Late fibrosis can occur in breast cancer patients treated with curative-intent radiotherapy. Predicting this toxicity is of clinical interest in order to adapt the irradiation dose delivered. Radiation-induced CD8 T-lymphocyte apoptosis (RILA) had been proven to be associated with less grade ≥2 late radiation-induced toxicities in patients with miscellaneous cancers. Tobacco smoking status and adjuvant hormonotherapy were also identified as potential factors related to late-breast-fibrosis-free survival. This article evaluates the predictive performance of the RILA using a ROC curve analysis that takes into account the dynamic nature of fibrosis occurrence. This time-dependent ROC curve approach is also applied to evaluate the ability of the RILA combined with the other previously identified factors. Our analysis includes a Monte Carlo cross-validation procedure and the calculation of an expected cost of misclassification, which provides more importance to patients who have no risk of late fibrosis in order to be able to treat them with the maximal irradiation dose. Performance evaluation was assessed at 12, 24, 36 and 50 months. At 36 months, our results were comparable to those obtained in a previous study, thus underlying the predictive power of the RILA. Based on specificity and cost, RILA alone seemed to be the most performant, while its association with the other factors had better negative predictive value results.
接受根治性放疗的乳腺癌患者可能出现晚期纤维化。为调整放射剂量，预测此类毒性反应具有临床意义。已有研究证实，放射诱导的CD8 T淋巴细胞凋亡（RILA）与多种癌症患者≥2级晚期放射毒性发生率降低相关。吸烟状况和辅助激素治疗也被确定为影响无晚期乳腺纤维化生存期的潜在因素。本文采用考虑纤维化发生动态特性的ROC曲线分析法评估RILA的预测效能，同时使用时依性ROC曲线方法评估RILA联合其他已知因素的预测能力。研究采用蒙特卡洛交叉验证程序，并计算误分类期望成本——该模型对无晚期纤维化风险的患者赋予更高权重，以便对其施以最大放射剂量。分别在12、24、36和50个月进行效能评估。36个月时，本研究结果与既往研究具有可比性，进一步证实了RILA的预测效力。基于特异性和成本考量，单独使用RILA显示出最佳效能，而联合其他因素则能获得更优的阴性预测值。
肿瘤(癌症)患者之家