Rising Incidence and Improved Survival of Anal Squamous Cell Carcinoma in Norway, 1987-2016.

Background: Anal squamous cell carcinoma (ASCC) is a rare, human papilloma virus-associated cancer. The purpose was to investigate the population-based incidence rates, age and gender distribution, and survival of ASCC.
Materials and Methods: All primary ASCC in 1987 to 2016 were identified in the Cancer Registry of Norway (N = 1548), with information on age, gender, stage, county of residence, radiotherapy, and survival.
Results: Median age was 66 years; 71% were females. World age-standardized incidence rates increased (1987-2016) from 0.79 (95% confidence interval [CI], 0.69-0.90) to 1.10 (95% CI, 1.00-1.22) per 100,000 person-years in females and, from 0.34 (95% CI, 0.28-0.42) to 0.47 (95% CI, 0.40-0.54) in males. Estimated annual percentage change was 1.7 (95% CI, 0.9-2.6) for females and 1.3 (95% CI, -0.1 to 2.7) for males. Incidence rates increased with age; the relative risk was higher in major cities. Five-year net survival increased from 63.4% to 72.7% (1987-2016), but for age ≥ 70 years remained ∼57%. Net survival was dependant on stage, age, and gender. Five-year net survival (1997-2016) was 76.4% after curative radiotherapy, and 18.0% after palliative radiotherapy.
Conclusion: ASCC incidence rates increased from 1987 to 2016, and survival improved for patients < 70 years. Five-year net survival was 76% after curative radiotherapy in Norway.
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