P-0279 - Ordinary rectal adenocarcinoma vs. primary rectal signet-ring cell carcinoma
|Date||28 June 2014|
|Event||World GI 2014|
|Topics|| Rectal Cancer
|Citation||Annals of Oncology (2014) 25 (suppl_2): ii14-ii104. 10.1093/annonc/mdu165|
Primary colorectal signet-ring cell cancer is a rare but distinctive primary neoplasm of the large bowel with still-controversial clinicopathologic features. There is little information comparing signet-ring cell carcinoma to common non-signet-ring cell rectal cancers. The aim of this study was to better define the clinicopathologic differences between these two distinct entities.
The data of 10 patients with primary rectal signet-ring cell carcinoma were compared with those of 157 consecutive patients with primary non-signet-ring cell rectal adenocarcinoma between January 2012 and December 2013. Signet-ring cell carcinoma lesions were those in which signet-ring cells constituted more then 50 percent of the tumor. For outcome analysis patients, after curative resection of signet-ring cell cancer, were matched for age, gender, tumour site and stage with patients suffering from poorly differentiated non-signet-ring cell rectal adenocarcinoma.
Mean age of the signet-ring cell carcinoma group was 46 +/- 9,4 years and median age was 52 (range, 32-56) years. Male-to-female ratio was 1.1. Lymphatic and peritoneal spread was more common among the signet-ring cell carcinoma group. Signet-ring cell carcinoma patients were significantly younger than patients with non-signet-ring cell colorectal adenocarcinoma (median age 52 years vs 64 years, P = 0.022). The most common tumour sites were the low rectum (45%). They presented with significantly more advanced tumour stages and a significantly higher frequency of distant metastases (48% vs 18%, P = 0.003).
Signet-ring cell cancer represents a rare but distinctive primary neoplasm of the large bowel. It is frequently diagnosed in an advanced tumor stage, thus showing an overall poorer prognosis than non signet rectal carcinoma. Usually only palliative surgery is possible. A high incidence of peritoneal seeding and a low incidence of hepatic metastasis is characteristic of signet-ring cell cancer.