Genealogical tree study as screening method in the Lynch syndrome prior to genetic test

Clinicopathological differences between familial colorectal cancer type X and sporadic cancer in an isolated area of spain

AIM

Very few studies have compared the epidemiological characteristics of patients with familial colorectal cancer Type X (FCCTX) with those of sporadic colorectal cancer (S-CRC). The aim of this study was to compare clinicopathological characteristics and survival between FCCTX and S-CRC in patients from a historically isolated geographical region.

METHOD

A retrospective study was carried out of patients with S-CRC and FCCTX treated in the Canary Islands. Family and personal history of colorectal cancer (CRC) were recorded, together with genetic (microsatellite instability), immunohistochemical and clinical variables.

RESULTS

Forty-eight (10.6%) of 451 patients were classified as FCCTX and the remaining 403 (89.4%) as S-CRC. Age at the diagnosis of tumour was significantly lower in FCCTX than in S-CRC (64.06 ± 12.65 years vs 69.13 ± 10.80 years; P = 0.01; Z = -2.48). Patients with FCCTX had a larger number of synchronous tumours (P = 0.09). Recurrence was significantly higher in FCCTX than in S-CRC (18.7% vs 8.6%; P = 0.01). Survival correlated significantly with the number of first-degree and second-degree relatives with CRC (P = 0.04; OR: 1.368, 95% CI: 1.01-1.84, and P = 0.04; OR: 1.363, 95% CI: 1.08-1.65) and with the total number of cases of CRC in the immediate family (P < 0.01; OR: 1.377, 95% CI: 1.17-1.61). Recurrence-free time was significantly lower in patients with FCCTX (log-rank = 0.01).

CONCLUSION

Significant differences were found in several demographic and clinicopathological variables between patients with FCCTX and patients with S-CRC. These included increased tumour presentation under the age of 50 years and a higher recurrence rate in patients with FCCTX, suggesting an increased risk of CRC in this group.