Phase III pilot study of dose escalation using conformal radiotherapy in prostate cancer: PSA control and side effects

Maximizing dosimetric benefits of IMRT in the treatment of localized prostate cancer through multicriteria optimization planning

We examine the quality of plans created using multicriteria optimization (MCO) treatment planning in intensity-modulated radiation therapy (IMRT) in treatment of localized prostate cancer. Nine random cases of patients receiving IMRT to the prostate were selected. Each case was associated with a clinically approved plan created using Corvus. The cases were replanned using MCO-based planning in RayStation. Dose-volume histogram data from both planning systems were presented to 2 radiation oncologists in a blinded evaluation, and were compared at a number of dose-volume points. Both physicians rated all 9 MCO plans as superior to the clinically approved plans (p<10(-5)). Target coverage was equivalent (p = 0.81). Maximum doses to the prostate and bladder and the V50 and V70 to the anterior rectum were reduced in all MCO plans (p<0.05). Treatment planning time with MCO took approximately 60 minutes per case. MCO-based planning for prostate IMRT is efficient and produces high-quality plans with good target homogeneity and sparing of the anterior rectum, bladder, and femoral heads, without sacrificing target coverage.

Analysis of late toxicity associated with external beam radiation therapy for prostate cancer with uniform setting of classical 4-field 70 Gy in 35 fractions: a survey study by the Osaka Urological Tumor Radiotherapy Study Group

We aimed to analyse late toxicity associated with external beam radiation therapy (EBRT) for prostate cancer using uniform dose-fractionation and beam arrangement, with the focus on the effect of 3D (CT) simulation and portal field size. We collected data concerning patients with localized prostate adenocarcinoma who had been treated with EBRT at five institutions in Osaka, Japan, between 1998 and 2006. All had been treated with 70 Gy in 35 fractions, using the classical 4-field technique with gantry angles of 0°, 90°, 180° and 270°. Late toxicity was evaluated strictly in terms of the Common Terminology Criteria for Adverse Events Version 4.0. In total, 362 patients were analysed, with a median follow-up of 4.5 years (range 1.0-11.6). The 5-year overall and cause-specific survival rates were 93% and 96%, respectively. The mean ± SD portal field size in the right-left, superior-inferior, and anterior-posterior directions was, respectively, 10.8 ± 1.1, 10.2 ± 1.0 and 8.8 ± 0.9 cm for 2D simulation, and 8.4 ± 1.2, 8.2 ± 1.0 and 7.7 ± 1.0 cm for 3D simulation (P < 0.001). No Grade 4 or 5 late toxicity was observed. The actuarial 5-year Grade 2-3 genitourinary and gastrointestinal (GI) late toxicity rates were 6% and 14%, respectively, while the corresponding late rectal bleeding rate was 23% for 2D simulation and 7% for 3D simulation (P < 0.001). With a uniform setting of classical 4-field 70 Gy/35 fractions, the use of CT simulation and the resultant reduction in portal field size were significantly associated with reduced late GI toxicity, especially with less rectal bleeding.

Conformal radiotherapy plus high dose rate brachytherapy prostate boost in patients with intermediate and high risk prostate cancer: our experience in Asian males

Purpose: Recent studies have shown increased prostate cancer control rates with radiation dose escalation. Herein the experience of dose escalation by high dose rate brachytherapy (HDR-BT) adjunct to the three-dimensional conformal radiation therapy (3D-CRT) for prostate cancer is presented.

Patients and methods: During the period between August 2005 and July 2007, patients with intermediate and high risk prostate cancer were treated with 3D-CRT of dose 46Gy ÷ 23 fractions to whole pelvis followed by: Arm A (102 patients): prostate boost with HDR-BT 14 Gy × 2 sessions and Arm B (103 patients): prostate boost via 3D-CRT of dose 26 Gy ÷ 13 fractions. Primary objectives were overall survival (OS), distant metastases free survival (DMFS) and PSA progression free survival (PPFS) rates. Secondary objectives were the toxicity profile and post-radiation histopathological response.

Results: At median follow up of 3.5 years, PPFS, DMFS and OS rates were; 97.8% versus 89.0% (p = 0.009), 98.1% versus 93.6% (p = 0.13) and 98.8% versus 91.6% (p = 0.24) in Arm A and Arm B. respectively. Grade 3 or 4 delayed genitourinary toxicities occurred in 2% and 4.8% of patients in Arm A and Arm B, respectively. Delayed grade 3 and 4 gastrointestinal toxicities were seen in 2% and 3.9% of patients in Arm A and Arm B, respectively. The post-radiation prostate biopsies were negative in 14/17(82.3%) and 9/15 (60%) in Arm A and Arm B, respectively.

Conclusion: 3D-CRT combined with HDR-BT resulted in better PPFS and lower morbidity than 3DCRT alone for intermediate and high risk prostate cancer.

Intensity modulated proton and photon therapy for early prostate cancer with or without transperineal injection of a polyethylen glycol spacer: a treatment planning comparison study

PURPOSE

Rectal toxicity is a serious adverse effect in early-stage prostate cancer patients treated with curative radiation therapy (RT). Injecting a spacer between Denonvilliers' fascia increases the distance between the prostate and the anterior rectal wall and may thus decrease the rectal radiation-induced toxicity. We assessed the dosimetric impact of this spacer with advanced delivery RT techniques, including intensity modulated RT (IMRT), volumetric modulated arc therapy (VMAT), and intensity modulated proton beam RT (IMPT).

