Guenzi Marina, Bosetti Davide, Lamanna Giorgio, Siffredi Guido, Bonzano Elisabetta, Gusinu Marco, Garelli Stefania, Pupillo Francesco, Corvò Renzo
Department of Radiation Oncology, IRCCS San Martino-IST, National Cancer Research Institute, Genoa - Italy.
Tumori. 2015 Mar-Apr;101(2):154-60. doi: 10.5301/tj.5000232. Epub 2015 Apr 2.
The aim of this study was to evaluate retrospectively the planned dose distribution and acute toxicity of adjuvant hypofractionated whole breast radiotherapy (RT) delivered in the prone vs. supine position.
Twenty-four patients were enrolled; 12 underwent adjuvant RT with a supine setup and 12 with a prone setup. We included patients according to breast volume (≥500 mL), disease stage (≤pT2/pN1), and clinical/biological features. Patients received a regimen of 35 Gy in 10 fractions for 2.5 weeks, and a concomitant boost of 3/4 Gy in 1 fraction/week. Target coverage was assessed by volume, V90, V95, V100, V103 and V105. Heart, LADCA and ipsilateral lung doses were evaluated according to volume, maximum dose, mean dose, V14, V10 and V5. We evaluated acute skin toxicity during RT, at the end of treatment, and after 1 month according to RTOG scales.
Radiobiological equivalence was warranted with satisfactory BED values: considering α/β = 4 for breast cancer, the 10-fraction schedule equaled 74 or 77 Gy depending on the boost dose (3 Gy vs. 4 Gy, respectively). Toxicity was low and similar for supine and prone treatments. Dose sparing was significant in the ipsilateral lung in the prone position (median Dmax: 28.7 Gy vs. 38.4 Gy; median Dmean: 0.8 Gy vs. 6.3 Gy; median V14: 0.6% vs. 13.5%; median V5: 0 vs. 19.3%, p<0.001).
This novel 10-fraction schedule is feasible and well tolerated; the prone position allows better saving of OARs, with a statistically significant value for the ipsilateral lung.
本研究的目的是回顾性评估俯卧位与仰卧位辅助性大分割全乳放疗（RT）的计划剂量分布和急性毒性。
纳入24例患者；12例采用仰卧位进行辅助放疗，12例采用俯卧位。根据乳房体积（≥500 mL）、疾病分期（≤pT2/pN1）和临床/生物学特征纳入患者。患者接受2.5周内分10次给予35 Gy的方案，并每周1次分1次给予3/4 Gy的同步加量。通过体积、V90、V95、V100、V103和V105评估靶区覆盖情况。根据体积、最大剂量、平均剂量、V14、V10和V5评估心脏、左前降支冠状动脉和同侧肺的剂量。我们根据RTOG量表在放疗期间、治疗结束时和1个月后评估急性皮肤毒性。
通过令人满意的生物等效剂量（BED）值保证了放射生物学等效性：考虑到乳腺癌的α/β = 4，10分次方案根据加量剂量（分别为3 Gy和4 Gy）相当于74或77 Gy。仰卧位和俯卧位治疗的毒性均较低且相似。俯卧位时同侧肺的剂量 sparing 显著（中位Dmax：28.7 Gy对38.4 Gy；中位Dmean：0.8 Gy对6.3 Gy；中位V14：0.6%对13.5%；中位V5：0对19.3%，p<0.001）。
这种新的10分次方案是可行的且耐受性良好；俯卧位能更好地保护危及器官，对同侧肺具有统计学显著意义。
