Parallel Toxicities: A Comparative Analysis of Chemotherapy-Induced Neutropenia and Alopecia.

Chemotherapy-induced neutropenia (CIN) and chemotherapy-induced alopecia (CIA) are significant toxicities affecting cancer patients. CIN is a potentially fatal complication of chemotherapy caused by myelosuppression and increased infection susceptibility, while CIA, although not fatal, severely affects treatment adherence and mental health. This study provides a comprehensive comparative analysis of CIN and CIA, focusing on patient, disease, treatment, and genetic risk factors. Key risk factors for CIN and CIA include age, poor performance status, body mass index (BMI), laboratory abnormalities, and pre-existing comorbidities. Both toxicities were significantly associated with breast cancer patients, although CIN patients were more likely to have hematological cancer, and CIA patients were more likely to have solid tumors. Notably, anthracyclines, alkylators, and taxanes frequently induce both toxicities, although their timelines and clinical implications differed. There was no clear overlap between genetic predispositions and toxicities beyond single-nucleotide polymorphisms (SNPs) in the ABCB1 gene. This is the first study to directly compare CIN and CIA, offering insights into personalized oncology care. Understanding the risk factors implicated in the development of CIN and CIA will enable physicians to manage patient outcomes.