ESTRO 2023 - Abstract Book

S992

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ESTRO 2023

Conclusion Our results are consistent with those reported in the literature. Stereotactic re-irradiation of recurrent/secondary H&N cancer is feasible. However, local-recurrence rates remain non-negligible, warranting further research. Radiosensitizer use is currently under study. Therefore, establishing a balance between therapeutic modifications and toxicity is essential.

PO-1238 chemoradiotherapy induced hypomagnesemia is associated with superior survival in laryngeal cancer

O. Karakoyun Celik 1 , O. Uncu 2 , B. Ayaydin 3

1 Manisa Celal Bayar University, Radiation Oncology, Manisa, Turkey; 2 Manisa Celal Bayar University , Radiation Oncology , MAnisa , Turkey; 3 Manisa Celal Bayar University , Radiation Oncology, Manisa, Turkey Purpose or Objective Magnesium levels can decrease during radiochemotherapy of patients with head and neck cancer. Although magnesium supplementation is provided during the treatment, some patients may continue to have hypomagnesemia at the end of the treatment. The aim of this study was to investigate the effect of hypomagnesemia on survival in patients with localy advanced laryngeal cancer who underwent to curative-intend chemoradiotherapy. Materials and Methods Ninety patients with Stage III (50%) and IV (50%) laringeal cancer who received definitive chemoradiotherapy from January 2016 to June 2020 were analyzed. Median age was 65 years old, with 87 male and 3 female patients. All patients had squamous cell carcinoma of the larynx. Majority of patients receieved weekly cisplatinium 40 mg/m2(78%) concurrent with radiotherapy. Pathology features, TNM staging, weekly weight loss, weekly laboratory results including magnesium, neutrophly / lymphocyte ratio, creatinin, Eastern Cooperative Oncology Group performance status and comorbities were recorded. The association between hypomagnesemia and survival was performed with statistical package from SPSS. Survival was evaluated via Kaplan-Meier methods. Results Before the treatment, the mean magnesium level of the patients was 2.0 (0,6-2,78) mg/dl. Hipomagnesemia was present in 15.5% of patients (14/90). Magnesium supplementation was given to the patients who were found to have low magnesium levels during weekly chemotherapy courses. After the chemoradiotherapy, the mean magnesium level of patients was 1,85 (1,10-2,49) mg/dl. Hypomagnesemia was found in 35.5 % (32/90) of patients. Hypomagnesemia were observed more frequently in patients who received concurrent chemotherapy compared to those who did not receive concurrent chemotherapy (p:0,02). Although there was no statistically significant correlation between the pretreatment magnesium levels and overall survival (OS), a statistically significant correlation was found between the posttreatment magnesium levels and OS in this patient population in favor of hypomagnesemia (p: 0, 01). Conclusion The data on the survival effect of hypomagnesemia due to anticancer treatments are confusing and insufficient. We have found that radiotherapy or chemoradiotherapy induced hypomagnesemia is associated with better survival in our locally advanced laryngeal cancer patient population.

PO-1239 Metastatic LNs distribution and proposed individualized prophylactic neck irradiation in NPC

L. Wang 1 , Z. Wu 2 , Q. He 2 , L. Zhang 2 , F. Li 3 , H. Wang 2 , W. Li 1 , Y. Han 2

1 the Third Affiliated Hospital of Kunming Medical University, Department of Radiotherapy, Kunming, China; 2 Hunan Cancer Hospital & the Affiliated Cancer Hospital of Xiangya School of Medicine, Department of Radiation Oncology, Changsha, China; 3 Hunan Cancer Hospital & the Affiliated Cancer Hospital of Xiangya School of Medicine, Department of Imaging, Changsha, China