Published online May 27, 2019. doi: 10.4240/wjgs.v11.i5.247
Peer-review started: April 2, 2019
First decision: April 20, 2019
Revised: May 9, 2019
Accepted: May 23, 2019
Article in press: May 23, 2019
Published online: May 27, 2019
Driven by remarkable improvements in life expectancy, the world is facing a dramatic increase in the number and proportion of its elderly. The incidence and mortality rates for colorectal cancer (CRC) increases with age, resulting in a greater burden on healthcare. Moreover, the life expectancy of an elderly patient with CRC may depend less on the malignant disease and more on their pre-morbid condition. Data shows that good surgical outcomes can be achieved in the elderly, but individualized evaluation of treatment goals and communication of realistic anticipated outcomes are essential.
With advanced age and chronic illness, the decision to undergo major surgery in the elderly patient can be challenging. Not infrequently, patients and their family members decline operative intervention due to age-related concerns. Even to the surgeon, the benefit of resection in certain individuals may not be so clear-cut. Moreover, the elderly are under-represented and under-prioritized in randomized trials, resulting in difficulty in generalizing existing data. Established risk stratification methods are commonly used but have well described flaws. This motivated us to develop a specific prognostic assessment tool to quantify the risk of mortality and predict survival after surgery in the elderly.
We aimed to analyze our outcomes following major elective colorectal surgery in the elderly to determine factors significantly influencing mortality. A pre-operative scoring system predicting post-operative outcomes more objectively could then be derived, facilitating the decision-making process for both surgeons and patients.
Data for all patients aged 70 and above who underwent elective surgery for non-metastatic CRC at Singapore General Hospital Department of Colorectal Surgery from 1 January 2005 to 31 December 2012 were obtained from hospital electronic records. Patients with evidence of distant disease, those who underwent emergency surgery or had surgery for benign colorectal conditions were excluded from the analysis. Instances of surgery for CRC recurrence occurring in the same patient over the study period were also excluded. Information for an equivalent group of elderly patients electively operated on at Kyungpook National University Chilgok Hospital, Daegu, South Korea, was retrieved over the same duration.
A total of 1267 patients were identified for analysis. The median post-operative length of stay was 8 [interquartile range (IQR) 6-12] d and median follow-up duration was 47 (IQR 19-75) mo. Median OS was 78 (IQR 65-85) mo. Following multivariate analysis, the factors significant for predicting overall mortality were serum albumin < 35 g/dL, serum carcinoembryonic antigen ≥ 20 µg/L, T stage 3 or 4, moderate tumor cell differentiation or worse, mucinous histology, rectal tumors, and pre-existing chronic obstructive lung disease. Advanced age alone was not found to be significant. The Korean cohort consisted of 910 patients. The Singapore cohort exhibited a poorer OS, likely due to a higher proportion of advanced cancers. Despite the clinicopathologic differences, there was successful validation of the model following recalibration. An interactive online calculator was designed to facilitate post-operative survival prediction, available at http://bit.ly/sgh_crc.
Advanced age per se is not a risk factor for poorer survival outcomes and patients should not be denied surgery based on age alone. However, there is a need for more objective pre-operative risk stratification in this vulnerable group of patients. Our novel scoring system predicting mortality following major resection uses parameters which are available before the surgery and can assist in the counselling and decision-making process between surgeons, their patients and families. Validation with an external Asian population strengthens the generalizability of this scoring method.
While it was not possible compare our cohort with cancer patients who had not had surgery over the study duration, this information should be considered for future studies. The dissimilarity in survival between the cohorts may reflect the shortcomings of comparison between the populations of two distinct geographical locations, but eventual validation of the model notwithstanding these variations can be considered a strength. To ensure predictive accuracy of the model, further validation including re-identification of a correction factor with possible recalibration should be undertaken before use in separate populations.