Biochemical relapse-free survival in 400 patients treated with I-125 prostate brachytherapy: the Guildford experience.

A total of 1200 patients had undergone I-125 prostate brachytherapy (BXT) in our centre. We present prospective outcome data for the first 400 treated patients. Data were analysed from a prospective database of 400 consecutive patients treated with permanent prostate BXT between March 1999 and December 2003. Patients were stratified into low (49%), intermediate (36%) and high (15%) risk as defined by the Memorial Sloan-Kettering Prognostic Index. Patients received 145 Gy BXT alone (41%), BXT with 3 months neoadjuvant androgen deprivation (NAAD) (39%), 45 Gy external beam radiotherapy (EBRT) with 110 Gy BXT (3%) or a combination of NAAD, 45 Gy EBRT and 110 Gy BXT (17%). Biochemical relapse-free survival (bRFS) and prostate-specific antigen (PSA) nadirs were analysed for treatment received in each risk group. Median follow-up was 54 months (range, 38-96 months) with a mean patient age of 63 years. Prostate cancer-specific survival was 99.5%. Twenty-eight patients (7%) experienced biochemical failure according to the 2006 Radiation Therapy Oncology Group-American Society for Therapeutic Radiology and Oncology (RTOG-ASTRO) Phoenix Consensus definition (PSA nadir plus >or=2 ng ml(-1)): nine low-, fourteen intermediate- and five high-risk patients. When stratified by treatment group for low-, intermediate- and high-risk groups, the 5-year actuarial bRFS was 98, 89 and 100% for BXT; 91, 87 and 88% for NAAD and BXT; 100, 80 and 100% for EBRT and BXT; and 100, 92 and 88% for NAAD, EBRT and BXT, respectively. Overall 4- and 5-year PSA

Interstitial low dose rate brachytherapy for prostate cancer--a focus on intermediate- and high-risk disease.

AIMS: To investigate the role of brachytherapy in intermediate- and high-risk prostate cancer. We report our results and a review of published studies. MATERIALS AND METHODS: Between March 1999 and April 2003, 300 patients were treated with low dose rate 1-125 interstitial prostate brachytherapy and followed prospectively. The patients were stratified into low-, intermediate- and high-risk groups and received brachytherapy alone or in combination with external beam radiotherapy (EBRT) and/or neoadjuvant androgen deprivation (NAAD). One hundred and forty-six patients were classified as low risk, 111 as intermediate risk and 43 as high risk. Biochemical freedom from disease and prostate-specific antigen (PSA) nadirs were analysed for risk groups and for treatment received in each risk group. RESULTS: The median follow-up was 45 months (range 33-82 months) with a mean age of 63 years. Actuarial 5-year biochemical relapse-free survival for the low-risk group was 96%, 89% for the intermediate-risk group and 93% for the high-risk group. When stratified by treatment group, low-risk patients had a 5-year actuarial biochemical relapse-free survival of 94% for brachytherapy alone (n=77), 92% for NAAD and brachytherapy (n=66) and 100% for NAAD, EBRT and brachytherapy (n=3). In the intermediate-risk patients, biochemical relapse-free survival was 93% for brachytherapy alone (n=15), 94% for NAAD and brachytherapy (n=67), 75% for EBRT and brachytherapy (n=4) and 92% for NAAD, EBRT and brachytherapy (n=25). In the high-risk group, biochemical relapse-free survival was 100% for brachytherapy alone (n=2), 88% for NAAD and brachytherapy (n=7), 80% for EBRT and brachytherapy (n=5) and 96% for NAAD, EBRT and brachytherapy (n=29). Overall 3- and 4-year PSA = 0.5 ng/ml were achieved by 71 and 86%, respectively, and a 4-year PSA = 0.2 ng/ml was achieved by 63%. CONCLUSION: Although the role of combination treatment with pelvic EBRT and androgen therapy is not clear, our early results show that many patients with intermediate- and high-risk disease have excellent results with brachytherapy.

Biological equivalent dose assessment of the consequences of hypofractionated radiotherapy.

PURPOSE: To investigate the changes in biological effective dose (BED) that occur in high-dose regions within a target volume when radiotherapy is hypofractionated. METHODS AND MATERIALS: By comparing a standard prescription of 2 Gy per fraction that is matched to give the same BED as a hypofractionated schedule at a standard intersectional prescription point, the BED increments for late-tissue effects at a higher dose region within the planning target volume (PTV) are compared. The alternative approach of BED matching between a conventional and hypofractionated schedule at the high-dose region is also considered. The results are presented as a sequence of calculations that can be understood by practicing radiation oncologists and in graphical form. RESULTS: The BED increment at the high-dose region is marginally increased by hypofractionation, although the latter effect is relatively small: up to 5% additional BED due to hypofractionation for a 20% increase in physical dose when the prescribed fraction size is 6-7 Gy. BED matching for late effects between a conventional and hypofractionated schedule at the high-dose region produces lower BED values throughout the remaining PTV, but at the expense of a reduced tumor control BED. CONCLUSION: Clinical trials that use BED isoeffect matching for late reacting tissue effects to design a hypofractioned test schedule should include comprehensive calculations of the likely BED in high-dose regions.