Twenty-three studies (n=6678 participants) were included. Sixteen of the studies were retrospective, three prospective, two further potential prospective studies, one treatment programme and one pilot study. Seventeen studies were included in the assessment of complications (n=2928).
Biochemical outcome measures (e.g. PSA):
The majority of studies used the level of prostate specific antigen (PSA) in the blood as an outcome measure. However, the use of this outcome measure is controversial and it may not be a reliable indicator of response to treatment. In the short-term, PSA levels appeared to favour brachytherapy, especially amongst low risk patients. Similarly, brachytherapy combined with EBRT showed short-term improvements. However, both sets of evidence were mainly from uncontrolled or retrospective studies. Of the three studies comparing different treatment modalities, none found any major statistically significant differences between brachytherapy and other treatments.
Clinical outcome measures (e.g. digital rectal examination (DRE), biopsy, bone scans, CT scans):
The results of these studies mirror those of the biochemical studies, but suggest that such outcome measures are less sensitive than clinical methods at detecting recurrance.
Overall survival (n=10 studies):
Due to the relatively short period of follow-up in many studies, survival was often not reported. Only ten studies reported cancer death rates for brachytherapy patients and these were in the 2-3% range with the exception of one study, which showed significantly higher rates. However, this study dealt with recurrent disease.
Complications (n=17 studies):
Complications associated with brachytherapy included mild acute urethritis and proctitis for most patients. Long term complications were restricted to a low percentage of patients and were similar or lower than was observed for EBRT or RP treated patients. Few studies reported effects in terms of impotence. Only one retrospective study directly compared two treatment modalities and this favoured brachytherapy versus CRT. The authors of this study commented that the higher radiation dose in CRT seems to be a risk factor for impotence compared to brachytherapy.
Quality of evidence:
There was a lack of controlled trials, and incomplete reporting, limited comparisons with other treatment modalities, inadequate outcome data and difference in study populations make the assessment of evidence difficult. The methodological quality of the studies in terms of the classification of Jovell and Navarro-Rubio was fair for short-term biochemical survival, but poor for overall survival and complications.