Abstract B70: Does lack of surgical treatment contribute to disparities in race outcome in small bowel tumors?

Background: Small bowel tumors are rare and account for about 2% of all gastrointestinal cancers. However the incidence of small bowel tumors is rising, particularly in blacks. The aim of this study was to evaluate factors affecting survival in a large population based cohort of patients with small bowel tumors.

Methods: Four major histological types of small black tumors which were adenocarcinoma, carcinoid/neuroendocrine, sarcoma, and gastrointestinal stromal tumor were analyzed using the Surveillance, Epidemiology and End Results (SEER) (1973–2004). Patients with secondary malignancy were excluded. Survival outcomes were estimated by the Kaplan-Meier method, and Cox model adjusted for sex, age, race, tumor type and location, stage, year of diagnosis and surgery status was used to determine the characteristics independently associated with survival.

Results: There were 9,655 patients in the cohort of small bowel tumors with 8,323 whites and 1,332 black patients. The annual age-adjusted incidence for small bowel tumors in overall population has increased from 0.098, 0.147 to 0.167 per 100,000 populations in the periods 1973–1983, 1984–1993, and 1994–2004. The incidence rate rise is seen in both gender and race (black and white). Black males had the fastest rise with a 139% increase in diagnosis over the last three decades (0.153 per 100,000 population in 1973–1983 to 0.360 per 100,000 populations in 1994–2004). The most prevalent tumors in all races were adenocarcinoma and carcinoid/neuroendocrine compromising 43 and 46 percent of all small bowel tumors. Blacks were diagnosed at an earlier stage with 71% of the race diagnosed at localized and regional SEER stage compared to 68% of whites (p=0.002). Survival correlates with surgery in earlier stages (p<0.0001), however fewer blacks received surgery (62%) relative to whites (71%) (p=0.001). This trend with blacks receiving less surgery than whites was seen regardless of gender (p=0.002) (white: male and female 79.2% and 81.9%) (black: male and female 68.3% and 74.5%). Median survival was significantly higher in white (male 33 months, female 40 months) than blacks (male 23 months, female 29 months) (p<0.0001). In multivariate model adjusted for sex, age, race, tumor type and location, stage, year of diagnosis and surgery status, blacks are 21% more likely to die from small bowel tumors compared to whites patients (HR 1.21, 95% CI 1.11 to 1.32; p<0.0001).

Conclusions: Racial disparities exist in the incidence, treatment and outcomes of small bowel tumors. One reason for worse survival in blacks can be explained by lower frequency of surgical treatment. Our results suggest that treatment disparity may contribute to differences in outcome between race and small bowel tumors and highlights the need to increase surgical intervention for minority patients.