At the 2023 ASCO Genitourinary Cancers Symposium, Nicholas Van As, MD, Royal Marsden Hospital, United Kingdom, discusses the results from the PACE-A trial, comparing quality of life outcomes from surgery vs stereotactic body radiotherapy (SBRT) among patients with intermediate-risk localized and low-risk prostate cancer.

Overall, urinary symptoms, such as incontinence, and sexual function were worse for patients who underwent surgery, while bowel symptoms were worse for SBRT.

Transcript:

Good afternoon. My name is Professor Nicholas Van As, and I'm a medical director at the Royal Marsden and consultant clinical oncologist. It was my pleasure to present the results of the PACE-A study at the 2023 ASCO Genitourinary Cancers Symposium last week.

PACE-A is a study comparing surgery with SBRT for patients with intermediate-risk localized and low-risk prostate cancer. The reason we designed PACE-A was we felt men had multiple options for the treatment of localized disease. At the time the Da Vinci robot was becoming widely used and probably in many places was the surgical treatment of choice for prostate cancer. Da Vinci surgery has expanded dramatically since we started in 2011. And at the same time, SBRT was evolving as a treatment for localized prostate cancer — in the early days, mainly on the CyberKnife but has expanded to include treatment on all the other platforms.

We felt that it was really important to compare these treatment modalities, and that it was very important mainly to assess the quality of life issues associated with the different treatments. We do really expect that the cancer outcomes of both these treatment modalities in these patients will be very good. Most of these men luckily, are not destined to die of prostate cancer when they've been appropriately radically treated with either modality. Therefore the quality of life that they have beyond the treatment is really key.

We did expect that urinary symptoms or particularly continence would be likely to be a bit worse with surgery. And bowel symptoms were likely to be a bit worse with the SBRT. We had 2 co-primary endpoints. The first being, continence at 2 years measured by the use of urine pads — any use of urinary pads at 2 years. And then the second was the (Expanded Prostate Cancer Index Composite) EPIC-bowel by the subdomain, which again was measured at 2 years.

We aimed to recruit 234 patients, but we ended up only recruiting 123. What happened during COVID, the recruitment almost ground to a halt, and we had a 2-year period where almost no one was recruited. And the IDMC, the Independent Data Monitoring Committee, reviewed the data and said we were really unlikely to get any further useful information by recruiting another 10 to 20 patients and also unlikely to meet our accrual targets, so suggested we close the study and analyze the data.

And we found on analysis when we compared the co-primary endpoints of incontinence first of all, that for patients who'd had surgery, the rate of wearing pads at 2 years was 46.8% compared to SBRT where the rate was 4.5%. And that was highly statistically significant result. And likewise, when we compared the co-primary endpoints of bowel bother, we used the EPIC subdomain where the best score you can achieve is 100. For surgery, it was 97.3, and the score for SBRT was 88.7. And again, this was significantly different. SBRT was slightly worse than surgery, but actually bowel bother was very, very minor in both groups of patients. Bowel bother was described as "no problem at all" in 87% of patients for surgery and 54% for SBRT. "A very small problem"in 4 patients for surgery and 14 for SBRT. And then "a small problem"for no patients for surgery and 6 for SBRT. Only 1 patient in the study had a moderate problem. So actually mild problems were very minor in both arms of the study, but they were a bit worse in SBRT.

The next thing we looked at was sexual bother. Again, this was using the EPIC subdomain. And again, the best score you can achieve is 100. For surgery it was 29.3 and for SBRT it was 57.7. Again, this was highly significant difference in the results. And that maintained at the two-year period. At the start of treatment, roughly about up to 70% of men in both arms had normal sexual functions. So already 30% had impaired sexual function. There was a big drop in the patients who had surgery and some improvement over time, but it got back to about a score of 25. And likewise, with SBRT, there was a drop and then it improved, but it remained at a score of around 57.

We found generally that overall that the urinary symptoms were obviously worse with surgery, and bowel symptoms were worse with SBRT, and sexual function was worse with surgery. The cancer outcomes from the study will be reported when we reach a 5-year follow-up, but the study isn't powered to determine cancer outcomes. It's been powered as a quality-of-life study.

Source:

Van As NJ, Tree A, Ostler PJ, et al. PACE-A: An international phase 3 randomised controlled trial (RCT) comparing stereotactic body radiotherapy (SBRT) to surgery for localised prostate cancer (LPCa)—Primary endpoint analysis. Presented at 2023 ASCO Genitourinary Cancers Symposium; February 17-19; San Francisco, CA. Abstract 298