Baseline anemia in patients with biliary tract cancer (BTC) and its association with survival: A retrospective cohort study

Background:The prognostic significance of anemia in BTC is unknown, but is common and may be multifactorial; data regarding its causes are limited. This study interrogated a large institutional database to examine the effect of anemia on overall survival (OS) in BTC, and explore factors associated with anemia. Methods:This Princess Margaret Cancer Centre cohort study included patients with BTC with available baseline hemoglobin (Hb) (1987-2016). Anemia was defined as Hb < 132 mg/dL for men > 60 years, < 137mg/dL for men aged 20-59, and < 122mg/dL in women. Additional relevant covariates were included in multivariable Cox regression for OS, and linear regression for association with Hb. Results:Of 1398 patients included, 711 (51%) were anemic at baseline (mean Hb 112 mg/dL). Anemic versus non-anemic patients were older (median age 66 vs 64 yrs, p = 0.006), had worse ECOG PS (12% ECOG 2-3 vs 6%, p < .001), BMI < 20 (31% vs 27%, p = 0.006) and elevated neutrophil:lymphocyte ratio (NLR), (64% vs 47%, p < .001), but cancer staging was not significantly different. Anemia was associated with shorter OS on univariate (HR 1.35, p < .001) and multivariable (HR 1.39, p < .001) regression (Table). Factors associated with lower Hb included older age, male gender, worse ECOG PS, tumor site, thrombocytopenia, elevated NLR. Conclusions:Baseline anemia was associated with shorter survival following diagnosis of BTC, independent of tumor stage or ECOG PS. Clinicians should be aware of this prognostic marker; validation in prospective datasets is warranted.