Rectal toxicity and rectal dosimetry in low-dose-rate (125)I permanent prostate implants: a long-term study in 1006 patients

A Randomized Trial Comparing Quality of Life After Low-Dose Rate or High-Dose Rate Prostate Brachytherapy Boost With Pelvic External Beam Radiation Therapy

PURPOSE

To compare health-related quality of life (QoL) in urinary, bowel, and sexual domains after combined external beam radiation therapy (EBRT) and either low-dose rate (LDR) or high-dose rate (HDR) prostate brachytherapy (BT).

METHODS AND MATERIALS

Eligible men with intermediate or high-risk prostate cancer treated with combined pelvic EBRT and BT were randomly assigned to either HDR (15 Gy) or LDR (110 Gy) boost. International Prostate Symptom Score, Index of Erectile Function, and Expanded Prostate Cancer Composite were collected at baseline, 1, 3, 6, and 12 months, every 6 months to 3 years and then annually along with prostate-specific antigen/testosterone. Fisher's exact test compared categorical variables and the Mann-Whitney U test Expanded Prostate Cancer Index Composite (EPIC) domain scores.

RESULTS

From January 2014 to December 2019, a random number generator assigned 195 men: 108 to HDR and 87 to LDR. Median age was 71 years. Risk group was high in 57% and unfavorable intermediate in 43%. Androgen deprivation (used in 74%) began with 3 months neoadjuvant and continued for median 12 months. Baseline EPIC scores were similar for the LDR/HDR cohorts: 89 and 88 respectively for Genito-urinary; 92 and 93 for Gastro-intestinal. EPIC urinary scores decreased at 1 month for HDR but recovered promptly to a steady state by 6 months. LDR scores reached a nadir at 3 months with slow recovery to 18 months, after which urinary QoL was similar for HDR and LDR. Bowel QOL scores fell in both cohorts reaching respective nadirs at 12 months. HDR patients recovered close to baseline and maintained higher scores than LDR patients to 5 years. The decline for LDR patients remained more than the minimum clinically important difference out to 5 years.

CONCLUSIONS

The patient experience for combined EBRT and prostate BT is improved with HDR BT. Urinary QoL improves over time to be equivalent between the 2 modalities after 18 months, but LDR patients report lasting bowel symptoms.

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.

Biological effective dose in analysis of rectal dose in prostate cancer patients who underwent a combination therapy of VMAT and LDR with hydrogel spacer insertion

This study aimed to evaluate rectal dose reduction in prostate cancer patients who underwent a combination of volumetric modulated arc therapy (VMAT) and low‐dose‐rate (LDR) brachytherapy with insertion of hydrogel spacer (SpaceOAR). For this study, 35 patients receiving hydrogel spacer and 30 patients receiving no spacer were retrospectively enrolled. Patient was treated to doses of 45 Gy to the primary tumor site and nodal regions over 25 fractions using VMAT and 100 Gy to the prostate using prostate seed implant (PSI). In VMAT plans of patients with no spacer, mean doses of rectal wall were 43.6, 42.4, 40.1, and 28.8 Gy to the volume of 0.5, 1, 2, and 5 cm³, respectively. In patients with SpaceOAR, average rectal wall doses decreased to 39.0, 36.9, 33.5, and 23.9 Gy to the volume of 0.5, 1, 2, and 5 cm³, respectively (p < 0.01). In PSI plans, rectal wall doses were on average 78.5, 60.9, 41.8, and 14.8 Gy to the volume of 0.5, 1, 2, and 5 cm³, respectively, in patients without spacer. In contrast, the doses decreased to 34.5, 28.4, 20.6 (p < 0.01), and 8.5 Gy (p < 0.05) to rectal wall volume of 0.5, 1, 2, and 5 cm³, respectively, in patient with SpaceOAR. To demonstrate rectal sum dose sparing, dose‐biological effective dose (BED) calculation was accomplished in those patients who showed >60% overlap of rectal volumetric doses between VMAT and PSI. In patients with SpaceOAR, average BED_sum was decreased up to 34%, which was 90.1, 78.9, 65.9, and 40.8 Gy to rectal volume of 0.5, 1, 2, and 5 cm³, respectively, in comparison to 137.4, 116.7, 93.0, and 50.2 Gy to the volume of 0.5, 1, 2, and 5 cm³, respectively, in those with no spacer. Our result suggested a significant reduction of rectal doses in those patients who underwent a combination of VMAT and LDR with hydrogel spacer placement.

Influence of hydrogel spacer placement with prostate brachytherapy on rectal and urinary toxicity

OBJECTIVE

To determine the influence of rectal hydrogel spacer placement (HSP) on late rectal toxicity outcomes in prostate cancer patients treated with low-dose-rate (LDR) brachytherapy, with or without supplemental external beam radiotherapy (EBRT).

PATIENTS AND METHODS

A total of 224 patients underwent LDR brachytherapy with HSP, as monotherapy or combined with EBRT, between January 2016 and December 2019. Dosimetric variables reflecting the extent of rectal sparing and late rectal toxicity outcomes were evaluated. This spacer cohort was retrospectively compared to a similar patient group (n = 139) in whom HSP was not used.

RESULTS

Hydrogel spacer placement was associated with significantly reduced rectal doses for all dosimetric variables; the median percentage rectal dose to 1 cc of rectum and rectal dose to 2 cc of rectum of the spacer cohort were all significantly lower compared to the non-spacer cohort. The incidence rates of overall (any grade) and grade ≥2 rectal toxicity were lower in patients with HSP compared to patients who did not undergo HSP: 12% and 1.8% vs 31% and 5.8%, respectively. The 3-year cumulative incidence of overall rectal toxicity was significantly lower with HSP than without (15% vs 33%; P < 0.001), corresponding to an overall rectal toxicity reduction on univariable analysis (hazard ratio 0.45, 95% confidence interval 0.28-0.73; P = 0.001). In this patient cohort treated with prostate brachytherapy, none of the urethral dosimetric variables or the presence or absence of HSP was associated with late urinary toxicity.

