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Purpose Multibeam intensity modulated radiation therapy (IMRT) enhances the therapeutic index by increasing the dosimetric coverage of the targeted tumor tissues while minimizing volumes of adjacent organs receiving high doses of RT. The tradeoff is that a greater volume of lung is exposed to low doses of RT, raising concern about the risk of radiation pneumonitis (RP). Methods and Materials Between July 2010 and January 2013, patients with node-positive breast cancer received inverse-planned, multibeam IMRT to the breast or chest wall and regional nodes, including the internal mammary nodes (IMNs). The primary endpoint was feasibility, predefined by dosimetric treatment planning criteria. Secondary endpoints included the incidence of RP grade 3 or greater and changes in pulmonary function measured with the Common Terminology Criteria for Adverse Events version 3.0 scales, pulmonary function tests and community-acquired pneumonia questionnaires, obtained at baseline and 6 months after IMRT. Clinical follow-up was every 6 months for up to 5 years. Results Median follow-up was 53.4 months (range, 0-82 months). Of 113 patients enrolled, 104 completed follow-up procedures. Coverage of the breast or chest wall and IMN was comprehensive (median 48.1 Gy and 48.9 Gy, respectively). The median volume of lung receiving a high dose (V20Gy) and a low dose (V5) was 29% and 100%, respectively. The overall rate of respiratory toxicities was 10.6% (11/104), including 1 grade 3 RP event (0.96%). No differences were found in pulmonary function test or community-acquired pneumonia scores after IMRT. The 5-year rates of locoregional recurrence-free, disease-free, and overall survival were 93.2%, 63.6%, and 80.3%, respectively. Conclusions Multibeam IMRT in patients with breast cancer receiving regional nodal irradiation was dosimetrically feasible, based on early treatment planning criteria. Despite the large volume of lung receiving low-dose RT, the incidence of grade 3 RP was remarkably low, justifying inverse-planned IMRT as a treatment modality for patients with high-risk breast cancer in whom conventional RT techniques prove inadequate.

Purpose A 2-arm, double-blinded randomized trial was conducted to evaluate the efficacy of 0.1% mometasone furoate (MF) versus Eucerin Original (E) cream in preventing the development of moderate to severe acute radiation dermatitis (ARD) in breast cancer patients receiving postmastectomy radiation (PMRT). Methods Breast cancer patients undergoing chest wall with or without nodal radiation therapy (RT) (50 Gy) were eligible. Randomization (1:1) was to MF or E, applied twice daily from day 1 of PMRT to 14 days after PMRT. Patients were stratified by RT technique, body mass index, and reconstruction status. Daily bolus of 3 to 10 mm was applied in all patients. The primary endpoint was the development of provider-assessed grade ≥2 (Common Terminology Criteria for Adverse Events version 4.03) ARD with moist desquamation or any grade ≥3 dermatitis. Secondary endpoints were time to occurrence of maximum-grade dermatitis and patient-reported skin symptoms using a skin-related quality of life questionnaire, Skindex-16. Assessments were performed at baseline, weekly during PMRT, and 2 weeks after PMRT. Results 124 patients were enrolled between May 2013 and February 2016. Of those, 35% had pathologic stage III disease, 6% had cT4d disease, and 68% underwent reconstruction. Sixty percent received 3-dimensional conformal RT with photons only to the chest wall, 18% received electrons and photons, and 23% received inverse-planned intensity modulated RT. Groups were well balanced for age, skin type, and stage. The rate of moist desquamation was 54.8% in the entire cohort, with a significantly reduced incidence in the MF arm than in the E arm (43.8% vs 66.7%; P = .012). The MF arm had a lower incidence of maximum skin toxicities (P = .036) and longer time to development of grade 3 dermatitis (46 days vs 35.5 days, respectively; P ≤ .001). There was no difference in patient-reported skin outcomes between arms. Conclusions Breast cancer patients receiving MF during PMRT experienced significantly reduced rates of moist desquamation in comparison with a control cream.

Conclusion: The additional evaluation of the BED distribution rather than only the dose distribution is important in diseases where the a/b ratios of tumor and OARs differ. SIB schemes are radiobiologically more advantageous than SEQ in breast target volume and OARs for equally prescribed BEDs for breast and boost. Author Disclosure: M.M. Aly: Research Grant; DAAD. Y. Abo-Madyan: Honoraria; Carl Zeiss, Merck. L. Jahnke: Consultant; ELEKTA. F. Wenz: Research Grant; Carl Zeiss, ELEKTA. Patent/License Fees/Copyright; Carl Zeiss. G. Glatting: Research Grant; DFG. Editorial Board; EANM. Physics Committee member; EANM. Co-Editor; DGMP.