Five-year outcome of intraoperative conformal permanent I-125 interstitial implantation for patients with clinically localized prostate cancer

Stereotactic Radiation Therapy versus Brachytherapy: Relative Strengths of Two Highly Efficient Options for the Treatment of Localized Prostate Cancer

Stereotactic body radiation therapy (SBRT) has become a valid option for the treatment of low- and intermediate-risk prostate cancer. In randomized trials, it was found not inferior to conventionally fractionated external beam radiation therapy (EBRT). It also compares favorably to brachytherapy (BT) even if level 1 evidence is lacking. However, BT remains a strong competitor, especially for young patients, as series with 10-15 years of median follow-up have proven its efficacy over time. SBRT will thus have to confirm its effectiveness over the long-term as well. SBRT has the advantage over BT of less acute urinary toxicity and, more hypothetically, less sexual impairment. Data are limited regarding SBRT for high-risk disease while BT, as a boost after EBRT, has demonstrated superiority against EBRT alone in randomized trials. However, patients should be informed of significant urinary toxicity. SBRT is under investigation in strategies of treatment intensification such as combination of EBRT plus SBRT boost or focal dose escalation to the tumor site within the prostate. Our goal was to examine respective levels of evidence of SBRT and BT for the treatment of localized prostate cancer in terms of oncologic outcomes, toxicity and quality of life, and to discuss strategies of treatment intensification.

Case Report: Role of an Iodinated Rectal Hydrogel Spacer, SpaceOAR Vue™, in the Context of Low-Dose-Rate Prostate Brachytherapy, for Enhanced Post-Operative Contouring to Aid in Accurate Implant Evaluation and Dosimetry

We present a case series of 13 consecutive patients with prostate cancer treated with low-dose-rate (LDR) brachytherapy, utilizing SpaceOAR Vue™, the recent iodinated iteration of the SpaceOAR™ hydrogel rectal spacer. Low- and favorable intermediate-risk patients receiving monotherapy and unfavorable intermediate- and high-risk patients undergoing a brachytherapy boost were included. Permanent brachytherapy can result in subacute and late rectal toxicity, and precise contouring of the anterior rectal wall and posterior aspect of the prostate is essential for accurate dosimetry to confirm a safe implant. Clearly visible on non-contrast CT imaging, SpaceOAR Vue™ can substantially aid in post-implant contouring and analysis. Not previously described in the literature in the context of LDR brachytherapy, we demonstrate the added clinical benefit of placing a well-visualized rectal spacer.

Ten-step method of high-dose LDR 125 I brachytherapy for intermediate-risk prostate cancer

Dose escalation is key for improved outcomes in intermediate‐risk prostate cancer, including unfavorable intermediate‐risk (UIR) cases. This educational report is designed to provide information about our quality high‐dose ¹²⁵I seed implantation monotherapy technique in which a biologically effective dose (BED) ≧ 200 Gy is applied for treatment of intermediate‐risk prostate cancer. This protocol is named the “Ten‐step Method,” where the rationale and principle of the method are based on the following four goals: (1) The entire prostate should be covered by the prescription isodose distribution with a sufficient margin from the prostatic capsule, achieving high D90 and V100 values by ¹²⁵I seed implantation. (2) The high‐dose cloud (240 Gy) should not invade the urethra or rectum. (3) In order to achieve goals (1) and (2), make the high‐dose cloud intentionally along the periphery (bilateral wall to anterior wall) away from the urethra and rectum. (4) In order to achieve goal (3), seeds at the periphery, except those anterior to the rectal wall, should be placed just 1mm inside the capsule. The data obtained from a total of 137 patients with intermediate‐risk prostate cancer treated with low‐dose‐rate (LDR) monotherapy are shown. The dosimetry parameters were monitored at 1 month after seed implantation by using CT and MRI fusion guidance. The data at 1 month after LDR were: Average D90, BED, and V100 of ¹²⁵I LDR monotherapy were 194.1 Gy, 207.3 Gy, and 99%, respectively. This ten‐step method was reproducible in 137 patients with intermediate‐risk prostate cancer, allowing administration of high‐dose monotherapy with excellent clinical outcomes.

Low-Dose-Rate Brachytherapy Combined With Ultrahypofractionated Radiation Therapy for Clinically Localized, Intermediate-Risk Prostate Cancer: Results From a Prospective Trial

PURPOSE

To report early toxicity and tumor control outcomes of Pd-103 brachytherapy with ultrahypofractionated stereotactic radiation therapy (RT) for intermediate-risk prostate cancer.

METHODS AND MATERIALS

This prospective trial included 40 patients with intermediate-risk prostate cancer who underwent low-dose-rate (Pd-103) brachytherapy (prescription dose, 100 Gy), followed 1 month later with ultrahypofractionated stereotactic RT (25 Gy in 5 fractions) to the prostate and seminal vesicles. The primary endpoint was the rate of grade 2+ genitourinary toxicity at 12 months using Common Terminology Criteria for Adverse Events v 4.0. Secondary endpoints included patient-reported quality-of-life metrics (International Prostate Scoring System [IPSS], International Index of Erectile Function, and Expanded Prostate Cancer Index Composite-bowel). Biochemical failure was defined as prostate-specific antigen nadir +2 ng/mL. Posttreatment biopsies were performed at between 24 and 36 months; median follow-up was 36 months.

RESULTS

The rate of grade 2 urinary toxicity at 12 months was 25% with no grade 3 urinary toxicity noted. Mean IPSS at baseline and 12 and 24 months was 5, 10, and 6.2, respectively. Mean change in IPSS from baseline at 12 months was +5.5 (interquartile range, 1-9.75) and +1.05 (interquartile range, -3 to 3.25) at 24 months. Grade 2 bowel toxicity was 5% at 12 months with no grade 3 bowel toxicity noted. Mean Expanded Prostate Cancer Index Composite-bowel domain scores at baseline and 12 months were 92.8 and 90.3, respectively. Of patients who were potent (International Index of Erectile Function ≥21) at baseline, 75% remained potent at 12 months. Of 40 patients, 28 underwent posttreatment prostate biopsy (PPB), which was negative (n = 20) or demonstrated severe treatment effect (n = 8). No patient had a positive PPB or developed biochemical failure during the follow-up period. One patient without a PPB developed osseous metastases at 18 months posttreatment in the absence of biochemical failure.

CONCLUSION

Low-dose-rate brachytherapy in combination with ultrahypofractionated stereotactic RT was safe and effective for intermediate-risk prostate cancer in early results of this trial.

Low dose rate prostate brachytherapy

Low dose rate (LDR) prostate brachytherapy is an evidence based radiation technique with excellent oncologic outcomes. By utilizing direct image guidance for radioactive source placement, LDR brachytherapy provides superior radiation dose escalation and conformality compared to external beam radiation therapy (EBRT). With this level of precision, late grade 3 or 4 genitourinary or gastrointestinal toxicity rates are typically between 1% and 4%. Furthermore, when performed as a same day surgical procedure, this technique provides a cost effective and convenient strategy. A large body of literature with robust follow-up has led multiple expert consensus groups to endorse the use of LDR brachytherapy as an appropriate management option for all risk groups of non-metastatic prostate cancer. LDR brachytherapy is often effective when delivered as a monotherapy, although for some patients with intermediate or high-risk disease, optimal outcome are achieved in combination with supplemental EBRT and/or androgen deprivation therapy (ADT). In addition to reviewing technical aspects and reported clinical outcomes of LDR prostate brachytherapy, this article will focus on the considerations related to appropriate patient selection and other aspects of its use in the treatment of prostate cancer.

