Kudos to Juanita Crook and colleagues for attempting to wrestle some scientific sense into recommendations for seed implant brachytherapy for prostate cancer.1
Unfortunately, there are no data from randomized trials on which to base a comparison of brachytherapy with prostatectomy and external beam radiotherapy for early-stage prostate cancer. The literature in the era of prostate-specific antigen (PSA) screening is too immature to allow one to accurately comment on disease-specific survival, with most studies having a follow-up period of 3–4 years after surgery, radiotherapy or brachytherapy.
Although results are promising for brachytherapy as monotherapy for patients at low risk (T1 or T2a tumour, Gleason score of 6 or lower and serum PSA level of 10 μg/L or less), we should remain skeptical about the durability of these results, just as we should be skeptical about the results of surgical and external radiotherapy series in the era of PSA screening.
It is even more difficult to make a recommendation concerning brachytherapy for patients at intermediate risk (T2b tumour, Gleason score of 7 or lower and serum PSA level of 10–20 μg/L). Very few such patients are included in the studies quoted by Crook and colleagues, and continuing evolution of the seed implantation technique is likely to affect outcomes for patients at intermediate risk even more dramatically than for those at low risk. In addition, because the intermediate-risk group encompasses a broad range of patients, any recommendation for the entire group is likely to be an oversimplification. A recent study showed that some patients with one intermediate risk factor do as well with brachytherapy alone as patients in the low-risk group described by Crook and colleagues.2
In my opinion, the authors' statement that “brachytherapy should be offered only to selected patients with favourable disease (T1c or T2a tumour, Gleason score of 6 or lower and serum PSA of 10 μg/L or less)” is too strongly worded for the evidence upon which it is based. It would be more appropriate if the word “only” were left out.
Signature
Ross Halperin
Assistant Professor Department of Radiation Oncology Cross Cancer Institute Edmonton, Alta.
References
- 1.Crook J, Lukka H, Klotz L, Bestic N, Johnston M, and the Genitourinary Cancer Disease Site Group of the Cancer Care Ontario Practice Guidelines Initiative. CMAJ 2001;164(7):975-81. [PMC free article] [PubMed]
- 2.Blasko JC, Grimm PD, Sylsvester JE, Cavanagh W. The role of external beam radiotherapy with I-125/Pd-103 brachytherapy for prostate carcinoma. Radiother Oncol 2000;57(3):273-8.s [DOI] [PubMed]