Investigation of prognostic factors, treatment modalities, treatment response and survival in stage II colon cancer cases

Introduction and Aim: Colon cancer is a common and deadly malignancy globally, the third most common cancer affecting both men and women. It is known that the stage of the disease is the most important criterion in the prognosis. Surgical resection is the primary treatment option for stage II colon cancer. Adjuvant therapy is not included in the standard treatment approach, its use is variable. In our study, we aimed to investigate the effects of T4 primary lesion, number of lymph nodes in the surgical sample, tumor perforation, intestinal obstruction, lymphovascular invasion, perivascular invasion, positive surgical margin, high grade/poorly differentiated histology, high serum CEA level before surgery, adjuvant chemotherapy protocols applied after surgical resection on prognosis and survival. Materials and Methods: 134 patients diagnosed with stage II colon cancer between 2013 and 2023 were included in the study. The clinical, laboratory and pathological data of the cases, observation after curative surgery and adjuvant chemotherapy protocols, treatment response, survival and their relationship with prognostic factors were discussed. Results: In our study, our parameters with statistical significance as poor prognostic factors; For progression-free survival, preoperative CEA level was >5 (p<0.001), clinical bowel obstruction, tumor perforation (p:0.020), PMS2 loss (p:0.040), perineural invasion (p<0,001). Our statistically significant parameters as poor prognostic factors for overall survival were surgical margin positivity (p:0.002), preoperative CEA level>5 (p:0.010), and recurrence of the disease (p<0.001). In our study, high preoperative CEA level, clinical bowel obstruction, tumor perforation, loss of PMS2, positive surgical margins are seen to be poor prognostic factors and are thought to be effective in adjuvant treatment planning. Conclusion: In our study, in cases with stage II colon cancer with high risk factors, high risk factors in terms of prognosis have significant features on survival, adjuvant chemotherapy application after curative surgical resection did not have a significant statistical benefit in survival, and we think that the decision should be individualized considering the clinical experience of the following oncologist and the patient's decision. Keywords: Stage 2 colon cancer, prognostic factors, adjuvant chemotherapy, progressian-free survival, overall survival