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Our results indicated that histology might be a useful prognostic marker for both early and advanced GC patients, with intestinal-type associated with a better outcome. This information could be used for stratification purpose in future clinical trials.

Tumour budding is associated with worse survival in stage II CRC, in particular in pT3N0M0 patients. It could therefore potentially be used when deciding whether to administer adjuvant chemotherapy in high-risk node negative CRC patients.

Background/Aim: About 15-20% of colorectal cancers (CRCs) have deficiency in a mismatch repair (MMR) protein. MMR has a high level of microsatellite instability (MSI-H). We have conducted this review and meta-analysis to determine the prognostic role of MSI-H status in stage II CRC. Materials and Methods: We searched PubMed, EMBASE, The Cochrane Library, Web of Science, and SCOPUS for studies reporting data on overall survival (OS) and disease-free or relapse-free survival (DFS or RFS) for MSI-H compared to microsatellite stable (MSS) CRC. Results: A total of 39 studies were analysed, including 12,110 patients. MSI-H status was associated with a significantly reduced risk of death (HR=0.64, 95%CI=0.52-0.8, p<0.01) and relapse (HR=0.59, 95%CI=0.45-0.77, p<0.01) in stage II CRC. Conclusion: MSI-H represents an important prognostic determinant in stage II CRC and may be considered when estimating the risk of recurrence in stage II CRC. Stage II colorectal cancer (CRC) is usually associated with a good prognosis; five-year overall survival (OS) rates range from 75 to 87.5% (1). However, the administration of postoperative 5-fluorouracil (5-FU)-based chemotherapy in this group of patients remains controversial, since it has been shown that survival gain generally does not exceed 5% (2). Several prognostic factors have been evaluated in order to identify a high-risk stage II CRC subgroup, for which adjuvant chemotherapy would have a better indication. High-risk features include an inadequate sampling of lymph nodes (less than 12), extension of primary tumor (pT4), poor differentiation (grade 3), acute onset of the disease with obstruction or perforation, lymph-vascular and perineural invasion, and close, indeterminate or positive resection margins (3). Recently, microsatellite instability status (MSI) has been identified as a reliable prognostic indicator in stage II CRC, with an additional role in predicting the lack of benefit of 5-FU-based adjuvant chemotherapy (4-6). These data have been replicated in the large randomized phase III Quick and Simple and Reliable (QUASAR) trial, where 2,291 patients with stage II CRC were randomized to receive adjuvant chemotherapy with 5-FU and folinic acid or to undergo observation. An analysis performed on these patients found a prognostic role for MMR status, even if it was not shown to be predictive of any benefit from adjuvant chemotherapy (6). Although a number of molecular markers of outcome in CRC has been proposed (BRAF/KRAS), there has been no clear consensus about their role in early stage CRC. Despite that a series of studies have investigated the relationship between MSI status and survival in CRC patients, they often included mixed populations of early (stage II-III) and advanced CRCs (stages IV). The aim of our study was to evaluate the prognostic significance of MMR status in stage II CRC by analyzing all the available data coming from prospective and retrospective studies.

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