Diagnosis of colon and rectal cancer in a large VA Medical Center practice: does fecal occult blood screening make a difference?

To the Editor: Screening of average-risk patients for colorectal cancer by annual fecal occult blood testing (FOBT), sigmoidoscopy, or colonoscopy has demonstrated efficacy in both the prevention and earlier detection of this malignancy in adults 50 years or older. (1, 2) In 1998, the Albany VA Medical Center launched a systematic program of colorectal cancer screening that uses home FOBT as the principal screening modality, based on its low cost, safety, and high patient acceptability. (3) Over the next 4 years, screening rates more than doubled, to 66%, with greater than 90% by FOBT in an eligible population numbering more than 27,800. This study examines the impact of this screening initiative on the discovery of colorectal cancers during years 3 to 5 of the program. Results indicate that detection of fecal occult blood in asymptomatic patients led to fewer than 5% of colorectal cancer diagnoses.

We reviewed computerized medical records of all patients with pathologically confirmed colorectal and anal cancer detected between January 2000 through December 2002 to identify all relevant screening tests, procedures, signs, symptoms, and laboratory studies. Specifically sought were rectal bleeding, melena, abdominal pain, vomiting, weight loss, palpable rectal mass, and anemia. Returned FOBT cards were processed in a central laboratory by the unrehydrated method.

Eighty-three patients with malignancies were identified (age, 70.3 [+ or -] 8.5 years; range, 40-84 years). Twelve were free of signs and symptoms before and at the time of diagnosis. In this asymptomatic group, home FOBT led to the diagnosis of colorectal cancer in 3, screening colonoscopy in 6, sigmoidoscopy in 2, and barium enema in 1.

Identification and pursuit of signs and symptoms including rectal bleeding (n = 46), anemia (n = 24), rectal mass (n = 11), and abdominal pain (n = 5) contributed to the diagnosis in the remaining 71 patients. Of these, 36 (51%) had undergone home FOBT within 12 months of diagnosis. Recognition of signs or symptoms prompted an FOBT order in 23 of the 36 tested, with 9 negative and 14 positive results. In these cases FOBT was used for diagnostic rather than screening purposes. The remaining 13 patients were free of signs and symptoms when tested with 10 negative and 3 positive results. The 3 FOBT-positive patients delayed evaluation until signs or symptoms developed. Tumor locations and mode of presentation are depicted in the Table. Overall, annual FOBT was performed no more than twice in 83% of patients. Tumor stage was more advanced only in symptomatic patients who were also FOBT-positive (3.0 [+ or -] 1.0, 1.7 [+ or -] 1.2, P < 0.01) when compared with the group of 12 asymptomatic patients identified by screening alone. (4)

Several points are noteworthy but should be interpreted within the scope of a retrospective investigation limited to detection of malignancies but not polyps. First, the identification of 3 of 83 cancers by asymptomatic FOBT screening supports the value of this approach and is consistent with prior investigations. Second, in contrast to colonoscopy, home FOBT is neither sensitive nor specific as a screen and is not validated as a diagnostic test. These limitations are reflected in the false-negative results for 10 asymptomatic patients and the 9 symptomatic patients in whom the test was ordered for diagnostic purposes. Third, this study reiterates the central importance of signs and symptoms in colorectal cancer diagnosis even in a heavily screened patient population. This point is underscored in 26 patients with cancer of the rectum and anus, 25 of whom had signs and symptoms, including 22 with rectal bleeding. The diagnostic value of this symptom in older patients is supported by a significant association between reported rectal bleeding, positive FOBT, and a subsequent diagnosis of colorectal cancer. (5) The fact that signs and symptoms are often underreported, overlooked, or incompletely documented highlights the significance of their 86% incidence reported here.

The Department of Veterans Health Affairs has the highest rate of colorectal cancer screening in the United States, but no screening program will achieve 100% compliance. (3) Moreover, the benefit of annual FOBT screening is cumulative over 8 to 18 years, and the value of one or two annual screens is low. (1, 2) These realities provide a perspective on the important but limited role of home FOBT screening in clinical practice, particularly during the early years of a screening program. The undeniable benefits of FOBT screening may supplement but cannot replace the value of a personalized diagnostic approach in an aging patient population.

This material is based on work supported in part by the Office of Research and Development, Department of Veterans Affairs, and was approved by the Albany VA Medical Center Institutional Review Board.

Table. Tumor locations with corresponding signs and symptoms

                       No. of              Rectal
Tumor location         patients  Anemia    bleeding

Anorectal              26         9 (35%)  22 (85%)
Sigmoid                28         6 (21%)  16 (57%)
Proximal to sigmoid    29         9 (31%)   8 (28%)
Totals                 83        24 (29%)  46 (55%)

                     Signs/        No signs/
Tumor location       symptoms      symptoms

Anorectal            25 (96%) (a)   1
Sigmoid              20 (71%)       8
Proximal to sigmoid  26 (90%)       3
Totals               71 (86%)      12

(a) Including 11 masses palpated by digital rectal examination.

References

1. Walsh MEJ, Terdiman JP. Colorectal cancer screening scientific review. JAMA 2003; 289: 1288-1296.

2. Faivre J, Dancourt V, Lejeune C, et al. Reduction in colorectal cancer mortality by fecal occult blood screening in a French controlled study. Gastroenterology 2004;126:1674-1680.

3. Jha AK, Prelin JB, Kizer KW, et al. Effect of the transformation of the Veterans Affairs Health Care System on the quality of care. N Engl J Med 2003;348:2218-2227.

4. Colon and rectum. In: American Joint Committee on Cancer. AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002. pp. 113-124.

5. Fijten GH, Starmans R, Muris JWM, et al. Predictive value of signs and symptoms for colorectal cancer in patients with rectal bleeding in general practice. Fam Pract 1995;12:279-286.

Peter A. Engel, MD

Gurjeet S. Kahlon, MD

Syed Shah, MD

Albany VA Medical Center

Geriatrics and Extended Care

Department of Medicine, Division of Geriatrics

Albany Medical College 

Albany, NY

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