Postmastectomy radiotherapy and concomitant adjuvant chemotherapy versus adjuvant chemotherapy alone in premenopausal breast cancer patients with positive axillary nodes.

Aims: To evaluate the efficacy of postmastectomy radiotherapy (RT) combined with adjuvant chemotherapy compared to adjuvant chemotherapy alone as regards overall survival (OS), overall disease-free survival (ODFS), local disease-free survival (LDFS) and distant disease-free survival (DDFS).
Methods: We reviewed retrospectively two non-randomized groups of premenopausal high-risk breast cancer patients treated from 1985 to 1990 in the following Institutions: Department of Radiation Oncology of Brescia University, "Istituto del Radio O. Alberti" (IRA), and Department of Oncology of Brescia Hospital "Beretta Foundation" (BF). A total of 163 patients was found to satisfy the criteria of the current analysis: 81 patients received adjuvant chemotherapy alone [6 cycles CMF(1-8)] at BF and 82 patients received postoperative radiotherapy and chemotherapy [8 cycles CMF(1-21)] at IRA. A modified CMF schedule was chosen at IRA to avoid the feared increase in toxicity due to the association with RT. Primary surgical treatment was modified radical mastectomy with axillary node dissection in both cases.
Results: A statistically significant improvement in OS was found in systemic adjuvant therapy patients compared to those also given RT (77.6% vs 59%; P = 0.0025). No statistically significant improvement in ODFS was found in the CMF(1-8) arm compared to the RT and CMF(1-21) stm: 51.6% vs 43.6%; P = 0.46. A statistically significant improvement in LDFS at 5 years was found in irradiated patients (89.3% vs 76.2%; P <0.05). The DDFS was also improved, although without evidence of statistical significance, in the CMF(1-8) group: at 5 years 65% vs 44% (P = 0.059).
Conclusions: The study confirmed that RT reduces the risk of local recurrence but without a statistically significant reduction in mortality. The lack of a survival benefit may somehow reflect the dose reduction in CMF(1-21). The evidence that CMF(1-8) offers undoubtable advantages over the CMF(1-21) regimen in OS and, perhaps, in distant control suggests that the dose intensity of CMF in this setting may also be important. In fact, although many CMF(1-8) patients received a dose intensity lower than 100%, 95% of them received a dose intensity higher than the maximum one of the CMF(1-21) patients. Although our results should be interpreted with caution, they seem to provide further rationale for testing the association of postoperative radiotherapy and the CMF(1-8) regimen in stage II breast cancer with positive nodes and treated with demolitive surgery, as already done in the conservative management of breast cancer, also in view of the new support therapies now available (i.e. hematologic growth factors).