Trends in incidence and survival in anal adenocarcinoma: A SEER study of racial and age disparities.
Authors: Peshin Supriya , Modi Shivani , Dharia Adit , Iqbal Rabia , Anwar Junaid , Borra Rahul , Moka Nagaishwarya 
Published: January 2025

1

Background:
Anal adenocarcinoma, a rare but increasingly diagnosed malignancy, has demonstrated rising incidence rates, warranting a deeper analysis of its epidemiology and outcomes across demographic factors like race and age.
Methods:
A retrospective analysis of data from SEER database (2000-2020) was conducted. Incidence rates per 100,000 individuals and 5-year survival outcomes were compared across racial groups (White, Black, Asian, Hispanic) and age categories (≤50 years, 51-70 years, >70 years). Additionally, trends were analyzed across two decades: 2000-2010 and 2010-2020. This study investigates epidemiological trends of anal adenocarcinoma, focusing on variations in incidence and survival outcomes by race and age, with specific comparisons between the periods 2000-2010 and 2010-2020.
Results:
Incidence of anal adenocarcinoma increased from 0.7 per 100,000 in 2000 to 1.6 per 100,000 in 2020. From 2000 to 2010, incidence increased rose 0.7 to 1.0 per 100,000, and from 2010 to 2020, it rose from 1.0 to 1.6 per 100,000. Rates were highest among Black individuals, increasing from 1.5 per 100,000 (2000-2010) to 2.3 (2010-2020), followed by White (1.2 to 1.5), Hispanic (0.8 to 1.0), and Asian populations (0.3 to 0.5). Age-related outcomes showed that in 2000-2010, patients aged ≤50 years had a 5-year survival rate of 75% versus 55% in age 51-70 versus 35% for >70 years. In 2010-2020, these rates dropped to 70%, 50%, and 30% in respective age groups. Racial disparities in survival were evident: Black patients had a 5-year survival rate of 40% (2000-2010) and 35% (2010-2020), significantly lower than White patients, who had rates of 65% (2000-2010) and 60% (2010-2020).
Conclusions:
The incidence of anal adenocarcinoma has steadily increased from 2000 to 2020, particularly among the Black population, while survival rates have declined. Additionally, survival rates are lower in individuals older than 70 years. Highlighting disparities in incidence and outcomes, further research is essential to uncover the underlying causes and develop targeted interventions to mitigate risks and improve patient outcomes. Keywords: anal adenocarcinoma, epidemiology, race, age, survival rates, disparities.

This table summarizes the key trends in anal adenocarcinoma incidence and survival by race and age over the two decades from 2000 to 2020. The increases in incidence, particularly among Black individuals, and the worsening survival rates, especially in older and Black populations, are notable findings from the study.

Category
2000-2010
2010-2020
Change (2000-2020)

Incidence per 100,000 (Overall)
0.7 → 1.0
1.0 → 1.6
+0.9

Incidence by Race

- White
1.2 → 1.5
1.5 → 1.5
+0.3

- Black
1.5 → 2.3
2.3 → 2.3
+0.8

- Hispanic
0.8 → 1.0
1.0 → 1.0
+0.2

- Asian
0.3 → 0.5
0.5 → 0.5
+0.2

5-Year Survival by Age

- ≤50 years
75%
70%
-5%

- 51-70 years
55%
50%
-5%

- >70 years
35%
30%
-5%

5-Year Survival by Race

- White
65%
60%
-5%

- Black
40%
35%
-5%