Characteristics, incidence, and survival of unknown stage cancer: A US population-based study

This study examines the extent of unknown stage cancer incidence for 24 cancer sites in the U.S. based on reporting source, selected variables, and cancer lethality.

Analyses included 5,447,023 malignant cancer cases diagnosed during 2015-2021, collected by 22 population-based cancer registries in the Surveillance, Epidemiology, and End Results (SEER) Program. Poisson regression estimated adjusted rate ratios.

Approximately 9.4 % of males and 7.2 % of females had unstaged cancer, significantly varying by reporting source. Levels of unstaged cancer identified by hospital, physician, or other; autopsy; death certificate; or nursing/convalescent home/hospice were 7.8 %, 32.6 %, 97.0 %, and 82.0 % in males and 5.8 %, 31.2 %, 97.1 %, and 82.4 % in females, respectively. Rates increased with age when the reporting source was hospital, physician, or other but decreased with age for autopsy, death certificate, or nursing/convalescence home/hospice. Unstaged cancer rates were similar between men and women (r = 0.93, p < 0.0001, not including breast cancer). However, men were seen to have a 60 % higher rate of unstaged cancer (95 % CI 59 %-61 %) compared to women. Rates increased with age, decreased with income, and were 11 % (95 % CI 10 %-12 %) higher in Blacks (vs. Whites), and 11 % (95 % CI 10 %-12 %) higher in Hispanics (vs. non-Hispanics). A significant negative association was found between unstaged cancer percentages and 5-year relative survival rates for both sexes.

Males, older age, Blacks, Hispanics, and lower income patients are more susceptible to not receiving a cancer stage because of higher comorbid illness, more aggressive cancer, and less ability to pay for treatment.