Abstract
BACKGROUND: American Indian/Alaska Native (AI/AN) people in the United States experience cancer disparities, but little is known about cancer patterns specific to each Tribal Nation. This study describes cancer incidence (2014-2018), trends (1998-2018), and stage of diagnosis across the Navajo Nation, one of the largest sovereign tribal nations worldwide. METHODS: Cases from six Arizona, New Mexico, and Utah counties covering most of the Navajo Nation were identified by population-based cancer registries and linked with Indian Health Services patient registrations. Cancer incidence and stage at diagnosis were compared between Navajo and non-Hispanic White persons in the same counties. Trends from 1998 through 2018 were analyzed using Joinpoint regression. RESULTS: Navajo people had significantly higher incidence than non-Hispanic White people of gallbladder (incidence rate ratio [RR] = 6.25), stomach (RR = 3.19), kidney (RR = 1.89), myeloma (RR = 1.80), and liver cancers (RR = 1.79) and a lower incidence of cancers of the lung (RR = 0.16), female breast (RR = 0.49), leukemia (RR = 0.49), prostate (RR = 0.62), pancreas (RR = 0.79), and non-Hodgkin lymphoma (RR = 0.79). Diagnostic stage was not different for breast, cervical, and colorectal cancers, but two thirds of patients with cervical and colorectal cancer were diagnosed in later/unknown stages. Although all-site cancer rates did not change significantly from 1998 through 2018 among Navajo people, a significant decrease was found from 2010 through 2018 (-2.1% annual percentage change, p < .01). CONCLUSIONS: Navajo people experience a higher incidence of kidney, stomach, liver, myeloma, and gallbladder cancers and a lower incidence of cancers of the breast, prostate, lung, non-Hodgkin lymphoma, and leukemia. Tailored and targeted prevention efforts may help reduce cancer disparities in the Navajo Nation.