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, 2N0 Mx. The patients received3-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, χ2 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, χ2test). 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.

Assessment of contralateral mammary gland dose in the treatment of breast cancer using accelerated hypofractionated radiotherapy

AIM:To measure the dose distribution,related to the treatment planning calculations,in the contralateral mammary gland of breast cancer patients treated with accelerated hypofractionated 3-dimensional conformal radiotherapy.METHODS:Thirty-four prospectively selected female patients with right breast cancer (pN0,negative surgical margins) were treated with breast-conserving surgery.A total dose of 42.5 Gy (2.66 Gy/fraction) was prescribed;it was requested that planning target volumes be covered by the 95% isodose line.The contralateral mam-mary gland was defined on CT simulation.The dose received was evaluated by dose volume histograms.RESULTS:The measured contralateral breast doses were:(1) Dose maximum:290-448 cGy [Equivalent (Eq) 337-522 cGy];(2) Mean dose:45-70 cGy (Eq 524815 cGy);and (3) Median dose:29-47 cGy (337-547 cGy) for total primary breast dose of 42.5 Gy in 16 equal fractions.The spearman rho correlation showed statistical significance between the contralateral breast volume and maximum dose (P=0.0292),as well as mean dose (P=0.0025) and median dose (P=0.046) to the breast.CONCLUSION:Minimizing the dose to the contralateral breast has to be one of the priorities of the radiation oncologist when using short schedules because of the radiosensitivity of this organ at risk.Further study is necessary to assess the long-term clinical impact of this schedule.