Department of Radiation Oncology, Olivia Newton-John Cancer Wellness & Research Centre, Austin Health, Heidelberg, Victoria, Australia.
Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Victoria, Australia.
J Med Radiat Sci. 2022 Dec;69(4):439-447. doi: 10.1002/jmrs.611. Epub 2022 Jul 30.
Anal cancer (AC) is F-FDG-PET avid and has been used to evaluate treatment response several months after chemoradiotherapy. This pilot study aimed to assess the utility of semi-automated contouring methods and quantitative measures of treatment response using F-FDG-PET imaging at the early time point of 1-month post-chemoradiotherapy.
Eleven patients with AC referred for chemoradiotherapy were prospectively enrolled into this study, with 10 meeting eligibility requirements. F-FDG-PET imaging was obtained pre-chemoradiotherapy (TP1), and then 1-month (TP2), 3-6 months (TP3) and 9-12 months (TP4) post-chemoradiotherapy. Manual and semi-automated (Threshold) contouring methods were used to define the primary tumour on all F-FDG-PET images. Resultant contours from each method were interrogated using quantitative measures, including volume, response index (RI), total lesion glycolysis (TLG), SUV , SUV and SUV . Response was assessed quantitatively as reductions in these measures and also qualitatively against established criteria.
Nine patients were qualitatively classified as complete metabolic responders at TP2 and all 10 at TP3. All quantitative measures demonstrated significant (P < 0.05) reductions at TP2 for both Manual and Threshold methods. All reduced further at TP3 and again at TP4 for Threshold methods. TLG showed the highest reduction at all post-chemoradiotherapy time points and classified the most responders for each method at each time point. All patients are recurrence-free at minimum 4-year follow-up.
Based on our small sample size, semi-automated methods of disease definition using F-FDG-PET imaging are feasible and appear to facilitate quantitative response classification of AC as early as 1-month post-chemoradiotherapy. Early identification of treatment response may potentially improve disease management.
肛门癌（AC）对 F-FDG-PET 具有亲和力，并已用于评估化学放疗后数月的治疗反应。这项初步研究旨在评估在化学放疗后 1 个月的早期使用 F-FDG-PET 成像进行半自动勾画方法和定量测量治疗反应的效用。
11 例肛门癌患者被前瞻性纳入本研究，其中 10 例符合入选标准。在化学放疗前（TP1）进行 F-FDG-PET 成像，然后在 1 个月（TP2）、3-6 个月（TP3）和 9-12 个月（TP4）后进行化学放疗。手动和半自动（阈值）勾画方法用于定义所有 F-FDG-PET 图像上的原发肿瘤。使用定量指标分析每种方法的结果轮廓，包括体积、反应指数（RI）、总病灶糖酵解（TLG）、SUV、SUV 和 SUV。根据既定标准，通过定量测量和定性评估来评估反应。
9 例患者在 TP2 时被定性为完全代谢反应者，10 例患者在 TP3 时均为完全代谢反应者。手动和阈值方法在 TP2 时所有定量指标均显著降低（P<0.05）。所有定量指标在 TP3 和 TP4 时均进一步降低，仅阈值方法。TLG 在所有化学放疗后时间点均显示出最高的降低，并在每个时间点为每种方法分类了最多的反应者。所有患者在至少 4 年的随访中均无复发。
根据我们的小样本量，使用 F-FDG-PET 成像的疾病定义半自动方法是可行的，并且似乎可以在化学放疗后 1 个月尽早对肛门癌进行定量反应分类。早期识别治疗反应可能会改善疾病管理。
