Department of Radiation Oncology, BC Cancer, Vancouver, BC, Canada.
Department of Radiation Oncology, BC Cancer, Vancouver, BC, Canada.
Int J Radiat Oncol Biol Phys. 2021 Aug 1;110(5):1360-1369. doi: 10.1016/j.ijrobp.2021.01.019. Epub 2021 Jan 21.
Bolus use during postmastectomy radiation therapy doubles the risk of grade 2 and 3 skin toxicity. Despite its unknown benefit, bolus is often prescribed during postmastectomy radiation therapy for patients without skin involvement.
For women with breast cancer receiving photon 3-dimensional conformal radiation therapy, bolus was used routinely for chest walls but was omitted for breast reconstructions by about half of radiation oncologists from 2007 to 2011. Eligible patients had newly diagnosed invasive breast cancers without skin involvement (pT1-4a, any-N, M0) treated with adjuvant or neoadjuvant radiation therapy. For the bolus and no-bolus groups, we compared the cumulative incidence of local recurrence (LR) and locoregional recurrence (LRR) with distant recurrence and death as competing risks and breast cancer mortality (BCM). Multivariable analysis of LR and BCM included stage, subtype, lymphovascular invasion, grade, margin status, beam energy, bolus use, hormone therapy, chemotherapy, and reconstruction.
Systemic therapy was used for 98% of the 1887 patients. The bolus group had 1569 patients and the no-bolus group had 318 patients. Bolus was used in 51% (281/550) of patients treated with reconstruction and 96% (1288/1337) of patients treated without reconstruction. The 10-year outcomes (95% confidence interval) in patients treated with and without bolus were, respectively: LR 1.9% (1.3-2.7) versus 0.9% (0.3-2.6), LRR 3.1% (2.3-4.0) versus 3.2% (1.6-5.5), and BCM 19.4% (17.3-21.6) versus 18.3% (13.9-23.2). On multivariable analysis, bolus use was not associated with better LR (hazard ratio = 1.4 [0.3-6.4]) or BCM (hazard ratio = 0.8 [0.5-1.2]).
For patients treated with mastectomy, radiation therapy, and modern systemic therapy, the cumulative incidence of LR was low, with or without bolus. Because bolus use increases toxicity and does not reduce LR or BCM, it should no longer be used routinely for patients without skin involvement who receive systemic therapy.
在乳腺癌根治术后放疗中使用推量会使 2 级和 3 级皮肤毒性的风险增加一倍。尽管其益处未知，但在 2007 年至 2011 年间，仍有一半左右的放射肿瘤学家在为没有皮肤受累的乳腺癌患者进行根治术后放疗时开具推量处方。
对于接受光子三维适形放疗的乳腺癌患者，常规使用胸壁推量，但约一半的放射肿瘤学家在 2007 年至 2011 年间对乳房重建患者不使用推量。符合条件的患者为新诊断的无皮肤受累的浸润性乳腺癌（pT1-4a，任何-N，M0），接受辅助或新辅助放疗。对于推量组和非推量组，我们比较了局部复发（LR）和局部区域复发（LRR）与远处复发和死亡的累积发生率，将远处复发和死亡作为竞争风险，并比较了乳腺癌死亡率（BCM）。LR 和 BCM 的多变量分析包括分期、亚型、脉管侵犯、分级、切缘状态、射束能量、推量使用、激素治疗、化疗和重建。
系统治疗用于 1887 例患者中的 98%。推量组 1569 例，非推量组 318 例。在接受重建治疗的患者中，有 51%（281/550）使用了推量，在未接受重建治疗的患者中，有 96%（1288/1337）使用了推量。接受和不接受推量治疗的患者 10 年结局（95%置信区间）分别为：LR 1.9%（1.3-2.7）vs. 0.9%（0.3-2.6），LRR 3.1%（2.3-4.0）vs. 3.2%（1.6-5.5），BCM 19.4%（17.3-21.6）vs. 18.3%（13.9-23.2）。多变量分析显示，推量使用与更好的 LR（风险比=1.4[0.3-6.4]）或 BCM（风险比=0.8[0.5-1.2]）无关。
对于接受乳房切除术、放疗和现代系统治疗的患者，LR 的累积发生率较低，无论是否使用推量。由于推量使用会增加毒性，且不会降低 LR 或 BCM，因此对于接受系统治疗且无皮肤受累的患者，不应再常规使用推量。