A retrospective analysis after low-dose-rate prostate brachytherapy with permanent 125I seed implant: clinical and dosimetric results in 70 patients

Aims and background

To evaluate the biochemical disease-free survival (bDFS) rate after 125I permanent-implant prostate brachytherapy.

Methods

Patients with a diagnosis of prostate adenocarcinoma and adequate PSA follow-up were selected for this retrospective study. Brachytherapy with permanent 125I seeds was performed as monotherapy, with a prescribed dose of 145 Gy to the prostate. Patients were stratified into recurrence risk groups according to the National Comprehensive Cancer Network (NCCN) guidelines. Biochemical failure was defined using the American Society of Therapeutic Radiology and Oncology (ASTRO) guidelines. The post-implant D90 (defined as the minimum dose covering 90% of the prostate) was obtained for each patient. Two cutoff points were used to test the correlation between D90 and bDFS results: 130 Gy and 140 Gy. bDFS was calculated from the implant date to the date of biochemical recurrence. Univariate and multivariate analysis were performed using the SPSS software and included clinical stage, pretreatment PSA, Gleason score (GS), androgen deprivation therapy, D90, and risk groups. In the univariate analysis we used a cutoff point of 5.89 ng/mL for PSA and 5 for GS.

Results

From June 2003 to April 2007, 70 patients were analyzed. The patients' distribution into recurrence risk groups was as follows: 39 patients (56%) in the low-risk group, 23 patients (33%) in the intermediate-risk group, and 8 patients (11%) in the high-risk group. At a median follow-up of 47 months (range, 19–70 months) bDFS was 88.4%, with a global actuarial 5-year bDFS of 86%. Disease-related factors including initial PSA level, GS and risk group were significant predictors of biochemical failure (P = 0.01, P = 0.01, P = 0.006, respectively). In multivariate analysis, risk group (P = 0.005) and GS (P = 0.03) were statistically significant.

Conclusion

Our data are in agreement with those in the literature and, despite the short follow-up, confirm the advantage of brachytherapy for patients at low and intermediate risk of recurrence.

[Toxicity and quality of life comparison of iodine 125 brachytherapy and stereotactic radiotherapy for prostate cancers]

Quality of life is a major issue for good prognostic prostate cancer, for which brachytherapy is one of the reference treatments. Stereotactic Body Radiotherapy (SBRT) is a recent alternative however not yet validated as a standard treatment. This review of the literature reports and compares the toxicities and the quality of life, either after exclusive brachytherapy with iodine 125 or after SBRT. The comparison is made with the limitations of the absence of randomized trial comparing the two treatment techniques. Acute toxicity appears to be lower after SBRT compared to brachytherapy (from 10 to 40 % versus 30 to 40 %, respectively). Conversely, acute and late gastrointestinal toxicity (from 0 to 21 % and from 0 to 10 % of grade 2, respectively) appears more frequent with SBRT. Late urinary toxicity seems identical between both techniques (from 20 to 30 % of grade 2), with a possible urinary flare syndrome. Both treatments have an impact on erectile dysfunction, although it is not possible to conclude that a technique is superior because of the limited data on SBRT. SBRT has better bowel and urinary (irritation or obstruction) quality of life scores than brachytherapy; while sexual and urinary incontinence remain the same. The absence of randomized trial comparing SBRT with brachytherapy for prostate cancers does not allow to conclude on the superiority of one technique over another, thus justifying a phase III medicoeconomic evaluation.

Evaluation of the Effects of Prostate Radiation Therapy on Occludin Expression and Ultrasonography Characteristics of the Bladder

PURPOSE

To evaluate the effects of radiation dose in prostate radiation therapy (RT) on occludin expression and ultrasonography characteristics of the bladder.

METHODS AND MATERIALS

Urine samples of 64 prostate RT patients were collected before, at regular intervals during, and 3 months after RT. Occludin expression analysis was performed, and bladder wall echogenicity and echotexture were investigated by ultrasound and the gray-scale histogram analysis method. The bladder equivalent uniform dose (EUD) was derived from individually produced dose treatment plan for each patient. Clinical scoring for bladder-specific symptoms was done using the Radiation Therapy Oncology Group Acute Radiation Morbidity Scoring Criteria Scale.

RESULTS

Thirty patients (47%) experienced at least 1 of the studied bladder symptoms (grade ≥1 endpoints), including urinary pain, frequency, urgency, straining, incontinence, hematuria, dysuria, and nocturia. For these patients there were significant changes in urine occludin levels after starting the treatment compared with the baseline urine samples (P=.023). The mean bladder EUD that caused a significant change in occludin level, which occurred after the 15th RT session, was 26.9 Gy (range, 13.2-36.5 Gy, P=.020). In all patients a significant reduction in bladder echogenicity (P=.0137) and a significant change in its echotexture (P=.047) was found after the 10th RT session, after which the EUD to the bladder reached 17.9 Gy (range, 8.8-24.3 Gy).

CONCLUSIONS

Significant changes in occludin expression level and bladder wall echogenicity and echotexture occurred during prostate RT. Our findings suggest that a significant reduction in bladder echogenicity and increase in occludin expression during treatment can be associated with acute urinary complications.

Quantitative analysis of genitourinary toxicity after iodine-125 brachytherapy for localized prostate cancer: Followup of the International Prostate Symptom Score and Overactive Bladder Symptom Score

PURPOSE

To analyze genitourinary toxicity by followup of the International Prostate Symptom Score (IPSS) and Overactive Bladder Symptom Score (OABSS) after prostate brachytherapy.

METHODS AND MATERIALS

Six hundred eighty patients were treated with iodine-125 brachytherapy for localized prostate cancer. IPSS, OABSS, and two categories of IPSS questions (storage symptom score [IPSS-S] and voiding symptom score [IPSS-V]) were evaluated.

RESULTS

The median followup was 54 months (range, 24-108). All scales showed rapid increases followed by gradual decreases. The median times to IPSS peak and resolution were 1 and 6 months, respectively. The resolution rates of IPSS, IPSS-S, IPSS-V, and OABSS at the last followup were 84.2%, 86.3%, 89.5%, and 83.0%, respectively. The difference between IPSS baseline and peak was greater for larger preimplant prostate volumes (≥25 mL, p = 0.004). The time to resolution was longer for higher biologic effective dose (BED) (≥210 Gy, p = 0.019 [IPSS]), in those with larger prostate volumes (≥25 mL, p = 0.025 [OABSS]), in younger patients (younger than 70 years, p = 0.043 [IPSS-S]), and in those with androgen deprivation therapy (ADT) use (p = 0.049 [IPSS-V]). Urge incontinence, included in the OABSS, was observed more commonly in older patients (75 years and older, p = 0.018), with ADT use (p < 0.001), and for higher BED (≥210 Gy, p = 0.006).

