Sunday, March 27, 2005

Another chat about ovarian cancer

In the comments on the OC post below, emma goldman asked how it can be diagnosed earlier. I'm no expert, but I've heard that some cases that are caught early are discovered by accident—a woman is having surgery for some other reason, and while the surgeon's in there, he or she sees the cancer. And maybe some cases are picked up incidentally on ultrasound, CT, or MRI scans done for other reasons (although my aunt S. had an abdominal CT scan about a month before her diagnosis that didn't show the tumors that were EVERYWHERE in her abdomen, just as the earlier ultrasound also showed nothing much amiss).

The research that's going on now is aimed at finding some way to diagnose this terrible cancer earlier, when survival rates are much higher. My cousin L. is enrolled in an early-detection screening program (a research study). It involves annual transvaginal ultrasound exams (using what I like to call the cooter wand) and quarterly CA-125 tests. The study folks also draw blood for genetic testing.

When a mutation is present in the famous BRCA-1 or BRCA-2 gene, an individual may be at increased risk of breast or ovarian cancer. There's another genetic mutation that involves cancer of the ovaries and colon. Aunt S. tested negative for these known mutations, so even though her mother died of OC, S.'s case is officially considered "sporadic" rather than hereditary. However, who's to say that there aren't other genetic mutations that also predispose people to OC? While the known mutations aren't present in my cousin L., the genetic counselors didn't tell her she could relax—they told her to get into a screening program ASAP and get her ovaries out by 40.

One goal of the screening study L. is participating in is to identify other mutations or markers that are linked to OC. They draw blood and store it; when a suspicious mutation is discovered, they can check the blood samples and see if they confirm a link between OC and the mutation. Maybe in another decade, they'll have identified some more reliable markers of cancer risk. This aspect of the study provides no benefit at all to the participants, but it might help identify women at risk in the future.

The researchers are also trying to find a better way of using CA-125 screening (which misses most early cases and gives a lot of false-positives). They check levels every 3 months, which will allow them to monitor any changes in an individual woman's levels. In medical practice, generally the cutoff level for concern is 35 U/mL. If a study participant usually runs a CA-125 level of, say, 15, an increase to 25 would prompt a closer look. L. likes that aspect, but who knows if changes in low CA-125 levels mean anything? We just don't know yet.

What about prevention? Basically, anything you can do to reduce the amount of work your ovaries do. Having more babies and starting childbearing earlier on means less ovulation (you don't ovulate while you're pregnant). Breastfeeding tends to interfere with ovulation, and is associated with a reduced risk of ovarian cancer. Taking the the other OC—oral contraception, aka the pill—also prevents ovulation and cuts cancer risk. Getting your tubes tied also helps. I daresay it's a helluva lot easier to quit smoking to reduce your risk of lung cancer than it is to reverse the course of time and have children earlier to reduce your risk of ovarian cancer.

Ovarian cancer is so scary because it's like you're driving down the highway and there's a Mack truck bearing down on you, head on. Only it's invisible, so it's tough to veer out of its way. If it hits you, odds are the crash is going to be horrendous. And the only way to prevent the crash is not to have gotten in your car in the first place. It's not a fair fight. If we are ever going to get this truck off the road, we need to fund more research.


Emma Goldman said...

Thanks for taking the time to write this, O, even though it unfortunately confirmed what I remembered, i.e., that there isn't a simple (or even complex), reliable screening mechanism. This is one of the scarier things out there.

Orange said...

Did you see cancerbaby's answer to your question in the older OC post? She recommends the rectovaginal exam (yay!).