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

Trimodality Therapy With Iodine-125 Brachytherapy, External Beam Radiation Therapy, and Short- or Long-Term Androgen Deprivation Therapy for High-Risk Localized Prostate Cancer: Results of a Multicenter, Randomized Phase 3 Trial (TRIP/TRIGU0907)

PURPOSE

This phase 3 randomized investigation was designed to determine whether 30 months of androgen deprivation therapy (ADT) was superior to 6 months of ADT when combined with brachytherapy and external beam radiation therapy (EBRT) for localized high-risk prostate cancer.

METHODS AND MATERIALS

This study was conducted at 37 hospitals on men aged 40 to 79 years, with stage T2c-3a, prostate-specific antigen >20 ng/mL, or Gleason score >7, who received 6 months of ADT combined with iodine-125 brachytherapy followed by EBRT. After stratification, patients were randomly assigned to either no further treatment (short arm) or 24 months of adjuvant ADT (long arm). According to the Phoenix definition of failure, the primary endpoint was the cumulative incidence of biochemical progression. Secondary endpoints included clinical progression, metastasis, salvage treatment, disease-specific mortality, overall survival, and grade 3+ adverse events. An intention-to-treat analysis was conducted using survival estimates determined using competing risk analyses.

RESULTS

Of 332 patients, 165 and 167 were randomly assigned to the short and long arms, respectively. The median follow-up period was 9.2 years. The cumulative incidence of biochemical progression at 7 years was 9.0% (95% CI, 5.5-14.5) and 8.0% (4.7-13.5) in the short and long arms, respectively (P = .65). The outcomes of secondary endpoints did not differ significantly between the arms. Incidence rates of endocrine- and radiation-related grade 3+ adverse events for the short versus long arms were 0.6 versus 1.8% (P = .62) and 1.2 versus 0.6% (P = .62), respectively.

CONCLUSIONS

Both treatment arms showed similar efficacy among selected populations with high-risk features. The toxicity of the trimodal therapy was acceptable. The present investigation, designed as a superiority trial, failed to demonstrate that 30-month ADT yielded better biochemical control than 6-month ADT when combined with brachytherapy and EBRT. Therefore, a noninferiority study is warranted to obtain further evidence supporting these preliminary results.

Uncertainty in magnetic resonance imaging-based prostate postimplant dosimetry: Results of a 10-person human observer study, and comparisons with automatic postimplant dosimetry

PURPOSE

Uncertainties in postimplant quality assessment (QA) for low-dose-rate prostate brachytherapy (LDRPBT) are introduced at two steps: seed localization and contouring. We quantified how interobserver variability (IoV) introduced in both steps impacts dose-volume-histogram (DVH) parameters for MRI-based LDRPBT, and compared it with automatically derived DVH parameters.

METHODS AND MATERIALS

Twenty-five patients received MRI-based LDRPBT. Seven clinical observers contoured the prostate and four organs at risk, and 4 dosimetrists performed seed localization, on each MRI. Twenty-eight unique manual postimplant QAs were created for each patient from unique observer pairs. Reference QA and automatic QA were also performed for each patient. IoV of prostate, rectum, and external urinary sphincter (EUS) DVH parameters owing to seed localization and contouring was quantified with coefficients of variation. Automatically derived DVH parameters were compared with those of the reference plans.

RESULTS

Coefficients of variation (CoVs) owing to contouring variability (CoVcontours) were significantly higher than those due to seed localization variability (CoVseeds) (median CoVcontours vs. median CoVseeds: prostate D90-15.12% vs. 0.65%, p < 0.001; prostate V100-5.36% vs. 0.37%, p < 0.001; rectum V100-79.23% vs. 8.69%, p < 0.001; EUS V200-107.74% vs. 21.18%, p < 0.001). CoVcontours were lower when the contouring observers were restricted to the 3 radiation oncologists, but were still markedly higher than CoVseeds. Median differences in prostate D90, prostate V100, rectum V100, and EUS V200 between automatically computed and reference dosimetry parameters were 3.16%, 1.63%, -0.00 mL, and -0.00 mL, respectively.

