The Effect of Bolus on Local Control for Patients Treated with Mastectomy and Adjuvant Radiotherapy

Abstract

Purpose/Objective(s): Trastuzumab (H) improves disease-free and overall survival in HER2+ breast cancer (BC) when added to adjuvant chemotherapy. We describe the impact of H on locoregional failure rates (LFRs). Materials/Methods: 3505 patients (pts) with HER2+ BC were randomized. This analysis included 2763 eligible pts who had lumpectomy (L) or mastectomy (M) with radiotherapy (RT) or M without RT in this 3-arm phase 3 trial of adjuvant doxorubicin (A), cyclophosphamide (C), paclitaxel (T)

A Delphi study and International Consensus Recommendations: The use of bolus in the setting of postmastectomy radiation therapy for early breast cancer

“…t h e g r e e n j o u r n a l . c o m [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Unfortunately, the use of bolus was not evident from large, randomized trials that led to significant changes in radiation oncology practice, since they failed to address the utilization of bolus in PMRT.…”

“…[Mode 1; median 1; IQR 1-2]. This statement is based on the systematic review summary [32] conducted as part of this project and a recent large study published by Nichol and colleagues [6]. The use of bolus was associated with similar local recurrence rates (3.5% with bolus vs. 3.6% without) when compared to PMRT without bolus for studies included in the systematic review and was supported by three comparative studies, with no significant difference in local recurrence risk factors between treatment groups [2,4,5,32].…”

“…Approximately 82% of the local recurrences are within the subcutaneous tissue and/or skin, with most of the remainder found in the pectoralis muscle. Rib, sternal and intercostal muscle recurrences are uncommon [6,68] and usually considered distant recurrences [69]. Seldomly, deep chest-wall recurrences are a result of direct invasion from tumour involvement of retro-pectoral lymph nodes, Rotter's lymph nodes, or internal mammary nodes (i.e., true loco-regional recurrence, LRR) [70].…”

“…The explanation for the results shown in appendix 4 are based on the systematic review [32] and a recent publication by Nichol et al [6]. Nichol and colleagues [6] compared outcomes of mastectomy in patients without skin involvement and reported local recurrence rate of 1.9% with bolus and 0.9% without bolus.…”

“…Bolus serves as a tissue equivalent material that shifts the 95-100% isodose towards the skin and subcutaneous tissue (depending on the thickness of bolus and subcutaneous tissue) [1]. The need for bolus for all breast cancer patients planned for PMRT has been questioned due to skin toxicity as seen in a number of studies [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], clinician surveys [21][22][23][24][25], and national guidelines [26]. All studies showed huge variability in terms of bolus indications and use, with no proven optimum regimen pertaining to thickness, schedule (i.e., daily, alternating days), bolus material, and RT planning characteristics (such as beam energy)…”