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Hypofractionated Whole Breast Radiation Therapy for Large-breasted Patients

2009; Elsevier BV; Volume: 75; Issue: 3 Linguagem: Inglês

10.1016/j.ijrobp.2009.07.516

1879-355X

Raquibul Hannan, M. Spierer, William Skinner, Rafi Kabarriti, C. Chen, Karen De Amorim Bernstein, Ezekiel H. Landau, E. B. Miller, Hong Liang, Shalom Kalnicki,

Breast Lesions and Carcinomas

Large breasts have been excluded in hypofractionation trials due to concerns of suboptimal dose distribution and toxicity. The prone technique was introduced to produce a more homogeneous dose distribution and thereby an improved toxicity profile in large-breasted patients. With the use of IMRT prone breast technique, it may be possible to overcome the limitations of hypofractionation in large-breasted patients. In this study, we retrospectively review the DVH parameters and clinical toxicity in large-breasted patients treated with the hypofractionated regimen of 42.4 Gy using IMRT prone technique. We selected 21 consecutive patients treated at our institution between 2005 and 2007 with chest wall separation >25 cm or PTV > 1500cc and who received hypofractionated radiation of 42.4Gy delivered in 16 fractions using the IMRT prone technique. All patients had localized invasive breast cancer or DCIS treated with lumpectomy. All patients also received a boost of 9.6Gy in 4 fractions. DVH data were collected from Varian's ARIA 8.6 treatment planning software. Patient charts were reviewed for acute and late toxicity measured using RTOG/EORTC radiation morbidity scale. Median chest wall separation was 25.07 cm (range: 19 - 29.4 cm), and the median PTV was 1970 cc (range: 1511 - 3773cc). DVH analysis showed the mean PTV V95 was 87.8% (range: 66.2 - 94.9%) and mean V105 was 3.28% (range: 0.1 - 18.2%). There were no hot spots >107%. The mean D05% for heart was 2.12 Gy (range: 0.52 - 4.1) and mean V10Gy was 0.36% (range : 0 - 1.88%). The mean D05% for total lung and ipsilateral lung was 2.42Gy (range: 0.91 - 4.34Gy) and 4.91Gy (range: 1.91 - 21.35Gy) respectively, while the V20Gy was 0.45% (range: 0 - 2.53) and 0.96% (range: 0 - 5.19) respectively. 71% and 19% of patients experienced acute RTOG grade 1 and 2 skin toxicity, respectively. No patients experienced RTOG Grade 3 or 4 acute or late skin toxicity. At a median follow up of 11 months (range: 0 - 26 months), the RTOG late skin toxicity grade was 0 in 67% and 1 in 33% of patients. No cardiac or pulmonary toxicity was reported. There were no local recurrences. Adequate PTV coverage with acceptable hot spots was achieved using IMRT and prone technique in a patient population with large breasts. In addition, there was excellent sparing of organs at risk. These DVH parameters were reflected in the minimal clinical acute and late toxicity. Hypofractionation is likely a viable alternative for large breasted women when used with a prone technique and IMRT. A larger cohort of patients is currently undergoing data analysis.