In a recent study led by Danielle A Bischof, MD of Johns Hopkins and published in JAMA Surgery, the authors propose a new way of estimating disease-free survival for GIST patients – Conditional Disease-free Survival (CDFS). This estimate, which only applies to patients with a primary tumor who have had a complete surgical resection, is different from the other tools that already exist for predicting survival, as it is based on the time the patient has survived post surgery. There are several tools already available such as the National Institutes of Health (NIH) criteria and Memorial Sloan Kettering Cancer Center’s models, which use different criteria for their calculations, including tumor size, location, mitotic rate and other factors.
Findings based on survival over time
In contrast, CDFS varies based on the time the patient has already survived post-surgery, and changes over time. For example, in the study, which was retrospective and looked at 502 patients in seven major US and Canadian academic cancer centers between January 1, 1998 and December 31, 2012, patients who were disease free for one year had an 82% chance of remaining disease-free for an additional three years (i.e. CDFS was 82%). For patients who had been disease-free for three years, the percentage chance of remaining disease-free for an additional three years rose to 89%, and for patients who had been disease-free for five years, the percentage chance of remaining disease-free for an additional three years further increased to 92%. As can be seen by these numbers, the researchers concluded that CDFS improves over time following resection. They noted, “This is valuable information about long-term prognosis to communicate to patients who are disease free after a period following surgery.”
It is important to remember that these are just tools to help inform GIST treatment decisions. Nothing is better than your own judgment and doctor’s guidance.