CONCLUSIONS

The IPSS and OABSS showed similar patterns of change. Urinary symptoms improved more rapidly in those with high baseline IPSS levels. The OABSS was useful for following urinary symptoms after prostate brachytherapy. Age, ADT use, preimplant prostate volume, and BED were significantly associated with urinary outcomes.

Institutional long-term outcomes at the first Canadian center performing intraoperatively planned low-dose-rate brachytherapy alone in low- and intermediate-risk prostate cancer

PURPOSE

The aim of this study is to report the long-term outcomes and toxicities from a large cohort of patients with localized prostate cancer treated with low-dose-rate intraoperatively planned brachytherapy.

METHODS AND MATERIALS

Prostate-specific antigen levels, urinary symptoms, and erectile function were recorded at baseline, and each followup visit was then entered into a prospective database. Urinary toxicity requiring procedural intervention was retrospectively verified using an integrated electronic medical system. A separate cross-sectional survey was performed to measure postimplant sexual function.

RESULTS

A total of 822 patients with low and favorable intermediate-risk prostate cancer were treated at our institution between 2003 and 2013. The Kaplan-Meier estimates for biochemical recurrence for our cohort were 95% and 87% at 5 and 10 years, respectively. Cystoscopy, transurethral resection of prostate, or dilatation was required for 7.1% of 720 patients with more than 2 years of followup. At a median followup of 3.7 years, 64.4% of patients retained adequate erectile function for intercourse, with 54% of patients who were no longer sexually active postimplant reporting social factors as the primary reason.

CONCLUSIONS

Our institutional experience with intraoperative low-dose-rate prostate brachytherapy yielded excellent long-term results with a low incidence of urinary and sexual toxicity.

Comparative study of late rectal toxicity in prostate cancer patients treated with low-dose-rate brachytherapy: With or without supplemental external beam radiotherapy

PURPOSE

Supplemental external beam radiation therapy (sEBRT) is often prescribed in men undergoing low-dose-rate (LDR) brachytherapy. A population of patients was analyzed to assess the effect of sEBRT on late rectal toxicity. It was hypothesized that sEBRT + LDR would be associated with a higher risk of late rectal toxicity.

METHODS AND MATERIALS

This retrospective cohort study examined LDR brachytherapy patients, treated with or without sEBRT, with a minimum of 5-year followup. Longitudinal assessments were evaluated using the computerized patient record system. The Kaplan-Meier method was used for analysis.

RESULTS

Median followup was 7.5 years for 245 patients from 2004 to 2007. sEBRT was administered to 33.5%. Followup beyond 5 years was available for 89%. Overall rates of Grade ≥2 and ≥3 rectal toxicities were 6.9% and 2.9%, respectively. The risk of Grade ≥2 rectal toxicity was 2.8-fold higher for patients receiving sEBRT (95% confidence interval: 1.1-7.2; p = 0.02). The risk of Grade ≥3 rectal toxicity was 11.9-fold higher for patients who received sEBRT (1.5-97.4, 95% confidence interval; p = 0.003). Six of seven patients with a Grade ≥3 rectal toxicity received sEBRT, including one who required an abdominoperineal resection. Median post-LDR D90, V150, V200, and R100 values were 103.3%, 59.4%, 30.1%, and 0.5 cc.

CONCLUSIONS

In a cohort of LDR brachytherapy patients with high rates of followup, sEBRT + LDR was associated with significantly higher risk of Grade ≥2 and ≥3 late rectal toxicity. This analysis supports previous findings and maintains concern about the supplemental use of external beam radiation therapy with LDR brachytherapy while its benefit for tumor control has yet to be prospectively validated.

Long-term outcome of magnetic resonance spectroscopic image-directed dose escalation for prostate brachytherapy

PURPOSE

To report the long-term control and toxicity outcomes of patients with clinically localized prostate cancer, who underwent low-dose-rate prostate brachytherapy with magnetic resonance spectroscopic image (MRSI)-directed dose escalation to intraprostatic regions.

METHODS AND MATERIALS

Forty-seven consecutive patients between May 2000 and December 2003 were analyzed retrospectively. Each patient underwent a preprocedural MRSI, and MRS-positive voxels suspicious for malignancy were identified. Intraoperative planning was used to determine the optimal seed distribution to deliver a standard prescription dose to the entire prostate, while escalating the dose to MRS-positive voxels to 150% of prescription. Each patient underwent transperineal implantation of radioactive seeds followed by same-day CT for postimplant dosimetry.

RESULTS

The median prostate D90 (minimum dose received by 90% of the prostate) was 125.7% (interquartile range [IQR], 110.3-136.5%) of prescription. The median value for the MRS-positive mean dose was 229.9% (IQR, 200.0-251.9%). Median urethra D30 and rectal D30 values were 142.2% (137.5-168.2%) and 56.1% (40.1-63.4%), respectively. Median followup was 86.4 months (IQR, 49.8-117.6). The 10-year actuarial prostate-specific antigen relapse-free survival was 98% (95% confidence interval, 93-100%). Five patients (11%) experienced late Grade 3 urinary toxicity (e.g., urethral stricture), which improved after operative intervention. Four of these patients had dose-escalated voxels less than 1.0 cm from the urethra.

CONCLUSIONS

Low-dose-rate brachytherapy with MRSI-directed dose escalation to suspicious intraprostatic regions exhibits excellent long-term biochemical control. Patients with dose-escalated voxels close to the urethra were at higher risk of late urinary stricture.

Time Course and Accumulated Risk of Severe Urinary Adverse Events After High- Versus Low-Dose-Rate Prostate Brachytherapy With or Without External Beam Radiation Therapy

PURPOSE

Severe urinary adverse events (UAEs) include surgical treatment of urethral stricture, urinary incontinence, and radiation cystitis. We compared the incidence of grade 3 UAEs, according to the Common Terminology Criteria for Adverse Events, after low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy, as well as after LDR plus external beam radiation therapy (EBRT) and HDR plus EBRT.

METHODS AND MATERIALS

Men aged >65 years with nonmetastatic prostate cancer were identified from the Surveillance, Epidemiology, and End Results-Medicare database who were treated with LDR (n=12,801), HDR (n=685), LDR plus EBRT (n=8518), or HDR plus EBRT (n=2392). The populations were balanced by propensity weighting, and the Kaplan-Meier incidence of severe UAEs was compared. Propensity-weighted Cox proportional hazards models were used to compare the adjusted hazard of UAEs. These UAEs were compared with those in a cohort of men not treated for prostate cancer.

RESULTS

Median follow-up was 4.3 years. At 8 years, the propensity-weighted cumulative UAE incidence was highest after HDR plus EBRT (26.6% [95% confidence interval, 23.8%-29.7%]) and lowest after LDR (15.7% [95% confidence interval, 14.8%-16.6%]). The absolute excess risk over nontreated controls at 8 years was 1.9%, 3.8%, 8.4%, and 12.9% for LDR, HDR, LDR plus EBRT, and HDR plus EBRT, respectively. These represent numbers needed to harm of 53, 26, 12, and 8 persons, respectively. The additional risk of development of a UAE related to treatment for LDR, LDR plus EBRT, and HDR plus EBRT was greatest within the 2 years after treatment and then continued to decline over time. Beyond 4 years, the risk of development of a new severe UAE matched the baseline risk of the control population for all treatments.

