Can the addition of regional radiotherapy counterbalance important risk factors in breast cancer patients with extracapsular invasion of axillary lymph node metastases?
OBJECTIVE
To evaluate if locoregional radiotherapy (RT) versus local irradiation only can alter the pattern of failure in breast cancer patients with extranodal invasion.


METHODS
From 08/1988 to 06/1998, 81 patients with extranodal invasion were treated with adjuvant RT (median total dose: 50.4 Gy), 46/81 only locally, 35/81 loco regionally due to presumed adverse parameters. The mean number of resected (positive) lymph nodes was 17 (seven). 78 patients received adjuvant systemic treatment(s).


RESULTS
Patients treated with locoregional RT had significantly more often lymphatic vessel invasion (LVI; 63% vs. 28%; p = 0.003), T3/T4 tumors (43% vs. 17%; p = 0.014), and four or more positive lymph nodes (91% vs. 46%; p < 0.001) than patients irradiated only locally. Disease progression occurred in 24/81 patients (locoregional RT: 26% vs. local RT: 33%). The above risk factors were highly significant of worse outcome. Despite their overrepresentation in the locoregional RT group, no difference was found between both groups in regard to disease-free survival (DFS; p = 0.83) and overall survival (OS; p = 0.56), suggesting that regional RT was able to counterbalance the increased risk. There was even a trend toward a better 3-year DFS, 61% in locoregional RT and 37% in local RT, in the subgroup of patients with four or more positive lymph nodes. In a Cox regression model, higher T-stage, four or more positive lymph nodes, and LVI remained significant. For DFS and distant metastasis-free survival (DMFS), the absence of estrogen receptors and the omission of regional RT were also significant.


CONCLUSIONS
Our data suggest that the addition of regional RT might be beneficial in selected subgroups of patients with extranodal invasion and other poor prognostic factors.
Gruber
Günther
G
Department of Radiation Oncology, Inselspital, University of Bern, Switzerland. guenther.gruber@insel.ch
Berclaz
Gilles
G
Altermatt
Hans-Jörg
HJ
Greiner
Richard H
RH
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D015412:Mastectomy, Segmental; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors