[乳癌] non-low risk breast DCIS 是否需要tumor bed boost

關於 breast DCIS 接受手術後, 去做術後全乳房放療是否需要加上tumor bed boost, 一直是個還沒有解決的問題

在2022年8月, 有篇phase III RCT很好的探討了這個問題, 以下就來一探究境吧!

收案條件為non-low risk breast DCIS: 18歲以上, 手術切除乾淨(margin至少1mm), N0

a. Age < 50 years; 

OR 

b. Age 50 years plus at least one of the following:

• Symptomatic presentation

• Palpable tumour

• Multifocal disease

• Microscopic tumour size ≥ 1.5 cm in maximum dimension

• Intermediate or high nuclear grade

• Central necrosis

• Comedo histology

• Radial surgical resection margin < 10 mm. Patients with superficial or deep resection margin of < 10 mm are eligible if surgery has not removed all of the intervening breast tissue from the subcutaneous tissue to the pectoralis fascia.

實驗分組共分成四組:

有tumor bed boost(16Gy/8Fr) vs. no tumor bed boost; 50Gy/25Fr vs. 42.5Gy/16Fr, 共收案1608人

結果發現The 5-year free-from-local-recurrence rates were 92·7% (95% CI 90·6–94·4%) in the no-boost group and 97·1% (95·6–98·1%) in the boost group (hazard ratio 0·47; 0·31–0·72; p<0·001). The boost group had higher rates of grade 2 or higher breast pain (10% [8–12%] vs 14% [12–17%], p=0·003) and induration (6% [5–8%] vs 14% [11–16%], p<0·001).

=> 翻譯成白話文就是tumor bed boost 在 non low-risk breast DCIS 可以降低local recurrence, 但是副作用明顯提高

Ref: 

1. Chua BH, Link EK, Kunkler IH, et al. Radiation doses and fractionation schedules in non-low-risk ductal carcinoma in situ in the breast (BIG 3-07/TROG 07.01): a randomised, factorial, multicentre, open-label, phase 3 study. Lancet. 2022;400(10350):431-440. doi:10.1016/S0140-6736(22)01246-6