A prospective feasibility study of a 1-mm bolus for postmastectomy radiotherapy

• Published in: BMC cancer Vol. 21; no. 1; pp. 109 - 6
• Main Authors: Kawamoto, Terufumi, Shikama, Naoto, Kurokawa, Chie, Hara, Naoya, Oshima, Masaki, Sasai, Keisuke
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 02.02.2021; BioMed Central; BMC
• Subjects: Adult; Aged; Bolus; Breast cancer; Breast Neoplasms - pathology; Breast Neoplasms - radiotherapy; Breast Neoplasms - surgery; Care and treatment; Chest; Clinical trials; Dermatitis; Dosimetry; Dosimetry analysis; Feasibility Studies; Female; Follow-Up Studies; Hospitals; Humans; Mastectomy - methods; Methods; Middle Aged; Patients; Postmastectomy radiotherapy; Postoperative care; Prognosis; Prospective Studies; Radiation therapy; Radiodermatitis - epidemiology; Radiodermatitis - pathology; Radiodermatitis - prevention & control; Radiotherapy; Radiotherapy Dosage; Radiotherapy, Adjuvant - methods; Radiotherapy, Adjuvant - standards; Skin; Standard deviation; Thoracic Wall - radiation effects; Toxicity; Japan; United States > US; Dosimetry analysis; Breast cancer; Bolus; Postmastectomy radiotherapy
• ISSN: 1471-2407; 1471-2407
• DOI: 10.1186/s12885-021-07851-3

The optimal chest wall bolus regimen for postmastectomy radiotherapy (PMRT) remains unknown. We aimed to prospectively evaluate the use of a 1-mm-thick daily tissue-equivalent bolus in patients who received PMRT using thermoluminescent dosimeters (TLDs) and skin toxicity assessment. Patients with a 1-mm-thick daily bolus during PMRT were prospectively enrolled at The Juntendo University Hospital. The surface dose was measured in vivo under the 1-mm-thick bolus on the chest wall. We assessed the acute skin toxicity weekly during PMRT, and 1, 2, 4, and 12 weeks after the completion of PMRT. A total of 19 patients aged 32-79 years old received PMRT from July 2019 to January 2020. All patients completed the protocol treatment without interruptions, and the median follow-up was 32 weeks. In vivo dosimetry analysis revealed surface doses between 77 and 113% of the prescribed dose, with a mean of 92% of the prescribed radiation dose, and a standard deviation of 7% being delivered. Grade 2 dermatitis was found in 10 patients (53%), and Grade 3 dermatitis was found in one patient (5%). All cases of Grade 2 and 3 dermatitis were improved 4 weeks after PMRT. There were no cases of Grade 4 dermatitis and no chest wall recurrences during the treatment or follow-up period. Results confirmed the feasibility of using a 1-mm-thick daily bolus for PMRT, exhibiting an appropriate dose buildup and acceptable skin toxicity without treatment interruptions. The University Hospital Medical Information Network Clinical Trials Registry, UMIN000035773 . Registered 1 July 2019.