CONCLUSION

Hydrogel rectal spacer placement is a safe procedure, associated with significantly reduced rectal dose. HSP translates to a decrease in overall late rectal toxicity in patients receiving dose-escalated brachytherapy-based procedures.

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.

Focal low dose-rate brachytherapy for low to intermediate risk prostate cancer: preliminary experience at an Australian institution

Background

Focal treatment for prostate cancer (PCa) is a hybrid approach combining ablative treatment of the involved prostate gland and continued active surveillance (AS) of the unaffected gland. Low dose-rate (LDR) brachytherapy can be used as a lesion-targeted focal therapy, however, further studies are required to support its use. The aim of this study is to evaluate the dosimetry, toxicity and oncological outcomes of men receiving lesion-targeted focal LDR brachytherapy for low to intermediate risk PCa.

Methods

This is a retrospective cohort study of 26 men with unifocal, low to intermediate grade PCa diagnosed on a combination of multiparametric-magnetic resonance imaging (mp-MRI) and targeted plus template transperineal (TP) biopsy, who received focal LDR brachytherapy at a single institution. Brachytherapy involved a single monotherapy implant using iodine-125 seeds to deliver a prescribed dose of 145 Gy to the index lesion.

Results

The mean focal planning target volume (F-PTV) as a percentage of the prostate volume was 24.5%. The percentage of the focal gross tumour volume (F-GTV) receiving 100% of the prescription dose was 100% for 12 patients and ≥98% for 18 patients. The median follow-up for toxicity and biochemical control outcomes was 23.1 [interquartile range (IQR) 19.1–31.3] and 24.2 (IQR 17.9–30.0) months, respectively. Grade 2 urinary and erectile toxicities were reported by 29.2% and 45.8% of patients, respectively, with resolution of urinary symptoms to baseline by last follow-up. There were no grade ≥3 urinary or erectile toxicities or grade ≥2 rectal toxicity. All 21 patients who underwent a repeat mp-MRI and TP biopsy at 12–24 months post-treatment were negative for clinically significant disease and 25 (96.2%) patients were free from biochemical failure (FFBF).

Conclusions

Focal LDR brachytherapy is associated with a favourable toxicity profile and a high rate of control of significant PCa at 12–18 months post-treatment. We have commenced the LIBERATE prospective registry in focal LDR brachytherapy based on the highly encouraging outcomes of this initial experience.

Polyethylene glycol-based hydrogel rectal spacers for prostate brachytherapy: a systematic review with a focus on technique

INTRODUCTION

Radiation dose to the rectum in prostate brachytherapy (PBT) can be reduced by the use of polyethylene glycol (PEG) hydrogel spacers. This reduces the rate of rectal toxicity and allows dose escalation to the prostate. Our objectives were to provide an overview of technique for injection of a PEG hydrogel spacer, reduction in rectal dosimetry, gastrointestinal toxicity and potential complications.

METHODS

We systematically reviewed the role of PEG hydrogel spacers in PBT using the Cochrane and PRISMA methodology for all English-language articles from January 2013 to December 2019. Data was extracted for type of radiotherapy, number of patients, type of PEG-hydrogel used, mean prostate-rectum separation, rectal dosimetry, acute and late GI toxicity, procedure-related complications and the technique used for hydrogel insertion.

RESULTS

Nine studies (671 patients and 537 controls) met our inclusion criteria. Of these 4 used DuraSeal® and 5 used SpaceOAR®. The rectal spacing achieved varied between 7.7-16 mm. Failure of hydrogel insertion was seen only in 12 patients, mostly related to failure of hydrodissection in patients undergoing salvage PBT. Where reported, the rectal D2 cc was reduced by between 21.6 and 52.6% and the median rectal V75% cc was reduced by between 91.8-100%. Acute GI complications were mostly limited to grade 1 or 2 toxicity (n = 153, 33.7%) with low levels of grade 3 or 4 toxicity (n = 1, 0.22%). Procedure-related complications were limited to tenesmus (0.14%), rectal discomfort (1.19%), and bacterial prostatitis (0.44%).

CONCLUSIONS

PEG hydrogel spacers are safe to insert. Gel insertion is easy, fast and has a low rate of failure. These studies convincingly demonstrate a significant reduction in rectal dosimetry. Although the results of spacers in reducing rectal toxicity is promising, these need to be confirmed in prospective randomised trial.

Acute and late side-effects after low dose-rate brachytherapy for prostate cancer; incidence, management and technical considerations

PURPOSE

To review common reported side effects and complications after primary LDR-BT (monotherapy) and discuss some of the technical aspects that could impact the treatment outcomes.

METHODS AND MATERIALS

A literature search was undertaken using medical subject headings (MeSH) complemented by the authors' personal and institutional expertise.

RESULTS

The reported incidence of acute and late grade 2 or above urinary, bowel and sexual side effects is very variable across the literature. The learning curve and the implant quality have a clear impact on the toxicity outcomes. Being aware of some of the technical challenges encountered during the procedure and ways to mitigate them could decrease the incidence of side effects. Careful planning of seed placement and seed deposition allow sparing of the organs at risk and a lower incidence of urinary and gastro-intestinal toxicity.

CONCLUSIONS

Low dose-rate brachytherapy remains a standard monotherapy treatment in the setting of favorable-risk prostate cancer. High disease control and low long-term toxicities are achievable in expert hands with a good technique.