CONCLUSIONS

Toxicity differences were observed between LDR and HDR, but the differences did not meet statistical significance. However, combination radiation therapy (either HDR plus EBRT or LDR plus EBRT) increases the risk of severe UAEs compared with HDR alone or LDR alone. The highest increased risk of urinary toxicity occurs within the 2 years after therapy and then declines to an approximately 1% increase in incidence per year.

Urinary adverse effects of pelvic radiotherapy

Objective

Radiation is an integral part of the treatment of many pelvic tumors. The cellular death induced by radiotherapy (RT) benefits cancer control but can also result in adverse effects (AEs) on the organ being treated or those adjacent to it. RT for cancers of the pelvis (bladder, prostate, rectum, uterus or cervix) can result in AEs in the urinary tract. While the acute urinary AEs of pelvic RT are well described, late AEs are less well characterized. The burden of treatment for late AEs may be large given the prevalence of tumors in the pelvis and the high utilization of RT to treat them.

Review

For prostate cancer, grade 1 and 2 urinary AEs following external beam radiation therapy (EBRT) are reported to occur in 20-43% and 7-19%, respectively, with a follow up of 10 years. Three-year cumulative risk for grade ≥2 urinary AEs is 28-30%. Following brachytherapy (BT), rates of urinary AEs at 5 years are reported to be 36%, 24%, 6.2% and 0.1% for Radiation Therapy Oncology Group (RTOG) grade 1, 2, 3, and 4, respectively. For bladder cancer, with a median follow-up of 5 years, 7-12% of patients who receive RT experience urinary AEs of grade 3 or more. For cervical cancer, there remains a 0.25% per year risk of severe AEs for at least 25 years following RT, and ureteral stricture is a well-described AE. For endometrial cancer, severe urinary AEs are rare, but at 13 years of follow up, patients report a significantly worse quality of life with respect to urinary function. In rectal cancer, preoperative RT has a lower risk of AEs than postoperative RT, and few urinary AEs are reported in the literature.

Conclusions

Urinary AEs can manifest long after RT, and there is a paucity of studies describing rates of these long-term AEs. It is important that the possible complications of RT are recognized by providers and properly communicated to patients so that they are able to make informed decisions about their cancer treatment.

Urinary and Rectal Toxicity Profiles After Permanent Iodine-125 Implant Brachytherapy in Japanese Men: Nationwide J-POPS Multi-institutional Prospective Cohort Study

PURPOSE

To assess, in a nationwide multi-institutional cohort study begun in 2005 and in which 6927 subjects were enrolled by 2010, the urinary and rectal toxicity profiles of subjects who enrolled during the first 2 years, and evaluate the toxicity profiles for permanent seed implantation (PI) and a combination therapy with PI and external beam radiation therapy (EBRT).

METHODS AND MATERIALS

Baseline data for 2339 subjects out of 2354 patients were available for the analyses. Toxicities were evaluated using the National Cancer Institute's Common Terminology Criteria for Adverse Events, and the International Prostate Symptom Scores were recorded prospectively until 36 months after radiation therapy.

RESULTS

Grade 2+ acute urinary toxicities developed in 7.36% (172 of 2337) and grade 2+ acute rectal toxicities developed in 1.03% (24 of 2336) of the patients. Grade 2+ late urinary and rectal toxicities developed in 5.75% (133 of 2312) and 1.86% (43 of 2312) of the patients, respectively. A higher incidence of grade 2+ acute urinary toxicity occurred in the PI group than in the EBRT group (8.49% vs 3.66%; P<.01). Acute rectal toxicity outcomes were similar between the treatment groups. The 3-year cumulative incidence rates for grade 2+ late urinary toxicities were 6.04% versus 4.82% for the PI and the EBRT groups, respectively, with no significant differences between the treatment groups. The 3-year cumulative incidence rates for grade 2+ late rectal toxicities were 0.90% versus 5.01% (P<.01) for the PI and the EBRT groups, respectively. The mean of the postimplant International Prostate Symptom Score peaked at 3 months, but it decreased to a range that was within 2 points of the baseline score, which was observed in 1625 subjects (69.47%) at the 1-year follow-up assessment.

CONCLUSIONS

The acute urinary toxicities observed were acceptable given the frequency and retention, and the late rectal toxicities were more favorable than those of other studies.

Is it necessary to perform week three dosimetric analysis in low-dose-rate brachytherapy for prostate cancer when day 0 dosimetry is done? A quality assurance assessment

PURPOSE

To determine whether computed tomography/magnetic resonance imaging-based day 0 (d0) dosimetry is a meaningful predictor of day 21 (d21) dosimetry in low-dose-rate brachytherapy for localized prostate cancer.

METHODS AND MATERIALS

The study population consisted of 277 men with localized (T1-2 N0 M0), low-/intermediate-risk prostate cancer treated with low-dose-rate brachytherapy. Computed tomography/magnetic resonance imaging fusion was used for postimplant dosimetry at d0 and d21. Logistic regression was used to construct receiver operating characteristic curves for achieving each constraint at d21, based on d0 D90 and V100, and Youden's index was used to evaluate cutpoints. Freedom from biochemical failure (FBCF) was estimated with the Kaplan-Meier method.

RESULTS

The median d0 D90 increased from 133 to 150 Gy at d21, and median d0 V100 increased from 87% to 91%. For achieving the D90 constraint at d21, the optimal cut-point for d0 D90 was 135 Gy, with 84% of these patients maintaining a d21 D90 > 145 Gy. For achieving the D90 constraint at d21, the optimal cut-point for d0 V100 was 87%, with 83% of these patients maintained a d21 V100 > 90%. There was no improvement in FBCF in patients with a d0 D90 > 135 Gy or D90 > 145 Gy. Similarly, there was no improvement in FBCF in patients with a d0 V100 > 87% or V100 > 90%.

CONCLUSIONS

Meeting dosimetric constraints on d0 does not obviate d21 dosimetric analysis. Constraints used for dose prescriptions on d0 are not the ideal predictors of d21 dosimetry.

A review of rectal toxicity following permanent low dose-rate prostate brachytherapy and the potential value of biodegradable rectal spacers

Permanent radioactive seed implantation provides highly effective treatment for prostate cancer that typically includes multidisciplinary collaboration between urologists and radiation oncologists. Low dose-rate (LDR) prostate brachytherapy offers excellent tumor control rates and has equivalent rates of rectal toxicity when compared with external beam radiotherapy. Owing to its proximity to the anterior rectal wall, a small portion of the rectum is often exposed to high doses of ionizing radiation from this procedure. Although rare, some patients develop transfusion-dependent rectal bleeding, ulcers or fistulas. These complications occasionally require permanent colostomy and thus can significantly impact a patient's quality of life. Aside from proper technique, a promising strategy has emerged that can help avoid these complications. By injecting biodegradable materials behind Denonviller's fascia, brachytherpists can increase the distance between the rectum and the radioactive sources to significantly decrease the rectal dose. This review summarizes the progress in this area and its applicability for use in combination with permanent LDR brachytherapy.

