The Natural History of Non-Polypoid Colorectal Neoplasms

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Radiographic analysis

Matsui and colleagues12 reported a retrospective analysis of a series of colorectal cancers that were missed by double-contrast barium enema examinations. They found six depressed and seven flat lesions (41%) could be retrospectively identified as antecedent lesions that gave rise to 32 advanced cancers. The authors found that all depressed lesions developed into nonprotuberant-type advanced colorectal cancers, whereas flat or polypoid lesions had a possibility to develop into either

Colonoscopic analysis

Matsui and colleagues14 reported eight early colorectal cancers that were incidentally followed by colonoscopy. Thirty-five cases, including 14 NP-CRN as initial lesions, were reviewed. They found that NP-CRN progressed to submucosally invasive cancer, retaining its non-polypoid configuration, and some flat lesions developed depressed areas during their progression. Although the authors also estimated the speed of growth compared with polypoid and non-polypoid lesions, they could not conclude

The importance of the depressed-type NP-CRN

Matsuda and colleagues17 analyzed 6638 colorectal neoplasms, excluding advanced cancers, treated in National Cancer Center Hospital, Tokyo, Japan. There were 4471 (67%) and 2167 (33%), polypoid and non-polypoid colorectal neoplasms, respectively. Among all non-polypoid lesions, there were 178 (2.7%) depressed lesions, 109 (61%) of which were diagnosed as high-grade dysplasia or submucosally invasive cancer. Among 5538 (83%) lesions that were identified as low- or high-grade dysplasia, the

The Japan polyp study

To clarify the natural history of NP-CRN, a large cohort study focused on the detection of NP-CRN is required. Matsuda and colleagues23 reported the results of multicenter retrospective cohort study to evaluate 5-year incidence of advanced neoplasia after initial colonoscopy. The authors studied 5309 patients with a median follow-up period of 5.1 years. Endoscopists diagnosed 13 invasive cancers on follow-up within 3 years. The initial colonoscopies were performed by Japanese endoscopists who

Summary

The natural history of NP-CRN is mostly unknown. The results of small observational studies suggest that NP-CRN lesions develop into invasive cancer with minimal size expansion. Among NP-CRN lesions, depressed lesions show more aggressive behavior and frequently develop into invasive cancers compared with polypoid lesions, regardless of their low incidence. A large prospective cohort study focused on the detection of NP-CRN is currently ongoing.

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References (24)

  • S. Tsuda et al.

    Flat and depressed colorectal tumours in a southern Swedish population: a prospective chromoendoscopic and histopathological study

    Gut

    (2002)
  • R.M. Soetikno et al.

    Prevalence of nonpolypoid (flay and depressed) colorectal neoplasms in asymptomatic and symptomatic adults

    JAMA

    (2008)
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