Weight loss (WL) as a predictive factor for immune oncology (IO).

Abstract

e14528 Background: WL is an adverse prognostic factor/symptom reported in ~40% cancer (ca) patients (pts) at diagnosis agnostic to site or histologic grade. The mechanism of WL in ca, however, remains elusive. The role of energetic waste in ca WL is doubtful (it neglects likely dietary compensation). On the other hand, lymphocytic activation, a clonal, energetically demanding process is accompanied with anorexia limiting caloric intake which leads frequently to WL if protracted over months as seen in lymphoma (B-symptom) or indecisive immune engagement (Eng) with tuberculosis. WL of > 5% of body weight, was an adverse prognosticator and exclusion criterion in non-small cell lung cancer (NSCLC) chemotherapy (CT) trials, likely due to CT or steroids' abrogation of the putative, limited immune ca containment. We hypothesized that WL in ca reflects months of immune Eng, ineffective as it may be at containing the tumor, but nevertheless representing immune Eng with the ca. Such cases stand the best chance for IO benefit. Notably, IO impact in ca mirrors the 40% of WL in ca pts. Methods: Tumor registry retrieved data from all stage 4 cancers treated with monotherapy IO in our institution. We dichotomized pts to beneficiaries (B) or non-beneficiaries (NB). Bs survive longer than median survival for the respective stage/line of therapy in each ca derived from published trials. To account for missing WL data prior to IO, we reasoned that weight gain of ≥10 lbs (reliably charted over 1 year from IO infusions) is acceptable surrogate for WL and met our criteria. Results: WL in our cohort (n = 53) of Melanoma, NSCLC, renal cell carcinoma, and bladder ca was 43% of B; 10% in NB (ratio > 4:1) rejecting the null hypothesis (p < 0.05). PDL-1, Tumor Mutation Burden, both inconclusive in identifying durable benefit, were limited in our set precluding further analysis. Conclusions: Our results support, though do not prove, that WL identifies the appropriate IO pts. Improved outcome despite a historically-adverse prognosticator (WL); the fact that IO was the only ca therapy used, both support our interpretation. We hope to stimulate others to examine independent larger datasets to confirm this notion and to allow comprehensive subset analyses. For WL to be utilized properly the relevant clinical context is crucial, accounting for GI obstructing ca (esophageal ca), enzymatic anomalies (pancreatic ca), volume fluctuations (cirrhosis), catabolism (prolonged hospitalization), or dental issues, to name a few. Additionally, factors such as tumor bulk, perhaps discerned from the T of TNM staging, deserve examination since more vigorous immune activation against larger targets could produce more impact on appetite and caloric intake. Finally, available clinical trial datasets, not tumor registries, might provide a more crisp, reliable source as we continue this investigation. WL can, with confirmatory work, be clinically incorporated as a predictive factor for IO benefit.