Permanent seed brachytherapy for clinically localized prostate cancer: long-term outcomes in a 700 patient cohort

PURPOSE

Few large European studies have evaluated long-term outcomes for permanent prostate brachytherapy (PPB) as monotherapy for clinically localized prostate cancer. The objective of the present study was to evaluate long-term survival in this patient profile.

METHODS AND MATERIALS

Retrospective study of 700 patients who underwent transperineal ultrasound-guided iodine-125 PPB (145 Gy) between January 2000 and July 2012. Median age was 64.8 years (range, 35-79). Most patients (638 of 700; 91%) had low-risk disease (D'Amico criteria). Eighty-five patients (12%) received hormonal treatment. Overall survival, cause-specific survival, and biochemical relapse-free survival were calculated and estimated using actuarial and Kaplan-Meier methods. Differences between groups were assessed using the log-rank test.

RESULTS

Median followup was 63 months (range, 6-164). At 5- and 10-year followup, respectively, overall survival was 94% (95% confidence interval [CI], 92-96) and 84% (95% CI, 78-90); cause-specific survival was 100% and 97% (95% CI, 95-99); and biochemical relapse-free survival was 95% (95% CI, 93-97) and 85% (95% CI, 79-91).

CONCLUSIONS

The long-term results presented in this report confirm previous studies and provide additional support for the use of PPB in patients with favorable-risk prostate cancer. Seed brachytherapy provides excellent long-term results in this patient profile.

A novel greedy heuristic-based approach to intraoperative planning for permanent prostate brachytherapy

This paper presents a greedy heuristic‐based double iteration and rectification (DIR) approach to intraoperative planning for permanent prostate brachytherapy. The DIR approach adopts a greedy seed selection (GSS) procedure to obtain a preliminary plan. In this process, the potential seeds are evaluated according to their ability to irradiate target while spare organs at risk (OARs), and their impact on dosimetric homogeneity within target volume. A flexible termination condition is developed for the GSS procedure, which guarantees sufficient dose within target volume while avoids overdosing the OARs. The preliminary treatment plan generated by the GSS procedure is further refined by the double iteration (DI) and rectification procedure. The DI procedure removes the needles containing only one seed (single seed) and implements the GSS procedure again to get a temporary plan. The DI procedure terminates until the needles number of the temporary plan does not decrease. This process is guided by constantly removing undesired part rather than imposing extra constrains. Following the DI procedure, the rectification procedure attempts to replace the remaining single seeds with the acceptable ones within the existing needles. The change of dosimetric distribution (DD) after the replacement is evaluated to determine whether to accept or to withdraw the replacement. Experimental results demonstrate that the treatment plans obtained by the DIR approach caters to all clinical considerations. Compared with currently available methods, DIR approach is faster, more reliable, and more suitable for intraoperative treatment planning in the operation room.

PACS number: 87

Late rectal toxicity after low-dose-rate brachytherapy: incidence, predictors, and management of side effects

As clinical outcomes for patients with clinically localized prostate cancer continue to improve, patients and physicians are increasing making treatment decisions based on concerns regarding long-term morbidity. A primary concern is late radiation proctitis, a clinical entity embodied by various signs and symptoms, ranging from diarrhea to rectal fistulas. Here, we present a comprehensive literature review examining the clinical manifestations and pathophysiology of late radiation proctitis after low-dose-rate brachytherapy (BT), as well as its incidence and predictors. The long-term risks of rectal bleeding after BT are on the order of 5-7%, whereas the risks of severe ulceration or fistula are on the order of 0.6%. The most robust predictor appears to be the volume of rectum receiving the prescription dose. In certain situations (e.g., salvage setting, for patients with increased radiosensitivity, and following aggressive biopsy after BT), the risk of these severe toxicities may be increased by up to 10-fold. A variety of excellent management options exist for rectal bleeding, with endoscopic methods being the most commonly used.

In vivo visualization of prostate brachytherapy seeds with photoacoustic imaging

We conducted a canine study to investigate the in vivo feasibility of photoacoustic imaging for intraoperative updates to brachytherapy treatment plans. A fiber coupled to a 1064-nm Nd:YAG laser was inserted into high-dose-rate brachytherapy needles, which diffused light spherically. These needles were inserted through the perineum into the prostate for interstitial light delivery and the resulting acoustic waves were detected with a transrectal ultrasound probe. Postoperative computed tomography images and ex vivo photoacoustic images confirmed seed locations. Limitations with insufficient light delivery were mitigated with short-lag spatial coherence (SLSC) beamforming, providing a 10-20 dB contrast improvement over delay-and-sum (DAS) beamforming for pulse energies ranging from 6.8 to 10.5 mJ with a fiber-seed distance as large as 9.5 mm. For the same distance and the same range of energy densities, signal-to-noise ratios (SNRs) were similar while the contrast-to-noise ratio (CNR) was higher in SLSC compared to DAS images. Challenges included visualization of signals associated with the interstitial fiber tip and acoustic reverberations between seeds separated by ≤ 2 mm. Results provide insights into the potential for clinical translation to humans.

Dosimetric evaluation of clinical target volume in the postimplant analysis of low-dose-rate brachytherapy for prostate cancer

PURPOSE

Brachytherapy is an effective single treatment modality for low- and intermediate-risk prostate cancer. In this study, we defined a clinical target volume (CTV) and evaluated its dosimetry 1 month after the low-dose-rate brachytherapy procedure.

METHODS AND MATERIALS

One hundred ninety-eight consecutive patients treated for prostate cancer by iodine-125 seed brachytherapy were assessed. Prostate dosimetry was stratified according to British Columbia Cancer Agency criteria, with good implants having both V100 (percentage of target volume that receives 100% of the prescribed dose) > 85% and D90 (percentage of the prescribed dose received by 90% of the target volume) > 90%, suboptimal implants with V100 of 75-85%, or D90 80-90%, whereas poor implants were defined as those with V100 < 75 or D90 < 80%. CTV dosimetry stratification was performed according to the same dose coverage criteria, albeit to the CTV.

RESULTS

One hundred ninety-two patients (97%) had good prostate radiation coverage, whereas only 165 patients (83%) had good postimplant CTV dosimetry. Patients with suboptimal vs. good CTV dosimetry had prostate edema of 7.8 ± 0.2% vs. 0.2 ± 0.1%, respectively (p = 0.001).

CONCLUSIONS

Prostate seed implants with optimal dosimetry to prostate may still have suboptimal D90 and V100 for the CTV, especially in the presence of postimplant edema. A consensus is needed for definition and evaluation of CTV in postimplant setting for low-dose-rate prostate brachytherapy.

Do theoretical potential and advanced technology justify the use of high-dose rate brachytherapy as monotherapy for prostate cancer?

