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© 2003 American Society for Clinical Oncology
Prognosis After Rectal Cancer Treatment in Blacks and Whites: Advanced Stage at Diagnosis or Other Factors?Thomas Jefferson University, Philadelphia, PA MULTIPLE STUDIES have demonstrated that black patients have a less favorable prognosis and suffer higher death rates than do whites with colorectal cancer.1–11 A review of data from the Surveillance, Epidemiology, and End Results (SEER) Program for the years 1992 to 1997 showed significant disparities in 5-year relative survival rates for all stages of colorectal cancer, with overall survival of 60.2% for whites and 51.2% for blacks. This difference in mortality has been attributed to a number of factors, the most important of which was believed to be a more advanced stage of disease at the time of diagnosis.12,13 However, other possible factors include lack of access to and use of resources in the health care system, presence of comorbid diseases and medical conditions, tolerance of treatment, and tumor responsiveness to treatment.14 Because there was a similar distribution among stages for whites and blacks during this period, the SEER report further identified a worse 5-year survival for blacks, not only for overall survival but for each stage—localized, regional, or metastatic disease.13 There was little information in these reports exploring potential differences in the aggressiveness of tumors or inherent tumor biology. In addition, the specific treatment received by patients was not delineated, and therefore, the role of treatment differences as a potential contributing factor in disparities among ethnic groups was not defined. Although a larger percentage of black patients present with advanced stage disease, several studies have shown that even after controlling for tumor stage at diagnosis, black patients have worse survival than whites.11,13 Furthermore, after adjusting for other factors such as poverty, socioeconomic conditions, and treatment differences, there was still no clear explanation for survival differences or outcomes. Because most studies incorporated an admixture of proximal, transverse, and distal colon tumors, specified outcomes for rectal cancer as a single entity were not delineated. In this issue of the Journal of Clinical Oncology, Dignam et al12 examined the recurrence-free survival (RFS), disease-free survival (DFS), and survival for 104 blacks and 1,071 whites with rectal cancer. All patients participated in and were treated in two randomized trials of the National Surgical Adjuvant Breast and Bowel Project (NSABP). Because the clinical characteristics and extent of disease were similar and treatment delivery was restricted to a defined plan, other determinants of prognosis could be investigated in this randomized trial. Thus, the evaluation of differences in these two groups could potentially identify issues associated with disparities in mortality. These authors previously reported equivalent RFS but slightly increased mortality among blacks relative to whites who participated in NSABP colon cancer trials.15 In the study of Dignam et al,12 the white patient population was slightly older, with 31.8% of whites being 65 years or older compared with 22.7% of blacks. Blacks more often had lymph node–positive disease, with 72.7% of blacks and 65.6% of whites having lymph node metastases. They also underwent abdominoperineal resection significantly more often: 67.3% of blacks compared with 46.8% of whites. The results further confirmed disparities in outcomes: 5-year RFS was 53.7% for whites and 45.0% for blacks (P = .08); 5-year DFS was 48.2% for whites and 40.0% for blacks (P = .08); 5-year survival was 60.3% for whites and 48.0% for blacks (P = .01) Although Dignam et al12 describe overall survival, DFS, and RFS, little information is given regarding whether any differences were observed in other prognostic factors that may be important determinants of recurrence, including tumor biology and surgery-related factors such as extent of lymph node examination. It is well recognized that local recurrence after curative surgery for rectal adenocarcinoma is a major problem with a potential negative effect on survival. Although pathologic stage is the most important tumor-related factor,16 other important prognostic indicators (and thus determinants of outcomes) were not described in this study. Previous reports indicate that factors such as margins of excision (including circumferential margin), en bloc resection of adherent tumors, avoidance of inadvertent perforation, gross microscopic appearance of the mesorectum, and the total number of lymph nodes in the specimen could affect overall outcomes in the management of rectal cancer.17 Are these factors important? It would seem so. At 2-year follow-up in patients with rectal cancer, the overall