3670 - The Geriatric 8 Score is Associated with Determination of Treatment Strategy and Survival Outcomes for Curative Radiotherapy of Head and Neck Cancer in the Elderly

T. Katsuta¹, I. Nishibuchi², Y. Murakami¹, N. Imano¹, J. Hirokawa¹, and T. Sadatoki³; ¹Department of Radiation Oncology, Graduate School of Biomedical Health Sciences, Hiroshima University, Hiroshima, Japan, ²Department of Radiation Oncology, Hiroshima University Hospital, Hiroshima, Japan, ³Department of Radiation Oncology, Graduate School of Biomedical Health Sciences, Hiroshima University, Hiroshim, Japan

Purpose/Objective(s): For patients with head and neck cancer (HNC), radiotherapy (RT) is a one of the options for curative treatment. Evidence-based guidelines concerning locally advanced HNC patients in the elderly are lacking, and accurate patient selection for optimal care management is challenging. Recently the Geriatric 8 (G8) screening tool has been attracting attention in the oncology field. In this study, we aimed to clarify the association of the G8 Score with deciding the treatment strategy, overall survival (OS) and safety of RT for HNC in the elderly. Materials/

Methods: Forty-one advanced HNC patients aged =65 years who received definitive RT from December 2018 to 2022. The G8 screening tool was performed at the first visit to the radiation oncology department. The treatment strategy was decided by a conference between the radiation oncologist and otolaryngologist, and the G8 score was not used to determine the treatment strategy. Standard treatment (standard CRT) was set as RT:70 Gy/35fr with concurrent chemotherapy, which was cisplatin at 100mg/m² every 3 weeks. The dose reduction or change to other drugs was defined as reduced CRT. We used the Kaplan - Meier method for estimating OS. For evaluating acute toxicity, the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 was used. The Mann-Whitney-U test was used for the statistics, and the significance level was set at p<0.05. The Receiver Operating Characteristic (ROC) curve was used to determine the cutoff value.
Results: The Median follow-up time was 25 months (range: 0-59) for survivors. The primary sites were 33 pharyngeal (3 naso-, 8 oro- and 22 hypo-pharyngeal) cancers and 6 oral cancers and 2 laryngeal cancers. The mean G8 score by treatment strategy were 14.4 (range: 11-17) for standard CRT group (n=11), 13.8 (range: 10-17) for reduced CRT group (n=22), and 9.9 (range: 8-15) for RT alone group (n=8). The G8 score was significantly higher in standard and reduced CRT group than RT alone group (p<0.01), while there were no significant differences between standard and reduced CRT group. The cut-off value of the G8 score calculated by the ROC curve was 12.5 points, indicating the use of chemotherapy. The 2-year OS rates for standard CRT, reduced CRT and RT alone group were 100%, 70% and 47%, respectively, and significantly lower in RT alone group than other groups (p<0.01). For acute toxicities, higher G8 scores were correlated with = grade 3 acute mucositis. However, 4 patients (36%) in standard CRT, 4 (18%) in reduced CRT and none in RT alone had grade 3 mucositis. No patient had = grade 4 toxicities.
Conclusion: Our results suggest that the G8 screening tool may be useful in determining the treatment strategy of definitive RT for HNC in the elderly, taking into account safety considerations. The use of chemotherapy is highly dependent on prognosis, and future development of concomitant chemotherapy and new treatment for the frail condition is expected.