Low-dose rate brachytherapy (LDR-BT), involving implantation of radioactive seeds into the prostate, is an established monotherapy for most low-risk and select intermediate- and high-risk prostate cancer patients. High-dose rate brachytherapy (HDR-BT) is an advanced technology theorized to be more advantageous than LDR-BT from a radiobiological and radiophysics perspective, to the patient himself, and in terms of resource allocation. Studies of HDR-BT monotherapy have encouraging results in terms of biochemical control, patient survival, treatment toxicity and erectile preservation. However, there are still certain limitations that preclude recommending HDR-BT monotherapy for prostate cancer outside the setting of a clinical trial. HDR-BT monotherapy should be considered experimental at present.

Combining theoretical potential and advanced technology in high-dose rate brachytherapy boost therapy for prostate cancer

External beam radiation therapy (EBRT) combined with brachytherapy (BT) is an attractive treatment option for select patients with clinically localized prostate cancer. Either low- or high-dose rate BT may be combined with EBRT ('LDR-BT boost,' 'HDR-BT boost,' respectively). HDR-BT boost has potential theoretical benefits over LDR-BT boost or external beam radiation therapy monotherapy in terms of radiobiology, radiophysics and patient convenience. Based on prospective studies in this review, freedom from biochemical failure (FFBF) rates at 5 years for low-, intermediate- and high-risk patients have generally been 85-100%, 68-97%, 63-85%, respectively; late Radiotherapy and Oncology Group Grades 3 and 4 genitourinary and gastrointestinal toxicities are seen in <8% of patients. HDR-BT boost is now a relatively well-established treatment modality for certain intermediate-risk and high-risk prostate cancer patients, though limitations exist in drawing conclusions from the currently published studies.

SIU/ICUD Consultation on Urethral Strictures: Posterior urethral stenosis after treatment of prostate cancer

Posterior urethral stenosis can result from radical prostatectomy in approximately 5%-10% of patients (range 1.4%-29%). Similarly, 4%-9% of men after brachytherapy and 1%-13% after external beam radiotherapy will develop stenosis. The rate will be greater after combination therapy and can exceed 40% after salvage radical prostatectomy. Although postradical prostatectomy stenoses mostly develop within 2 years, postradiotherapy stenoses take longer to appear. Many result in storage and voiding symptoms and can be associated with incontinence. The evaluation consists of a workup similar to that for lower urinary tract symptoms, with additional testing to rule out recurrent or persistent prostate cancer. Treatment is usually initiated with an endoscopic approach commonly involving dilation, visual urethrotomy with or without laser treatment, and, possibly, UroLume stent placement. Open surgical urethroplasty has been reported, as well as urinary diversion for recalcitrant stenosis. A proposed algorithm illustrating a graded approach has been provided.

Five-year outcomes after iodine-125 seed brachytherapy for low-risk prostate cancer at three cancer centres in the UK

OBJECTIVE

To report the outcomes of >1000 men with low-risk prostate cancer treated with low-dose-rate (LDR) brachytherapy at three large UK cancer centres.

PATIENTS AND METHODS

A total of 1038 patients with low-risk prostate cancer (prostate-specific antigen [PSA] ≤10 ng/mL, Gleason score 6, ≤T2b disease) were treated with LDR iodine 125 (I-125) brachytherapy between 2002 and 2007. Patients were treated at three UK centres. PSA and clinical follow-up was performed at each centre. Biochemical recurrence-free survival was reported for the cohort.

RESULTS

The median (range) PSA follow-up for the whole group was 5 years (4 months to 9 years). A total of 79 patients had biochemical failure, defined by a rise in PSA level: 16 patients fulfilled the ASTRO definition of biochemical failure, 25 patients fulfilled the Phoenix definition and 38 patients fulfilled both definitions. The 5-year biochemical relapse-free survival (bRFS) rate was 94.1% by the ASTRO definition and 94.2% by the Phoenix definition. The absence of neoadjuvant hormone therapy was predictive of inferior biochemical control as defined by the Phoenix definition (P = 0.033).

CONCLUSIONS

Our prospective multicentre series showed excellent bRFS with LDR I-125 brachytherapy for patients with low-risk prostate cancer. Further work is necessary to define the role of neoadjuvant androgen deprivation therapy in combination with brachytherapy.

Mid-term outcome of permanent prostate iodine-125 brachytherapy in Japanese patients

OBJECTIVES

To analyze mid-term oncological outcomes of low-dose rate brachytherapy in Japanese patients.

METHODS

Between 2003 and 2010, 604 consecutive patients with clinically localized prostate cancer were treated with low-dose rate brachytherapy at Jikei University Hospital in Tokyo, Japan. Median follow up was 48 months. Of these patients, 260 (43%) were treated with neoadjuvant therapy, 45 (7.5%) with adjuvant hormonal therapy and 75 (12.4%) with supplemental external beam radiation therapy. Biochemical recurrence was defined as the prostate-specific antigen nadir plus 2 ng/mL.

RESULTS

Of the 604 patients, 219 (36.2%) were low risk, 361 (59.8%) were intermediate risk and 24 (4.0%) had high-risk disease. The median biologically effective dose was 174.4 Gy2. At 8 years, biochemical recurrence-free survival, cancer-specific survival, and overall survival were 82.2%, 100% and 95.6%, respectively. Biochemical recurrence-free survival at 8 years was 89.9%, 79.4% and 52.5%, for the low-, intermediate-, and high-risk groups, respectively. Biochemical recurrence-free survival for the high-risk group was significantly lower than the low- and intermediate-risk groups (P < 0.001). Biochemical recurrence-free survival did not differ significantly by biologically effective dose stratification. In multivariate analysis, younger age (P = 0.045), higher prostate-specific antigen (P = 0.004), higher Gleason score (P = 0.006) and higher clinical T stage (P = 0.008) were significant covariates associated with biochemical recurrence. The addition of hormonal therapy or external beam radiation therapy was associated with significantly better outcomes than low-dose rate brachytherapy monotherapy (P = 0.0021 and 0.010). Just four patients experienced G3 genitourinary or gastrointestinal toxicity.

CONCLUSIONS

Low-dose rate brachytherapy results in excellent mid-term oncological outcomes and acceptable toxicity in Japanese patients. In our experience, biologically effective dose does not represent a significant predictor for biochemical recurrence.

Improving prostate brachytherapy quality assurance with MRI-CT fusion-based sector analysis in a phase II prospective trial of men with intermediate-risk prostate cancer

PURPOSE

We combined sector analysis with MRI-CT fusion to comprehensively assess postimplant dosimetry after prostate brachytherapy.

METHODS AND MATERIALS

Subjects were 50 men with intermediate-risk prostate cancer treated with (125)I brachytherapy in a prospective phase II clinical trial. On Day 30 after the implantation, dosimetry was evaluated in the prostate base, midgland, and apex regions on fused MRI-CT scans and CT scans. Volumes of each sector receiving 100% of the prescribed dose (V100) and doses to 90% of each sector (D90) were also calculated on the ultrasonogram used for treatment planning and compared with values derived from CT and fused MRI-CT scans.