Live implant dosimetry may be an effective replacement for postimplant computed tomography in localized prostate cancer patients receiving low dose rate brachytherapy

PURPOSE

To determine if Live Implant Dosimetry (LIDO) utilizing intraoperative transrectal ultrasound (TRUS) is equivalent to postimplant CT dosimetry (either day 0 or day 30) in patients with localized prostate cancer (PC) treated with low dose rate (LDR) prostate seed brachytherapy.

METHODS AND MATERIALS

The treated population consisted of 628 men with localized (T1-T2) PC. All d'Amico risk categories (low, intermediate, and high) were included, and 437 patients were treated with monotherapy (160 Gy) [low and low tier intermediate], and the remainder (191) [high tier intermediate and high risk] with an implant boost (106 Gy) post external beam radiation, to a volume including the prostate and seminal vesicles (46 Gy). LIDO with intraoperative TRUS, postimplant CT (day 0 and day 30) were performed in all cases. Prostate volumes (V), V₁₀₀ (prostate) and dose (D) D₉₀ (prostate), D₃₀ (urethra), and Rectum D_2cc, were recorded. No urinary catheter was used on Day 30 CT.

RESULTS

More than 91.33% of monotherapy patients reached the target D₉₀ according to LIDO while only 82.99% of Day 0 CT and 92.82% of Day 30 CT achieved target D₉₀. When considering V₁₀₀, monotherapy patients recorded target dosimetry in 90.93%, 82.31%, and 92.02% of cases assessed by LIDO, Day 0 CT and Day 30 CT, respectively. Strong correlations are observed in D₉₀, Rectum D_2cc and Urethra D₃₀ across imaging modalities but V₁₀₀ and V₁₅₀ were poorly correlated due to the relative quantification of this parameter and high degree of error in measurement. Of all monotherapy patients with satisfactory dosimetry on LIDO, 94.82% reached target D₉₀ at day 30 CT and 94.19% reached target V₁₀₀.

CONCLUSIONS

LIDO and CT are both effective tools for assessing postimplant dosimetry. Patients with satisfactory LIDO dosimetry are highly likely to have equivalent dosimetry on CT at follow-up, indicating that postimplant CT may be eliminated in PC a patients implanted with this technique.

The impact of a rectal hydrogel spacer on dosimetric and toxicity outcomes among patients undergoing combination therapy with external beam radiotherapy and low-dose-rate brachytherapy

PURPOSE

Rectal hydrogel spacers have been shown to decrease rectal radiation dose and toxicity. In this study, we compared prostate and rectal dosimetry and acute toxicity outcomes in patients who had and had not received a rectal hydrogel spacer prior to combination therapy with external beam radiotherapy and low-dose-rate brachytherapy.

MATERIALS AND METHODS

All patients with intermediate-risk and high-risk prostate cancer who received combination therapy at our institution were identified between 2014 and 2019. Dosimetric outcomes of brachytherapy implants and quality of life (QOL) outcomes were compared between patients who had and had not received a hydrogel spacer.

RESULTS

A Total of 168 patients meeting our inclusion criteria were identified. Twenty-two patients had received a rectal hydrogel spacer, among whom the mean separation between the rectum and prostate was 7.5 mm, and the V100_rectum was reduced by 47% (0.09 cc vs. 0.17 cc, p = 0.04). There was no difference in the percentage of patients achieving a D90 of ≥100 Gy between those who had and had not received a spacer. The mean rate of change in I-PSS and SHIM scores did not differ between the two groups at 2 months after PID.

CONCLUSION

LDR brachytherapy appears feasible after the placement of a rectal hydrogel spacer. While there was a significantly reduced V100_rectum among patients who had received a hydrogel spacer, there was no statistically significant difference in patients achieving a D90_prostate of ≥100 Gy. Although there was no difference appreciated in QOL scores, the length of follow-up was limited in the rectal-spacer group.

Predictive factors of rectal hemorrhage in patients with localized prostate cancer who underwent low-dose-rate brachytherapy

BACKGROUND

This study aimed to evaluate the association between clinical covariates or the prescribed radiation dose for the prostate and rectal hemorrhage in patients with prostate cancer (PCa) who received iodine-125 low-dose-rate brachytherapy (LDR-BT group) or the combination of LDR-BT and external beam radiation therapy (CMT group).

METHODS AND MATERIALS

In this retrospective study, we reviewed the clinical records of 298 consecutive PCa patients with clinical stage T1c/T2 who underwent LDR-BT between August 2004 and August 2016 at a single institution. The prescribed minimum peripheral doses were 145 Gy for the LDR-BT group and 104 Gy for the CMT group. The dosimetric parameters analyzed were minimal dose received by 90% of the prostate gland, biologically effective dose, and rectal volume receiving 100% (RV100) or 150% of the prescribed dose. The endpoint of this study was the onset of any-grade clinical rectal hemorrhage after treatment.

RESULTS

The median follow-up period was 6.8 years. The 5-year overall survival rate was found to be 98.3%, and two patients (0.7%) reported biochemical recurrence during follow-up period. A total of 33 patients (11%) experienced rectal hemorrhage. However, ≥ grade 2 rectal hemorrhage occurred in eight patients (2.7%). On multivariate analysis, CMT, RV100 ≥ 0.66 mL, and hemorrhoids before treatment were identified as predictors of rectal hemorrhage after radiation therapy.

CONCLUSIONS

Maximal reduction of the rectal dose seems very important to prevent serious rectal hemorrhage. In addition, we should consider the risk of rectal toxicities in patients with abnormalities in the rectal mucosa, especially hemorrhoids.

