Conclusion

The evidence reviewed herein underscores that obesity is not merely a comorbid condition but a central driver of oncogenesis, primarily through the creation of a chronic inflammatory and immunosuppressive state. A pivotal, and increasingly recognized, mechanism is the obesity-induced acceleration of cellular senescence and the resultant SASP. The metabolic milieu of obesity, characterized by a distinct adipokine profile and insulin resistance, actively fuels the SASP, creating a feed-forward loop of inflammation that permeates the tumor microenvironment. This cascade, mediated by factors like IL-6, IL-8, MCP-1, and IL-1β, promotes hallmark capabilities of cancer cells while simultaneously erecting barriers to effective anti-tumor immunity and conventional therapies.

The interplay between metabolic hormones — leptin, adiponectin, resistin, and insulin — and the SASP cytokine network provides a molecular framework that may explains the heightened cancer risk and worsened prognosis observed in individuals with obesity. This integrated framework reveals multiple therapeutic vulnerabilities at distinct points in the obesity-SASP-cancer cascade. Pharmacological senescent cell clearance with senolytic agents (dasatinib, quercetin, navitoclax) has demonstrated proof-of-concept feasibility in early human studies and is now entering early-phase oncology trials. IL-1β blockade has yielded the most compelling clinical signal to date, with the CANTOS trial demonstrating that canakinumab reduces incident lung cancer and cancer mortality in a metabolically inflamed population, a finding that directly validates the mechanistic axis reviewed herein, even as its broader oncological application awaits prospective confirmation. Metabolic interventions including metformin offer a clinically immediate and accessible route to reducing SASP-driving hyperinsulinemia, inflammasome activation, and adipose tissue dysfunction, though definitive prospective trial evidence for oncological benefit remains limited and mixed. A critical unresolved challenge across all three therapeutic strategies is the absence of validated, obesity-specific SASP biomarkers distinguish their obesity-driven component from age-related senescence, and predict therapeutic response. Developing such biomarkers, in parallel with adipokine profiling panels (leptin/adiponectin ratio, resistin, circulating IL-6, and IL-1β), represents a critical translational priority. Ultimately, the most effective clinical approach will likely require combination strategies that simultaneously address adipose tissue dysfunction (metabolic interventions and weight management), SASP amplification (senolytics or senomorphics), and specific pro-tumorigenic cytokines (IL-1β or IL-6 blockade), integrated within personalized oncology frameworks that stratify patients by metabolic phenotype. Advancing this agenda requires purposefully designed clinical trials that embed mechanistic biomarker assessment, enroll patients stratified by obesity-associated metabolic dysregulation, and use SASP cytokine dynamics as pharmacodynamic endpoints — a research priority that the mechanistic insights of this review are intended to support.

Future Directions and Clinical Implications

Several translational priorities emerge from the mechanistic gaps identified in this review.

First, the development of validated, obesity-specific SASP biomarker panels that reliably distinguish obesity-driven senescence from age-related senescence remains the most critical unresolved challenge in the field; without such tools, patient stratification for SASP-targeted trials is not feasible.

Second, future clinical trials in obesity-related cancers should embed SASP cytokines, specifically IL-6, IL-1β, IL-8, and MCP-1, as pre-specified pharmacodynamic endpoints rather than secondary exploratory measures, enabling direct mechanistic validation of the obesity-SASP-cancer axis in human populations.

Third, combination strategies that simultaneously target adipose tissue dysfunction through metabolic intervention, SASP amplification through senolytic or senomorphic agents, and specific pro-tumorigenic cytokines through targeted blockade have not been tested in any clinical trial and represent the logical next step beyond the single-agent approaches evaluated to date. Advancing this agenda requires trials that enroll patients stratified by metabolic phenotype including BMI, adipokine profile, and degree of insulin resistance rather than treating obesity as a binary covariate.

Limitations

Several important limitations apply to the mechanistic framework presented in this review.

First, the majority of mechanistic evidence linking obesity-associated adipokines to SASP amplification and pro-tumorigenic cytokine production derives from in vitro cell line experiments and murine dietary obesity models with little clinical trials (mentioned in Table 1). While these models have provided foundational mechanistic insight, they may not fully replicate the complexity and heterogeneity of human obesity-associated malignancies.

Second, the attribution of cancer risk to adipose-driven immunopathology specifically remains difficult to disentangle in human observational data. Establishing causality and identifying the dominant mechanistic pathway in clinical populations are central challenges in the field. The epidemiological association between obesity and cancer risk is consistently demonstrated, but the mechanistic primacy of SASP-mediated immune remodeling over other obesity-associated oncogenic pathways has not been established in prospective human studies.

Third, the cancer-preventive effects attributed to adiponectin in epidemiological studies may be confounded by correlated variables including insulin sensitivity, physical activity, and overall metabolic health — all of which track with adiponectin levels and independently affect cancer risk. Whether the inverse associations between adiponectin and cancer incidence are causally driven by adiponectin itself or by these correlated metabolic parameters cannot be determined from observational data. The adiponectin-IL-8 and adiponectin-MCP-1 evidence bases are more limited and predominantly mechanistic, without convergent human epidemiological support.

Finally, a critical limitation across the entire mechanistic framework reviewed is the absence of validated, obesity-specific SASP biomarkers that reliably distinguish the obesity-driven component of SASP from age-related senescence in human clinical populations. Without such biomarkers, it is not possible to confirm in prospective clinical settings whether the adipokine-SASP-cancer axis operates as the mechanistic framework presented in this review proposes, or to identify which patients with obesity are most likely to benefit from SASP-targeted therapeutic interventions. Developing and validating such biomarkers, in parallel with adipokine profiling panels, represents the most critical translational priority identified by this review.