Prognostic Survival Associated With Left-Sided vs Right-Sided Colon Cancer: A Systematic Review and Meta-analysis.

Prognostic Survival Associated With Left-Sided vs Right-Sided Colon Cancer: A Systematic Review and Meta-analysis.

JAMA Oncol. 2016 Oct 27;:

Authors: Petrelli F, Tomasello G, Borgonovo K, Ghidini M, Turati L, Dallera P, Passalacqua R, Sgroi G, Barni S

Abstract
Importance: Primary tumor location is emerging as an important prognostic factor owing to distinct biological features. However, the side of origin of colon cancer (CC) still does not represent a prognostic parameter when deciding for adjuvant or palliative chemotherapy.
Objective: To determine the prognostic role of left vs right-sidedness of primary tumor location in patients with CC.
Data Sources: We searched PubMed, EMBASE, The Cochrane Library, Web of Science, LILACS, CINAHL, and SCOPUS for prospective or retrospective studies reporting data on overall survival for left-sided colon cancer (LCC) compared with right-sided colon cancer (RCC).
Study Selection: Studies were selected if: (1) side of CC was reported among variables entered into survival analysis, (2) survival information was available (overall survival [OS] was reported in the article as hazard ratio (HR) according to multivariate analysis, (3) articles were published in the English language.
Data Extraction and Synthesis: Data were pooled using HRs for OS of LCC vs RCC according to fixed or random-effects models. Subgroup analysis and multivariate random-effects model meta-regression was also implemented adjusting for stage distribution, sample size, race, year of publication, type and quality of studies, and adjuvant chemotherapy.
Main Outcomes and Measures: HRs for OS (the primary outcome measure) were pooled to provide an aggregate value. In this analysis, all HRs with 95% CIs were pooled to obtain prognostic information on the location of the primary tumor (left vs right location site of CC) independent of other common clinicopathological covariates.
Results: An analysis was made from the 66 studies conducted. It included 1 437 846 patients with a median follow-up of 65 months. Left sided primary tumor location was associated with a significantly reduced risk of death (HR, 0.82; 95% CI, 0.79-0.84; P < .001) and this was independent of stage, race, adjuvant chemotherapy, year of study, number of participants, and quality of included studies.
Conclusions and Relevance: Based on these results, CC side should be acknowledged as a criterion for establishing prognosis in all stages of disease. It should be considered when deciding treatment intensity in metastatic settings, and should represent a stratification factor for future adjuvant studies.

PMID: 27787550 [PubMed - as supplied by publisher]

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