Disparities in Cancer Incidence, Stage, and Mortality at Boston Health Care for the Homeless Program

Introduction: Homeless people have a high burden of cancer risk factors and suboptimal rates of cancer screening, but the epidemiology of cancer has not been well described in this population. We assessed cancer incidence, stage, and mortality in homeless adults relative to general population standards.

Methods: We cross-linked a cohort of 28,033 adults seen at Boston Health Care for the Homeless Program in 2003-2008 to Massachusetts cancer registry and vital registry records. We calculated age-standardized cancer incidence and mortality ratios (SIRs and SMRs). We examined tobacco use among incident cases and estimated smoking-attributable fractions. Trend tests were used to compare cancer stage distributions with those in Massachusetts adults. Analyses were conducted in 2012-2015.

Results: During 90,450 person-years of observation, there were 361 incident cancers (SIR=1.13, 95% CI=1.02, 1.25) and 168 cancer deaths (SMR=1.88, 95% CI=1.61, 2.19) among men, and 98 incident cancers (SIR=0.93, 95% CI=0.76, 1.14) and 38 cancer deaths (SMR=1.61, 95% CI=1.14, 2.20) among women. For both sexes, bronchus and lung cancer was the leading type of incident cancer and cancer death, exceeding Massachusetts estimates more than twofold. Oropharyngeal and liver cancer cases and deaths occurred in excess among men, whereas cervical cancer cases and deaths occurred in excess among women. About one third of incident cancers were smoking-attributable. Colorectal, female breast, and oropharyngeal cancers were diagnosed at more-advanced stages than in Massachusetts adults.

Conclusions: Efforts to reduce cancer disparities in homeless people should include addressing tobacco use and enhancing participation in evidence-based screening.