Hereditary Cancer in Clinical Practice (Feb 2019)

Lack of association between screening interval and cancer stage in Lynch syndrome may be accounted for by over-diagnosis; a prospective Lynch syndrome database report

  • Toni T. Seppälä,
  • Aysel Ahadova,
  • Mev Dominguez-Valentin,
  • Finlay Macrae,
  • D. Gareth Evans,
  • Christina Therkildsen,
  • Julian Sampson,
  • Rodney Scott,
  • John Burn,
  • Gabriela Möslein,
  • Inge Bernstein,
  • Elke Holinski-Feder,
  • Kirsi Pylvänäinen,
  • Laura Renkonen-Sinisalo,
  • Anna Lepistö,
  • Charlotte Kvist Lautrup,
  • Annika Lindblom,
  • John-Paul Plazzer,
  • Ingrid Winship,
  • Douglas Tjandra,
  • Lior H. Katz,
  • Stefan Aretz,
  • Robert Hüneburg,
  • Stefanie Holzapfel,
  • Karl Heinimann,
  • Adriana Della Valle,
  • Florencia Neffa,
  • Nathan Gluck,
  • Wouter H. de Vos tot Nederveen Cappel,
  • Hans Vasen,
  • Monika Morak,
  • Verena Steinke-Lange,
  • Christoph Engel,
  • Nils Rahner,
  • Wolff Schmiegel,
  • Deepak Vangala,
  • Huw Thomas,
  • Kate Green,
  • Fiona Lalloo,
  • Emma J. Crosbie,
  • James Hill,
  • Gabriel Capella,
  • Marta Pineda,
  • Matilde Navarro,
  • Ignacio Blanco,
  • Sanne ten Broeke,
  • Maartje Nielsen,
  • Ken Ljungmann,
  • Sigve Nakken,
  • Noralane Lindor,
  • Ian Frayling,
  • Eivind Hovig,
  • Lone Sunde,
  • Matthias Kloor,
  • Jukka-Pekka Mecklin,
  • Mette Kalager,
  • Pål Møller

DOI
https://doi.org/10.1186/s13053-019-0106-8
Journal volume & issue
Vol. 17, no. 1
pp. 1 – 8

Abstract

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Abstract Background Recent epidemiological evidence shows that colorectal cancer (CRC) continues to occur in carriers of pathogenic mismatch repair (path_MMR) variants despite frequent colonoscopy surveillance in expert centres. This observation conflicts with the paradigm that removal of all visible polyps should prevent the vast majority of CRC in path_MMR carriers, provided the screening interval is sufficiently short and colonoscopic practice is optimal. Methods To inform the debate, we examined, in the Prospective Lynch Syndrome Database (PLSD), whether the time since last colonoscopy was associated with the pathological stage at which CRC was diagnosed during prospective surveillance. Path_MMR carriers were recruited for prospective surveillance by colonoscopy. Only variants scored by the InSiGHT Variant Interpretation Committee as class 4 and 5 (clinically actionable) were included. CRCs detected at the first planned colonoscopy, or within one year of this, were excluded as prevalent cancers. Results Stage at diagnosis and interval between last prospective surveillance colonoscopy and diagnosis were available for 209 patients with 218 CRCs, including 162 path_MLH1, 45 path_MSH2, 10 path_MSH6 and 1 path_PMS2 carriers. The numbers of cancers detected within 3.5 years since last colonoscopy were 36, 93, 56 and 33, respectively. Among these, 16.7, 19.4, 9.9 and 15.1% were stage III–IV, respectively (p = 0.34). The cancers detected more than 2.5 years after the last colonoscopy were not more advanced than those diagnosed earlier (p = 0.14). Conclusions The CRC stage and interval since last colonoscopy were not correlated, which is in conflict with the accelerated adenoma-carcinoma paradigm. We have previously reported that more frequent colonoscopy is not associated with lower incidence of CRC in path_MMR carriers as was expected. In contrast, point estimates showed a higher incidence with shorter intervals between examinations, a situation that may parallel to over-diagnosis in breast cancer screening. Our findings raise the possibility that some CRCs in path_MMR carriers may spontaneously disappear: the host immune response may not only remove CRC precursor lesions in path_MMR carriers, but may remove infiltrating cancers as well. If confirmed, our suggested interpretation will have a bearing on surveillance policy for path_MMR carriers.

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