Rare cancer incidence and mortality trends among older adults in Martinique: a population-based registry study, 2008–2022

Rare cancers account for approximately 25% of all cancers worldwide, and around 50% of cancer cases occur in people aged ≥ 65 years. However, they remain underrepresented in epidemiological research, particularly in the Caribbean. We conducted a population-based cohort study using data from the Martinique Cancer Registry and French National Mortality Database. Age-standardized incidence and mortality rates (ASIR and ASMR) were estimated, and Annual Percent Change (APC) were calculated for patients aged ≥ 65 years by tumor site and sex. Between 2008 and 2022, 778 older adults were diagnosed with rare cancers in Martinique (61% men), with 442 deaths recorded (64.5% men). Overall incidence and mortality showed no statistically significant trends in either sex (men: APC for mortality was +0.23%, 95% CI −2.46 to 2.99, p = 0.869). Significant trend was rising gallbladder cancer mortality in men (APC + 10.35%; 95% CI 1.99–19.38; p = 0.014). The mortality burden was predominant in men for laryngeal cancer (86.1%), melanoma of the skin (81.8%), and esophageal cancer (77.6%). Rare cancer patterns in older adults in Martinique reflect tumor biology, demographic aging, and healthcare constraints. Rare cancer mortality underscores critical gaps in access and timely oncological referral. Strengthening cancer registries are essential to inform Caribbean evidence-based rare cancer control.