B. Carey

Outcomes Following Iodine-125 Monotherapy for Localized Prostate Cancer: The Results of Leeds 10-Year Single-Center Brachytherapy Experience

PURPOSEnThis study reports the 10-year experience of permanent brachytherapy monotherapy at a single UK center.nnnMETHODS AND MATERIALSnBetween March 1995 and September 2004, 1,298 patients underwent trans-rectal ultrasound (TRUS) planned transperineal brachytherapy delivering 145 Gy using I-125. No patient received supplemental external beam; 44.2% received neoadjuvant hormones. In 688, CT postimplant dosimetry was available. Outcome data were analyzed in terms of overall survival (OS), disease specific survival (DSS), and PSA relapse-free survival (PSA-RFS).nnnRESULTSnThe mean age was 62.9 (range, 34-83) years. Median follow-up was 4.9 years (range, 2.03-11.7 years). OS and DSS were 85% and 95%, respectively, at 10 years. Twenty-one patients died from prostate cancer (1.6%) and 34 (2.5%) from unrelated causes. Seventy-four (5.7%) developed evidence of clinical failure. Overall PSA-RFS was 79.9% and 72.1% at 10 years (American Society for Therapeutic Radiology and Oncology [ASTRO] and Nadir+2 definitions, respectively). Higher presenting PSA or Gleason score and use of neoadjuvant hormones were associated with an increased risk of biochemical failure (p <0.01). Biochemical control was achieved in 86.4%, 76.7%, and 60.6% (ASTRO) and 72.3%, 73.5%, and 57.6% (Nadir+2) of patients in low-, intermediate-, and high-risk groups, respectively. Biochemical control was achieved in 88% of patients with D(90) > or =140 Gy and in 78% of patients with D(90) <140 Gy (p <0.01).nnnCONCLUSIONSnI-125 brachytherapy alone achieved excellent rates of medium-term biochemical control in both low- and selected intermediate-risk localized prostate cancer patients. Postimplant dosimetry improved with experience and longer follow-up, confirming the relationship of D(90) with biochemical control.

Outcomes from Gleason 7, intermediate risk, localized prostate cancer treated with Iodine-125 monotherapy over 10 years

BACKGROUND AND PURPOSEnThe effect of predominating Gleason grade (3+4 versus 4+3) in Gleason sum score (GS) 7 prostate cancer (PCa) on brachytherapy outcomes is unclear. The 10 year experience of permanent brachytherapy monotherapy at a single UK centre for GS 7, intermediate risk (Memorial Sloan-Kettering model), PSA < or = 10 ng/ml, localised PCa is reported.nnnMATERIALS AND METHODSnBetween 1995 and 2004, the outcomes of 187 patients with GS 7 PCa (PSA < or = 10 ng/ml) were analysed from a cohort of 1298 men treated with permanent Iodine-125 prostate brachytherapy, including PSA relapse-free survival (PSA-RFS).nnnRESULTSnMedian follow-up was 5.0 years (range 2.0-10.1 years). One patient has died of PCa. At 10 years, PSA-RFS was 82.4%/78% (ASTRO consensus and nadir +2 definitions). For GS 3+4, 5 year PSA-RFS was 86.7%/87.9% and for GS 4+3: 85.2%/96.6% respectively, with no significant difference between groups. Five year PSA-RFS (ASTRO) of 92.6% was seen for D(90) > or = 140 Gy (50% total), compared with 77.0% below 140 Gy (p=0.08).nnnCONCLUSIONSnIodine-125 brachytherapy monotherapy achieved good rates of medium term biochemical control in GS 7, intermediate risk localised PCa patients. There was a trend to improved outcomes in men with a D90 in excess of 140 Gy.

Second Primary Cancers Occurring after I-125 Brachytherapy as Monotherapy for Early Prostate Cancer

AIMSnProstate brachytherapy may be associated with a lower risk of radiation-induced second primary cancer (SPC) as a significantly smaller volume of normal tissue is irradiated when compared with external beam techniques. Limited data are available as it has been a routine treatment option for less than 20 years. This study identified cases of SPC in patients who underwent I-125 prostate brachytherapy as monotherapy in a single institution.nnnMATERIALS AND METHODSnSPC incidence was retrieved by conducting a UK cancer registry search (Northern and Yorkshire Cancer Registry and Information Service) for 1805 consecutive patients with localised prostate cancer who received monotherapy with I-125 brachytherapy from 1995 to 2006 at a single public hospital. Of 1730 UK residents, the completeness of the registry match was 91% (1574 patients). The mean age at treatment (interquartile range) of the cohort was 63 (58-68) years with 1100 patients (70%) over the age of 60 years at treatment. The median (range) follow-up was 8 (6-10) years with 487 patients (31%) having 10 years or more.nnnRESULTSnIn total, 170 patients (10.8%) were diagnosed with second primaries (1 year or more after implant); 20 of these were bladder and 10 rectal cancers. The 10 year cumulative incidences were 14.6, 1 and 0.84% for any second malignancy, bladder and rectal cancer, respectively. Only the standardised incidence rate (SIR) for bladder cancer was higher at 1.54 (95% confidence interval 0.96-2.46) compared with the general population. The SIR for bladder cancer was higher in the first few years after treatment, suggesting that the increased incidence of bladder cancer is due to increased urological surveillance.nnnCONCLUSIONSnOverall, the incidence of SPC after I-125 is comparable with other published data with no significant excess more than 5 years from treatment. Mortality secondary to SPC of the bladder or rectum is unusual.

The Effect of Dose and Quality Assurance in Early Prostate Cancer Treated with Low Dose Rate Brachytherapy as Monotherapy

AIMSnTo examine the relationship between post-implant computed tomography dosimetry and long-term prostate-specific antigen relapse-free survival in patients treated with iodine 125 (I-125) low dose rate prostate brachytherapy as monotherapy and, second, to audit recent practice against Royal College of Radiologists (RCR) guidelines after the re-introduction of post-implant dosimetry for all patients in our centre.nnnMATERIALS AND METHODSnBetween March 1995 and September 2007, 2157 consecutive patients with localised prostate cancer underwent I-125 permanent prostate brachytherapy as monotherapy in a single UK centre. All patients were transrectal ultrasound planned delivering a 145 Gy (TG 43) minimum peripheral dose. None received supplemental external beam radiotherapy. Post-implant computed tomography-based dosimetry was undertaken between 4 and 6 weeks after treatment and was available for 711 (33%). Outcomes were analysed in terms of the relationship of D90 to prostate-specific antigen relapse-free survival (nadir 2+ definition) and all patients had a minimum follow-up of 5 years. For contemporary patients from 2011, quality metrics from post-implant computed tomography as defined by RCR guidelines are presented.nnnRESULTSnA mean D90 of 138.7 Gy (standard deviation 24.7) was achieved for the historic cohort. Biochemical control at 10 years was 76% in patients with D90 > 140 Gy and 68% in those with D90 < 140 Gy (P < 0.01). In current practice, over the last 3 years the mean (standard deviation) D90 has increased from 154 (15.3) Gy in 2011 to 164 (13.5) Gy in 2013. Similarly, an increase in the mean (standard deviation) V100 from 92 (4.4) to 95 (3.2) % is noted over time. No difference between clinicians was noted.nnnCONCLUSIONnD90 values of less than 140 Gy continue to be predictive of increased risk of recurrence of prostate cancer across risk groups with longer follow-up. Quality assurance can be used to ensure improved and consistent implant quality in a team with multiple clinicians.