The first of its kind, the study shows that women with lobular breast cancer often respond poorly to chemotherapy. Yet in the study, these women had better survival rates than women with a more common type of breast cancer who respond well to chemotherapy, researchers say.
"We always have thought that a poor response to chemotherapy indicated a worse prognosis, but that is not true for every woman with breast cancer," says the study's lead researcher, Massimo Cristofanilli, MD, a breast oncologist at The University of Texas M.D. Anderson Cancer Center in Houston, in a news release. Having a poor response to chemotherapy means that despite chemotherapy, breast cancer cells were still found in the breast or lymph nodes.
This "striking finding" means that women with lobular breast cancer may not need chemotherapy before surgery, he says.
The most common type of invasive breast cancer is ductal, accounting for almost 80% of breast cancers. Lobular breast cancers account for almost 15%.
Cristofanilli's study appears in this month's issue of the Journal of Clinical Oncology.
Breast Cancer Treatment Success
In their study, Cristofanilli and his colleagues analyzed medical records from six breast cancer studies. The 1,034 women in the studies had locally advanced breast cancer -- either the lobular form or the more common ductal form, which involves the milk ducts. All the women had been treated with chemotherapy to shrink their tumors before surgery.
Researchers found that women with invasive lobular breast cancer had a poorer response to chemotherapy, yet they had better overall survival rates.
- 41% of lobular breast cancer patients were left with breast cancer within the lymph nodes after chemo, yet 80% were cancer-free five years after treatment.
- 26% of the ductal breast cancer patients still had evidence of breast cancer in the lymph nodes after chemo, but only 72% were cancer-free five years after treatment.
Oncologists may change their approach to treating lobular cancer patients, he says. Therapies using hormones called aromatase inhibitors may be the better approach.
"Before this study, I don't think anyone realized the disease should be treated differently," says Cristofanilli.
"In the end, our study indicates that chemotherapy, with its toxic effects, may not be the best standard of care for women with invasive lobular carcinoma," he says.