Supplementary Material for: Association of Biological Age with Tumor Microenvironment in Patients with Esophageal Adenocarcinoma

Introduction: Esophageal cancer is the seventh most common cancer worldwide and typically tends to manifest at an older age. Marked heterogeneity in time-dependent functional decline in older adults results in varying grades of clinically manifest patient fitness or frailty. The biological age-related adaptations that accompany functional decline have been shown to modulate the non-malignant cells comprising the tumor microenvironment (TME). In the current work, we studied the association between biological age and TME characteristics in patients with esophageal adenocarcinoma.
Methods: We comparatively assessed intratumoral histologic stroma quantity, tumor immune cell infiltrate, and blood leukocyte and thrombocyte count in 72 patients stratified over 3 strata of biological age (younger <70 years, fit older ≥70 years, and frail older adults ≥70 years), as defined by a geriatric assessment.
Results: Frailty in older adults was predictive of decreased intratumoral stroma quantity (B = -14.66% stroma, P = 0.022) relative to tumors in chronological-age-matched fit older adults. Moreover, in comparison to younger adults, frail older adults (P = 0.032), but not fit older adults (P = 0.302), demonstrated a lower blood thrombocyte count at the time of diagnosis. Lastly, we found an increased proportion of tumors with a histologic desert TME histotype, comprising low stroma quantity and low immune cell infiltration, in frail older adults.
Conclusion: Our results illustrate the stromal-reprogramming effects of biological age and provide a biological underpinning for the clinical relevance of assessing frailty in patients with esophageal adenocarcinoma, further justifying the need for standardized geriatric assessment in geriatric cancer patients.