Choi YH, et al. - Researchers investigated the risk of colorectal cancers (CRCs) in familial colorectal cancer type X (FCCTX) families vs Lynch syndrome (LS) families. The same improved DFS and overall survival seen is association with LS in not seen in those with CRCs occurring in the context of FCCTX, and that variance could be pertinent in deciding management.

Methods

• Researchers used the Colon Cancer Family Registry to identify 168 FCTTX and 780 LS families.
• In these families, they compared the estimates of risk of first and second colorectal cancers (CRCs) and the risk of cancer-related deaths and disease-free survival (DFS) following a first CRC.
• They used a survival analysis approach, developed to model the occurrence of successive cancers (ie, first and second CRCs) during competing risk events (ie, death from any causes).

Results

• In individuals with LS vs FCCTX family members, an excess risk of first and second CRC was documented.
• From FCCTX vs LS families, the observed DFS rates were comparable in men but lower in women for an average age at first CRC of 60 years in FCCTX families and 50 years in LS families, eg, 75.1% (95% confidence interval [CI] = 69.0% to 80.9%) vs 78.9% (95% CI = 76.3% to 81.3%) for the 10-year DFS.
• In FCCTX families vs LS families, a higher 10-year risk of cancer-related death was noted, eg, 15.4% in men (95% CI = 10.9% to 19.8%) and 19.3% in women (95% CI = 13.6% to 24.7%) vs 8.9% (95% CI = 7.5% to 11.4%) and 8.7% (95% CI = 7.1% to 10.8%), respectively.