CONCLUSIONS

Seed localization introduces substantially less variability in postimplant QA than does contouring for MRI-based LDRPBT. While automatic seed localization may potentially help improve workflow efficiency, it has limited potential for improving the consistency and quality of postimplant dosimetry.

The oncologic and safety outcomes of low-dose-rate brachytherapy for the treatment of prostate cancer

Around 40 years have passed since a modern low-dose-rate (LDR) brachytherapy for prostate cancer was introduced. LDR brachytherapy has become one of the definitive treatment options besides radical prostatectomy (RP) and external beam radiation therapy (EBRT). LDR brachytherapy has several advantages over EBRT such as a higher prescribed dose to the prostate gland while avoiding unnecessary irradiation of organs at risk, a precipitous dose gradient, a brief treatment time, and a short hospital stay. Previous reports revealed that the long-term oncologic outcomes of LDR brachytherapy are superior to those of EBRT. The oncologic outcomes of low- to intermediate-risk patients are equivalent to those of RP using the recurrence definition of surgery of prostate specific antigen (PSA) >0.2 ng/mL, while the oncologic outcomes of LDR brachytherapy as tri-modality (combined EBRT and androgen deprivation therapy) for high-risk patients is superior to that of RP using the recurrence definition of surgery. In respect of toxicity, urinary disorders such as urgency and frequency are often observed after the acute phase of treatment, but these events usually resolve, while the quality of life of urinary continence is well preserved for a long time. Erectile function decreases yearly, but is relatively preserved compared to RP. In conclusion, the most noteworthy strength of LDR brachytherapy for low- to intermediate-risk patients is the "brief treatment time" that provides long recurrence-free survival, while that for high-risk patients who received LDR brachytherapy (tri-modality) is "excellent disease control."

Comparison of chronic gastrointestinal and genitourinary toxicities between brachytherapy and external beam radiotherapy for patients with prostate cancer: A systematic review and meta-analysis

BACKGROUND

125I BT is an effective radiotherapy for prostate cancer. However, comparison data of GI and GU toxicities between BT, BT + EBRT, and EBRT-alone patient groups is limited.

OBJECTIVE

To define the GI and GU toxicities in prostate cancer to prevent adverse events after treatment.

METHODS

We searched published studies in PubMed, Cochrane, and Embase databases up to December 31, 2022. The endpoints were the RRs of GI and GU toxicities. Pooled data were assessed using a random-effects model.

RESULTS

Fifteen eligible studies were included into this analysis. LDR-BT had significantly lower RRs than LDR-BT + EBRT for acute GI (2.13; 95% CI, 1.22-3.69; P= 0.007) and late GI toxicities (3.96; 95% CI, 1.23-12.70; P= 0.02). Moreover, EBRT had significantly higher RRs than LDR-BT for acute GU (2.32; 95% CI, 1.29-4.15; P= 0.005) and late GU toxicities (2.38; 95% CI, 1.27-4.44; P= 0.007). HDR-BT had significantly higher RRs for acute GU toxicities than LDR-BT alone (0.30; 95% CI, 0.23-0.40; P< 0.00001).

CONCLUSION

The results implied that BT with and without EBRT can result in both GI and GU toxicities in patients with prostate cancer, with LDR-BT leading to a poorer urinary function than EBRT.

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.

Low dose rate brachytherapy for primary treatment of localized prostate cancer: A systemic review and executive summary of an evidence-based consensus statement

PURPOSE

The purpose of this guideline is to present evidence-based consensus recommendations for low dose rate (LDR) permanent seed brachytherapy for the primary treatment of prostate cancer.

METHODS AND MATERIALS

The American Brachytherapy Society convened a task force for addressing key questions concerning ultrasound-based LDR prostate brachytherapy for the primary treatment of prostate cancer. A comprehensive literature search was conducted to identify prospective and multi-institutional retrospective studies involving LDR brachytherapy as monotherapy or boost in combination with external beam radiation therapy with or without adjuvant androgen deprivation therapy. Outcomes included disease control, toxicity, and quality of life.

