Prone versus supine position for adjuvant breast radiotherapy: a prospective study in patients with pendulous breasts.

Purpose: To analyze dosimetric parameters of patients receiving adjuvant breast radiotherapy (RT) in the prone versus supine position. Methods and materials: Forty-one out of 55 patients with pendulous breasts and candidates for adjuvant RT were enrolled in the study after informed consent. They underwent computed tomography (CT)-simulation in both prone and supine position. Target and non target volumes were outlined on CT images. Prescribed dose was 50 Gy delivered by two tangential photon fields followed by 10 Gy electron boost. Target coverage and dose homogeneity to clinical target volume (CTV) and planning target volume (PTV) were assessed by V95, V105 and V107 and dose to lung, heart and left anterior descending coronary artery (LAD) by V5, V10, V20, and mean and maximum dose. Data were analyzed by Student\u2019s t-test. Results: CTV and PTV coverage was significantly better in supine than in prone position. Lung V5, V10, and V20 were significantly lower in prone than in supine position. Heart V5, V10, V20, and LAD mean and maximum dose, in the 17 patients with left breast tumor, were lower in prone than in supine position, but without statistical significance. Based on treatment planning data and on treatment feasibility, 29/41 patients (70.7%) were treated in prone position. Acute and late toxicities of patients treated in prone and in supine position were not statistically different. Conclusion: Prone position is a favorable alternative for irradiation of mammary gland in patients with pendulous breasts and in our series was adopted in 71% of the cases

Common variants of eNOS and XRCC1 genes may predict acute skin toxicity in breast cancer patients receiving radiotherapy after breast conserving surgery

Purpose: To evaluate the impact of functional polymorphisms in genes related to DNA repair mechanisms (XRCC1, TP53, MSH2, MSH3, XPD), oxidative stress response (GSTP1, GSTA1, eNOS, SOD2) and fibroblast proliferation (TGFb1) on the risk of acute skin toxicity in breast cancer patients receiving radiotherapy. Material and methods: Skin toxicity was scored according to the Radiation Therapy Oncology Group cri- teria in 286 breast cancer patients who received radiotherapy after breast conserving surgery. Genotyp- ing was conducted by PCR-RFLP analysis and real-time PCR allelic discrimination assay on genomic DNA extracted from peripheral blood. Results: In the multivariate analysis, nominally significant associations, before multiple testing corrections, were found between XRCC1 T-77C (T carriers vs. CC, OR: 2.240, 95% CI: 1.015–4.941, P = 0.046), eNOS G894T polymorphisms (TT vs. G carriers, OR: 2.473, 95% CI: 1.220–5.012, P = 0.012), breast diameter (OR: 1.138, 95% CI: 1.001–1.293, P = 0.048), boost dose-fractionation (3 Gy vs. no boost, OR: 4.902, 95% CI: 1.458–16.483, P = 0.010) and Pgrade 2 acute radiation skin toxicity in breast cancer patients. Conclusions: As our exploratory study suggests that XRCC1 T-77C and eNOS G874T may confer an increased risk of acute skin reactions to radiotherapy in breast cancer patients, further confirmatory studies are warranted to determine the clinical significance