Late development of metachronous colorectal cancer

Abstract

The incidence of metachronous colorectal cancer has been reported to be 1 to 5 percent, with most of the cases being discovered within ten years of the initial cancer. A retrospective review of all colorectal cancer patients was conducted at the Southern Illinois University Affiliated Hospitals to determine the incidence of metachronous colorectal cancer at the authors' institution. In this study, a metachronous cancer was defined as a second colorectal primary occurring at least three years following discovery of the initial lesion. Between 1978 and 1984, there were 24 patients with metachronous colorectal cancer identified in an operative series of 707 patients for a frequency of 3.4 percent. These metachronous cancers were discovered at intervals ranging from 3 to 35 years. Sixteen (67%) metachronous lesions occurred 11 years of more after the original cancer. Synchronous or interval adenomatous colorectal polyps were noted in 17 (71 percent) of the patients. Thirteen of the metachronous cancers appeared in the right colon, while six were distributed throughout the transverse and descending colon, and five were in the rectosigmoid region. The incidence of late-appearing metachronous colorectal cancers and the propensity to occur in the right colon underscores the need for evaluation of the entire colon as part of lifelong follow-up of the colorectal cancer patient.

Epidemiology and prognosis of synchronous colorectal cancers

“…A similar definition was used in four other studies1, 7–9. In six further studies, cancers diagnosed within a year of the initial diagnosis were classified as synchronous3, 4, 6, 18–20 and, in another, those diagnosed within 3 years21. Discrepancies may also result from the size of the studied populations, population characteristics (excluding or not excluding ulcerative colitis and genetic syndrome), and the period studied.…”

Metachronous colorectal cancers result from missed lesions and non-compliance with surveillance

“…[3][4][5][6] Although the updated society guidelines 7-10 include recommendations on the surveillance intervals after CRC surgery, the proportion of a second primary CRCdfurther referred to as metachronous CRC (mCRC)ddid not decrease over the past decade, ranging from 1% to 4% of all patients with CRC. [11][12][13][14][15][16][17][18][19] In the early 80s, Tornqvist et al 11 found that mCRCs account for 2.1% of all CRCs, in a cohort of curatively treated patients with CRC. Two decades later, Green et al 12 found 42 mCRC cases over 15,000 person-years of follow-up, corresponding to a proportion of 1.3%.…”

A novel high-specificity approach for colorectal neoplasia: Detection of K-ras2 oncogene mutation in normal mucosa

“…Although only 1 sample from each site was examined in this study, the sensitivity of our method might be increased by obtaining more specimens. Metachronous colorectal cancer has been reported to be relatively frequent (1.1–4.8% of colorectal patients) with most second primaries being discovered within 10 years of the initial colorectal cancer 31, 32. We found K‐ ras mutations in normal mucosa samples from some patients who had undergone colorectal tumor resections more than 1 year before.…”