What is the treatment of choice for all breast cancer patients? Chemotherapy? Wrong.
According to guidelines recently adopted in Europe unveiled this weekend at a conference in Texas, very few women with breast cancer get chemotherapy in future. The new approach calls for choosing a treatment based on each woman's particular type of tumor.
So far all decisions were being made on the size of the tumor and the involvement of the lymph nodes. The treatment differed according to the amount of cancer one had. Under the new rules, hormone status — whether a tumor's growth depends on estrogen or progesterone — becomes the single most important factor in picking treatment. The approach here would be more a hormone blocker rather than chemotherapy.
Women have reason to dread chemotherapy. Chemo is a sledgehammer that comes down heavily on all rapidly dividing cells—whether they are out-of-control cancerous cells or healthy ones that naturally grow quickly, like those lining the mouth and stomach. That is why chemotherapy causes hair loss, nausea and mouth sores.
But the worst part is that chemotherapy helps only about 15 percent of breast cancer patients after the usual surgery to remove their tumors. Roughly 25 percent of them get worse despite receiving chemotherapy. More shocking, as many as 60 percent of them would have been fine with hormones alone.
'It is not to say that chemotherapy is no value. It is just to say that the value is smaller in women with hormone-driven disease,' said Dr. Robert Carlson, a Stanford University physician who led the U.S. guideline-writing group. The question now is to determine whether the benefit is so small that oncologists should not be recommending chemotherapy.
There have been several developments of late which help doctors decide who really needs chemotherapy. First is the realization that breast cancer is an umbrella of diseases with different causes, arise from different types of cells, are driven by different genes, and tend to be different in women before or after menopause.
For instance, as many as three-fourths of women after menopausal have tumors fueled by estrogen, called ER-positive disease. In these cases, drugs that block this hormone, like tomoxifen and aromatase inhibitors, a new class of medications can successfully combat those cancers — whether or not they have spread to lymph nodes.
On the other hand, women before menopause often have tumors that are ER-negative and orchestrated by bad genes. Hormones do not help in that case; these women benefit most from chemotherapy.
If hormone drugs are highly focused pin-head hammers compared to chemotherapy, medication like Herceptin is even more refined, targeting the one-fourth of breast cancers that have too much of protein on cell surfaces called HER-2 and leaves healthy cells alone.
A woman's HER-2 status is the next factor doctors will consider, after hormone status, in choosing treatments under the new guidelines.
You can see the possibilities: half of HER-2 tumors are ER-positive, but only 10 percent of ER-positive tumors are HER-2-negative. These are not black-and-white distinctions, either. Tumors can be weakly ER-positive or negative; same for HER-2.
Doctors are now armed with new high-tech lab tests to sort out the gray areas. These tests measure the activity of dozens of genes and reveal which ones are most active and what treatments would work best.
One such test, Oncotype DX, is becoming popular among doctors after presentations at the Texas cancer meeting last year showed its ability to predict which women benefit from tamoxifen and which do best on chemotherapy.
The test is expensive — $3,400 — but many insurers cover it because it often prevents even more costly and unnecessary chemo. It is the test of choice when situations are complex and treatment choices aren't obvious.
Here, the accuracy of lab tests becomes a life-or-death matter, as doctors rely on them to determine factors like hormone and HER-2 status. Doctors warn about the wide variation in the quality of such tests, whether low- or high-tech.
The new guidance was developed by the National Comprehensive Cancer Network, a group of leading cancer treatment centers, in cooperation with the American Cancer Society. They soon will be published and are available now on the network's web site, http://www.nccn.org.
