Rectal function following brachytherapy with or without supplemental external beam radiation: Results of two prospective randomized trials

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).

Patient-reported long-term rectal function after permanent interstitial brachytherapy for clinically localized prostate cancer

PURPOSE

To evaluate the effect of permanent interstitial brachytherapy with or without supplemental therapies on long-term rectal function using a patient-administered quality-of-life instrument.

METHODS AND MATERIALS

One hundred thirty four of the initial 219 prostate brachytherapy patients who remain alive and have participated in a prospective evaluation of rectal function were mailed the rectal function assessment score (R-FAS). Of the 134 patients, 3 have a colostomy because of colorectal cancer, 2 failed to respond, and 129 (99.2% of eligible patients) returned a completed R-FAS. R-FAS ranges from 0 to 27 with lower scores indicative of better bowel function. Median followup was 14 years. Multiple clinical, treatment, and dosimetric parameters were evaluated for impact on bowel function.

RESULTS

For the current cohort, R-FAS was 3.35, which was comparable to the 1999 (4.29), 2002 (3.92), and 2006 (4.00) surveys. In the 2011 survey, 10 (7.8%), 17 (13.1%), and 102 (78.3%) patients reported bowel function to be worse, improved, or unchanged after brachytherapy. No patient has developed a rectal ulcer or fistula. The number of preimplant bowel movements, tobacco, and diabetes mellitus correlated with R-FAS. Consistent with the previous thee surveys, patient's perception of overall rectal quality of life was inversely related to the use of supplemental external beam radiation.

CONCLUSIONS

Long-term rectal function after prostate brachytherapy is favorable with a small number of patients reporting deterioration in bowel function. The judicious use of supplemental external beam radiation with particular attention to rectal doses may further improve long-term function.

Low-dose rate brachytherapy for men with localized prostate cancer

BACKGROUND

Localized prostate cancer is a slow growing tumor for many years for the majority of affected men. Low-dose rate brachytherapy (LDR-BT) is short-distance radiotherapy using low-energy radioactive sources. LDR-BT has been recommended for men with low risk localized prostate cancer.

OBJECTIVES

To assess the benefit and harm of LDR-BT compared to radical prostatectomy (RP), external beam radiotherapy (EBRT), and no primary therapy (NPT) in men with localized prostatic cancer.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1950), and EMBASE (from 1980) were searched in June 2010 as well as online trials registers and reference lists of reviews.

SELECTION CRITERIA

Randomized, controlled trials comparing LDR-BT versus RP, EBRT, and NPT in men with clinically localized prostate cancer.

DATA COLLECTION AND ANALYSIS

Data on study methods, participants, treatment regimens, observation period and outcomes were recorded by two reviewers independently.

MAIN RESULTS

We identified only one RCT (N = 200; mean follow up 68 months). This trial compared LDR-BT and RP. The risk of bias was deemed high. Primary outcomes (overall survival, cause-specific mortality, or metastatic-free survival) were not reported. Biochemical recurrence-free survival at 5 years follow up was not significantly different between LDR-BT (78/85 (91.8%)) and RP (81/89 (91.0%)); P = 0.875; relative risk 0.92 (95% CI: 0.35 to 2.42).For severe adverse events reported at 6 months follow up, results favored LDR-BT for urinary incontinence (LDR-BT 0/85 (0.0%) versus RP 16/89 (18.0%); P < 0.001; relative risk 0) and favored RP for urinary irritation (LDR-BT 68/85 (80.0%) versus RP 4/89 (4.5%); P < 0.001; relative risk 17.80, 95% CI 6.79 to 46.66). The occurrence of urinary stricture did not significantly differ between the treatment groups (LDR-BT 2/85 (2.4%) versus RP 6/89 (6.7%); P = 0.221; relative risk 0.35, 95% CI: 0.07 to 1.68). Long-term information was not available.We did not identify significant differences of mean scores between treatment groups for patient-reported outcomes function and bother as well as generic health-related quality of life.