Institutional patient accrual volume and the treatment quality of I‑125 prostate seed implantation in a Japanese nationwide prospective cohort study

PURPOSE

It is unclear whether experience at high-volume institute improves the treatment quality of prostate seed implantation. The aim of this study was to evaluate the effect of institutional experience on postimplant dosimetric parameters in a nationwide prospective cohort study.

METHODS

From July 2005 to June 2007, 2354 patients were registered in the Japanese Prostate Cancer Outcome Study of Permanent I‑125 Seed Implantation (J-POPS), and 1126 patients treated with seed implantation alone were evaluated. As a surrogate for institutional experience, we classified the J‑POPS institutions as high-volume (patient accrual volume was ≥120 patients per institution) or low-volume institutions (patient accrual volume was <120 patients per institution). To compare treatment quality between institutions, we evaluated the postimplant dosimetric parameters including D90, V100/150 (prostatic dose parameters), UD5/90, U200 (urethral dose parameters), and rectum R100/150 (rectal dose parameters).

RESULTS

In the 5 high-volume institutions (n = 601 patients), most of the patients were treated with >144 Gy of D90, whereas in the 20 low-volume institutions (n = 525) some of the patients were treated with <144 Gy. The V100 of most of the high-volume institution patients were >90%, whereas in the low-volume institutions a considerable percentage of patients showed lower V100. Although there was no correlation between D90 and rectal dose parameters, UD90 had a moderate positive correlation with D90 in both the high- and low-volume institutions. U200 varied more widely in the low-volume institutions.

CONCLUSIONS

Our findings indicate that the institutional patient accrual volume is associated with the treatment quality of I‑125 prostate seed implantation.

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.

Pelvic Catastrophe after Elastic Band Ligation in an Irradiated Rectum

Chronic radiation proctopathy is a frequent complication after both pelvic external radiation therapy and brachytherapy and most commonly presents as rectal bleeding. Deep rectal ulcers and fistulae are much rarer and more clinically challenging consequences. We present the case of a 72-year-old male with a history of prostate adenocarcinoma treated with brachytherapy, who was referred to our institution due to a deep painful rectal ulcer refractory to medical treatment. The ulcer presented shortly after a haemorrhoid elastic band ligation and progressed to rectourethral fistulisation despite both faecal and urinary diversion. Our case demonstrates the importance of favouring a conservative approach when dealing with an irradiated rectum.

Placement of an absorbable rectal hydrogel spacer in patients undergoing low-dose-rate brachytherapy with palladium-103

PURPOSE

Rates of rectal toxicity after low-dose-rate (LDR) brachytherapy for prostate cancer are dependent on rectal dose, which is associated with rectal distance from prostate and implanted seeds. Placement of a hydrogel spacer between the prostate and rectum has proven to reduce the volume of the rectum exposed to higher radiation dose levels in the setting of external beam radiotherapy. We present our findings with placing a rectal hydrogel spacer in patients following LDR brachytherapy, and we further assess the impact of this placement on dosimetry and acute rectal toxicity.

METHODS AND MATERIALS

Between January 2016 and April 2017, 74 patients had placement of a hydrogel spacer, immediately following a Pd-103 seed-implant procedure. Brachytherapy was delivered as follows: as a monotherapy to 26 (35%) patients; as part of planned combination therapy with external beam radiotherapy to 40 (54%) patients; or as a salvage monotherapy to eight (11%) patients. Postoperative MRI was used to assess separation achieved with rectal spacer. Acute toxicity was assessed retrospectively using Radiation Oncology Therapy Group radiation toxicity grading system. Rectal dosimetry was compared with a consecutive cohort of 136 patients treated with seed implantation at our institution without a spacer, using a 2-tailed paired Student's t test (p < 0.05 for statistical significance).

RESULTS

On average, 11.2-mm (SD 3.3) separation was achieved between the prostate and the rectum. The resultant mean rectal volume receiving 100% of prescribed dose (V_100%), dose to 1 cc of rectum (D_1cc), and dose to 2 cc of rectum (D_2cc) were 0 (SD 0.05 cc), 25.3% (SD 12.7), and 20.5% (SD 9.9), respectively. All rectal dosimetric parameters improved significantly for the cohort with spacer placement as compared with the nonspacer cohort. Mean prostate volume, prostate V₁₀₀ and dose to 90% of gland (D₉₀) were 29.3 cc (SD 12.4), 94.0% (SD 3.81), and 112.4% (SD 12.0), respectively. Urethral D₂₀, D_5cc, and D_1cc were 122.0% (SD 17.27), 133.8% (SD 22.8), and 144.0% (SD 25.4), respectively. After completing all treatments, at the time of first the followup, 7 patients reported acute rectal toxicity-6 experiencing Grade 1 rectal discomfort and 1 (with preexisting hemorrhoids) experiencing Grade 1 bleeding.

CONCLUSIONS

Injection of rectal spacer is feasible in the post-LDR brachytherapy setting and reduces dose to the rectum with minimal toxicity. Prostate and urethral dosimetries do not appear to be affected by the placement of a spacer. Further studies with long-term followup are warranted to assess the impact on reduction of late rectal toxicity.

