King Faisal Specialist Hospital and Research Centre Riyadh, Riyadh
F. Alsamari, M. Aldehaim, A. Aldakheel, K. Shehzad, M. S. Anwar, G. Mohamed, M. Almahmoud, H. Ghebeh, and N. M. Alrajhi; King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
Purpose/Objective(s): Radiation-induced lymphopenia has been identified as a prognostically adverse factor in several cancers, including those affecting the brain, lung, pancreas, and cervix. The impact of this condition on head and neck cancers, particularly nasophargenal carcinoma (NPC), is not well-defined. This study aims to explore the association between radiation-induced lymphopenia and clinical outcomes in NPC patients. Materials/
Methods: The records of NPC patients who were enrolled in a prior trial between 2012-2018 at our institution were reviewed. All patients had definitive radiotherapy utilizing a 3-D CRT and IMRT system with a dose of 70 Gy. The absolute lymphocyte count was collected at three different time points: pre-treatment, weekly during treatment, and 12 weeks post-treatment. Patient-related, tumor-related, and treatment-related characteristics, as well as clinical outcomes and lymphocyte counts during radiotherapy were collected. Severity of lymphopenia was graded according to CTCAE v4.0. Survival rates were estimated using the Kaplan-Meier method and compared with log-rank tests. Results: A total of 107 were evaluated (81 males and 26 females with a median age of 44; range 19-62). The majority of patients had WHO class III (94.4%). The median radiation total dose was 70 Gy. All patients had induction chemotherapy followed by concurrent chemoradiotherapy. 76 (82.6%) patients developed grade 3 (G3) lymphopenia and 16 (17.4%) patients developed grade 4 (G4) lymphopenia during treatment. The median follow-up time was 85 months. The 5-year overall survival (OS) rate was 88%. The 5-year progression-free survival (PFS) rate was 76%. 5-year locorgional recurrence free survival was 86%. 5-year distant metastasis free survival (DMFS) rate was 81%. There was no significant difference in overall survival, progression-free survival, nor distant metastasis-free survival rates in those who developed G3/G4 lymphopenia compared with those who did not. Conclusion: The occurrence of severe lymphopenia (grades 3 and 4) during radiotherapy in this NPC cohort did not demonstrate an impact on the survival rates assessed. This study suggests that the prognostic implications of radiation-induced lymphopenia in NPC may differ from other malignancies, highlighting the need for further investigation.
