***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: Updating the previous review through December 2009 identified 41 additional papers, for a grand total of 278 references. Two-hundred and fourty-two of them were excluded because they analyzed survival (n=27), were repetitive (n=29), letters/reviews (n=71) or had no data (n=115). Thirty-six studies on 12,127 patients remained included: 23 showed a detrimental effect of PBT; 22 used multivariable analyses, and 14 found an independent PBT effect. Pooled estimates of PBT effect on recurrence in randomised studies yielded an OR of 1.42 (95% CI, 1.20 to 1.67) against transfused patients. Stratified meta-analyses confirmed these findings also by site and stage of disease, regardless of timing, type, and in a dose-related fashion, although heterogeneity was detected. Data on surgical techniques was not available for further analysis. This updated meta-analysis confirms the previous findings and supports the association of PBT on the recurrence of curable colorectal cancers. However, since heterogeneity was detected and the effect of surgical technique could not be assessed, a causal relationship cannot still be claimed. Carefully restricted indications for PBT seems necessary.
Output:

This review include 36 studies, identified from 278 references retrieved until December 2009, and report a moderate association between colorectal cancer recurrence and perioperative transfusions, with an OR of 1.42 (95% CI, 1.20 to 1.67). Similar estimates are present in several subgroup meta-analyses, as well as in meta-analyses stratified for known risk factors. These findings support carefully restricted indications for perioperative blood transfusions in colorectal cancer patients operated for cure, and continue to await the results of studies addressing the role of surgeon-related risk factors on the need for transfusion and disease recurrence.