Intermediate-onset colorectal cancer: a clinical and familial boundary between both early and late-onset colorectal cancer

<p>Comparative studies of colorectal cancer (CRC) according to the age of onset<br> have found differences between early-onset CRC (EOCRC) and late-onset CRC<br> (LOCRC). Using this as a starting point, we wished to determine whether intermediateonset<br> CRC (IOCRC) might also be considered as an independent group within CRC.<br> We performed a retrospective comparative study of the clinicopathological and familial<br> features, as well as of the symptoms and their duration, of a total of 272 subjects<br> diagnosed with CRC classified into three groups according to the age-of-onset (98<br> EOCRC, 83 IOCRC and 91 LOCRC). The results show that from a clinicopathological<br> point of view, IOCRC shared certain features with EOCRC (gender, prognosis), and<br> with LOCRC (multiple primary CRCs), whereas it also had characteristics that were<br> specific for IOCRC (mean number of associated polyps). A gradual progression was<br> observed from EOCRC to LOCRC from a greater family aggregation to sporadic cases,<br> in parallel with a change of Lynch Syndrome cases to the sporadic microsatellite<br> instability pathway, with the IOCRC being a boundary group that is more related to<br> EOCRC. With respect to symptoms, duration and correlation with stages, IOCRC<br> appeared more similar to EOCRC. Clinically, IOCRC behaves as a transitional group<br> between EOCRC and LOCRC, with features in common with both groups, but also<br> with IOCRC-specific features. Excluding cases with familial cancer history, the<br> awareness for EOCRC diagnosis should be extended to IOCRC.</p>