Prognostic Variables in 1814 Sporadic Colon Cancers: A Review of Experience from a Single Institution from 1999–2005

Abstract

Introduction: Singapore has one of the highest age-standardized incidence rates for colorectal cancer (CRC) at 35.1% in men and 29.9% in women which is almost double that of our neighboring Southeast Asian countries. Surgery is presently the mainstay in treatment of this cancer. This present study evaluates the clinical and prognostic characteristics of sporadic cancers treated by surgical resection in a single institution in an Asian population.Methods: 1814 consecutive patients with CRC from 1999-2005 treated in the Department of Colorectal Surgery in Singapore General Hospital were reviewed. The clinciopathological characteristics of these patients were collected from a prospectively collected database maintained in the department since 1987. Univariate analysis was performed, and survival curves were constructed using the Kaplan-Meier method. Multivariate analysis was carried out on independent prognostic factors that were positive on univariate analysis. Results:All patients had a minimum follow up duration of 5 years unless they were lost to follow up. There were 921 (50.8%) males and 893 (49.2%) females with a median age of 67 years (interquartile range 22-99). The predominant location of the tumour was left-sided ie distal to (and including) the splenic flexure (n=1272, 70%), and the majority presented at an advanced AJCC stage III and IV (n=1018, 56%). The most common site for solitary metastasis is in the liver (n=194, 49%) followed by the lungs (6%). Locoregional recurrence is low at 2.6% (n=46) and distant recurrence is noted at 16.8% (n=297). Disease recurrence are 5.7%, 18.1%, and 27.5% for Stages I, II and III respectively. The median five-year Cancer Specific Survival (CSS) is 58.7 % (95% CI 56.2%-61.2%). On multivariate analysis, a high pre-operative CEA , poorly-differentiated tumour grade, signet ring cell tumours, high tumour stage (T3/T4), nodal disease (N1/N2), presence of both perineural invasion and vascular emboli were all significant factors that worsened CSS. Conclusion:Our dataset confirms the current favourable survival of colonic cancers in our country which is comparable to data from the West. Future challenges in management of patients involve improving staging, selection of high risk of recurrence of patients for closer monitoring and further adjuvant treatment to improve survival and reduce locoregional recurrence.