RESULTS

Fused MRI-CT scans revealed lower-than-expected doses for the whole prostate (V100=91.3%, D90=152.9Gy) compared with CT scans (98.5% and 183.6Gy, p<0.0001) and lower doses to the prostate base (V100=79%, D90=130Gy) vs. CT (96% and 170Gy, p<0.0001). However, lower doses to the prostate base did not adversely affect biochemical outcomes in men with biopsy-proven disease at the base. At a median followup time of 42 months, the mean prostate-specific antigen level for all patients was 0.3ng/mL, and no patient had experienced biochemical or clinical progression or recurrence.

CONCLUSIONS

MRI-CT fusion-based sector analysis was feasible and revealed significantly lower doses to the prostate base than doses estimated from CT alone, although this did not affect biochemical outcomes. MRI-CT fusion-based sector analysis may be useful for developing MRI-based dosimetric markers to predict disease outcomes and treatment-related morbidity.

Biochemical outcomes for patients with intermediate risk prostate cancer treated with I-125 interstitial brachytherapy monotherapy

BACKGROUND AND PURPOSE

Routine use of I-125 interstitial brachytherapy (BT) alone in intermediate risk (IR) prostate cancer is controversial. It is often combined with external beam radiotherapy (EBRT). The biochemical outcome of a large cohort of only IR disease treated with BT monotherapy is reported.

MATERIALS AND METHODS

Between 2003 and 2007, 615 patients with Memorial Sloan-Kettering Cancer Centre (MSKCC) defined IR disease (one risk factor only-T2b, or Gleason score (GS) 7, or raised initial PSA (iPSA) 10.1-20ng/ml) were treated with BT monotherapy. ASTRO (3 consecutive rises) and Phoenix (nadir plus 2) criteria defined biochemical failure. Potential prognostic factors (pre- and post-implant dosimetric indices, GS 3+4 versus 4+3, androgen deprivation therapy (ADT)) were analysed.

RESULTS

Median follow-up was 5.0years. Forty-three patients had stage T2b, 180 had raised iPSA, 392 had GS 7 disease. ADT was received by 108 patients. The 5-year biochemical no evidence of disease (bNED) rates are 87.3% (by ASTRO), 88.6% (by Phoenix). Stratification by risk factor (T2b, GS7, raised iPSA) demonstrated raised iPSA to have poorer outcome only by Phoenix criteria (p=0.0002). Other potential prognostic variables were non-significant.

CONCLUSION

Good rates of biochemical control can be achieved in the medium term with BT monotherapy in IR disease. Raised iPSA correlated with a poorer outcome.

Treatment outcomes and morbidity following definitive brachytherapy with or without external beam radiation for the treatment of localized prostate cancer: 20-year experience at Mount Sinai Medical Center

OBJECTIVES

To present our treatment algorithm and 20-year experience in treating prostate cancer with brachytherapy since 1990, with focus on cancer-control outcomes and treatment-related morbidity.

METHODS AND MATERIALS

We selected patients treated for localized prostate cancer with brachytherapy, combination therapy with external beam radiotherapy, and adjuvant androgen deprivation therapy as prescribed by our Mount Sinai risk stratification and treatment algorithm. Outcomes were analyzed with respect to biochemical failure, distant metastases, prostate cancer-specific survival, and overall survival. Morbidity was assessed with respect to urinary, sexual, and rectal outcomes.

RESULTS

In total, 2,495 patients met inclusion criteria. The 12-year actuarial freedom from biochemical failure was 83% (low risk: 90%, intermediate risk: 84%, and high risk: 64%); freedom from distant metastasis was 95%; prostate cancer-specific survival was 95%; and overall survival was 70%. On multivariate analysis, significant associations were found between cancer control and risk group, total biologically effective dose, and androgen deprivation therapy. With regard to morbidity, potency was preserved in 61%, and urinary symptoms improved in 35%. The 12-year actuarial freedom from urinary retention events was 90% and from severe rectal bleed was 93%.

CONCLUSIONS

Brachytherapy, as administered via the Mount Sinai algorithm, remains an efficacious and benign treatment option for patients with localized prostate cancer of all risk groups.

Impact of experience and technical changes on acute urinary and rectal morbidity in low-dose prostate brachytherapy using loose seeds real-time implantation

PURPOSE

To assess the impact of experience and technical changes on morbidity during the first year after permanent prostate brachytherapy.

METHODS AND MATERIALS

From July 2003 to May 2010, 150 patients with prostate cancer underwent low-dose iodine-125 prostate brachytherapy as a monotherapy by the same medical team (one urologist and one radiation oncologist). Patients were divided into three periods: P1 (n = 64), P2 (n = 45), and P3 (n = 41) according to technical changes: use of an automatic stepper from P2, use of a high-frequency ultrasound probe in P3. Urinary toxicity was analyzed according to the incidence of acute urinary retention (AUR), Delta International Prostate Symptom Score (Δ IPSS) defined as IPPS maximal - IPSS at baseline, and proportion of patients with Δ IPSS ≥5 and IPSS total >15. The Radiation Therapy Oncology Group classification was used to evaluate the rectal morbidity.

RESULTS

The incidence of AUR (6% overall) decreased significantly with time: 12.5% (8/64) during P1, 2.2% (1/45) in P2, and 0% in P3 (p = 0.014). Mean Δ IPSS (11.6) remained stable during the three periods. Patients with Δ IPSS ≥5 and IPSS total >15 were 58.7%, 58.1%, and 56.1% for P1, P2, and P3 (p = 0.96), respectively. Grade 1 and 2 proctitis were observed in 15.3% and 9.3% of the patients without any significant difference between the three periods.

CONCLUSION

The incidence of AUR decreased significantly with time. This was probably because of the experience of the practitioner and the use of an automatic stepper that allowed reducing prostatic traumatism. Experience and technical changes did not seem to affect rectal morbidity.

Evaluation of dosimetry and excess seeds in permanent brachytherapy using a modified hybrid method: a single-institution experience

Permanent prostate brachytherapy is frequently performed worldwide, and many studies have demonstrated its favorable outcomes. Implant seeds used in this procedure contain a precise amount of radionuclide and are completely sealed. Because these seeds are not manufactured in Japan, they are expensive (6300 yen per seed) and therefore need careful management as a radioisotope. The proper implantation technique requires considerable procedure time, good dosimetric outcomes and simple radioactive isotope management. To evaluate the modified hybrid interactive technique based on these considerations, we assessed 313 patients who underwent hybrid interactive brachytherapy without additional external beam radiotherapy. We evaluated the duration of the procedure, dosimetric factors and the total number of excess seeds. The dosimetric results from computed tomography on Day 30 of follow-up were: 172 Gy (range 130-194 Gy) for pD90, 97.8% (83.5-100%) for pV100, 54.6% (27.5-82.4%) for pV150, 164 Gy (120-220 Gy) for uD90, 194 Gy (126-245 Gy) for uD30, 210 Gy (156-290 Gy) for uD5, 0.02 ml (0-1.2 ml) for rV100 and 0 ml (0-0.2 ml) for rV150. The number of excess seeds was determined by subtracting the number of implanted seeds from the expected number of seeds calculated from previously proposed nomograms. As per our method, nine excess seeds were used for two patients, whereas using the nomograms, the number of excess seeds was approximately eight per patient. Our modified hybrid interactive technique reduced the number of excess seeds while maintaining treatment quality.

