大多数患者在趴卧位接受全乳房放射治疗。然而，两项随机试验显示，趴卧位能降低急性毒性。此外，在大多数患者中，趴卧位可减少有风险器官的剂量。为了验证这些发现，我们使用 REQUITE 数据比较了两种体位在毒性结果、照片评估和剂量测定上的差异。REQUITE 是一个国际多中心前瞻性观察研究，招募了2069名乳腺癌患者接受放射治疗。收集了毒性、健康相关生活质量（HRQoL）和剂量测定的数据，以及照片评估。匹配病例对照分析比较了趴卧位治疗患者（n=268）与趴卧位治疗患者（n=493）。变量间进行了精确匹配，包括使用调强放射治疗、增强、淋巴结照射、化疗和分层，以及最接近的乳房体积。主要终点是放疗结束时的皮炎、2年时的萎缩和照片评估的美容结果。在最后一次治疗分次中，皮炎 (p=.28) 和任何 HRQoL 领域没有显著差异，但趴卧位治疗增加了乳房水肿的风险 (p<.001)。2年时，趴卧位治疗患者的乳房萎缩较少 (p=.01)，并具有更高的形象评分 (p<.001) 和社交功能评分 (p<.001)。照片评估显示在2年时的美容结果无显著差异 (p=.22)。在趴卧位治疗中，左侧患者的平均心脏剂量 (MHD) 显著降低 (1.29 Gy vs 2.10 Gy, p<.001)，所有患者的同侧肺平均剂量 (MLD) 也显著降低 (2.77 Gy vs 5.89 Gy, p<.001)。趴卧位放疗的同侧肺平均剂量 (MLD) 和平均心脏剂量 (MHD) 较趴卧位治疗较低，尽管在放疗过程中发生乳房水肿的风险较高。2年后的照片评估显示美容结果无差异，但趴卧位治疗患者的乳房萎缩较少，对身体形象的 HRQoL 领域产生积极影响。

Most patients receive whole breast radiotherapy in a supine position. However, two randomised trials showed lower acute toxicity in prone position. Furthermore, in most patients, prone positioning reduced doses to the organs at risk. To confirm these findings, we compared toxicity outcomes, photographic assessment, and dosimetry between both positions using REQUITE data.REQUITE is an international multi-centre prospective observational study that recruited 2069 breast cancer patients receiving radiotherapy. Data on toxicity, health-related quality of life (HRQoL), and dosimetry were collected, as well as a photographic assessment. A matched case control analysis compared patients treated prone (n = 268) versus supine (n = 493). Exact matching was performed for the use of intensity-modulated radiotherapy, boost, lymph node irradiation, chemotherapy and fractionation, and the nearest neighbour for breast volume. Primary endpoints were dermatitis at the end of radiotherapy, and atrophy and cosmetic outcome by photographic assessment at two years.At the last treatment fraction, there was no significant difference in dermatitis (p = .28) or any HRQoL domain, but prone positioning increased the risk of breast oedema (p < .001). At 2 years, patients treated in prone position had less atrophy (p = .01), and higher body image (p < .001), and social functioning (p < .001) scores. The photographic assessment showed no difference in cosmesis at 2 years (p = .22). In prone position, mean heart dose (MHD) was significantly lower for left-sided patients (1.29 Gy vs 2.10 Gy, p < .001) and ipsilateral mean lung dose (MLD) was significantly lower for all patients (2.77 Gy vs 5.89 Gy, p < .001).Prone radiotherapy showed lower MLD and MHD compared to supine position, although the risk of developing breast oedema during radiotherapy was higher. At 2 years the photographic assessment showed no difference in the cosmetic outcome, but less atrophy was seen in prone-treated patients and this seems to have a positive influence on the HRQoL domain of body image.