Outcome of Infantile Malignant Solid Tumors: A Single-Center Experience.

Malignant solid tumors diagnosed during the first year of life represent a rare but clinically significant subgroup of pediatric cancers. Their biological behavior, treatment responses, and prognosis differ substantially from tumors diagnosed in older children due to developmental immaturity and age-related therapeutic limitations. We retrospectively analyzed 88 infants diagnosed with malignant solid tumors before 12 months of age at a single tertiary center between March 2011 and March 2023. Demographic, clinical, pathological, and treatment data were collected. Overall survival (OS) was estimated by Kaplan-Meier analysis, and prognostic factors were evaluated using univariate and multivariate Cox regression models. Of the 98 initially screened patients, 88 were eligible for analysis. The median age at diagnosis was 7 months, with a median follow-up of 42 months. The most common tumor locations were intra-abdominal (64.7%), brain (20.5%), and bone/soft tissue (12.5%). Neuroblastoma was the leading diagnosis (30.7%), with spontaneous regression observed in 29.6% of cases. Atypical teratoid rhabdoid tumor (ATRT) was the most frequent brain tumor (9.1%). The 5-year OS for the entire cohort was 78.3%. Brain tumors were associated with significantly higher mortality (HR 4.32, = 0.01), while intra-abdominal tumors predicted improved survival (HR 0.31, = 0.02). Infantile malignant solid tumors display heterogeneous clinical behavior and outcomes. While favorable results can be achieved in neuroblastoma and soft tissue sarcomas, brain tumors, particularly ATRT, remain a therapeutic challenge. Age-specific, risk-adapted treatment strategies and earlier detection are critical to improving survival and reducing long-term sequelae in this vulnerable population.