A breast cancer treatment study published in the New England Journal of Medicine this week has the national media hopping–and me wondering why.

The study throws into question the use of Taxol (paclitaxel) as an effective chemotherapy drug for women with HER2-negative, ER-positive (estrogen receptive positive) breast cancer.

Researchers went back and retrieved frozen tissue samples from 1,500 women with breast cancer who were part of a 3,121-participant study back in the ’90s. The original 3,000+ women in the study, all lymph node-positive (cancer had spread to their lymph nodes, but not beyond), received the chemo regimen ACT: Adriamycin, Cytoxan, and Taxol. The original study concluded it was effective. Many women today continue to get that therapy, often referred to as TAC or ACT chemotherapy.

Now, using sophisticated tools unavailable at the time of the study, researchers have discovered that Taxol’s effectiveness was tied to the type of cancer its recipients had. It did lower the risk of recurrence in all of those who were HER2-positive (tumors are HER-2 positive in about 20 percent of all breast cancer cases).

The Taxol part of the ACT cocktail was ineffective for those who were HER2-negative and ER-positive. To quote the abstract, “Patients with a HER2-positive breast cancer benefited from paclitaxel, regardless of estrogen-receptor status, but paclitaxel did not benefit patients with HER2-negative, estrogen-receptor–positive cancers.” The AC part of ACT appears to be effective for all patients.

Yeah, and…? How unusual is it for health information of any kind to change as the years go by? I mean, smoking cigarettes used to be considered GOOD for you; take a look at ads from the ’40s and ’50s quoting dentists recommending cigarettes for your teeth. Eggs are good for you… no, they’re bad… no, really, they’re good… This is the nature of scientific research; it evolves. If it didn’t, we’d still be applying leeches to one another to suck out the bad humours in our blood.

So, Taxol is no longer considered appropriate for women with ER-positive, HER2-negative breast cancer. Great information; keep the AC, ditch the T for those of us with ER-positive, HER2-negative breast cancer. Let’s update our databases and run with this new fact.

Now, I’m not being totally cavalier about this. Taxol has some wicked side effects, including bone and joint pain and, even more bothersome, some pretty severe tingling (neuropathy) in the hands and feet. Unfortunately, about 18% of women in the original study were forced to live with this distressing tingling months and even years after they’d finished chemo. If you’re one of these women, I’m sorry for you. Just as I’m sorry for the women who had radical mastectomies because surgeons hadn’t yet discovered that a lumpectomy would work just as well. And women who developed lung cancer after radiation, back when radiation oncologists didn’t have the tools that have since been developed to fine-focus those deadly rays.