Hematological Toxicity of Accelerated Versus Conventional Radiotherapy with or without Concurrent Chemotherapy in Locally Advanced Head and Neck Squamous Cell Carcinoma: A Retrospective Study

Background: Concurrent chemoradiotherapy (CCRT) is the standard treatment for locally advanced head and neck squamous cell carcinoma (LA-HNSCC). While it improves survival, hematologic toxicity remains a major limitation. Accelerated radiotherapy schedules may intensify myelosuppression by shortening bone marrow recovery intervals. This study compared Grade 3 hematologic toxicity between accelerated and conventional CCRT. Methods: We retrospectively analyzed 83 biopsy-proven LA-HNSCC patients treated between 2012 and 2022. Eligible patients were 18–70 years old, with ECOG 0–2, normal baseline hematologic and biochemical profiles, and no prior malignancy or distant metastasis. Most received weekly cisplatin (40 mg/m²); five received weekly docetaxel (20 mg/m²) due to cisplatin contraindications. Hemoglobin, leukocytes, lymphocytes, and platelets were assessed weekly and graded per CTCAE v4.0. Patients were grouped as non-toxic (Grade 0–2) or Grade 3 toxic. Logistic regression identified predictors of toxicity. Results: 83 LA-HNSCC patients were analyzed (42 accelerated vs. 41 conventional radiotherapy). Baseline characteristics were comparable. In radiotherapy-only patients, hematologic changes were minimal, with a slightly higher MCH (p = 0.029) and limited Grade 3 leukopenia (25% vs. 0%), indicating negligible marrow suppression. In contrast, accelerated concurrent chemoradiotherapy (CCRT) produced significantly greater myelosuppression, with lower mean hemoglobin (p = 0.044), leukocytes (p = 0.035), and lymphocytes (p = 0.047). Grade 3 anemia, leukopenia, and lymphopenia occurred in 15.4%, 69.2%, and 38.5% of accelerated CCRT patients versus 11.1%, 16.7%, and 11.1% in the conventional CCRT group. Multivariate analysis identified fractionation type as the sole independent predictor of both WBC (p < 0.001) and lymphocyte (p = 0.014) toxicity. Conclusion: Accelerated CCRT is associated with higher Grade 3 hematologic toxicity, particularly anemia and lymphopenia. Conventional fractionation is more marrow-sparing. Vigilant monitoring and supportive care are essential to maintain treatment compliance and reduce interruptions.