Adjuvant chemotherapy and acute toxicity in hypofractionated radiotherapy for early breast cancer.

AIM: To evaluate the effect of chemotherapy to the acute toxicity of a hypofractionated radiotherapy (HFRT) schedule for breast cancer.
METHODS: We retrospectively analyzed 116 breast cancer patients with T1, 2N0Mx. The patients received 3-D conformal radiotherapy with a total physical dose of 50.54 Gy or 53.2 Gy in 19 or 20 fractions according to stage, over 23-24 d. The last three to four fractions were delivered as a sequential tumor boost. All patients were monitored for acute skin toxicity according to the European Organization for Research and Treatment of Cancer/Radiation Therapy Oncology Group criteria. The maximum monitored value was taken as the final grading score. Multivariate analysis was performed for the contribution of age, chemotherapy and 19 vs 20 fractions to the radiation acute skin toxicity.
RESULTS: The acute radiation induced skin toxicity was as following: grade I 27.6%, grade II 7.8% and grade III 2.6%. No significant correlation was noted between toxicity grading and chemotherapy (P = 0.154, χ(2) test). The mean values of acute toxicity score in terms of chemotherapy or not, were 0.64 and 0.46 respectively (P = 0.109, Mann Whitney test). No significant correlation was also noted between acute skin toxicity and radiotherapy fractions (P = 0.47, χ(2) test). According to univariate analysis, only chemotherapy contributed significantly to the development of acute skin toxicity but with a critical value of P = 0.05. However, in multivariate analysis, chemotherapy lost its statistical significance. None of the patients during the 2-years of follow-up presented any locoregional relapse.
CONCLUSION: There is no clear evidence that chemotherapy has an impact to acute skin toxicity after an HFRT schedule. A randomized trial is needed for definite conclusions.