Low dose rate (seed) brachytherapy for prostate cancer in men under 60 years

Low dose rate (seed) brachytherapy for prostate cancer in men under 60 years

What did the study show?

Langley et al. reported (Jan 2018) on the outcomes of men treated with seed implant (LDR) brachytherapy. The study suggests that low-dose-rate brachytherapy is a very effective treatment, with excellent long-term control of prostate cancer in men aged ≤ 60 years at time of treatment.

597 patients with a median age of 57 (range 44-60) years were followed up for a median of 8.9 years (1.5- 17.2 years range of follow up). The 10-year relapse-free survival rates (this means the percentage of men who, at 10 years, have no evidence of recurrent cancer) using the Phoenix definition for biochemical failure were as follows:

• 95% for low risk prostate cancer
• 90% for intermediate risk prostate cancer
• 87% for high-risk prostate cancer

Of the 597 men, only six (1%) died from prostate cancer during follow-up.

Erectile function was preserved in 75% of men who were potent before treatment.

Important points to highlight from the study?

1. These results are excellent. It is interesting to note that in Australia, LDR brachytherapy probably would not be used for high risk prostate cancer.

2. The follow up period is reasonably long, but prostate cancer has a long natural history, which means that it can take many years for it to declare itself if it is going to come back, and therefore it takes a long time to know if treatment has been effective.

3. The median follow-up was 8.9 years, but the calculation of biochemical recurrence (a sign of prostate cancer coming back by a continued rise in PSA) was worked-out from a median follow-up of 5.9 years. As we know with many other studies in cancer, the longer the follow up period, the more men may develop recurrent prostate cancer. This is true of any form of treatment, whether it be radical prostatectomy, radiation or brachytherapy.

4.The rate of prostate cancer mortality is very encouraging, but again, follow-up was relatively short, and recurrences and deaths can occur in the period 10-15 years after treatment.

5. Experience is important in prostate brachytherapy. This study reported excellent dosing of the prostate (how much radiation was delivered to the prostate). This can be measured by something called the D90, which indicates the quality of the seed implant. In this study, these values were excellent. In Adelaide, these figures are very carefully assessed by an expert team of radiation physicists after any seed implant.

6. Because this was not a randomised study, one cannot make any direct comparisons between surgery and brachytherapy, and this is an important discussion for any prostate cancer patient. It is ideal if you can discuss your treatment options with someone who is able to offer you both treatments, or at least work in a practice where both treatments are available. This is likely to reduce any bias in advice given to you.

Summary

These are excellent outcomes for both cancer control and preservation of erectile function. LDR brachytherapy is a very good treatment option for younger (or older) men with prostate cancer. The decision about your treatment needs to be discussed in detail with a urologist who can offer both options for treatment.

Langley SM, Soares R, Uribe J, et al. Long-term oncological outcomes and toxicity in 597 men ≤60 years of age at time of low dose rate brachytherapy for localised prostate cancer. BJU Int 2017