Clinical outcomes of 125I brachytherapy with and without external-beam radiation therapy for localized prostate cancer: results from 300 patients at a single institution in Japan

The aim of this study was to determine the outcomes and adverse events for 300 men with prostate cancer treated with 125iodine (125I) brachytherapy with and without external-beam radiation therapy (EBRT) at a single institution in Japan. Between February 2005 and November 2011, 300 consecutive patients with clinically localized prostate cancer were treated with 125I brachytherapy at the Nagoya University Hospital. A total of 271 men were treated with implants with doses of 145 Gy, and 29 men were treated with implants with doses of 110 Gy combined with EBRT (40-50 Gy/20-25 fractions). The median patient age was 69 years (range, 53-83 years). The median follow-up period was 53 months (range, 5-99 months). According to the National Comprehensive Cancer Network risk classification, 132 men (44%) had low-risk, 147 men (29%) had intermediate-risk and 21 men (7%) had high-risk disease. The 5-year overall survival rate, biochemical relapse-free survival rate, and disease-specific survival rates were 93.5%, 97.3% and 98.5%, respectively. Two men (0.6%) died of prostate cancer and 10 men (3.3%) died of other causes. Seventeen men (5.6%) experienced Grade 2 rectal bleeding in all: 12 (41.4%) of 29 in brachytherapy with EBRT, and 5 (1.8%) of 271 in brachytherapy alone. The rates of Grade 2 and 3 genitourinary toxicity were 1.0% and 1.7%, respectively. Excellent local control was achieved at our hospital for localized prostate cancer with 125I brachytherapy with and without EBRT. Gastrointestinal and genitourinary toxicities were acceptable.

[Evaluation and results of ablative therapies in prostate cancer]

OBJECTIVE

To perform a state of the art about methods of evaluation and present results in ablative therapies for localized prostate cancer.

METHODS

A review of the scientific literature was performed in Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of keywords. Publications obtained were selected based on methodology, language and relevance. After selection, 102 articles were analysed.

RESULTS

Analyse the results of ablative therapies is presently difficult considering the heterogeneity of indications, techniques and follow-up. However, results from the most recent and homogeneous studies are encouraging. Oncologically, postoperative biopsies (the most important criteria) are negative (without any tumor cells in the treated area) in 75 to 95%. Functionally, urinary and sexual pre-operative status is spared (or recovered early) in more than 90% of the patients treated. More and more studies underline also the correlation between the results and the technique used considering the volume of the gland and, moreover, the "index lesion" localization.

CONCLUSION

The post-treatment pathological evaluation by biopsies (targeted with MRI or, perhaps in a near future, with innovative ultrasonography) is the corner stone of oncological evaluation of ablative therapies. Ongoing trials will allow to standardize the follow-up and determine the best indication and the best techniques in order to optimize oncological and functional results for each patient treated.

[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.

ACR appropriateness criteria: Permanent source brachytherapy for prostate cancer

PURPOSE

To provide updated American College of Radiology (ACR) appropriateness criteria for transrectal ultrasound-guided transperineal interstitial permanent source brachytherapy.

METHODS AND MATERIALS

The ACR appropriateness criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

RESULTS

Permanent prostate brachytherapy (PPB) is a treatment option for appropriately selected patients with localized prostate cancer with low to very high risk disease. PPB monotherapy remains an appropriate and effective curative treatment for low-risk prostate cancer patients demonstrating excellent long-term cancer control and acceptable morbidity. PPB monotherapy can be considered for select intermediate-risk patients with multiparametric MRI useful in evaluation of such patients. High-risk patients treated with PPB should receive supplemental external beam radiotherapy (EBRT) along with androgen deprivation. Similarly, patients with involved pelvic lymph nodes may also be considered for such combined treatment but reported long-term outcomes are limited. Computed tomography-based postimplant dosimetry completed within 60 days of PPB is essential for quality assurance. PPB may be considered for treatment of local recurrence after EBRT but is associated with an increased risk of toxicity.

CONCLUSIONS

Updated appropriateness criteria for patient evaluation, selection, treatment, and postimplant dosimetry are given. These criteria are intended to be advisory only with the final responsibility for patient care residing with the treating clinicians.

Predictive factors of rectal toxicity after permanent iodine-125 seed implantation: Prospective cohort study in 2339 patients

PURPOSE

To evaluate the incidence and the associated factors of rectal toxicity in patients with prostate cancer undergoing permanent seed implantation (PI) with or without external beam radiation therapy (EBRT) in a nationwide prospective cohort study in Japan (J-POPS) during the first 2 years.

METHODS AND MATERIALS

A total of 2,339 subjects were available for the analyses. Rectal toxicity was evaluated using the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0.

RESULTS

The 3-year cumulative incidence for grade ≥2 rectal toxicity was 2.88%, 1.76%, and 6.53% in all subjects, PI group and EBRT combination therapy group, respectively. On multivariate analysis, among all subjects, grade ≥2 rectal toxicity was associated with rectal volumes receiving 100% of the prescribed dose (R₁₀₀; p < 0.0001) and EBRT combination therapy (p = 0.0066). R₁₀₀ in the PI group (p = 0.0254), and R₁₀₀ (p = 0.0011) and interactive planning (p = 0.0267) in the EBRT combination therapy group were also associated with grade ≥2 toxicity. The 3-year cumulative incidence of grade ≥2 rectal toxicity was 3.80% and 1.37% for R₁₀₀ ≥ 1 mL and R₁₀₀ < 1 mL, respectively, in the PI group (p = 0.0068), and 14.09% and 5.52% for R₁₀₀ ≥ 1 mL and R₁₀₀ < 1 mL, respectively, in the EBRT combination therapy group (p = 0.0070).

CONCLUSIONS

Rectal toxicity was relatively rare in this study compared with previous reports. For Japanese prostate cancer patients, R₁₀₀ < 1 mL in both PI and EBRT combination therapy groups and interactive planning in EBRT combination therapy group may be effective in decreasing the incidence of rectal toxicity.

Hemiablative Focal Low Dose Rate Brachytherapy: A Phase II Trial Protocol

BACKGROUND

The objective of focal brachytherapy (BT) is to provide effective prostate cancer control for low-risk disease but with reduced genitourinary, gastrointestinal and sexual side effects in a cost-effective way.

