Tumor Growth Kinetics and the Biological Cost of Treatment Delay in Oral Cancer

This prospective cohort study quantified the biological impact of treatment delay in oral squamous cell carcinoma (OSCC) through tumour kinetics. Between July 2020 and December 2023, 483 patients with treatment-naïve OSCC, Mumbai, underwent two pre-surgery cross-sectional imaging studies at least three weeks apart. Gross tumour volume (GTV) was measured to calculate weekly percentage growth and tumour volume doubling time (TVDT) using the Schwartz exponential model. The median interval between scans was 7.1 weeks (IQR, 5.9–9.4). Median GTV increased from 12.9 cm³ (IQR, 8.1–20.2) to 19.4 cm³ (IQR, 12.3–28.6), a 7.3% median weekly rise corresponding to a TVDT of 7.9 weeks. Tongue tumours grew fastest (9.6% per week; TVDT 6.2 weeks). Stage migration occurred in 30%, leading to more extensive resections in 28%. At 25 months’ median follow-up, 2-year overall survival (OS) and disease-specific survival were 67% and 73%, respectively. Patients with TVDT ≤8 weeks had lower OS (58% vs 74%, p=0.002). On multivariable analysis, TVDT ≤8 weeks, treatment delay >8 weeks, advanced T/N-category, and perineural invasion independently predicted worse outcomes. OSCC doubles in volume within 6–10 weeks, and tumour kinetics offer a quantifiable marker of aggressiveness that should inform scheduling and prognosis.