5-year brachytherapy outcomes vs. predicted surgical outcomes
Posted Jul 28 2010 12:00am
As an adjunct to the 12-year outcome data provided in the immediately preceding report come data from Canada that compare actual 5-year brachytherapy outcome data to predicted 5-year surgical outcome data for the same patients.
Pickles et al. have published this report based on data collected prospectively from their series of 1,254 consecutive patients diagnosed with low- and intermediate-risk prostate cancer and treated with brachytherapy (with or without neoadjuvant hormone therapy) between 1998 and 2005. Patients were deemed to have progressed after brachytherapy if their PSA rose to >0.4 ng/ml or any secondary treatment intervention was provided, so these data are based on a relatively strict definition of disease progression. The Kattan pre-treatment nomogram was then used to calulate predicted outcomes at 5 years for the entire series of patients if they had been treated with surgery as opposed to brachytherapy.
The results of this analysis show the following:
Median follow-up of the patients after brachytherapy is 56 months.
46 percent of the patients were diagnosed with clinical stage T1, and 54 percent with clinical stage T2 cancers.
25 percent of the patients were diagnosed with a Gleason score of 7.
The median PSA of the patients at diagnosis was 6.3 ng/ml (range, 0.3 to 19.6 ng/ml).
58 percent of the patients had low-risk disease at diagnosis, and 41 percent had intermediate-risk disease.
Neoadjuvant androgen deprivation therapy was used for 6 months in 92 percent of patients with intermediate-risk disease and in 46 percent of patients with low-risk disease.
The median PSA of all patients at last follow-up is 0.06 ng/ml.
At 5 years post-brachytherapy, 90.6 percent of patients had no biochemical evidence of progressive disease.
The predicted outcome of surgery in the same set of patients is that 86.8 percent of patients would have had no evidence of progressive disease.
The difference between the actual brachytherapy outcome and the predicted surgical outcome is statistically significant.
Once again, these data help to support the case that for patients with low and intermediate risk disease brachytherapy (when, to a large extent, combined with 6 months of androgen deprivation therapy) may well be a better treatment option than surgery. However, it is also worth asking how many of these patients would have met criteria for active surveillance and may never have needed treatment at all.