Anal canal cancer: a population-based reappraisal.
OBJECTIVE
This study was designed to obtain an updated population-based perspective on anal canal cancer incidence rates, demographics, and outcomes using a nationwide database. Eight-five percent of all carcinomas of the anus are anal canal cancers, and previous studies suggest that incidence rates may be rising. Although the most successful treatment for anal canal cancer has been chemoradiation, little information at the population-level exists regarding demographics, treatment, and survival.


METHODS
All patients diagnosed with anal canal cancer from 1973 to 1998 in the Surveillance Epidemiology and End Results cancer registry were analyzed. Data regarding demographics, cancer characteristics, treatment, and survival were assessed. Univariate and multivariate survival analyses were performed.


RESULTS
A total of 4,841 patients were studied (mean age was 61 years; 62 percent female). Female patients were significantly older than male patients (65 vs. 58 years; P < 0.0001). There was a yearly increase in incidence of anal canal cancers (from 1973-1998). Disease prevalence by stage was localized (53 percent), regional (38 percent), and distant (9 percent). Racial/stage differences were seen, because black patients had less localized disease than white patients (46 vs. 53 percent; P < 0.01). Overall five-year survival for the entire cohort was 53 percent, and cancer-specific survival was 84 percent. Survival improved per decade (based on year of diagnosis). Significant survival differences in race were noted, but were less when the receipt of treatment was considered.


CONCLUSIONS
Although most anal canal cancer reviews are single institutional series, this study was performed with population-based data. The incidence of anal canal cancer is increasing, and overall survival rates are improving. Important disparities in care were identified, which need to be addressed.
Maggard
Melinda A
MA
Robert Wood Johnson VA Clinical Scholars Program, West Los Angeles Veterans Administration, Los Angeles, California, USA.
Beanes
Steven R
SR
Ko
Clifford Y
CY
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001005:Anus Neoplasms / Q000208:ethnology / Q000401:mortality / Q000473:pathology*; D019992:Databases as Topic; D016021:Epidemiologic Studies; D005006:Ethnicity; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D016017:Odds Ratio; D016016:Proportional Hazards Models; D012737:Sex Factors; D016019:Survival Analysis; D015996:Survival Rate; D014481:United States / Q000453:epidemiology