New Perspectives in Multiple Primary Colorectal Cancer: A Surgical Approach.

Background: We identify the features of multiple primary colorectal cancer (MPCC), synchronous colorectal cancer (SCRC) and metachronous colorectal cancer (MCRC), and distinguish between the cases that require a more extensive surgery and those where the parameters of SCRC might be important to prevent the development of MCRC.

Methods: We gathered up consecutive individuals with MPCC, 50 for each category, and 100 consecutive individuals diagnosed with 'single' colorectal cancer. Clinical and familiar information was obtained. We classified both SCRC and MCRC according to locations.

Results: MPCC were associated with polyps, both in earlier stages and as sporadic forms. SCRC located in the right colon were most frequently of the mucinous type. MCRC developed SCRC in 24%, along the entire colon, with familiar cancer antecedents. SCRC patients undergoing a total colectomy were younger, with the cancer spread throughout the entire colon and a larger number of polyps, whereas MCRC were predominantly adenomatous polyps. We found 2 risk factors for SCRC that led to the development of MCRC: rectal location and higher number of polyps.

Conclusions: SCRC possibly involves more than an environmental component. MCRC appears to be the producer of polyps that evolve into cancer at different times, emphasising the idea of a genetic predisposition. Studies are required to find biomarkers that define patients with higher risk of developing MCRC within SCRC.