RESULTS

LDR prostate brachytherapy monotherapy is an appropriate treatment option for low risk and favorable intermediate risk disease. LDR brachytherapy boost in combination with external beam radiation therapy is appropriate for unfavorable intermediate risk and high-risk disease. Androgen deprivation therapy is recommended in unfavorable intermediate risk and high-risk disease. Acceptable radionuclides for LDR brachytherapy include iodine-125, palladium-103, and cesium-131. Although brachytherapy monotherapy is associated with increased urinary obstructive and irritative symptoms that peak within the first 3 months after treatment, the median time toward symptom resolution is approximately 1 year for iodine-125 and 6 months for palladium-103. Such symptoms can be mitigated with short-term use of alpha blockers. Combination therapy is associated with worse urinary, bowel, and sexual symptoms than monotherapy. A prostate specific antigen <= 0.2 ng/mL at 4 years after LDR brachytherapy may be considered a biochemical definition of cure.

CONCLUSIONS

LDR brachytherapy is a convenient, effective, and well-tolerated treatment for prostate cancer.

Tensor Regression-based Model to Investigate Heterogeneous Spatial Radiosensitivity After I-125 Seed Implantation for Prostate Cancer

BACKGROUND/AIM

We established a data-driven method for extracting spatial patterns of dose distribution associated with radiation injuries, based on patients with prostate cancer who underwent iodine-125 (I-125) seed implantation.

PATIENTS AND METHODS

Seventy-five patients underwent I-125 seed implantation for prostate cancer. We modeled the severity of lower urinary tract symptoms (LUTS) to be estimated using a linear model, which is formulated as an inner product between the dose distribution D and voxel-wise radiosensitivity B inside the prostate. For the estimation, tensor regression based on a low-rank decomposition with generalized fused lasso penalty was applied.

RESULTS

The spatial distribution of B was visually assessed. Positive parameters appeared dominantly in the region close to the urethra and the prostate base.

CONCLUSION

Our tensor regression-based model can predict intra-organ radiosensitivity in a data-driven manner, providing a compelling parameter distribution associated with the development of LUTS after I-125 seed implantation for prostate cancer.

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.

Incidence and dosimetric predictive factors of late rectal toxicity after low-dose-rate brachytherapy combined with volumetric modulated arc therapy in high-risk prostate cancer at a single institution: Retrospective study

PURPOSE

The purpose of this study is to investigate the incidence of rectal toxicity and to identify the associated dosimetric predictive parameters after I-125 seed low-dose-rate brachytherapy (LDR-BT) combined with volumetric modulated arc therapy (VMAT) and dose constraints.

METHODS AND MATERIALS

In total, 110 patients with high-risk prostate cancer received 110 Gy LDR-BT, followed by 45 Gy VMAT. Rectal toxicity was recorded according to Common Terminology Criteria for Adverse Events v.4.03. The dosimetric factors associated with LDR-BT and VMAT were analyzed to determine their relationship with rectal toxicity. Receiver operating characteristic (ROC) curve analysis was performed for ≥ grade 2 (G2) rectal toxicity prediction.

RESULTS

The follow-up duration was 10.1-115.2 months (median 60.5 months). Seven patients had G2 rectal hemorrhage, and none of the patients had grade 3 rectal hemorrhage. In the univariate analysis, the rectal volume receiving 100% of the prescribed dose (rV₁₀₀) (p < 0.001), the dose covering 2 cc of the rectum (rD_2cc) during LDR-BT (p = 0.002), and the combined rD_2cc during LDR-BT and VMAT (p = 0.001) were identified as predictors of G2 rectal hemorrhage. In the ROC curve analysis, the cutoff value was 0.46 cc for rV₁₀₀, 74.0 Gy for rD_2cc, and 86.8 GyEQD₂ for combined rD_2cc.

