Background: The prevalence of metastatic melanoma is increasing, necessitating the identification of patients who do not benefit from immunotherapy. This study aimed to develop a radiomic biomarker based on the segmentation of all metastases at baseline and the first follow-up CT for the endpoints best overall response (BOR), progression-free survival (PFS), and overall survival (OS), encompassing various immunotherapies. Additionally, this study investigated whether reducing the number of segmented metastases per patient affects predictive capacity. Methods: The total tumour load, excluding cerebral metastases, from 146 baseline and 146 first follow-up CTs of melanoma patients treated with first-line immunotherapy was volumetrically segmented. Twenty-one random forest models were trained and compared for the endpoints BOR; PFS at 6, 9, and 12 months; and OS at 6, 9, and 12 months, using as input either only clinical parameters, whole-tumour-load delta radiomics plus clinical parameters, or delta radiomics from the largest ten metastases plus clinical parameters. Results: The whole-tumour-load delta radiomics model performed best for BOR (AUC 0.81); PFS at 6, 9, and 12 months (AUC 0.82, 0.80, and 0.77); and OS at 6 months (AUC 0.74). The model using delta radiomics from the largest ten metastases performed best for OS at 9 and 12 months (AUC 0.71 and 0.75). Although the radiomic models were numerically superior to the clinical model, statistical significance was not reached. Conclusions: The findings indicate that delta radiomics may offer additional value for predicting BOR, PFS, and OS in metastatic melanoma patients undergoing first-line immunotherapy. Despite its complexity, volumetric whole-tumour-load segmentation could be advantageous.
背景:转移性黑色素瘤的发病率不断上升,亟需识别无法从免疫治疗中获益的患者。本研究旨在基于基线期和首次随访CT中所有转移灶的分割,开发一种用于评估最佳总体缓解(BOR)、无进展生存期(PFS)和总生存期(OS)的影像组学生物标志物,该标志物涵盖多种免疫治疗方案。同时,本研究探讨了减少每位患者分割转移灶数量是否会影响预测能力。方法:对146例接受一线免疫治疗的黑色素瘤患者的基线期和首次随访CT图像进行全肿瘤负荷(排除脑转移灶)的体积分割。针对BOR终点,以及6、9、12个月的PFS和OS终点,共训练并比较了21个随机森林模型。模型输入参数包括:仅临床参数、全肿瘤负荷Δ影像组学特征结合临床参数、或基于前十大转移灶的Δ影像组学特征结合临床参数。结果:全肿瘤负荷Δ影像组学模型在BOR(AUC 0.81)、6/9/12个月PFS(AUC 0.82/0.80/0.77)及6个月OS(AUC 0.74)预测中表现最优。基于前十大转移灶的Δ影像组学模型在9个月和12个月OS预测中表现最佳(AUC 0.71和0.75)。尽管影像组学模型在数值上优于临床模型,但未达到统计学显著性。结论:研究结果表明,Δ影像组学可能为预测接受一线免疫治疗的转移性黑色素瘤患者的BOR、PFS和OS提供附加价值。尽管全肿瘤负荷体积分割较为复杂,但其可能具有临床应用优势。