Focal Therapy vs. The Gold Standard

No doubt you’ve heard it before, and for sure you’ll hear it again. Radical prostatectomy (RP) is the “gold standard” of prostate cancer (PCa) treatment. Sounds impressive, right? When most people hear that phrase, they assume it means the best.

However, a standard simply means a baseline against which other things in the same category can be compared. The term originated when gold was the basis for a monetary system in which the value of paper currency and coins could be established.

The reason prostatectomy came to be the baseline for comparing the success of other treatments is simple. It has been around the longest so it has the most robust statistical records in terms of numbers treated and length of followup. Therefore, it makes sense to use RP data as the basis for comparison when you want to measure how long-term cancer control for focal therapy stacks up against that of RP.

The problem is, to date there is no focal treatment that’s been around as long as RP. The first method of ablation to gain acceptance in the late 1990s was cryotherapy (freezing), and it wasn’t long before a small number of urologists and interventional radiologists were cautiously applying it as a focal treatment for carefully chosen patients. What’s interesting is that focal cryo was largely patient-driven. It was patient demand for an alternative to RP—with its side effects that many men viewed as mutilating their manhood—that helped establish focal treatment in general.

All the while that RP remained the dominant treatment for PCa, more technologies were developed that followed on the heels of focal cryo: High Intensity Focused Ultrasound (HIFU) and Focal Laser Ablation (FLA) are the two most common, but photodynamic treatment and TULSA-PRO are gaining traction. However, the “younger” the method, the shorter the follow-up, because new methods haven’t been around long enough to track. It’s hard to compare, say, 6 years of HIFU follow-up with 46 years of RP follow-up.

A comparison study

Thus, I was happy to find an international, multi-center 2021 study that followed matched pairs of focal therapy (FT) patients vs. “gold standard” patients to evaluate cancer control results over a similar timeframe.^[i] The inclusion criteria for patients in this comparison were PSA < 20 ng/ml, Gleason ≤ 4 + 3 and stage ≤ T2c. The team identified 501 focal therapy (FT) cases which had 1 or 2 treatments and met the inclusion criteria; 420 had focal HIFU, and 81 had focal cryo. The team also identified 335 RP cases that met the inclusion criteria. They then matched 246 cases from the FT group with 246 from the RP group so the groups were essentially equivalent. Cancer control was defined as failure-free survival (no recurrence). Compare the results:

	FT group	RP group
Number of cases	246	246
Average age	63.3 years	63.4 years
Average PSA	7.9 ng/ml	7.9 ng/ml
Average follow-up	64 (30-89) months	49 (34-67) months
Avg. failure-free survival at 3 years	91%	86%
Avg. failure-free survival at 5 years	86%	82%
Avg. failure-free survival at 8 years	83%	79%

At first glance, you might think that since the FT group appears to have better failure-free percentages, the study “proved” that FT is better than RP. In fact, however, the differences are not statistically significant—that is, they are statistically comparable. The authors concluded, “In patients with non metastatic low- intermediate prostate cancer, oncological outcomes over 8 years were similar between focal therapy and radical prostatectomy.”

Don’t let that statement disappoint you. It’s actually extremely powerful, because it’s saying that for at least 8 years’ worth of follow-up, the “gold standard” is no better than focal treatment. If anyone should be disappointed, it would be the Old Guard of urologists who originally scoffed at focal treatment, stating that PCa is a multifocal disease, and only a radical, or whole-gland treatment, offers the best chance at cancer-control and disease-free survival.

Now, this study of nearly 500 patients has put the numbers in black and white. I can confidently say that when patients are meticulously qualified as FT candidates, their longevity is on equal footing with RP patients. I also believe that had FLA been one of the focal treatments in this study, the results would have been the same. I’m grateful to the research team members who assembled and analyzed cases from Nov. 2005 – Sep. 2018 in order to construct a side-by-side comparison showing that FT offers non inferior cancer control to patients.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

References

[i] Shah TT, Reddy D, Peters M, Ball D et al. Focal therapy compared to radical prostatectomy for non-metastatic prostate cancer: a propensity score-matched study. Prostate Cancer Prostatic Dis. 2021 Jun;24(2):567-574.