy allows and the prolonged period of exposure to the drugs.
“IP therapy is a much slower, more prolonged absorption into the bloodstream from the peritoneal cavity. You don't see the prolonged high levels in IV chemotherapy. You get peaks and then it comes back down,” she added.
But Crispens said there are drawbacks to IP therapy. In the most recent clinical trial, only four out of 10 women were able to complete the planned six cycles of treatment.
“One of the biggest problems is the catheter into the peritoneal cavity is an irritant and the body reacts to it, typically forming a sheath and clogging up the catheter and preventing it from working.”
Despite the drawbacks, survival rates still climbed to unusually high numbers. “The median survival rates for women with stage three or stage four ovarian cancer is only two to three years. If you add 16 months to that you're pushing median survival rates out to four to five years,” said Crispens.
But IP therapy isn't for all women with ovarian cancer. Crispens said women with stage I or very early disease need a small amount of chemotherapy as a precaution, but they don't need the high doses used in IP therapy.
Women with a recurrence of ovarian cancer are typically not good candidates because the cancer is usually too large or the patient may be resistant to chemotherapy.
IP therapy is also not the best line of treatment for women who, despite surgery, have greater than 1 centimeter of cancerous tissue left behind.
However, despite the drawbacks, Crispens said most women who have ovarian cancer do fit the bill for IP therapy. “Three quarters of women present at an advanced stage of the disease and we can perform surgery to remove as much as possible,” said Crispens.
Ovarian cancer has been said to be a cancer that is not silent, it whispers. Yet the warning signs, like bloating and frequent urination, are subtle and could be dismissed as common problems among aging women.
“Particularly as women approach the change in life,” added Crispens. “Early signs of ovarian cancer are often dismissed as irritable bowel syndrome before a diagnosis is made.”