Urinary and rectal complications of contemporary permanent transperineal brachytherapy for prostate carcinoma with or without external beam radiation therapy

Authors


Urinary and Rectal Complications of Contemporary Permanent Transperineal Brachytherapy for Prostate Carcinoma With or Without External Beam Radiation Therapy

We read the recently published article by Sarosdy1 with interest as we participated in the care of the patients referenced by this analysis. This analysis involved an apparent subset of 158 patients taken from our larger experience with this particular urologist that exceeds 500 patients. One problem with this report is that the author tends to follow primarily patients with complications or symptoms and does not have the same follow-up routine for patients who are doing well. This obviously skews the perception and statistics with regard to the incidence of complications.

The main weakness of this analysis is the use of posttreatment procedures as an endpoint. The use and timing of intervention with diagnostic procedures such as colonoscopy or transurethral resection of the prostate (TURP) is often a judgment call. One may have a lower threshold for performing a TURP or colonoscopy depending on one's tolerance for patient phone calls and clinic visits, especially in a private practice setting. Several standardized, validated metrics have been developed to quantify the effect of treatment complications on quality of life; however, none were used in Dr. Sarosdy's analysis.2

In addition, the portrayal of radiation dose in this article is misleading, especially when comparisons of total dose are made using the percentage of the prescribed dose, with the understanding that the prescribed dose is lowered for patients receiving combination therapy.

In discussing the v150 and v200 for these patients (each representing the volume of prostate that received 150% and 200% of the prescription dose, respectively), the author compares preimplant, ultrasound-based design values from other practitioners versus the values in this series as determined from computed tomography scans performed 3–4 weeks after implantation. The conclusions based on this comparison are considered tenuous at best. Different design techniques, the subjectivity associated with determining glandular borders, and resolution of the majority of the edema that results from the implant procedure cannot be neglected in making such a comparison. The lack of correlation between complications and these quantifiers in the literature only serves to highlight the speculative nature of the conclusions of Dr. Sarosdy's article.

It is equally difficult for us to understand the conclusion that rectal complications are related to dose. The only correlation noted between dose and complications presented implies a correlation between the performance of colonoscopies, an elective diagnostic procedure, and dose to the rectum.

The analysis focuses on the potential problems associated with the use of combined modality radiation treatment compared with monotherapy. This comparison has been studied previously by several authors using accepted methods and tools,3–5 with mixed conclusions. The exact risks associated with combination therapy may have yet to be defined, but its effectiveness has not. We must be mindful that prostate brachytherapy as monotherapy remains inappropriate for most patients with high-risk disease and perhaps many patients with intermediate-risk factors. Undertreatment with brachytherapy monotherapy for fear of complications could be considered unethical when other options exist (i.e., external beam radiation monotherapy).

We absolutely agree that good techniques with all cancer treatment regimens are imperative, including brachytherapy and external beam radiation therapy, but our broader experience with greater than 2000 prostate brachytherapy patients has shown that although severe complications do occur, they are quite rare.

It was this conclusion, based on experience and the world literature published to date, that led to the development and recent opening of RTOG (Radiation Therapy Oncology Group) 0232 (of which we are the principal investigators), a randomized, Phase III trial that compares brachytherapy alone with brachytherapy in combination with external beam radiation therapy for patients with intermediate-risk prostate carcinoma. Only after such a scientific study is conducted will we likely ever know the true risks and benefits of these treatments.

Bradley R. Prestidge M.D.*, William S. Bice Ph.D.*, * RTOG 0232, Texas Cancer Clinic, San Antonio, Texas.

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