4. Concept of Δ Quadrants (Tumor Dynamic Regimes)

This work introduces the Concept of Δ Quadrants (Tumor Dynamic Regimes), a theoretical framework that reconceptualizes tumor behavior as movement across structured dynamic states rather than as linear progression in size or burden. Instead of reducing cancer evolution to growth versus regression, the model classifies tumors according to qualitative regimes defined by directionality of biological change and internal adaptive activation. Across four dynamic quadrants—Stabilized Adaptive Containment, Accelerated Expansion, Destabilized Transitional State, and Adaptive Escape Consolidation—the framework proposes that therapeutic meaning is regime-dependent. The same intervention may stabilize, redirect, or fail depending on the tumor’s current dynamic organization. The work further integrates the concept of effective biological time (τᵦ), distinguishing chronological duration from transformation density. In this integrated model, oncology becomes a temporal physiology of evolving systems, where transitions, thresholds, metastability, and irreversibility are central to clinical interpretation. Rather than replacing established oncologic metrics, Δ Quadrants aim to reorganize them within a dynamic architecture that emphasizes trajectory, regime persistence, and therapeutic alignment. The framework is presented as conceptually structured, falsifiable, and open to empirical validation through longitudinal data modeling. Its ambition is not to add complexity, but to restore coherence to clinical reasoning by asking not merely how much a tumor has changed, but in which dynamic regime it currently exists—and whether intervention is aligned with that state.