Decision making for patients with T1 adenocarcinoma of the low rectum, when treatment options are limited to a transanal local excision or abdominoperineal resection, is challenging.
Dr Calvin Johnston and colleagues developed a contemporary decision analysis to assist patients and clinicians in balancing the goals of maximizing life expectancy and quality of life in this situation.
The team constructed a Markov-type microsimulation in open-source software.
The team of doctors reported that recurrence rates and quality-of-life parameters were elicited by systematic literature reviews.
Sensitivity analyses were performed on key model parameters.
The researchers report that their base case for analysis was a 65-year-old man with low-lying T1N0 rectal cancer.
The team determined the sensitivity of the model for sex, age up to 80, and T stage.
The main outcome measured was quality-adjusted life-years.
The doctors reported that in the base case, selecting transanal local excision over abdominoperineal resection resulted in a loss of 0.53 years of life expectancy but a gain of 0.97 quality-adjusted life-years.
One-way sensitivity analysis demonstrated a health state utility value threshold for permanent colostomy of 0.93.
|An abdominoperineal resection has a 3.5% longer life expectancy|
|Diseases of the Colon & Rectum:|
The research team assessed that this value ranged from 0.88 to 1.0 based on tumor recurrence risk. T
here were no other model sensitivities.
Some model parameter estimates were based on weak data.
Dr Calvin's team commented, "In our model, transanal local excision was found to be the preferable approach for most patients."
"An abdominoperineal resection has a 3.5% longer life expectancy, but this advantage is lost when the quality-of-life reduction reported by stoma patients is weighed in."
"The minority group in whom abdominoperineal resection is preferred are those who are unwilling to sacrifice 7% of their life expectancy to avoid a permanent stoma."
"This is estimated to be approximately 25% of all patients."
"The threshold increases to 12% of life expectancy in high-risk tumors."
"No other factors are found to be relevant to the decision."