Defining mild, moderate, and severe fatigue in cancer patients and survivors: E2Z02, a trial of the Eastern Cooperative Oncology Group.

Abstract

9099 Background: Although mild, moderate and severe categories have been used in clinical guidelines for fatigue management in cancer patients, the optimal cutpoints on a 0-10 scale for delineating these categories have not been replicated. Methods: A multicenter ECOG study (E2Z02) enrolled breast, lung, prostate, or colorectal cancer patients with any treatment status. Fatigue and symptom interference were measured on the 0-10 numerical rating scale of the M. D. Anderson Symptom Inventory (MDASI). The optimal boundaries for categorizing fatigue severity were determined by the largest F ratios from MANOVA (Serlin’s criteria, 1995). Logistic regression with robust standard errors was used to identify risk factors for moderate/severe fatigue for cancer survivors (defined as patients with no evidence of disease and receiving no cancer treatment). Results: The optimal cutpoints that identified 3 distinct levels of fatigue severity for the 2341 patients were: ratings of 1-3 as mild, 4-6 as moderate, and 7-10 as severe. Known-group validity for these cutpoints was established by significant differences of fatigue severity by ECOG performance status and patient-reported quality of life (all P<0.001). Using these cutpoints, 45% (983/2177) of patients undergoing active therapy had moderate/severe fatigue, with significant more mild fatigue in breast and colorectal cancer patients, while more severe fatigue in lung cancer patients (p<.001). Among cancer survivors, 29% (150/515) had moderate/severe fatigue (breast 31%, colorectal 27%, prostate 22%, lung 33%). Younger age (OR=0.97, 95% CI=0.95-0.99) and poor performance status (OR=4.21, 95% CI=2.36-7.51) were associated with more moderate/severe fatigue in cancer survivors. Survivor time was also associated with moderate/severe fatigue in breast and colorectal cancer survivors (>=5yrs vs. <5yrs: OR=0.23, P<0.01 for breast, OR=9.3, P=0.03 for colorectal). Conclusions: This multicenter study confirmed the standard cutpoints for fatigue severity used in NCCN fatigue management guidelines. It also provides a profile of moderate to severe fatigue prevalence for actively treated cancer patients and for cancer survivors.