OBJECTIVE

The aim of this study is to describe a phase II study examining technical and dosimetric feasibility and toxicity, quality of life changes, and local control with post-treatment biopsy outcomes in men with early stage low volume prostate cancer treated with focal iodine-125 seed BT.

METHODS

The study design is a prospective, multicenter trial with a planned sample size of 20 patients including men with a minimum age of 60 years, a life expectancy estimated to be greater than 10 years, with low or low-tier intermediate risk prostate cancer, unilateral disease on the biopsy, and a Gleason score of ≤3+4 and <25% cores involved. The investigations specific for the study are multi-parametric magnetic resonance imaging (Mp-MRI) baseline, at 20 and 36 months to rule out high grade disease and a transperineal mapping biopsy (baseline and at 36 months) for more accurate patient selection. The hemigland region will receive 144 Gy. Standard normal tissue constraints will be considered as for a whole gland (WG) implant. Dosimetric parameters will be evaluated at day 30 after the implant. Toxicity and quality of life will be evaluated with international validated questionnaires focusing on urinary, rectal, sexual domain, and general health-related quality of life. The patients will complete this assessment at baseline and then approximately every 6 months after the implant up to 10 years.

RESULTS

To date, one patient is involved in the trial. He underwent the pre-implant investigations which found bilateral disease. Therefore, a standard seed implant was performed. If the results from this trial provide evidence that the treatment is safe, feasible, and improves toxicity, funding will be sought to conduct a large, multicenter, randomized controlled trial (RCT).

CONCLUSIONS

This protocol is designed to show feasibility in delivering hemigland focal therapy with seed BT. It may answer crucial questions and obtain data which will enable downstream decisions on focal low dose rate (LDR) prostate BT.

CLINICALTRIAL

Clinicaltrial.gov NCT02643511; https://www.clinicaltrials.gov/ct2/show/NCT02643511 (Archived by Webcite at http://www.webcitation.org/6ghLCzIhY).

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.

[Localized prostate cancer: Radiotherapeutic concepts]

BACKGROUND

Radiation therapy is an established cornerstone in the treatment of prostate cancer. Significant advances in the techniques and therapeutic concepts have been made in recent decades.

OBJECTIVES

The objective of this article is to provide an overview of current standards of care and recent technical and conceptional developments.

CONCLUSIONS

Three-dimensional conformal radiotherapy has long been the standard of care for percutaneous radiotherapy. The development of intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT) have increased the precision of treatment, thus, reducing side effects and allowing dose escalation. LDR (low dose rate) and HDR (high dose rate) brachytherapy alone or in combination are a treatment option in localized prostate cancer with a distinct side effect profile. The roles of proton therapy and stereotactic radiotherapy should be further investigated in prospective trials.

Rectal Ulcers and Rectoprostatic Fistulas after (125)I Low Dose Rate Prostate Brachytherapy

PURPOSE

Radiation induced rectal ulcers and fistulas are rare but significant complications of low dose rate prostate brachytherapy for localized prostate cancer. We describe the incidence of ulcers and fistulas, and associated risk factors.

MATERIALS AND METHODS

We reviewed the records of 4,690 patients with localized prostate cancer who were treated with low dose rate (125)I prostate brachytherapy to a dose of 144 Gy with or without 6 months of androgen deprivation therapy. Patient, disease, comorbidity, treatment, dosimetric and posttreatment intervention factors were analyzed for an association with ulcer or fistula formation.

RESULTS

At a median followup of 53 months 21 cases were identified, including 15 rectal ulcer cases, of which 6 progressed to fistulas, and an additional 6 cases of fistulas with no prior documented ulcers. Overall 9 rectal ulcer cases (0.19%) and 12 fistula cases (0.26%) were identified. In 8 of 15 patients ulcers healed with conservative management. No fistulas healed without surgical management. Two patients with fistulas died. Eight patients diagnosed with rectal ulcers subsequently underwent rectal biopsies, after which fistulas developed in 3. One patient with a de novo fistula underwent a preceding biopsy. Urinary interventions such as transurethral resection of the prostate were performed after brachytherapy in 5 of 12 patients with fistulas compared to 0 of 9 with ulcers alone. Argon plasma coagulation of the rectum for hematochezia was performed after brachytherapy in 3 of 12 patients with fistulas.

CONCLUSIONS

Rates of post-brachytherapy rectal ulcers and fistulas are low as previously described. Post-brachytherapy interventions such as rectal biopsy, argon coagulation and urinary intervention may increase the risk of fistulas.

Comparison of genitourinary and gastrointestinal toxicity among four radiotherapy modalities for prostate cancer: Conventional radiotherapy, intensity-modulated radiotherapy, and permanent iodine-125 implantation with or without external beam radiotherapy

PURPOSE

To compare late genitourinary (GU) and gastrointestinal (GI) toxicity following different prostate cancer treatment modalities.

MATERIALS AND METHODS

This study included 1084 consecutive prostate cancer patients treated with conventional radiotherapy, intensity-modulated radiotherapy (IMRT), permanent iodine-125 implantation (PI) alone, and PI combined with external beam radiotherapy (PI+EBRT). The effects of treatment- and patient-related factors on late grade ⩾ 2 (G2+) GU/GI toxicity risk were assessed.

RESULTS

The median follow-up was 43 months (range, 12-97 months). Compared to the PI+EBRT, there was significantly less G2+ GU toxicity in the conventional radiotherapy (hazard ratio [HR] = 0.39; 95% CI, 0.20-0.77) and the IMRT (HR=0.45, 95% CI, 0.27-0.73). Compared to the PI+EBRT, there was significantly more G2+ GI toxicity in the IMRT (HR = 2.38; 95% CI, 1.16-4.87). In PI-related groups, prostate equivalent dose in 2 Gy fractions was a significant predictor of G2+ GU toxicity (p = 0.001), and the rectal volume receiving more than 100% of the prescribed dose was a significant predictor of G2+ GI toxicity (p = 0.001).