AUTHORS' CONCLUSIONS

Low-dose rate brachytherapy did not reduce biochemical recurrence-free survival versus radical prostatectomy at 5 years. For short-term severe adverse events, low-dose rate brachytherapy was significantly more favorable for urinary incontinence, but radical prostatectomy was significantly more favorable for urinary irritation. Evidence is based on one RCT with high risk of bias.

Robotic assistance for ultrasound-guided prostate brachytherapy

We present a robotically assisted prostate brachytherapy system and test results in training phantoms and Phase-I clinical trials. The system consists of a transrectal ultrasound (TRUS) and a spatially co-registered robot, fully integrated with an FDA-approved commercial treatment planning system. The salient feature of the system is a small parallel robot affixed to the mounting posts of the template. The robot replaces the template interchangeably, using the same coordinate system. Established clinical hardware, workflow and calibration remain intact. In all phantom experiments, we recorded the first insertion attempt without adjustment. All clinically relevant locations in the prostate were reached. Non-parallel needle trajectories were achieved. The pre-insertion transverse and rotational errors (measured with a Polaris optical tracker relative to the template's coordinate frame) were 0.25 mm (STD=0.17 mm) and 0.75 degrees (STD=0.37 degrees). In phantoms, needle tip placement errors measured in TRUS were 1.04 mm (STD=0.50mm). A Phase-I clinical feasibility and safety trial has been successfully completed with the system. We encountered needle tip positioning errors of a magnitude greater than 4mm in only 2 of 179 robotically guided needles, in contrast to manual template guidance where errors of this magnitude are much more common. Further clinical trials are necessary to determine whether the apparent benefits of the robotic assistant will lead to improvements in clinical efficacy and outcomes.

A comparison of acute and chronic toxicity for men with low-risk prostate cancer treated with intensity-modulated radiation therapy or (125)I permanent implant

PURPOSE

To compare the toxicity and biochemical outcomes of intensity-modulated radiation therapy (IMRT) and (125)I transperineal permanent prostate seed implant ((125)I) for patients with low-risk prostate cancer.

METHODS AND MATERIALS

Between 1998 and 2004, a total of 374 low-risk patients (prostate-specific antigen < 10 ng/ml, T1c-T2b, Gleason score of 6 or less, and no neoadjuvant hormones) were treated at Fox Chase Cancer Center (216 IMRT and 158 (125)I patients). Median follow-up was 43 months for IMRT and 48 months for (125)I. The IMRT prescription dose ranged from 74-78 Gy, and (125)I prescription was 145 Gy. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicity was recorded by using a modified Radiation Therapy Oncology Group scale. Freedom from biochemical failure was defined by using the Phoenix definition (prostate-specific antigen nadir + 2.0 ng/ml).

RESULTS

Patients treated by using IMRT were more likely to be older and have a higher baseline American Urological Association symptom index score, history of previous transurethral resection of the prostate, and larger prostate volumes. On multivariate analysis, IMRT was an independent predictor of lower acute and late Grade 2 or higher GU toxicity and late Grade 2 or higher GI toxicity. Three-year actuarial estimates of late Grade 2 or higher toxicity were 2.4% for GI and 3.5% for GU by using IMRT compared with 7.7% for GI and 19.2% for GU for (125)I, respectively. Four-year actuarial estimates of freedom from biochemical failure were 99.5% for IMRT and 93.5% for (125)I (p = 0.09).

CONCLUSIONS

The IMRT and (125)I produce similar outcomes, although IMRT appears to have less acute and late toxicity.

Rectal morbidity after permanent prostate brachytherapy with dose escalation to biologic target volumes identified by SPECT/CT fusion

PURPOSE

To evaluate rectal morbidity after dose escalation to biologic target volumes identified by capromab pendetide (ProstaScint) single-photon emission tomography images coregistered with computed tomography (SPECT/CT).

METHODS AND MATERIALS

Two hundred thirty-nine consecutive patients diagnosed with T1c-T3b NxM0 adenocarcinoma of the prostate were treated with brachytherapy seed implant (SI) dose escalation to SPECT/CT-identified biologic target volumes, from February 1997 through December 2002. Patients received SI (n=150) or external beam radiation therapy plus SI (n=89). Rectal morbidity was evaluated by clinician scoring using the modified Radiation Therapy Oncology Group criteria. The median followup was 47.2 (range 24.8-96.1) months.

