Clinical, histological and MMR status characterization of early onset rectal cancer; retrospective analysis of 150 cases

ANTELO, MARINA; GOLUBICKI, M; STACH, LUCÍA; CARBALLIDO, MARCELA; MENDEZ, GUILLERMO; ISEAS, SOLEDAD; CABANNE, ANA; ROCA, ENRIQUE; TROTTA, ANDRES; ALAZRAQUI, MARCIO

Auckland

Congreso; International society for gastrointestinal hereditary tumours?InSiGHT - 8th. Biennial Meeting; 2019

International society for gastrointestinal hereditary tumours

Aim: Rectal cancer in patients under 50 years of age has alarmingly increased during the last 20 years in several countries1,2,3. Based on our practice pattern, we also observe this trend at the Oncology Section of our Gastroenterological Hospital in Buenos Aires, Argentina, and believe it may be associated with a prominence of non- familial cases, MSS tumors and signet-ring cell histology. The aim of this study was to evaluate MMR status and it´s association with clinicopathologic features in patients with early onset rectal cancer.Patients and Methods: This is a retrospective cohort study of all patients diagnosed with rectal adenocarcinoma at 49 years old or younger, between 2008 to 2018, using the Lynch syndrome Tumor Screening Program registry. Those cases with MMR status characterization with MSI and/or MMR IHC were included for analysis. Age at diagnosis, CRC family history, synchronous/metachronous CRC and/or adenomas, TNM staging, and histological characteristics suggestive of MSI were the primary outcomes measured.Results: Among 850 patients with Amsterdam or Bethesda clinical criteria evaluated during 2008-2018 at our Program in the Oncology Section of Udaondo Hospital (Buenos Aires, Argentina), 185 patients with rectal cancer