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Article of the Month -- April 1997 THE ROLE OF AXILLARY DISSECTION IN MAMMOGRAPHICALLY DETECTED CARCINOMASteven M. Pandelidis, MD,* Kristi L. Peters, MS,† Mbaga S. Walusimbi, MD,* Roger L. Casady, MD,* Shelli V. Laux, RRA, CTR,‡ Sally H. Cavanaugh, PhD,† and Thomas L. Bauer, MD, FACS* DISCUSSION In a series of 1,624 patients, Recht and colleagues reported an axillary recurrence rate of 2.2 percent in patients treated with level I and II lymph node dissections (7). In the NSABP-4, there was an 18 percent axillary recurrence rate at 10 years in the group of patients treated with total mastectomy only. The investigators in the NSABP-4 concluded that although omission of axillary lymph node dissection led to a higher axillary failure rate, overall survival remained unaffected (8). Hellman and Harris argued that the NSABP-4 data are flawed because 35 percent of the patients who underwent "total mastectomy" had between 1 and 10 nodes incidentally removed during the procedure (2). Elimination of these patients from the study would weaken the statistical evidence that total mastectomy and total mastectomy plus axillary lymph node dissection produce equivalent survival results (2). Additionally, Feintman and coauthors reported that among long-term survivors (longer than 20 years) of carcinoma of the breast, 35 percent had positive nodes at the time of treatment (1). In their series, patients were treated with operation only. The authors suggest that the resection of the involved nodes leads to the cure (1). While controversy exists about the contribution of axillary dissection to the treatment of carcinoma of the breast, few would disagree that the procedure adds to the morbidity of operative treatment. Among patients with mammographically detected carcinomas, subgroups may exist in whom the risk of axillary metastases is so small that they can be spared the morbidity of node dissection. We and other authors have shown that axillary lymph node dissection is unnecessary in mammographically detected DCIS (3, 4, 9). In the York Hospital experience, 109 of 184 patients with DCIS underwent axillary lymph node dissection. No specimens revealed metastatic nodes. All 21 of our patients with invasive microscopic tumors underwent node dissection; no metastatic nodes were detected. Patients with T1a tumors (£0.5 cm.) were only rarely found to have positive nodes (3.7 percent). Silverstein and associates reported a similar rate (3.8 percent) (9). Among our 54 patients with T1b tumors, 11.7 percent had positive nodes; however, in only one instance did a well-differentiated T1b lesion metastasize to axillary nodes. The tumor was 0.6 cm and ER and PR negative. A patient with such a tumor may well be offered adjuvant chemotherapy even in the absence of positive nodes. The location of the primary tumor did not aid in predicting the presence or absence of metastases to axillary lymph nodes (Table III). Table IV illustrates that medical oncologists offer adjuvant therapy to certain patients with node-negative tumors. The larger the tumor, the more likely they are to offer chemotherapy or hormonal therapy. Almost 20 percent of the 52 patients with T1aN0 tumors and almost 34 percent of 166 patients with T1bN0 tumors received adjuvant therapy. Most patients (60 percent) with T1cN0 tumors received chemotherapy or hormonal therapy. Patients with negative nodes were more likely to receive adjuvant hormonal therapy than adjuvant cytotoxic therapy (Table IV). Strict criteria were not used to make the recommendation for adjuvant therapy, but rather those patients with tumors showing poor prognostic features were advised of the risks and benefits of specific types of adjuvant therapy. Patient age, performance status, and, of course, desires, influence the decision to offer adjuvant therapy. The average age of patients with T1a or T1b tumors who received chemotherapy was 53 years. No patients had well-differentiated tumors, and most tumors were ER or PR negative (75 percent) and aneuploid (83 percent). When considering differentiation, ER status, PR status, ploidy, and S phase, all patients who received chemotherapy had at least three poor prognostic features. Given the lesser risks of tamoxifen therapy compared with cytotoxic therapy, tamoxifen was more often offered to patients with nodes negative for metastasis. Almost all such patients had ER-positive tumors (98 percent). Because tamoxifen therapy decreases the risk of the development of contralateral carcinoma by 39 percent, and that in the Breast Cancer Prevention Trial high-risk patients without carcinoma are being offered tamoxifen, it does not seem unreasonable to offer tamoxifen to patients with T1a or T1b tumors (10). Despite the usual good prognosis for patients with T1aN0M0 or T1bN0M0 tumors, approximately 10 percent of such patients still die of metastatic disease (11). By analyzing prognostic features of primary tumors, we tried to offer adjuvant therapy only to those patients at high risk for recurrence. Based on our series of 517 mammographically detected invasive carcinomas, we can recommend that microscopic invasive tumors (n=21), and perhaps T1a tumors (n=61) and well-differentiated ER- and PR-positive T1b tumors (n=16), do not require an axillary lymph node dissection. Such a policy would have eliminated 98 axillary lymph node dissections (19 percent), and in two patients involved axillary lymph nodes would not have been detected. A larger confirmatory study is necessary to make any clear recommendations about the elimination of axillary dissection in well-differentiated, ER- and PR-positive T1b tumors. In any large series, on occasion, a small tumor that has regionally metastasized might be missed following a policy of selective lymph node dissection. Given the tendency for our medical oncologists to offer adjuvant treatment to patients with nodes negative for metastases and T1a or T1b tumors with poor prognostic indexes, such patients would probably receive chemotherapy or tamoxifen. The adjuvant therapy may control disease in the axilla as well as operative therapy does. Treating 98 women with microscopic invasive tumors, T1a tumors, or well-differentiated, ER- and PR-positive T1b tumors by axillary lymph node dissection for the sake of 2 women who have positive nodes seems ill-advised. Even if both women received adjuvant chemotherapy, as a group they would realize a 16 percent reduction in the risk of death from carcinoma of the breast. ____________________ Journal of the American College of Surgeons
BACKGROUND, STUDY DESIGN, AND RESULTS __________ |