Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada.
Department of Biostatistics, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
Clin Oncol (R Coll Radiol). 2018 Jul;30(7):427-432. doi: 10.1016/j.clon.2018.03.005. Epub 2018 Mar 23.
The use of bolus in post-mastectomy radiotherapy (PMRT) varies significantly between institutions. We report on chest wall recurrence and acute toxicity rates for PMRT patients treated with selective use of bolus.
We analysed PMRT patients who received adjuvant chest wall radiotherapy for invasive breast cancer between 2004 and 2009. Patient, tumour and cancer outcomes were collected from a prospective database, with additional radiotherapy and acute toxicity details supplemented retrospectively. Chest wall bolus was reserved for patients considered at high risk of local recurrence.
There were 314 patients suitable for analysis: 52 received bolus, 262 did not. The mean age was 53.2 years. The median follow-up was 4.2 years. The most common T stage was T2 (37%), followed by T3/T4 (33%). There were 229 patients (73%) who had N+ disease; 213 (68%) patients had grade 3 cancer. Oestrogen receptor was positive in 176 (56%) cases, progesterone receptor was positive in 134 (43%) and HER2 receptor was positive in 24 (8%). Lymphovascular space invasion was present in 146 patients (46%), dermal invasion in 30 patients (10%) and positive margin in 14 patients (4%). The 4 year chest wall recurrence rate was 14% (95% confidence interval 5.4-26.8%) in the bolus group and only 3.5% (95% confidence interval 1.6-6.4%) in the non-bolus group. On univariate analysis, use of bolus was associated with a significant difference in chest wall recurrence (hazard ratio 3.09; 1.15-8.33; P = 0.025). However, when taking into account margin status, this significance was lost (hazard ratio = 2.45; 95% confidence interval 0.80-7.50, P = 0.12). There was a higher rate of acute grade 2 skin toxicity in patients receiving bolus compared with those without, 40% versus 21% (P = 0.01).
The selective use of bolus resulted in a small risk of chest wall recurrence rates for low-risk patients. This suggests that the routine use of bolus in PMRT patients may be unnecessary.
在乳腺癌根治术后放疗（PMRT）中，肿块的使用在不同机构之间存在显著差异。我们报告了接受选择性使用肿块的 PMRT 患者的胸壁复发和急性毒性发生率。
我们分析了 2004 年至 2009 年间接受辅助胸壁放疗的浸润性乳腺癌 PMRT 患者。从前瞻性数据库中收集患者、肿瘤和癌症结局数据，并通过回顾性补充额外的放疗和急性毒性细节。胸壁肿块仅用于局部复发风险较高的患者。
共有 314 例患者适合分析：52 例接受肿块治疗，262 例未接受。平均年龄为 53.2 岁。中位随访时间为 4.2 年。最常见的 T 分期为 T2（37%），其次为 T3/T4（33%）。229 例（73%）患者有 N+疾病；213 例（68%）患者有 3 级癌症。176 例（56%）患者雌激素受体阳性，134 例（43%）孕激素受体阳性，24 例（8%）HER2 受体阳性。146 例（46%）患者有淋巴管血管侵犯，30 例（10%）患者有真皮侵犯，14 例（4%）患者有切缘阳性。在肿块组中，4 年胸壁复发率为 14%（95%置信区间 5.4-26.8%），而非肿块组仅为 3.5%（95%置信区间 1.6-6.4%）。单因素分析显示，使用肿块与胸壁复发显著相关（风险比 3.09；1.15-8.33；P=0.025）。然而，当考虑切缘状态时，这种显著性丧失（风险比=2.45；95%置信区间 0.80-7.50，P=0.12）。与未使用肿块的患者相比，使用肿块的患者急性 2 级皮肤毒性发生率更高，分别为 40%和 21%（P=0.01）。
低危患者选择性使用肿块可使胸壁复发率略有增加。这表明在 PMRT 患者中常规使用肿块可能是不必要的。
