A novel prognostic prediction model for recurrence in patients with stage II colon cancer after curative resection

Abstract

The present study aimed to clarify the risk factors for recurrence of stage II colon cancer in patients and to determine possible treatment options for postoperative adjuvant chemotherapy. A prediction model for recurrence in patients with stage II colon cancer after curative surgical resection was developed. The present study retrospectively investigated 436 patients who underwent curative resection for stage II colon cancer at Osaka International Cancer Institute and Yao Municipal Hospital between 2004 and 2012. Several clinicopathological factors were examined and the Cox regression model was used to develop a prediction model for recurrence. The prediction model was validated in an independent group of 213 patients who underwent surgery at Osaka University Hospital between 2001 and 2012. Univariate analysis revealed that preoperative serum carcinoembryonic antigen level, preoperative obstruction, tumor invasion, lymphatic invasion and venous invasion were significantly correlated with disease-free survival. Using these variables, a classification and regression tree was constructed as a prediction model. The prediction models were validated by external datasets in an independent patient group. The concordance indices for DFS after current surgical resection were 0.675 in the learning set and 0.552 in the validation set. To conclude, a novel, reliable and personalized prognostic model was developed to predict recurrence in patients with stage II colon cancer, which may help clinicians to determine and perform adjuvant chemotherapy.

Keywords: CART; adjuvant chemotherapy; prediction model; recurrence; stage II colon cancer.

Figure 1.

Kaplan-Meier survival curve for disease-free survival in patients with stage II colon cancer. The curve was plotted and compared with the generalized log-rank test. The median follow-up time was 4.67 years and the 5-year disease-free survival was 89.2%.

Figure 2.

CART to predict disease-free survival after curative surgical resection for stage II colon cancer. Preoperative serum CEA level, tumor invasion, lymphatic invasion and venous invasion were used to classify subgroups. This tree was subjected to Kaplan-Meier analysis and compared with log-rank test statistics for recurrence of CRC, and was subsequently separated into six nodes. Each node suggested each other risk. CART, classification and regression tree; CEA, carcinoembryonic antigen; CRC, colorectal cancer; v status, venous invasion status; ly status, lymphatic invasion status.

Figure 3.

Kaplan-Meier survival curve for disease-free survival in subgroups. There were five subgroups and the 5-year disease-free survival rate was 96.6% in group 1, 85.1% in group 2, 87.8% in group 3, 88.7% in group 4, 81.3% in group 5, and 68.6% in group 6.