RESULTS

The rate of acute Grades I and II toxicity was 29.9% and 3.7%, respectively, and chronic Grade I toxicity was 15.4%, 12.4%, 2.3%, and 1.8% at 1, 2, 3, and 4 years postimplant, respectively. Chronic Grade II toxicities were 1.8%, 1.9%, 1.5%, and 0.9% at 1, 2, 3, and 4 years, respectively. No Grade III rectal toxicity was reported. Chronic Grade IV rectal toxicity was 0.5% and 0.6% at 1.5 and 2.5 years, respectively. Ninety-six percent of patients reported freedom from all rectal toxicity after 3 years.

CONCLUSIONS

Dose intensification to occult tumor targets without increasing rectal toxicity may be achieved using SPECT/CT ProstaScint. Additional research to define the role of molecular imaging in prostate cancer is warranted.

Long-Term Rectal Function After Permanent Prostate Brachytherapy

PURPOSE

To evaluate the effect of prostate brachytherapy with or without supplemental therapies on long-term rectal function by means of a patient-administered quality-of-life instrument.

MATERIALS AND METHODS

As part of an ongoing prospective evaluation, 164 of an initial 209 patients who remain alive were mailed the Rectal Function Assessment Score (R-FAS) with a prestamped return envelope. R-FAS range from 0 to 27 with lower scores being indicative of better bowel function. Of the 162 eligible patients, 161 (99.4%) returned the survey. Median follow-up was 9.0 years (range 8.2-11.2 years). Clinical, treatment, and dosimetric parameters evaluated for bowel function included patient age, diabetes, hypertension, tobacco consumption, clinical T stage, elapsed time since brachytherapy, ultrasound volume, planning target volume, androgen deprivation therapy, supplemental external beam radiation, isotope, rectal dose, prostate D100/D150/D200, and prostate D90.

RESULTS

For the entire cohort, the current R-FAS was 3.59, which represented a nonstatistical improvement from prior surveys in 1999 (4.29) and 2002 (3.92) (P=0.134). Only 16 patients (9.9%) reported bowel function to be worse after brachytherapy. Of the clinical, treatment, and dosimetric parameters evaluated, only the number of preimplant bowel movements, tobacco use, and diabetes correlated with R-FAS. Despite lower rectal doses with Pd, isotope did not predict for bowel function. Consistent with prior surveys, patient perception of overall rectal quality of life was inversely related to supplemental external beam radiation (P=0.027).

CONCLUSION

Prostate brachytherapy adversely affects bowel function. However, in most patients the changes are minimal and slowly resolve with time. Overall rectal quality of life is inversely related to supplemental external beam radiation.

Prospective evaluation of quality of life after interstitial brachytherapy for localized prostate cancer

PURPOSE

Permanent interstitial brachytherapy (IB) has become an increasingly appealing therapeutic option for localized prostate cancer (LPC) among physicians and patients because it involves short hospitalization and treatment and its postulated low degree of toxicity may reduce its impact on the patients' quality of life (QoL). The aim of this prospective study was to assess the impact of IB on the QoL of patients with LPC.

METHODS AND MATERIALS

A validated self-completed questionnaire was administered to the patients before and after IB and then at yearly intervals. The items allowed the identification of seven subscales exploring physical well-being (PHY), physical autonomy (POW), psychological well-being (PSY), relational life (REL), urinary function (URI), rectal function (REC), and sexual function (SEX).

RESULTS

The assessment of the QoL of 147 patients treated between May 2000 and February 2005 revealed no relevant differences in the PHY scale scores 1 month after IB or later, and the same was true of the POW, PSY, and REL scales. Urinary function significantly worsened after IB and returned to pretreatment levels only after 3 years; the impact of the treatment on the URI scale was greater in the patients with good baseline urinary function than in those presenting more urinary symptoms before IB. Rectal and sexual functions were significantly worse only at the post-IB evaluation.

CONCLUSIONS

The results of the present study confirm that the impact of IB on the patients' QoL is low despite its transient negative effects on some function, and extend existing knowledge concerning QoL after IB.