recurrence in patients with complete total mesorectal excision (TME) was 21.5% versus 35.6% for those patients with incomplete TME. Furthermore, in patients with negative circumferential margins, the overall recurrence and survival were statistically significantly worse in patients with incomplete TME compared with those with a complete or nearly complete TME (28.6% v 14.9% and 90.5% v 76.9%, respectively). Thus, completeness of resection may be a prognostic factor. It has also been suggested that approximately 14 lymph nodes need to be examined in lymph node-negative rectal cancer specimens.18 Dignam et al12 do not discuss the number of lymph nodes examined nor the completeness of resection, so one cannot determine whether these factors potentially influenced outcomes. Other prognostic factors for rectal cancer relative to tumor biology, such as lymphatic, blood vessel, and neural invasion and molecular markers, also were not analyzed. Dignam et al12 confirm the fact that a more advanced stage at diagnosis remains the major cause of poorer outcomes in rectal cancer mortality for blacks. It is well recognized that socioeconomic factors and access to medical care may contribute to the presence of advanced stage at the time of disease presentation. Perhaps earlier screening, coupled with increased participation into randomized clinical trials, will further enhance current trends showing improvement in overall survival by enhancing quality of care in accordance with standardized treatment guidelines. Additional studies are needed to determine whether molecular, genetic, or inherent tumor biologic factors account for mortality disparities. REFERENCES 1. Ries LA, Eisner MP, Kosary CL, et al: SEER Cancer Statistics Review, 1973–1998. Bethesda, MD, National Cancer Institute, 2001 2. Parker SL, Davis KJ, Wingo PA, et al: Cancer statistics by race and ethnicity. CA Cancer J Clin 48:31–48, 1998[Abstract] 3. Axtell LM, Myers MH. Contrasts in survival of black and white cancer patients, 1960–73. J Natl Cancer Inst 60:1209–1215, 1978[Medline] 4. Young JL, Ries LG, Pollack ES. Cancer patient survival among ethnic groups in the United States. J Natl Cancer Inst 3:341–352, 1984 5. Wingo PA, Ries LA, Parker SL, et al: Long-term cancer patient survival in the United States. Cancer Epidemiol Biomarkers Prev 7:271–282, 1998[Abstract] 6. Chen VW, Fenoglio-Preiser CM, Wu XC, et al: Aggressiveness of colon carcinoma in blacks and whites. National Cancer Institute Black/White Cancer Survival Study Group. Cancer Epidemiol Biomarkers Prev 6:1087–1093, 1997[Abstract] 7. Demers RY, Severson RK, Schottenfeld D, et al: Incidence of colorectal adenocarcinoma by anatomic subsite. An epidemiologic study of time trends and racial differences in the Detroit, Michigan Area. Cancer 79:441–447, 1997[CrossRef][Medline] 8. Beart RW, Steele GD Jr, Menck HR, et al: Management and survival of patients with adenocarcinoma of the colon and rectum: A national survey of the Commission on Cancer. J Am Coll Surg 181:225–236, 1995[Medline] 9. Dayal H, Polissar L, Yang CY, et al: Race, socioeconomic status, and other prognostic factors for survival from colorectal cancer. J Chronic Dis 40:857–864, 1987[CrossRef][Medline] 10. Cooper GS, Yuan Z, Rimm AA. Racial disparity in the incidence and case-fatality of colorectal cancer: Analysis of 329 United States counties. Cancer Epidemiol Biomarkers Prev 6:283–285, 1997[Abstract]
11. Mayberry RM, Coates RJ, Hill HA, et al: Determinants of black/white differences in colon cancer survival. J Natl Cancer Inst 87:1686–1693, 1995 12. Dignam et al: J Clin Oncol 21:000–000, 2003 13. Ries LA, Wingo PA, Miller DS, et al: The annual report to the nation on the status of cancer, 1973–1997, with a special section on colorectal cancer. Cancer 88:2398–2424, 2000[CrossRef][Medline]
14. McCollum AD, Catalano PJ, Haller DG, et al: Outcomes and toxicity in African-American and Caucasian patients in a randomized adjuvant chemotherapy trial for colon cancer. J Natl Cancer Inst 94:1160–1167, 2002
15. Dignam JJ, Colangelo L, Tian W, et al: Outcomes among African-Americans and Caucasians in colon cancer adjuvant therapy trials: Findings from the National Surgical Adjuvant Breast and Bowel Project. J Natl Cancer Inst 91:1933–1940, 1999
16. Nelson H, Petrelli N, Carlin A, et al: Guidelines 2000 for colon and rectal surgery. J Natl Cancer Inst 93:583–596, 2001 17. Porter GA, Soskolne CL, Yakimets WW, et al: Surgeon-related factors and outcome in rectal cancer. Ann Surg 227:157–167, 1998[CrossRef][Medline]
18. Tepper JE, O’Connell MJ, Niedzwiecki D, et al: Impact of number of lymph nodes retrieved on outcome in patients with rectal cancer. J Clin Oncol 19:157–163, 2001
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Copyright © 2003 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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