EARLY ONSET COLORRECTAL CANCER: PHENOTYPICAL FEATURES AND ENDOSCOPIC FOLLOW-UP AFTER SURGERY

Aims:

To describe clinical and molecular characteristics of Early Onset Colorectal Cancer (EOCRC, < 45 years) and to identify high-risk groups for recurrence during surveillance after surgery.

Methods:

A retrospective cohort of 121 patients was included. Subgroups were formed according to the moment of detection of polyps in their follow-up at 10 years: Development of polyps at any time during the complete period of surveillance (group A), after 5 years (group B) within the first 5 years (group C) and no development of polyps (group D). Comparison of clinical and molecular variables between groups were made, including APC/p53 mutations and microsatellite instability (IMS).

Results:

Most frequent neoplasia locations were rectum (40.4%), left colon (35.5%) and right colon (23.1%). Primary lesions identified were Carcinoma in situ (CIS) (28,1%) and invasive adenocarcinoma (ADCA) (71, 9%) Non-Lynch familial aggregation was significantly associated to the development of polyps (51.9%, p = 0.001). Groups A and B included most of Lynch Syndrome patients (47.1% and 42.9% respectively). Patients in group A and B also showed greater total and disease-free survival. Group C included primarily patients with CIS and group D patients with ADCA (81.1%, p = 0.006). Patients with local or remote recurrence were distributed in groups C and D, with no differences in primary tumour location or mortality (61.5%). No significant association was identified between patients with APC/p53 mutation or IMS and the development of polyps.

Conclusions:

1. The most frequent locations were rectum and left colon, with histology of invasive ADCA.

2. Familial aggregation seems to be frequently associated with development of polyps

3. No relationship was found between APC, p53 and IMS mutations and development of polyps.

4. Better survival was found in groups with polyps at any time of follow-up or starting after 5 years.