CONCLUSION

Predictors of late ≥ G2 rectal hemorrhage are rV₁₀₀, rD_2cc, and combined rD_2cc. The incidence of rectal toxicity is low and acceptable in this setting and is highly dependent on the rectal dose of LDR-BT. The use of higher-quality LDR-BT and VMAT dose constraints may further reduce the rate of rectal hemorrhage.

Toxicity in patients treated with permanent prostate brachytherapy using intraoperatively built custom-linked seeds versus loose seeds

Purpose

Low-dose-rate brachytherapy (BT) with permanent iodine-125 radioactive seeds is a highly effective treatment option for low- and favorable intermediate-risk prostate cancer. However, optimal implantation is not always achieved due to edema or seeds loss. One way to improve seed placement is the use of stranded seeds called "intraoperatively built custom-linked seeds (IBCLS)" in an opposition to loose seeds (LS). To date, there are few data comparing toxicity rates between these two techniques. The aim of this study was to compare dosimetric parameters and toxicity rates at 2 years between both procedures in a matched-paired population.

Material and methods

Patients were considered for BT according to European guidelines. Among 548 patients treated at our institution, 105 patients in the loose seeds cohort were individually matched to 105 patients in the IBCLS group according to age, prostate volume, pre-operative international prostate symptom score (IPSS), clinical stage, and Gleason score. Erectile function was scored using the five-item international index of erectile function (IIEF-5) score. A multivariable linear mixed-effects model was applied to examine the association between total and individual scores (repeated measures) and covariates.

Results

Overall, 61 (29%) patients presented with a favorable intermediate-risk prostate cancer. There were no significant changes in IPSS over time (p = 0.57). During follow-up, the IIEF-5 was similar in the two groups, except at one month, where it was lower in the IBCLS group (10.9 vs. 6.9, p = 0.029). Also, there was no difference in grade ≥ 2 rectal toxicity. At 1 month, D_90Gy, V_150%, and V_100% were higher in the LS group compared to the IBCLS group.

Conclusions

Low-dose-rate prostate brachytherapy using IBCLS is a safe technique, with comparable toxicity profiles at 2 years compared to LS brachytherapy.

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.

Health Related Quality of Life in Japanese Patients with Localized Prostate Cancer: Comparative Retrospective Study of Robot-Assisted Laparoscopic Radical Prostatectomy Versus Radiation Therapy

Background

Radical prostatectomy and radiotherapy are standard treatments for localized prostate cancer. When making decisions about treatment, it is important to not only consider medical information such as the patient's age, performance status, and complications, but also the impact on quality of life (QOL) after treatment.

Our purpose was to compare health related quality of life (HRQOL) after robot-assisted laparoscopic radical prostatectomy (RARP) versus radiation therapy in Japanese patients with localized prostate cancer retrospectively.

Methods

Patients with localized prostate cancer receiving RARP or radiotherapy at Tottori University Hospital between October 2010 and December 2014 were enrolled in a retrospective observational study with follow-up for 24 months to December 2016. The Medical Outcome Study 8-Item Short-Form Health Survey was performed before treatment and 1, 3, 6, 12, and 24 months post-treatment.

Results

Complete responses to the questionnaire were obtained from 154/227 patients receiving RARP, 41/67 patients receiving intensity-modulated radiation therapy, 35/82 patients receiving low dose rate brachytherapy, and 18/28 patients given low dose rate brachytherapy plus external beam radiation therapy. The median physical component summary score of the Medical Outcome Study 8-Item Short-Form Health Survey was significantly lower at 1 month after prostatectomy than radiotherapy, but was similar for both treatments at 3 months, and was significantly higher at 6, 12 and 24 months after prostatectomy. The median mental component summary score was also significantly lower in the prostatectomy group at 1 month, but not from 3 months onwards.

Conclusion

Our study suggested that HRQOL was inferior at 1 month after RARP, however, recovered at 3 months after RARP and was better than after radiotherapy at 6, 12, and 24 months.

