1. Relativistic Tumoral Differentials as a Central Variable (Δ(t))

This work introduces Relativistic Tumoral Differentials (Δ(t)) as a central conceptual variable for understanding cancer dynamics as relational, time-dependent processes rather than static or absolute entities. Building on a relativistic interpretation of tumor biology, the framework proposes that tumor behavior emerges from directional differentials generated by tumor–microenvironment coupling, constraint structures, and therapeutic perturbations. Across four narrative parts, the article develops Δ(t) as an interpretive construct that explains dominance shifts, phase transitions, apparent paradoxes in treatment response, and the limits of prediction in oncology. Rather than offering computational procedures or formal derivations, the work remains intentionally non-procedural, focusing on conceptual coherence, clinical meaning, and ethical implications of directional intervention. This contribution is intended for researchers and clinicians interested in theoretical oncology, systems biology, and the philosophy of cancer, offering a unified lens through which tumor evolution, therapeutic timing, and irreversibility can be re-examined without reducing complexity to static metrics.