The impact of socioeconomic status on cancer care and survival.

Abstract

6004 Background: Primary cancers of the lung, esophagus, and pancreas account for over 35% of all cancer deaths in the US and a sizable share of cancer costs. Despite little improvement in survival rates over time, how aggressively patients with poor prognosis cancers are treated has increased dramatically. In this study, we examine the aggressiveness of treatment and cancer outcomes by socioeconomic status (SES). Methods: Using SEER-Medicare data (incident cases from 1992-2002, follow-up to 2005), we examined lung (n=68167), esophagus (n=4350), and pancreas (n=12779) cancers. We constructed a summary measure of SES based on US ZIP code data from the 2000 Census data linked to the patient’s ZIP code of residence. We assessed the effects of SES on treatment and 2-year survival rates. Results: Across SES groups, patients were similar with regard to cancer stage, though patients in the lowest SES group were much more likely to be black. The lowest SES patients were more likely to require urgent or emergent admissions and to be treated at very low volume hospitals and non-teaching hospitals. For all three cancer types, low SES patients were more likely to receive no cancer-directed treatment (e.g., 60% of the lowest SES patients received no treatment for pancreas cancer). Receipt of cancer-directed surgery, chemotherapy, and/or radiation therapy was consistently higher for the highest SES patients, with most patients receiving at one type of treatment and many receiving a combination of treatments. Crude hazard ratios (HR) for mortality suggested a slight survival benefit in the highest SES patients (compared to the lowest SES patients), but HR for esophagus and pancreas cancers were not significantly different once patient characteristics and cancer treatments were taken into account (HR 1.02; 95%CI 0.89-1.16 and HR 1.02; 95%CI 0.96-1.10, respectively). For lung cancer, results were marginally significant (HR 1.11; 95%CI 1.08-1.15). Conclusions: There is pronounced variation in types of cancer treatment received by different SES groups. Despite receiving more aggressive treatments, higher SES patients do not have improved survival rates. Reducing variation in treatment strategies may improve healthcare efficiency without changing patient outcomes.