Placement of SpaceOAR hydrogel spacer for prostate cancer patients treated with iodine-125 low-dose-rate brachytherapy

OBJECTIVES

The aim of the present study was to report on our early experience with hydrogel spacer (SpaceOAR) placement in combination with iodine-125 low-dose-rate brachytherapy for prostate cancer.

METHODS

From April 2018, SpaceOAR hydrogel spacer was placed in 100 consecutive patients undergoing iodine-125 low-dose-rate brachytherapy. Complications and the status of the placement were evaluated. Deformation of the prostate by the spacer was examined measuring prostate diameters and evaluating the change from preoperative status. The position of the prostate was similarly examined by evaluating the change in distance between the pubic symphysis and the prostate. Post-plan dosimetric data were compared with 200 patients treated without a spacer.

RESULTS

No complications were found during either the intraoperative or perioperative periods. The mean displacement distance of 11.64 mm was created, the mean value before spacer placement was 0.28 mm (P < 0.0001). The change of the prostate diameters showed a positive increase in all directions, with no significant negative change in any one direction. Regarding the change in distance between pubic symphysis and the prostate, no significant shortening trend was observed between the two groups (P = 0.14). Whereas the dosimetric parameters showed means of 0.001 and 0.026 cc for RV150 and RV100 in the spacer group, they were 0.025 and 0.318 cc, respectively, in the non-spacer group, showing a significant decrease in both parameters (P < 0.001).

CONCLUSIONS

Prostate deformation secondary to hydrogel placement might adversely affect dosimetric parameters in patients undergoing low-dose-rate brachytherapy. However, a significant reduction in the rectal dose can be adopted without adversely affecting the other parameters related to treatment outcome.

Low-dose-rate brachytherapy for prostate cancer: A 15-year experience in Japan

The history of prostate brachytherapy has passed one century. In 1983, modern low-dose-rate prostate brachytherapy using a transrectal ultrasound-guided procedure was introduced. In the early 1990s, low-dose-rate brachytherapy was introduced and rapidly spread across the USA due to its excellent oncological control, cost-effectiveness and technically easy procedure. Since low-dose-rate brachytherapy was introduced in Japan (2003), over 15 years have passed. More than 43 000 patients have undergone low-dose-rate brachytherapy. Japanese urologists and radiation oncologists are on course with leading brachytherapists in the USA. A nationwide prospective cohort study, J-POPS, was initiated in 2005. The J-POPS group also provides educational programs including an annual novel training course in low-dose-rate brachytherapy to familiarize urologists, radiation oncologists and pathologists with the procedure. Important information on Japanese patients has accumulated, especially by the J-POPS study group. The Japanese investigators reported excellent oncological outcomes of low-dose-rate brachytherapy, showing equivalent or superior efficacy to surgery in low- to intermediate-risk patients, and superior efficacy in high-risk patients using the surgery biochemical recurrence definition (prostate-specific antigen cut-off value of 0.2 ng/mL). Two randomized controlled studies (SHIP study: intermediate risk, and TRIP study: high risk) carried out by the J-POPS group are ongoing, and an additional follow-up study (J-POPS 2 study) has been started to evaluate survival outcomes over longer follow-up periods. Low-dose-rate brachytherapy is expected to provide a survival benefit, which must be confirmed by further studies with longer follow-up periods in the future.

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.

Changes in lower urinary tract symptoms after iodine-125 brachytherapy for prostate cancer

•

Patients who received BT experienced acute urinary morbidity 3 months after BT of the prostate.

•

Acute urinary symptoms gradually improved with time and returned to BL at 36 months.

•

Storage symptoms take longer to return to BL compared with voiding symptoms.

Purpose

To investigate chronological changes in lower urinary tract symptoms (LUTS) in patients who received iodine-125 brachytherapy (BT) for prostate cancer.

