Cancer incidence, stage at diagnosis, and trends across the Navajo Nation, 2014–2018

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.