CONCLUSION

The differences in the late G2+ GU/GI risk cannot be explained by the differences in treatment modalities themselves, but by the total radiation dose to the GU/GI tract, which had a causal role in the development of late G2+ GU/GI toxicity across all treatment modality groups.

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.

Effect of aging and long-term erectile function after iodine-125 prostate brachytherapy

PURPOSE

To evaluate long-term erectile function (EF) in men treated with iodine-125 prostate brachytherapy (PB) and to determine factors predictive for erectile dysfunction (ED), including natural decline because of aging.

METHODS

Two thousand nine hundred twenty-nine patients (implanted July 1989-June 2012) with baseline EF and greater than 10-month followup (FU) are included. About 78.9% had full and 7.9% had partial EF at baseline. EF was assessed on a physician-reported three-point scale. Poisson regression with generalized estimating equations was used to assess predictors of ED and Kaplan-Meier curves time to ED. The effect of aging was calculated from the declining rate of baseline EF seen in sequential 5-year age cohorts and from the Massachusetts Male Aging Study.

RESULTS

The median age was 66 years and median FU 3.5 years (maximum 14 years). About 1142 patients had more than 5 years of FU, and 43% had received 6 months of androgen deprivation therapy (ADT). Significant drop in EF was seen at 6 weeks after PB, with gradual decline thereafter. EF preservation at 5 years for age younger than 55, 56-59, 60-64, 65-69, and 70 year and older was 82%, 73%, 58%, 39%, and 23%, respectively. Comparisons of the 5-year age-related and treatment-related EF decline show that 50% of the long-term EF decline is related to aging. On univariate and multivariate analyses, age at implant, length of FU, hypertension, diabetes, and use of ADT (all p < 0.01) were significant predictors of ED.

CONCLUSION

More than 80% of young men have EF preserved 5 years after PB. Age, ADT, history of hypertension, and the natural decline in EF have negative impact on long-term EF after PB.

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.

Influence of body mass index and periprostatic fat on rectal dosimetry in permanent seed prostate brachytherapy

PURPOSE

We examined the influence of body mass index (BMI) and body fat distribution on rectal dose in patients treated with permanent seed brachytherapy for localized prostate cancer.

METHODS AND MATERIALS

We analyzed 213 patients treated with I125 seed brachytherapy for localized prostate cancer. BMI and rectal dosimetry data for all patients were available. Data on visceral and subcutaneous fat distribution at the level of the iliac crest (n = 140) as well as the distribution of periprostatic and subcutaneous fat at the symphysis pubis level were obtained (n = 117). Fat distribution was manually contoured on CT on day 30 after brachytherapy. The correlation between BMI, fat distribution and rectal dose (R100 (in cc), R150 (cc), D2 (Gy)) was analyzed using the Spearman correlation coefficient. Differences in rectal dose between tertiles of body fat distribution were calculated using nonparametric tests.

RESULTS

Periprostatic adipose was only weakly correlated with BMI (r = 0.0.245, p = 0.008) and only weakly correlated with the other fat measurements (r = 0.31-0.37, p < 0.001). On the other hand, BMI was correlated with all other fat measurements (≥0.58, p < 0.001). All the other fat measurements were strongly correlated with each other (r = 0.5-0.87, p < 0.001). Patients with an R100 of >1.3 cc (23% of patients) had less visceral fat (p = 0.004), less subcutaneous fat at the level of the iliac crest (p = 0.046) and a lower BMI (26.8 kg/m2 vs. 28.5 kg/m2, p = 0.02) than patients with an R100 of <1.3 cc. Results were very similar when comparing an R100 of >1.0 cc (34% of patients) across the tertiles. None of the tested linear regression models were predictive (max 12%) of dose to the rectum.

CONCLUSION

Dose to the rectum is dependent on BMI and body fat distribution. Periprostatic fat does not influence rectal dose. Dose to the rectum remains difficult to predict and depends on many factors, one of which is body fat distribution.

Penile necrosis requiring penectomy complicating recto-urethral fistula post prostate cancer external beam radiation and brachytherapy

Radiation therapy is a well-recognized treatment for unfavourable risk localized prostate cancer. Radiation induced recto-urethral fistulae are known rare complications particularly from brachytherapy. We report a case of a recto-urethral fistula 7 years post-external beam radiation and I-125 brachytherapy, which was complicated by a severe polymicrobial soft tissue infection. This infection required penectomy and pelvic exenteration with diverting colostomy, Indiana pouch urinary diversion and gracilis myo-cutaneuos flap closure of the perineum.

Measurement of the strength of iodine-125 seed moving at unknown speed during implantation in brachytherapy

The aim of this study is to demonstrate the feasibility of estimating the strength of the moving radiation source during patient implantation. The requirement for the counting time was investigated by comparing the results of the measurements for the static source with those for the source moving at 2, 5, 10 and 20 cm s(-1). The utilized source was (125)I with an air-kerma strength of 0.432 U (μGym(2)h(-1)). The detector utilized was a plastic scintillation detector (8 cm × 5 cm × 2 cm in thickness) set at 8 cm away from the needle to guide the source. Experiments were conducted in order to determine the most desirable counting time. Analysis using the maximum of the measured values while the source passed through the needle indicated that the results for the moving source increased more than those for the static source as the counting time decreased. The combined standard uncertainty, with the coverage factor of 1, was within 4% at the counting time of 100 ms. This investigation supported the feasibility of the method proposed for estimating the source strength during the implantation procedure, regardless of the source speed. The method proposed is a potential option for reducing the risk of accidental replacements of sources with those of incorrect strengths.

