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

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.

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.

Chronological changes of lower urinary tract symptoms after low-dose-rate brachytherapy for prostate cancer using SpaceOAR® system

Background

The aim of this study is to investigate chronological changes of lower urinary tract symptoms (LUTS) in patients with prostate cancer who underwent low-dose-rate brachytherapy (LDR-BT) followed by the insertion of SpaceOAR® system (SpaceOAR).

Methods

In this retrospective study, 483 patients with localized prostate cancer underwent LDR-BT at the Gifu University Hospital between August 2004 and December 2020. SpaceOAR was inserted in 30 patients after LDR-BT (SpaceOAR group), and 453 patients received LDR-BT alone (non-SpaceOAR group). The International Prostate Symptom Score (IPSS), Overactive Bladder Symptom Score (OABSS), quality of life due to urinary symptoms (IPSS-QOL), and uroflowmetry (UFM), including maximum flow rate (Qmax), voided volume, and post-voided residual urine (PVR), were evaluated before LDR-BT, and at 1, 3, 6, 9, and 12 months after LDR-BT. The outcomes were chronological changes in IPSS, OABSS, and IPSS-QOL compared to pretreatment values and those of covariates in relation to UFM.

Results

The IPSS, OABSS, IPSS-QOL, Qmax, and voided volume were not significantly associated with either group. According to the PVR interaction effect, the insertion of SpaceOAR was significantly affected by chronological changes in PVR (P = 0.001). Three months after LDR-BT, PVR in the SpaceOAR group was significantly higher than that in the non-SpaceOAR group (49.8 mL vs. 30.5 mL; P = 0.002).

Conclusion

SpaceOAR use may temporally increase PVR; however, IPSS, OABSS, IPSS-QOL, Qmax, and voided volume were not significantly associated with LUTS before and after LDR-BT. The combination of LDR-BT and SpaceOAR may be acceptable for treating patients with prostate cancer regarding the chronological changes in LUTS after brachytherapy.

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.

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.

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.

Comparison of chronological changes in urinary function in patients who underwent low-dose-rate brachytherapy for prostate cancer-A randomized controlled trial of alpha-1 adrenoceptor antagonist alone versus combination with cyclooxygenase-2 inhibitor

PURPOSE

To evaluate the add-on efficacy of a cyclooxygenase (COX)-2 inhibitor on the chronological changes in urinary function in patients who underwent low-dose-rate prostate brachytherapy.

METHODS AND MATERIALS

A total of 310 patients with prostate cancer who underwent low-dose-rate-brachytherapy were enrolled. Patients were randomized and allocated to the monotherapy group (tamsulosin alone: 0.2 mg/d) and the combination group (tamsulosin 0.2 mg/d plus celecoxib: 200 mg/d). We compared the chronological change in the international prostate symptom score (IPSS), the overactive bladder symptom score (OABSS), uroflowmetric parameters, and the frequency volume chart.

RESULTS

There was not a significant difference between the two groups in the chronological changes in IPSS and OABSS for 12 months after implantation. Regarding the frequency volume chart assessment, the mean daytime urinary frequency in the combination group at 3 and 6 months after implantation was significantly lower than that in the monotherapy group. Regarding IPSS recovery at 3 months after implantation, higher baseline IPSS and nonuse of external beam radiation therapy were independent factors, while smaller prostate volume and higher baseline IPSS were independent factors of IPSS recovery at 12 months after implantation based on multivariate analyses.

CONCLUSIONS

There was not an additional effect of a COX-2 inhibitor to the action of an alpha-1 adrenoceptor antagonist on concerning the chronological changes in IPSS and OABSS. The use of a COX-2 inhibitor reduced the daytime urinary frequency and postvoid residual after seed implantation.

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.

[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.

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.