Methods

We enrolled 706 patients who received BT. Of these, 265 (38%) received BT combined with external beam radiation therapy (EBRT). An International Prostate Symptom Score (IPSS), IPSS quality of life (IPSS-QOL) score, and overactive bladder symptom score (OABSS) were recorded before BT (baseline, BL), and 1, 3, 6, 12, 24, 36, 48, and 60 months after BT. The sum of frequency (2), urgency (4) and nocturia (7) of the IPSS questionnaire was defined as the storage symptoms score, whereas the sum of emptying (1), intermittency (3), weak stream (5), and hesitancy (6) was defined as the voiding symptom score.

Results

Total IPSS significantly increased at 3 months following BT compared with BL (mean score: 17.1 vs. 7.99, P < 0.001) and returned to BL by 36 months. The storage symptom score did not return to BL 36 months after BT. Total OABSS significantly increased 3 months after BT compared with BL (mean score: 6.52 vs. 3.45, P < 0.001), and returned to BL 48 months after BT. The IPSS-QOL score was the highest score (mean score: 2.46 vs. 3.9, P < 0.001) 3 months after BT and returned to BL 48 months after BT, however the IPSS-QOL score was lower than BL (mean score: 2.01 vs 2.46, P < 0.001) at 60 months. The risk factors for LUTS within 1 year after BT were BL IPSS (P < 0.001) and PV (P < 0.001). Patients who received combined EBRT experienced transient storage symptoms 24 and 36 months after BT, whereas those who received BT alone did not. However, the storage symptom score of the patients who received combined EBRT was improving 48 months after BT and eventually showed no significant difference compared with those treated with BT alone.

Conclusion

Three months after BT, LUTS, including storage symptoms, deteriorated the most but improved with time. The urinary symptom in patients who received combined EBRT can potentially flare again in 24 and 36 months after BT. Knowledge of changes in LUTS associated with BT may influence treatment recommendations and enable patients to make better-informed decisions.

Comparison of Image-Guided Intensity-Modulated Radiotherapy and Low-dose Rate Brachytherapy with or without External Beam Radiotherapy in Patients with Localized Prostate Cancer

To compare the outcome of low-dose rate brachytherapy (LDR-BT) and image-guided intensity-modulated radiotherapy (IG-IMRT) for localized prostate cancer, we examined 488 LDR-BT and 269 IG-IMRT patients. IG-IMRT treated older and advanced disease with more hormonal therapy than LDR-BT, which excluded T3b–T4 tumor and initial PSA > 50 ng/ml. The actuarial five-year biochemical failure-free survival rate was 88.7% and 96.7% (p = 0.0003) in IG-IMRT and LDR-BT, respectively; it was 88.2% (85.1% for IG-IMRT and 94.9% for LDR-BT, p = 0.0578) for the high-risk group, 95.2% (91.6% and 97.0%, p = 0.3361) for the intermediate IG-IMRT and 96.8% (95.7% and 97%, p = 0.8625) for the low-risk group. Inverse probability of treatment weighting (IPTW) involving propensity scores was used to reduce background selection bias. IPTW showed a statistically significant difference between LDR-BT and IG-IMRT in high risk (p = 0.0009) and high risk excluding T3-4/initial PSA > 50 ng/ml group (p = 0.0073). IG-IMRT showed more gastrointestinal toxicity (p = 0.0023) and less genitourinary toxicity (p < 0.0001) than LDR-BT. LDR-BT and IG-IMRT showed equivocal outcome in low- and intermediate-risk groups. For selected high-risk patients, LDR-BT showed more potential to improve PSA control rate than IG-IMRT.

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.

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.

Dosimetry advantages of intraoperatively built custom-linked seeds compared with loose seeds in permanent prostate brachytherapy

Purpose

The aim of this study was to compare the implant quality between intraoperatively built custom-linked seeds (IBCL) and loose seeds (LS) retrospectively.

