Doctors now recommend chemotherapy or tamoxifen to breast cancer patients with tumors larger than one centimeter (slightly less than one-half inch.) To learn if they might help women with tumors of one centimeter or smaller, researchers examined data from five earlier clinical trials, focusing on the 1,259 patients in those trials who had the small tumors. Eight-year survival rates ? the percentage of patients alive eight years after diagnosis ? were compared among groups of women with small breast cancers who received different treatments.

A Slight Increase in Survival

The researchers found adding tamoxifen after surgery increased the eight-year survival rate slightly, from 90% to 92% for patients whose tumors were estrogen receptor-positive (stimulated to grow by estrogen). The addition of chemotherapy to the tamoxifen increased the survival rate to 97% for those patients.

Among women with small estrogen receptor-negative cancers, chemotherapy did not improve survival. Eight-year survival was 91% with chemotherapy and 93% without it. Tamoxifen was not given to any of these women, because previous studies have shown the drug to be useful only for estrogen receptor-positive tumors.

Chemotherapy or tamoxifen given after surgery is known as adjuvant therapy ? or therapy given after the main treatment. "Even among patients with very small tumors, there are some who are going to have treatment failures [from surgery alone] and some of those can benefit from adjuvant therapy," says lead researcher Bernard Fisher, MD, scientific director of the National Surgical Adjuvant Bowel and Breast Project (NSABP) and a breast cancer surgeon at the University of Pittsburgh.

"We?re not saying all patients should get adjuvant therapy, but that things other than tumor size alone should be considered," Fisher adds.

Factors to Consider

He suggests doctors should consider the tumor?s cell type, grade (how abnormal the cancerous tissue appears under a microscope), and estrogen receptor status as well as other factors such as the patient?s age in deciding if chemotherapy or tamoxifen should be given to patients with small tumors.

But the authors of an accompanying editorial say most patients with small tumors have a favorable outcome without adjuvant therapy. "[I]t?s hard for me to believe that there might not well be significant toxicity [side effect] issues with chemotherapy that would compete with the potential limited benefits of therapy," says Marc E. Lippman, MD, lead author of the editorial and chair of the department of internal medicine at the University of MichiganHealth System.

An expert with the National Comprehensive Cancer Network (NCCN) says both the editorialists and the study authors are right on some points. "In patients with small breast tumors and no lymph node involvement, it really is an issue of looking at whether the toxicity [side effects] and expense of therapy justify the small but apparently real and expected benefits of the therapies that are applied," says Robert Carlson, MD, a professor of medicine at Stanford University who chairs the group that produces the NCCN breast cancer treatment guidelines. The NCCN is an alliance of leading cancer centers that develops and publishes the most widely accepted treatment guidelines.

Not Recommended by Guidelines

NCCN guidelines currently do not recommend adjuvant therapy for patients with tumors of one half centimeter or less, Carlson says. "But, certainly, node-negative patients with breast tumors of 0.6 to one centimeter in size have a high enough risk for recurrence that use of adjuvant chemotherapy or hormone therapy or both should be considered," he adds.

"That consideration should include a careful estimate of what the prognosis is, how much benefit the adjuvant therapy could provide, and what the woman has to accept in terms of side effects and risks to try to achieve that benefit," Carlson says. "From our perspective, it?s really the woman who has to balance those risk assessments for us and tell us as an individual whether she believes adjuvant therapy gives the balance of risks and benefits that is appropriate for her or not."

To view the NCCN guidelines for breast cancer treatment, click here.