Focal low-dose rate brachytherapy for the treatment of prostate cancer

Whole-gland low-dose rate (LDR) brachytherapy has been a well-established modality of treating low-risk prostate cancer. Treatment in a focal manner has the advantages of reduced toxicity to surrounding organs. Focal treatment using LDR brachytherapy has been relatively unexplored, but it may offer advantages over other modalities that have established experiences with a focal approach. This is particularly true as prostate cancer is being detected at an earlier and more localized stage with the advent of better detection methods and newer imaging modalities.

Predictive factors and management of rectal bleeding side effects following prostate cancer brachytherapy

PURPOSE

To report on the incidence, nature, and management of rectal toxicities following individual or combination brachytherapy following treatment for prostate cancer over a 17-year period. We also report the patient and treatment factors predisposing to acute ≥ grade 2 proctitis.

METHODS AND MATERIALS

A total of 2752 patients were treated for prostate cancer between October 1990 and April 2007 with either low-dose-rate brachytherapy alone or in combination with androgen depletion therapy (ADT) or external beam radiation therapy (EBRT) and were followed for a median of 5.86 years (minimum 1.0 years; maximum 19.19 years). We investigated the 10-year incidence, nature, and treatment of acute and chronic rectal toxicities following BT. Using univariate, and multivariate analyses, we determined the treatment and comorbidity factors predisposing to rectal toxicities. We also outline the most common and effective management for these toxicities.

RESULTS

Actuarial risk of ≥ grade 2 rectal bleeding was 6.4%, though notably only 0.9% of all patients required medical intervention to manage this toxicity. The majority of rectal bleeding episodes (72%) occurred within the first 3 years following placement of BT seeds. Of the 27 patients requiring management for their rectal bleeding, 18 underwent formalin treatment and nine underwent cauterization. Post-hoc univariate statistical analysis revealed that coronary artery disease (CAD), biologically effective dose, rectal volume receiving 100% of the prescription dose (RV100), and treatment modality predict the likelihood of grade ≥2 rectal bleeding. Only CAD, treatment type, and RV100 fit a Cox regression multivariate model.

CONCLUSIONS

Low-dose-rate prostate brachytherapy is very well tolerated and rectal bleeding toxicities are either self-resolving or effectively managed by medical intervention. Treatment planning incorporating adjuvant ADT while minimizing RV100 has yielded the best toxicity-free survival following BT.

DNA ploidy measured on archived pretreatment biopsy material may correlate with prostate-specific antigen recurrence after prostate brachytherapy

PURPOSE

To explore whether DNA ploidy of prostate cancer cells determined from archived transrectal ultrasound-guided biopsy specimens correlates with disease-free survival.

METHODS AND MATERIALS

Forty-seven failures and 47 controls were selected from 1006 consecutive low- and intermediate-risk patients treated with prostate (125)I brachytherapy (July 1998-October 2003). Median follow-up was 7.5 years. Ten-year actuarial disease-free survival was 94.1%. Controls were matched using age, initial prostate-specific antigen level, clinical stage, Gleason score, use of hormone therapy, and follow-up (all P nonsignificant). Seventy-eight specimens were successfully processed; 27 control and 20 failure specimens contained more than 100 tumor cells were used for the final analysis. The Feulgen-Thionin stained cytology samples from archived paraffin blocks were used to determine the DNA ploidy of each tumor by measuring integrated optical densities.

RESULTS

The samples were divided into diploid and aneuploid tumors. Aneuploid tumors were found in 16 of 20 of the failures (80%) and 8 of 27 controls (30%). Diploid DNA patients had a significantly lower rate of disease recurrence (P=.0086) (hazard ratio [HR] 0.256). On multivariable analysis, patients with aneuploid tumors had a higher prostate-specific antigen failure rate (HR 5.13). Additionally, those with "excellent" dosimetry (V100 >90%; D90 >144 Gy) had a significantly lower recurrence rate (HR 0.25). All patients with aneuploid tumors and dosimetry classified as "nonexcellent" (V100 <90%; D90 <144 Gy) (5 of 5) had disease recurrence, compared with 40% of patients with aneuploid tumors and "excellent" dosimetry (8 of 15). In contrast, dosimetry did not affect the outcome for diploid patients.

CONCLUSIONS

Using core biopsy material from archived paraffin blocks, DNA ploidy correctly classified the majority of failures and nonfailures in this study. The results suggest that DNA ploidy can be used as a useful marker for aggressiveness of localized prostate cancer. A larger study will be necessary to further confirm our hypothesis.

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.

Canadian prostate brachytherapy in 2012

Prostate brachytherapy can be used as a monotherapy for low- and intermediate-risk patients or in combination with external beam radiation therapy (EBRT) as a form of dose escalation for selected intermediate- and high-risk patients. Prostate brachytherapy with either permanent implants (low dose rate [LDR]) or temporary implants (high dose rate [HDR]) is emerging as the most effective radiation treatment for prostate cancer. Several large Canadian brachytherapy programs were established in the mid- to late-1990s. Prostate brachytherapy is offered in British Columbia, Alberta, Manitoba, Ontario, Quebec and New Brunswick. We anticipate the need for brachytherapy services in Canada will significantly increase in the near future. In this review, we summarize brachytherapy programs across Canada, contemporary eligibility criteria for the procedure, toxicity and prostate-specific antigen recurrence free survival (PRFS), as published from Canadian institutions for both LDR and HDR brachytherapy.