Material and methods

This study included 74 prostate cancer patients who were treated with permanent prostate brachytherapy (PPB) using IBCL (n = 37) or LS (n = 37) between July 2014 and June 2016. Dose-volume histogram (DVH) parameters, seed migration, and operation time were compared between the IBCL and LS groups. In addition to the standard target volume of the whole prostate gland, DVH parameters for prostate plus a 3 mm margin (CTV) were evaluated.

Results

In intraoperative planning, prostate V₁₅₀ was lower (54.8% vs. 59.6%, p = 0.027), and CTV V₁₀₀ (88.1% vs. 85.6%, p = 0.019) and D₉₀ (98.5% vs. 92.6%, p = 0.0033) were higher in the IBCL group compared with in the LS group. In post-implant dosimetry, prostate V₁₀₀ (96.9% vs. 95.2%, p = 0.020), CTV V₁₀₀ (85.6% vs. 81.7%, p = 0.046), and CTV D₉₀ (94.2% vs. 86.5%, p < 0.001) were higher, and prostate V₁₅₀ (57.1% vs. 64.5%, p = 0.0051) and CTV V₁₅₀ (31.5% vs. 35.7%, p = 0.046) were lower in the IBCL group compared with in the LS group. Regarding DVH changes between intraoperative planning and post-implant dosimetry, the decrease in prostate D₉₀ was significantly lower in the IBCL group than in the LS group (–1.16% vs. –4.17%, p < 0.001). For the IBCL group, the operation time was slightly but significantly longer than that for the LS group (50.5 minutes vs. 43.7 minutes, p = 0.011). However, the seed migration rate was significantly lower in the IBCL group than in the LS group (5% vs. 41%, p < 0.001).

Conclusions

Intraoperatively built custom-linked is more advantageous than LS in terms of dosimetric parameters and migration.

Predictive Factors for Prolonged Urination Disorder After Permanent 125I Brachytherapy for Localized Prostate Cancer

BACKGROUND

We assessed the change in LUTS after prostate brachytherapy to reveal factors for prolonged urination disorder.

MATERIALS AND METHODS

Four hundred and four patients received prostate brachytherapy at our institution and were followed-up for at least 2 years. We evaluated the correlation of mean IPSS changes and clinical factors. Using multivariate analysis, we also evaluated clinical factors with potential to delay IPSS resolution.

RESULTS

In cases with prostate volume more than 30 cm³, radiation dose to 90% of prostate volume (D90) more than 160 Gy, and radiation dose to 30% of the urethral volume (UD30) more than 240 Gy, mean IPSS levels were significantly higher, even 30 months after treatment. On multivariate analysis, baseline IPSS more than 8 points and D90 more than 160 Gy were significant predictors for delayed IPSS resolution.

CONCLUSION

Our data suggest that higher baseline IPSS and higher D90 were predictors for prolonged urination disorder.

Variability of treatment planning of seed implantation: A Japanese multicenter simulation study

PURPOSE

This multicenter study was conducted to evaluate the current variability of treatment planning of seed implantation in Japanese centers and the feasibility of two virtual trials.

METHODS AND MATERIALS

Two types of contour data were sent to 12 radiation oncologists with a request letter that asked them to make treatment plans on the data in the same manner as in their own practice. Five of the 12 radiation oncologists were asked to participate in the two virtual trials in which the D90 (dose to the hottest 90% of prostate volume) was 1) required to be set at just 180 Gy and 2) increased as much as possible without violating other limitations.

RESULTS

A relatively high dose with a small deviation was irradiated to the prostate in Japanese centers (mean D90 = 188 Gy; SD = 10 Gy). In the virtual trials, all five physicians could achieve 180 Gy for the D90 with a very small deviation, although the urethral dose showed relatively large deviations. Dose escalation without increase of urethral dose or V150 was difficult, although the rectum could be spared by most of the physicians.

CONCLUSION

Our study showed a relatively high dose with a small deviation was prescribed to the prostate in Japanese centers. Consolidated protocols such as D90 = 180 Gy could be available for future trials. Meanwhile, our study suggested that some cautions might be needed for urethral dose and the V150, even when a relatively low D90 was requested.

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.