[en] Purpose: The aims of this prospective study were to evaluate the outcome and the possibility of breast conserving treatment for patients with stage II larger than 3 cm or locally advanced non inflammatory breast cancer, after primary chemotherapy followed by external preoperative-dose irradiation. Materials and methods: Between April 1982 and June 1990, 147 consecutive patients with large breast cancer (stage II > 3 cm [n=50], stage IIIA [n=58], stage IIIB [n=35] and stage IV with isolated clinical supraclavicular or sub-clavicular node involvement [n=4] were treated. The median age was 49 years. Mean tumor size was 6 cm (range 1 - 16 cm). Sixty percent (n=88) of the patients were postmenopausal. Histological classification was : 120 infiltrating ductal carcinomas, 21 infiltrating lobular carcinomas, 4 medullary carcinomas and 2 mucosecreting carcinomas. Grade distribution according to Scarff, Bloom and Richardson was : 14 grade 1, 72 grade 2, 30 grade 3 and 31 non classified. Median follow-up was 94 months from the beginning of the treatment. The induction treatment consisted of 4 courses of chemotherapy (doxorubicin, vincristine, cyclophosphamide, 5-fluorouracil) every 4 weeks followed by preoperative irradiation (45 Gy to the breast and nodal areas) using 60Co in 141 patients and 6 MV photons in 6 patients. A fifth course of chemotherapy was given after radiation therapy and three different locoregional approaches were proposed depending on the tumoral response. In 52 patients (35%) with residual tumor larger than 3 cm in diameter or located behind the nipple or with bifocal tumors, mastectomy and axillary dissection were performed. Ninety-five other patients (65%) benefited from conservative treatment : 48 patients (33%) achieved complete remission and received a booster dose of 25 to 30 Gy to the initial tumor bed by external photon beam or by iridium 192 implant ; 47 patients (32%) who had a residual mass less than or equal to 3 cm in diameter were treated by wide excision and axillary dissection followed by a booster dose of 20 Gy to the excision site by iridium 192 implant. After completion of local therapy all patients received a sixth course of chemotherapy. A maintenance adjuvant chemotherapy regimen without anthracycline was prescribed (12 monthly cycles). Results: The overall response rate to induction chemotherapy was 59 % with 9 % complete tumor regression. After induction chemotherapy and preoperative-dose irradiation, the overall response rate was 74% with 40% complete tumor regression. Four percent of the patients experienced grade 3 or 4 chemotherapy toxic effects which were all reversible. The 5- and 10- year overall, disease-free survival, isolated local relapse and locoregional relapse with or without metastases rates were 79% and 66%, 66% and 60%, 4.2% and 7.5%, 12% and 17%, respectively. The 5- and 10- year locoregional relapse rates with or without metastases were 15% and 20% after radiotherapy alone, 14% and 22.5% after wide excision and radiotherapy and 6% and 6% after mastectomy, respectively. The 5- and 10- year locoregional relapse rate seemed higher after wide excision and radiotherapy or after radiotherapy alone than after mastectomy but the difference was not significant, p=0.067 and p=0.08, respectively. After conservative local treatment, the 5- and 10- year breast conserving rates with locoregional disease-free were 85.5% and 78.5%, respectively. For all patients included in this study, the 5- and 10- year breast conserving rates with locoregional disease-free were 55% and 50.5%, respectively. In univariate analysis, the possibility of breast conservative treatment was significantly related to initial tumor size (< 6 cm vs ≥ 6 cm in diameter, p < 0.0001), tumor response after induction chemotherapy (p < 0.0001), tumor response after induction chemotherapy and preoperative-dose irradiation (p < 0.0001) and T-stage (p=0.016). In multivariate analysis, two factors had a significant impact on the possibility of breast conservative treatment : tumor size (p = 0.0003) and tumoral response after induction chemotherapy and preoperative-dose irradiation (p < 0.0001). In univariate analysis, overall survival and disease-free survival were significantly influenced by tumor size (< 6 cm vs ≥ 6 cm in diameter, p=0.046 and 0.047, respectively), histological grade (grade 1 and 2 vs grade 3, p=0.0066 and 0.01, respectively), clinical stage (stage II and III vs stage IV, p=0.0017 and 0.004, respectively), tumor response to induction chemotherapy (p=0.027 and 0.0042, respectively) and tumor response after induction chemotherapy and preoperative-dose irradiation (p = 0.025 and 0.0042, respectively). In multivariate analysis, two factors had significant impact on overall survival and disease free-survival : tumor response after chemotherapy (p=0.012 and 0.0024, respectively) and clinical stage (p=0.0009 and 0.0052, respectively). Arm lymphedema was noted in 11% of the patients treated with axillary dissection and in 4% without axillary dissection. Limitation of shoulder movements was noted in 6% after mastectomy and axillary dissection and in 2% after wide excision and axillary dissection. None of patients developed congestive heart failure, extended pulmonary fibrosis, brachial plexopathy or rib fracture. Cosmetic results were satisfactory in 67% of patients after wide excision and radiotherapy and in 75% of patients treated by radiotherapy alone. Conclusion: Induction chemotherapy followed by preoperative-dose irradiation may permit the selection of some patients with locally advanced breast cancer or stage II more than 3 cm in diameter for conservative treatment. However, the impact of this treatment modality on long term survival remains to be established