Clinical predictors for sessile serrated polyposis syndrome: A case control study

AIM To compared individuals with serrated polyposis syndrome (SPS) to those with sessile serrated adenoma (SSA) and adenomas in the setting of endoscopists with high adenoma detection rates at a secondary and tertiary academic centre. METHODS Retrospectively we collated the clinical, endoscopic and histological features of all patients with SPS at St Vincent's public and private hospital in the last 3 years. Patients were identified by searching through 2 pathology databases. Variables explored included smoking status, symptoms, and family history of concurrent colorectal cancer, number and location of polyps. Patients with SPS were matched to two cohorts (1) patients with SSA not meeting World Health Organization (WHO) criteria for SPS over 3 years; and (2) patients with exclusively adenomas. The control cases were also matched according to gender and endoscopist. Adenoma detection rates ranged from 25% to 40%. RESULTS Forty patients with SPS were identified and matched with 40 patients in each control group. In total 15452 colonoscopies were performed over the study period which amounts to a prevalence of 1: 384 patients (0.26%) with SPS. Fourteen patients (35%) required more than 1 year to accumulate enough polyps to reach WHO criteria for SPS. The diagnosis of SPS was largely incidental and 5% SPS patients were diagnosed with colorectal cancer over 3 years. The chance of detecting a meta-synchronous adenoma was similar in those with SPS (42%) and those with SSA (55%), P = 0.49. The majority of patients (75%) meeting criteria for SPS were women. The mean age of those with SPS (45 years) was significantly lower than both cohorts with SSA (57 years) and adenomas (63 years), P = 0.01. On univariate analysis cigarette exposure, first-degree family history of colorectal cancer and a high BMI weren't significantly more associated with SPS compared to patients with SSA or patients with adenomas. However, patients with SPS (97%) and patients with SSAs not meeting SPS criteria (98%) were significantly more likely to be Caucasian compared to patients with adenomas (79%), P = 0.01. CONCLUSION The prevalence of SPS in our study was 0.26%. The vast majority of patients diagnosed with SPS were women. As a group, they were significantly younger compared to patients with SSA not meeting WHO criteria and patients with adenomatous polyps by more than a decade. Patients with SPS were no more likely to have a first degree relative with colorectal cancer or smoking history than the other two groups. Patients with serrated polyps were more likely to be Caucasian than patients with adenomas.