BACKGROUND: Debate regarding a nomenclature change for grade group 1 (GG 1) prostate cancer to noncancer has been revived, as this could be a powerful tool in reducing the overtreatment of indolent disease.

OBJECTIVE: To describe outcomes for all men diagnosed with GG 1 prostate cancer in the Danish population, with a focus on men followed conservatively.

DESIGN, SETTING, AND PARTICIPANTS: This was a population-based observational study using data from the Danish Prostate Registry.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We measured the cumulative incidence of curative treatment, endocrine treatment, and cause-specific mortality.

RESULTS AND LIMITATIONS: The cumulative incidence of endocrine therapy at 10 yr was 5.3% (95% confidence interval [CI] 4.3-6.3%) for men with initial active surveillance and 21% (95% CI 19-23%) for men with initial watchful waiting for localized GG 1. In the GG1 cohort, the prostate cancer-specific mortality rate at 15 yr was 14% (95 CI% 11-16%) for men on watchful waiting, 10% (95 CI% 6.7-14%) for men with prostate-specific antigen <10 ng/ml on watchful waiting, and 16% (95 CI% 13-19%) for men who did not receive curative-intent treatment or histological assessment. The study is limited by the historic nature of the observations over a period during which diagnostic procedures and treatments have evolved.

CONCLUSIONS: GG 1 cancer can lead to disease-specific mortality in men with localized prostate cancer, and changing the nomenclature for all men may lead to undertreatment.

PATIENT SUMMARY: Key opinion leaders have suggested that prostate cancers of Gleason grade group 1 (GG 1) should be renamed as noncancer to reduce overtreatment. The argument is that low-grade cancer does not metastasize. However, our nationwide population-based study showed that death from prostate cancer can occur in some men diagnosed with GG 1 disease. These men should be considered in discussions on changing the name for GG 1 prostate cancer.