Relationship between low hemoglobin levels and outcomes after treatment with radiation or chemoradiation in patients with cervical cancer: Has the impact of anemia been overstated?

Purpose: Previous reports have suggested that anemia increases rates of recurrence after radiation therapy for cervical cancer. However, these studies may not have fully corrected for confounding risk factors. Using a well-characterized cohort of cervical cancer patients, we examined the association between anemia and outcomes before and after the introduction of chemoradiation as standard of care. Methods and Materials: We reviewed the records of 2454 patients who underwent definitive radiation therapy from 1980 through 2011. Minimum hemoglobin level (Hgb_min) was recorded for 2359 patients (96%). Endpoints included freedom from central recurrence (FFCR), freedom from distant metastasis (FFDM), and disease-specific survival (DSS). Results: For the entire cohort, hemoglobin concentrations of 9, 10, and 12 g/dL before and during radiation were all significantly associated with FFCR, FFDM, and DSS (all P<.001) on univariate analysis. However, on multivariate analysis, only Hgb_min less than 10 g/dL during RT (RT-Hgb_<10) remained significant, and it was correlated with lower DSS (P=.02, hazard ratio [HR] = 1.28) and FFDM (P=.03, HR = 1.33) but not with FFCR. In a subset analysis of patients receiving chemoradiation (n=678), RT-Hgb_<10 was associated only with DSS (P=.008, HR = 1.49), not with FFCR or FFDM. In this subgroup, despite an association between RT-Hgb_<10 and DSS, the use of transfusion was not correlated with benefit.