LETTER TO THE EDITOR

Relationship Between Colorectal and Esophageal Cancer To the Editor--I read with interest the correspon- dences of Spigelman, s which discussed the putative relationship between colorectal and prostate cancers. I agree with Simon et al. that future research should assess the etiologic contribution of environmental and genetic factors to this relationship. The purpose of my

communication is to extend the concept that colorec- tal cancer is associated with other tumors by describ- ing an empiric relationship between colorectal and esophageal cancers.

In 1985, Sontag et al. 2 reported that precancerous Barrett's esophagus patients appear to have an in- creased risk of colorectal cancer. Since this original

report, this idea has become controversial because subsequent studies have produced conflicting data. Most recently, however, Howden and Homung 3 pre-

sented the results of their study and literature audit to the American Gastroenterological Association. Over- all, they found that the risk of colorectal cancer in Barrett's esophagus patients was more than six times greater than in those patients participating in colonic screening programs (odds ratio, 6.5). This observation can be explained by considering the immunologic manifestations of Barrett's esophagus. This lesion is

associated with T-lymphocyte dysfunction, and these

cells are central to tumoricidal immunosurveillance. If this immunosuppression is coupled to shared envi- ronmental/genetic risk factors, then it is logical to suspect an association between colorectal and esoph- ageal cancer in Barrett's patients. This is supported by the report of Kingston et al. 4

In summary, Barrett's patients may have an in-

creased risk of both colorectal and esophageal cancer. Potentially, Barrett's patients could benefit from aspi- rin chemoprophylaxis because there is evidence that

aspirin consumption can prevent both colorectal and esophageal cancers. 5

REFERENCES

1. Spigelman AD. Relationship between colorectal and prostate cancer [letter and reply]. Dis Colon Rectum 1995;38:555--6.

2. Sontag J, Schnell TG, Chejfec G, et al. Barrett's oesoph- agus and colonic turnouts. Lancet 1985;1:946-8.

3. Howden CW, Homung CA. The risk of colon neoplasms in Barrett's esophagus: a re-analysis of nine controlled studies [abstract]. Gastroenterology 1995;104:A482.

4. Kingston RD, Kiff RS, Walsh SH. Barrett's oesophagus and colonic cancer [letter]. Lancet 1988;1:63.

5. Morgan GP. NSAIDs and the chemoprevention of colon and oesophageal cancer [letter and reply]. Gut 1995;36: 153-4.

Gareth Morgan, B.Sc. (Hons)

Wales, United K ingdom

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