TAMOXIFEN WITH AND WITHOUT RADIATION AFTER PARTIAL MASTECTOMY IN PATIENTS WITH INVOLVED NODES

Purpose: To determine the effect of tamoxifen on local control. after partial mastectomy with and without adjuvant breast irradiation. Metho ds and Materials: A retrospective study of 97 node positive patients i dentified from the records of the London Regional Cancer Center includ ed 44 patients who received tamoxifen and breast irradiation (40 or 50 Gy plus booster dose) after partial mastectomy, and 53 patients who r eceived tamoxifen only after partial mastectomy. Base line characteris tics of the two groups were similar. Results: At 39 months actuarial f ollow-up there was a breast tumor recurrence (BTR) in 5% vs, 21% of pa tients when radiation was omitted (p = 0.0388), but there was no diffe rence in the cause-specific mortality of the two treatment groups. Cox Regression analysis (on only 10 BTR) showed age and adjuvant radiatio n as significant predictors of BTR. In patients not receiving radiatio n, no BTR was seen in 22 patients greater than or equal to 70 years of age at diagnosis vs, 8 BTR in 31 patients <70 years (p = 0.0130). All BTR occurred while patients were receiving tamoxifen. Conclusions: Ta moxifen alone with omission of radiation after partial mastectomy prov ides inferior breast tumor control in node positive patients. This is especially true for patients under 70 years of age. Patients aged 70 y ears or older at the time of diagnosis of breast cancer who receive ta moxifen have a low rate of breast tumor recurrence when radiation is o mitted. These patients represent a group for whom radiation might not be necessary.