PET-based prognostic survival model after radiotherapy for head and neck cancer.

PURPOSE: The aims of this multicentre retrospective study of locally advanced head and neck cancer (LAHNC) treated with definitive radiotherapy were to (1) identify positron emission tomography (PET)-18F-fluorodeoxyglucose (18F-FDG) parameters correlated with overall survival (OS) in a training cohort, (2) compute a prognostic model, and (3) externally validate this model in an independent cohort. MATERIALS AND METHODS: A total of 237 consecutive LAHNC patients divided into training (n = 127) and validation cohorts (n = 110) were retrospectively analysed. The following PET parameters were analysed: SUVMax, metabolic tumour volume (MTV), total lesion glycolysis (TLG), and SUVMean for the primary tumour and lymph nodes using a relative SUVMax threshold or an absolute SUV threshold. Cox analyses were performed on OS in the training cohort. The c-index was used to identify the highly prognostic parameters. A prognostic model was subsequently identified, and a nomogram was generated. The model was externally tested in the validation cohort. RESULTS: In univariate analysis, the significant PET parameters for the primary tumour included MTV (relative thresholds from 6 to 83% and absolute thresholds from 1.5 to 6.5) and TLG (relative thresholds from 1 to 82% and absolute thresholds from 0.5 to 4.5). For the lymph nodes, the significant parameters included MTV and TLG regardless of the threshold value. In multivariate analysis, tumour site, p16 status, MTV35% of the primary tumour, and MTV44% of the lymph nodes were independent predictors of OS. Based on these four parameters, a prognostic model was identified with a c-index of 0.72. The corresponding nomogram was generated. This prognostic model was externally validated, achieving a c-index of 0.66. CONCLUSIONS: A prognostic model of OS based on primary tumour and lymph node MTV, tumour site, and p16 status was proposed and validated. The corresponding nomogram may be used to tailor individualized treatment.

Split-course hypofractionated radiotherapy for aged and frail patients with head and neck cancers. A retrospective study of 75 cases.

PURPOSE: To assess the efficacy and the tolerance of a split course hypofractionated (SCH) radiotherapy (RT) protocol in head and neck cancer (HNC) for eldery and/or unfit patients (pts). PATIENTS AND METHODS: Pts with HNC treated by SCH-RT in two institutions were included retrospectively. The main SCH RT regimen was two courses of 30 grays (Gy)/10 fractions separated by 2-4 weeks, without any systemic therapy. RESULTS: Between February 2012 and January 2019, 75 consecutive patients were analyzed. The median age was 80 years (range: 45.7-98.2) and 53 (70.7%) were men. Sixty-one (81.3%) pts had stage III/IV disease and 54 (72%) had at least two comorbidities. All of them were treated with intensity-modulated radiotherapy. Median follow-up was 10.6 months (range: 3.1-58.3). Local control at 12 and 24 months was 72.8% IC95%[62-85.5] and 51.7% IC95%[38.1-70.1] respectively. Progression free survival (PFS) at 12 and 24 months were 47.7% IC95%[37.4-60.8] and 41% IC95%[15-36.4] respectively, with a median of 11.5 months IC95%[8.9-17]. OS at 12 and 24 months were 60.4% IC95%[50-73.1] and 41% IC95%[30.6-54.9] respectively, with a median of 19.3 months IC95%[11.9-25.8]. Acute and late grade 3 or higher toxicities occurred for 6 (8%) and 3 (4%) pts. CONCLUSION: The present SCH-RT regimen seems effective, well-tolerated and could represent an alternative to palliative strategies for pts deemed unfit for standard exclusive RT.