Periodical assessment of genitourinary and gastrointestinal toxicity in patients who underwent prostate low-dose-rate brachytherapy

BACKGROUND

To compare the periodical incidence rates of genitourinary (GU) and gastrointestinal (GI) toxicity in patients who underwent prostate low-dose-rate brachytherapy between the monotherapy group (seed implantation alone) and the boost group (in combination with external beam radiation therapy (EBRT)).

METHODS

A total of 218 patients with a median follow-up of 42.5 months were enrolled. The patients were divided into 2 groups by treatment modality, namely, the monotherapy group (155 patients) and the boost group (63 patients). The periodical incidence rates of GU and GI toxicity were separately evaluated and compared between the monotherapy group and the boost group using the National Cancer Institute - Common Terminology Criteria for Adverse Events, version 3.0. To elucidate an independent factor among clinical and postdosimetric parameters to predict grade 2 or higher GU and GI toxicity in the acute and late phases, univariate and multivariate logistic regression analyses were carried out.

RESULTS

Of all patients, 78.0% showed acute GU toxicity, and 7.8% showed acute GI toxicity, while 63.8% showed late GU toxicity, and 21.1% showed late GI toxicity. The incidence rates of late GU and GI toxicity were significantly higher in the boost group. Multivariate analysis showed that the International Prostate Symptom Score (IPSS) before seed implantation was a significant parameter to predict acute GU toxicity, while there were no significant predictive parameters for acute GI toxicity. On the other hand, combination with EBRT was a significant predictive parameter for late GU toxicity, and rectal volume (mL) receiving 100% of the prescribed dose (R100) was a significant predictive parameter for late GI toxicity.

CONCLUSIONS

The boost group showed higher incidence rates of both GU and GI toxicity. Higher IPSS before seed implantation, combination with EBRT and a higher R100 were significant predictors for acute GU, late GU and late GI toxicity.

Segmental dosimetry, toxicity and long-term outcome in patients with prostate cancer treated with permanent seed implants

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: The development of side effects characteristic for the different treatment methods with impact on the patients' quality of life plays a growing role for individual patients with early stage prostate cancer. Using permanent brachytherapy a high dose to the prostate can be applied with a steep dose gradient to the normal tissue. However, small partial volumes of normal tissue may be exposed to high doses inducing special side effects including lower urinary tract symptoms and/or erectile dysfunction. In the literature there are only few publications so far regarding segmental dosimetry and its influence on side effects and the results are conflicting. We could not identify any dosimetric parameter in segmental dosimetry that may have an influence at certain time intervals on the development of side effects such as lower urinary tract symptoms or erectile dysfunction. However, we could state clearly that the preoperative situation is the most important factor for postoperative outcome.

OBJECTIVE

To report on the side effects of patients with low to low-intermediate risk prostate cancer treated with permanent interstitial brachytherapy with special emphasis on segmental dosimetry.

PATIENTS AND METHODS

A series of 186 consecutive patients treated for early stage prostate cancer receiving definitive I-125 brachytherapy (permanent seed implantation) between November 2001 and April 2005 at our institution were examined for the development of side effects. Morbidity was assessed prospectively using the International Prostate Symptom Score (IPSS) and the International Index of Erectile Function (IIEF-5) in a mean follow-up interval of 30 months. The scores were correlated with segmental dosimetry performed 6 weeks after the implantation.

RESULTS

The mean postoperative dose to 90% of the prostate volume (D90) was 180.2 Gy, the mean preoperative IPSS 7.2 and the mean IIEF-5 14.35, with all scores showing a maximum deterioration after 6 weeks with normalization after 24 months. After correlating the segmental dosimetry and the scores at different time intervals, only the baseline scores remained statistically significant in multivariate regression analysis at all time intervals (P < 0.00).

CONCLUSIONS

We could not demonstrate a correlation of segmental dosimetry with induction of side effects. There is no relationship between dose exposure of partial volumes and the development of radiation-induced toxicities. The preoperative situation regarding lower urinary tract symptoms and erectile function are the most important factors for postoperative outcome.

Stereotactic body radiation therapy for prostate cancer: is the technology ready to be the standard of care?

Prostate cancer is the second most prevalent solid tumor diagnosed in men in the United States and Western Europe. Stereotactic body radiation therapy (SBRT) is touted as a superior type of external beam radiation therapy (EBRT) for the treatment of various tumors. SBRT developed from the theory that high doses of radiation from brachytherapy implant seeds could be recapitulated from advanced technology of radiation treatment planning and delivery. Moreover, SBRT has been theorized to be advantageous compared to other RT techniques because it has a treatment course shorter than that of conventionally fractionated EBRT (a single session, five days per week, for about two weeks vs. eight weeks), is non-invasive, is more effective at killing tumor cells, and is less likely to cause damage to normal tissue. In areas of the US and Europe where there is limited access to RT centers, SBRT is frequently being used to treat prostate cancer, even though long-term data about its efficacy and safety are not well established. We review the impetus behind SBRT and the current clinical evidence supporting its use for prostate cancer, thus providing oncologists and primary care physicians with an understanding of the continually evolving field of prostate radiation therapy. Studies of SBRT provide encouraging results of biochemical control and late toxicity. However, they are limited by a number of factors, including short follow-up, exclusion of intermediate- and high-risk patients, and relatively small number of patients treated. Currently, SBRT regimens should only be used in the context of clinical trials.

Risk factors for rectal bleeding associated with I-125 brachytherapy for prostate cancer

The purpose of this study was to determine the risk factors for rectal bleeding after prostate brachytherapy. Between April 2005 and September 2009, 89 patients with T1c-2cN0M0 prostate cancer were treated with permanent I-125 seed implantation alone. The prostate prescription dose was 145 Gy, and the grade of rectal bleeding was scored according to the Common Terminology Criteria for Adverse Events version 4.0. Post-treatment planning was performed with fusion images of computerized tomography and magnetic resonance imaging 4-5 weeks after brachytherapy. Patient characteristics and dosimetric parameters were evaluated to determine risk factors for bleeding. The calculated parameters included the rectal volume in cubic centimeters that received >50-200% of the prescribed dose (RV50-200) and the minimal doses received by 1-30% of the rectal volume (RD1-30). The median follow-up time was 42 months (ranging 18-73 months). Grade 1 rectal bleeding occurred in 24 (27.0%) patients, but no Grade 2 or severe bleeding was observed. Usage of anticoagulants had a significant correlation with the occurrence of bleeding (P = 0.007). The RV100-150 and RD1-10 were significantly higher in patients with rectal bleeding than in those without bleeding. The RV100 was identified as a possible threshold value; the 3-year rectal bleeding rate in patients with an RV100 > 1.0 cm(3) was 36%, whereas that with an RV100 ≤ 1.0 cm(3) was 14% (P < 0.05). Although no Grade 2 morbidity developed in this study, the RV100 should be kept below 1.0 cm(3), especially in additional dose-escalated brachytherapy.