“How long do I have, doctor?” is a question on the minds of many patients diagnosed with metastatic colorectal cancer. In light of a new study published in Annals of Oncology entitled “A Simple Technique to Estimate Best and Worst Case Survival in Patients with Metastatic Colo-rectal Cancer Treated with Chemotherapy,” clinicians may be able to give a more accurate indication of prognoses to their patients.
“Previous work has suggested that clinicians often overestimate prognosis, and we hope that this study and others will provide more objective estimates on which to base discussions with patients and their families,” said lead author Dr. Matt Williams of Imperial College Healthcare NHS Trust, London, in a news story from The Oncology Report. The researchers, who also included Dr. R.A. Singer from Kent and Canterbury Hospital and Dr. A. Lerner from The Royal Surrey County Hospital, wanted to find a simple, accurate method for determining patient survival.
To do so, the team looked at 46 randomized phase 3 clinical trials using chemotherapy in patients with metastatic colo-rectal cancer conducted between 2000 and 2011. Over 29,000 patients in 96 cohorts were represented by the data and were documented for demographics, treatment, and survival. The mean overall survival was 16.8 months.
90%, 75%, 25%, and 10% survival times (the times at which the given percent of patients were alive) were calculated by multiplying the mean overall survival by 0.25, 0.5, 2.0, and 3.0, respectively. These numbers gave a cumulative agreement of 88%, with the estimated survival time falling within 75-133% of the actual survival time.
The worst agreement came from predicting survival at the earliest time (90% patient survival). This was likely due to the narrow time window of defining this point. “Our definition of agreement allows for approximately 5 weeks’ difference between the actual and predicted values, which is a narrow time window and thus more susceptible to random variation,” the researchers stated in the report.
These results are similar to previous work conducted in the cases of breast and lung cancers, despite the differences in patient survival times. “Taken with previous studies, these findings are likely to be valid across a large range of patients,” said Dr. Williams. “We would encourage clinicians to think of prognosis as a trajectory and to consider quoting survival ranges instead of point estimates, in discussions with patients.”