Rectal-wall dose dependence on postplan timing after permanent-seed prostate brachytherapy

PURPOSE

Dose to rectal wall after permanent-seed prostate brachytherapy is dependent on distance between posterior prostatic seeds and anterior rectal wall and is influenced by postimplant periprostatic edema. We analyzed the effect of postplan timing on anterior rectal-wall dose.

METHODS AND MATERIALS

Twenty patients received permanent seed 125I brachytherapy as monotherapy (145 Gy). Implants were preplanned by use of transrectal ultrasound (TRUS) and carried out by use of preloaded needles. Postimplant dosimetry was calculated by use of magnetic resonance imaging-computed tomography fusion on Days 1, 8, and 30. The anterior rectal-wall dose is reported as the isodose enclosing 1.0 or 2.0 cc of rectal wall and as the RV100 in cc.

RESULTS

The dose to rectal wall increased progressively over time. The median increase in dose to 1.0 cc of rectal wall (RD [1 cc]) from Day 1 to 30 was 39.2 Gy (p < 0.001). RV100 increased from a median of 0.07 cc on Day 1 to 0.67 cc on Day 30. The most significant predictor of rectal-wall dose (RD [1 cc], RD [2 cc], or RV100) was the time of evaluation (p < 0.001).

CONCLUSION

Although periprostatic edema cannot be quantified by postimplant imaging, the dose to the anterior rectal wall increases significantly over time as prostatic and periprostatic edema resolve. Critical-organ dose reporting and guidelines for minimizing toxicity must take into account the time of the assessment.

Rectal toxicity profile after transperineal interstitial permanent prostate brachytherapy: Use of a comprehensive toxicity scoring system and identification of rectal dosimetric toxicity predictors

PURPOSE

To better understand rectal toxicity after prostate brachytherapy, we employed the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE version 3.0), a comprehensive system with distinct and separately reported gastrointestinal adverse event items (unlike Radiation Therapy Oncology Group morbidity scoring), to evaluate item-specific postimplant rectal toxicities.

METHODS AND MATERIALS

We analyzed 135 patients treated with brachytherapy +/- hormonal therapy, using CTCAE v3.0 to score acute/late rectal toxicities (median follow-up, 41 months). Dosimetric parameters were evaluated for ability to predict toxicities.

RESULTS

Use of CTCAE yielded a novel rectal toxicity profile consisting of diarrhea, incontinence, urgency, proctitis, pain, spasms, and hemorrhage event rates. No item had a < 5% Grade 1-2 acute toxicity rate (except spasms). Rectal dosimetry predicted late toxicities: for diarrhea, 5% Grade 1 toxicity rate for %V25 (percent of rectal volume receiving 25% of prescribed prostate dose) < or = 25% vs. 60% for %V25 > 25% (p < 0.001); for maximum toxicity, 10% Grade 1 toxicity rate for %V10 < or = 40% vs. 44% for %V10 > 40% (p = 0.007).

CONCLUSIONS

A comprehensive understanding of item-specific postimplant rectal toxicities was obtained using CTCAE. Rectal %V25 > 25% and %V10 > 40% predicted worse late diarrhea and maximum toxicity, respectively.

Estimating the risk of long-term erectile, urinary and bowel symptoms resulting from prostate cancer treatment

Reports on long-term complications resulting from treatment for localized prostate cancer are very inconsistent. In order to estimate the risks of long-term erectile dysfunction, urine symptoms and bowel symptoms following prostatectomy (RP), external conventional or conformal beam radiation (ERT or CRT) and brachytherapy (BRT), 98 papers from the PubMed and Cochrane Clinical Trial databases were selected, reviewed and critically evaluated. The majority of papers were institution-based retrospective and prospective follow-up studies; only two of these studies measured the risk of developing more than one treatment complication. Due to differences in study designs and populations, it is difficult to directly compare studies and not meaningful to calculate summary estimates. In addition to focusing on randomized clinical trials and well-designed population based studies, future research should adopt standardized methodologies and should measure the risk of developing more than one treatment complication.