The Study of Mismatch Repair [MMR] Genes and Clinicopathological Risk Factors in Treatment of Stage-II Colon Cancer: Preliminary Report of 2-Year Follow-up at Chulabhorn Hospital
Worawit Chaiwiriyawong MD1, Thaniya Sricharunrat MD2, Wandee Udomchaiprasertkul MSc3, Chutima Rukrung BNS4, Warapan Ratreewijit RN5, Thitiphong Suntharayuth BSc4, Pinitporn Khanpaeng RN5, Vitoon Chinswangwatanakul MD6, Chum-ut Phanthunane MD1, Teerapat Ungtrakul MD7, Wisut Lamlertthon MD, MHSc7, Bunchorn Siripongpreeda MD7
Affiliation : 1 Department of Medical Oncology, Chulabhorn Hospital, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand 2 Department of Pathology, Chulabhorn Hospital, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand 3 Molecular Biology and Genomic Research Laboratory, Division of Research and International Relations, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand 4 Data Management Unit, Division of Research and International Relations, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand 5 Nursing Division, Chulabhorn Hospital, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand 6 Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand 7 Faculty of Medicine and Public Health, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand
Background : Early-stage colon cancer is increasingly detected by colonoscopic screening. The development of adjuvant chemotherapy in patients
with stage-II colon cancer remains a challenge. In Thailand, the clinicopathological risk factors [CPR] are currently used as criteria for the selection
of adjuvant chemotherapy in each patient. Previous reports showed that mismatch repair gene [MMR] status could be a prognostic factor for the
decision on adjuvant chemotherapy.
Objective : To determine the characteristics of MMR status and CPR of Thai colon cancer cases, with treatment follow-up in stage-II colon cancer by
MMR and CPR.
Materials and Methods : This was a preliminary report of patients with stage-II colon cancer who received treatment at Chulabhorn Hospital. MMR
status was determined by microsatellite instability [MSI] testing and CPR was determined in each patient. Patients with deficient MMR and low
CPR received post-surgery surveillance whereas those with proficient MMR and/or high CPR were treated with adjuvant chemotherapy (5-FU/LV).
The follow-up of adverse events, serious adverse events, disease-free survival [DFS], and overall survival [OS] was at the third and fifth years.
Results : During July 4, 2014 to December 31, 2016, there were 31 cases of stage-II colon cancer. All of them were at the stage of T3NoMo (IIA). High
CPR and low CPR were found in 20 cases (64.52%) and 11 cases (35.48%), respectively. There were 28 cases with MMR testing results. Proficient
MMR (MSI-low) was observed in 23 cases (82.14%). There were 3 cases with disease recurrence, all of which were in proficient MMR group and
received adjuvant chemotherapy. Serious adverse events were found in 2 cases with infection during febrile neutropenia after chemotherapy but no
treatment-related death was observed. DFS and OS could not yet be evaluated.
Conclusion : Incidence of proficient MMR (MSI-low) in Thai patients with stage-II colon cancer was comparable to that of other countries (80 to
90%). Treatment by adjuvant chemotherapy using MMR status and CPR was feasible with low serious adverse events.
Keywords : Colon cancer, Mismatch repair gene, Clinicopathological risk factors, MSI, Proficient MMR
