Many patients ask whether they should have chemotherapy for breast cancer when no cancer was found in the lymph nodes. The issues around the importance of axillary dissections and the use of chemotherapy after lymph node dissection are complicated and can only be addressed adequately on an individual basis. However, there is reason for optimism and some recent studies demonstrate how far we have come in the management of breast cancer.
With current technology, mammograms are detecting breast cancer at earlier stages. When lymph nodes are involved with cancer, removing these nodes not only removes residual cancer cells but provides important information concerning prognosis. When no cancer is found in the lymph nodes, the overall prognosis is very good. Several recent publications have reported that when the tumor in the breast is less than 1 centimeter and no cancer cells are found in the lymph nodes, survival 8 years after either mastectomy or lumpectomy/axillary dissection and radiation is about 86%. Treatment with Tamoxifen, when patients have tumors with estrogen receptors increases the overall survival at 8 years from 86% to 93%.
Stated in another way, 86 of 100 women with small tumors and no involved axillary lymph nodes will be free of detectable disease 8 years later regardless of any additional hormone therapy or chemotherapy. If Tamoxifen is given to all women with estrogen receptor positive tumors, the survival will improve and 93 of 100 women will be alive at 8 years. Since 86 of those would have been free of disease whether they were treated with Tamoxifen or not, the real benefit is for the 7 women who would have had recurrent cancer if they had not received Tamoxifen. Therefore, while all 100 women receive Tamoxifen, 14 are at risk of recurrent cancer and 7 will benefit from the treatment. Since Tamoxifen is generally well tolerated, most women elect to have treatment with Tamoxifen. Paradoxically, the decision to treat patients with chemotherapy in addition to Tamoxifen is difficult because the outlook for these patients is very good.
With these factors in mind, we can look at the value of chemotherapy for women with small tumors and no lymph node involvement. Since we know that 93 of 100 women will be free of disease 8 years after surgery and Tamoxifen, the use of chemotherapy will not help these 93 patients. Of the 7 remaining patients that could potentially benefit from chemotherapy, 2 will benefit, resulting in an overall survival at 8 years of 95% by combining both Tamoxifen and chemotherapy after surgery. Unfortunately, this means that while 2 will derive benefit from the treatment 100 women will receive chemotherapy. Since chemotherapy can cause significant toxicities, including nausea, vomiting, hair loss and susceptibility to infections, the decision to use chemotherapy is very difficult. Until there are tests which will reliably identify the patients who will have a recurrence of cancer, the decision to treat with chemotherapy is one that can only be determined by weighing the risk of a possible recurrence of cancer against the toxicities of the treatment. Sincerely,