Authors' objectives

To determine if an optimal method of implantation could be identified, and to compare and contrast techniques currently in use for brachytherapy in the treatment of prostate cancer.

Searching

MEDLINE (January 1, 1985 to August 1, 1998) was searched for articles published in the English language. The MeSH terms used were 'prostatic neoplasms', 'prostatic neoplasms brachytherapy', 'prostatic neoplasms interstitial brachytherapy', and 1985 to 1998.

Study selection

Assessment of study quality

The authors did not state that they assessed validity.

Data extraction

Studies were reviewed and coded by two reviewers.

Methods of synthesis

Results of the review

Fifty-three studies that discussed evaluable techniques of implantation were included in the analysis (included a minimum of 6155 patients).

52% used preoperative ultrasound to determine the target volume to be implanted, 16% used preoperative computerised tomography (CT) scans, and 18% placed seeds with an open surgical technique. An additional 11% of studies placed seeds or needles under ultrasound guidance using interactive real-time dosimetry. The number and distribution of radioactive sources to be implanted or the method used to prescribe dose was determined using nomograms in 27% of studies, a least squares optimisation technique in 11%, or not stated in 35%. In the remaining 26%, sources were described as either uniformly, differentially, or peripherally placed in the gland. To evaluate implant quality, 28% of studies calculated some type of dose-volume histogram, 21% calculated the matched peripheral dose, 19% the minimum peripheral dose, 14% used some type of CT-based qualitative review and, in 18% of studies, no implant quality evaluation was mentioned. Six studies correlated outcome with implant dose. One study showed an association of implant dose with the achievement of a PSA nadir <=0.5. Two studies showed an improvement in biochemical control with a D90 (dose to 90% of the prostate volume) of 120 to 140Gy or higher, and 2 additional studies found an association of clinical outcome with implant dose. One study correlated implant quality with biopsy results. Of the articles included, 33 discussed evaluable treatment results, but only 16 reported findings based upon pre-treatment PSA and biochemical control. Three- to 5-year biochemical control rates ranged from 48% to 100% for pre-treatment PSAs <= 4, 55% to 90% for PSAs between 4 and 10, 30% to 89% for PSAs > 10, <= 20 and < 10% to 100% for PSAs > 20. Due to substantial differences in patient selection criteria (e.g. median Gleason score, clinical stage, pre-treatment PSA), number of patients treated, median follow-up, definitions of biochemical control, and time points for analysis, no single technique consistently produced superior results.

Authors' conclusions

Our comprehensive review of prostate cancer brachytherapy literature failed to identify an optimal treatment approach when studies were analysed for treatment outcome based upon pre-treatment PSA and biochemical control. Although several well-designed studies showed an improvement in outcome with total dose or implant quality, the numerous techniques for implantation and the varied inconsistent methods to specify dose or evaluate implant quality suggest that standardised protocols should be developed to objectively evaluate this treatment approach. These protocols have recently been suggested and, when implemented, should significantly improve the reporting of treatment data and, ultimately, the efficacy of prostate brachytherapy.

CRD commentary

The review includes a clearly stated objective. Some relevant details of primary studies were presented in a tabular format. However, MEDLINE was the only electronic database searched and the search strategy was limited to English language publications which means that some important information may have been missed. No attempt was made to search for unpublished data and the presence of publication bias cannot be ruled out. Information about the methodology of the review process (such as how decisions on the relevance of primary studies were made, and how discrepancies between reviewers were resolved) was very limited and the validity of the included studies was not investigated.

The authors' conclusions seem to follow from the results. However, in view of the above limitations they should be interpreted with caution.

Implications of the review for practice and research

The authors do not state any further implications for clinical practice or research. However, they do note that future treatment protocols for permanent seed implants should be dictated by prospective RCTs and not on the current single-institution treatment programmes.

Bibliographic details

Vicini F A, Kini V R, Edmundson G, Gustafson G S, Stromberg J, Martinez A. A comprehensive review of prostate cancer brachytherapy: defining an optimal technique. International Journal of Radiation Oncology, Biology, Physics 1999; 44(3): 483-491. [PubMed: 10348275]

Indexing Status

Subject indexing assigned by NLM

MeSH

Brachytherapy /methods /standards; Dose-Response Relationship, Radiation; Humans; Male; Prostate-Specific Antigen /blood; Prostatic Neoplasms /blood /radiotherapy; Radiopharmaceuticals /therapeutic use; Radiotherapy Dosage; Treatment Outcome

AccessionNumber

11999001154

Database entry date

30/09/2000

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.