METHODS AND MATERIALS

Eight prostate cancer patients were simulated for RT with or without spacer. Plans were computed for IMRT, VMAT, and IMPT using the Eclipse treatment planning system using both computed tomography spacer+ and spacer- data sets. Prostate ± seminal vesicle planning target volume [PTV] and organs at risk (OARs) dose-volume histograms were calculated. The results were analyzed using dose and volume metrics for comparative planning.

RESULTS

Regardless of the radiation technique, spacer injection decreased significantly the rectal dose in the 60- to 70-Gy range. Mean V(70 Gy) and V(60 Gy) with IMRT, VMAT, and IMPT planning were 5.3 ± 3.3%/13.9 ± 10.0%, 3.9 ± 3.2%/9.7 ± 5.7%, and 5.0 ± 3.5%/9.5 ± 4.7% after spacer injection. Before spacer administration, the corresponding values were 9.8 ± 5.4% (P=.012)/24.8 ± 7.8% (P=.012), 10.1 ± 3.0% (P=.002)/17.9 ± 3.9% (P=.003), and 9.7 ± 2.6% (P=.003)/14.7% ± 2.7% (P=.003). Importantly, spacer injection usually improved the PTV coverage for IMRT. With this technique, mean V(70.2 Gy) (P=.07) and V(74.1 Gy) (P=0.03) were 100 ± 0% to 99.8 ± 0.2% and 99.1 ± 1.2% to 95.8 ± 4.6% with and without Spacer, respectively. As a result of spacer injection, bladder doses were usually higher but not significantly so. Only IMPT managed to decrease the rectal dose after spacer injection for all dose levels, generally with no observed increase to the bladder dose.

CONCLUSIONS

Regardless of the radiation technique, a substantial decrease of rectal dose was observed after spacer injection for curative RT to the prostate.

Effects of genetically engineered stem cells expressing cytosine deaminase and interferon-beta or carboxyl esterase on the growth of LNCaP rrostate cancer cells

The risk of prostate cancer has been increasing in men by degrees. To develop a new prostate cancer therapy, we used a stem cell-derived gene directed prodrug enzyme system using human neural stem cells (hNSCs) that have a tumor-tropic effect. These hNSCs were transduced with the therapeutic genes for bacterial cytosine deaminase (CD), alone or in combination with the one encoding human interferon-beta (IFN-β) or rabbit carboxyl esterase (CE) to generate HB1.F3.CD, HB1.F3.CD.IFN-β, and HB1.F3.CE cells, respectively. CD enzyme can convert the prodrug 5-fluorocytosine (5-FC) into the activated form 5-fluorouracil (5-FU). In addition, CE enzyme can convert the prodrug CPT-11 into a toxic agent, SN-38. In our study, the human stem cells were found to migrate toward LNCaP human prostate cancer cells rather than primary cells. This phenomenon may be due to interactions between chemoattractant ligands and receptors, such as VEGF/VEGFR2 and SCF/c-Kit, expressed as cancer and stem cells, respectively. The HB1.F3.CE, HB.F3.CD, or HB1.F3.CD.IFN-β cells significantly reduced the LNCaP cell viability in the presence of the prodrugs 5-FC or CPT-11. These results indicate that stem cells expressing therapeutic genes can be used to develop a new strategy for selectively treating human prostate cancer.

Late gastrointestinal and urogenital side-effects after radiotherapy--incidence and prevalence. Subgroup-analysis within the prospective Austrian-German phase II multicenter trial for localized prostate cancer

PURPOSE

In general late side-effects after prostate cancer radiotherapy are presented by the use of actuarial incidence rates. The aim of this analysis was to describe additional relevant aspects of late side effects after prostate cancer radiotherapy.

MATERIALS AND METHODS

All 178 primary prostate-cancer patients were treated within the Austrian-German multicenter trial by three-dimensional radiotherapy up to a local dose of 70 Gy (low/intermediate-risk) or 74 Gy (high-risk), respectively. Late gastrointestinal/urogenital (GI/GU) side-effects were prospectively assessed by the use of EORTC/RTOG score. Maximum side-effects, actuarial incidence rate and prevalence rates, initial appearance and duration of ≥grade 2 toxicity were evaluated.

RESULTS

Median follow-up was 74 months. Late GI/GU side-effects ≥grade 2 were detected in 15% (27/178) and 22% (40/178). The corresponding 5-year actuarial incidence rates for GI/GU side-effects were 19% and 23%, whereas the prevalence was 1-2% and 2-7% after 5 years, respectively. Late side effects ≥grade 2 appeared within 5 years after radiotherapy in all patients with GI side-effects (27/27) and in 85% (34/40) of the patients with GU side-effects, respectively and lasted for less than 3 years in 90% (GI) and 98% (GU).

CONCLUSIONS

This study demonstrates that the majority of late GI and GU side effects after primary external beam radiotherapy for prostate cancer are transient. Using only actuarial incidence rates for reporting side effects may lead to misinterpretation or overestimation. The combination of incidence and prevalence rates provides a more comprehensive view on the complex issue of late side effects.

Improvement in prostate cancer survival over time: a 20-year analysis

PURPOSE

This study aimed to evaluate the changes in outcome for men with localized prostate cancer treated with definitive external beam radiation therapy during a 20-year period at a comprehensive cancer center.

METHODS

We categorized 2675 men with prostate cancer treated at MD Anderson Cancer Center with definitive external beam radiation therapy with or without androgen deprivation therapy into 3 treatment eras: 1987 to 1993 (n = 722), 1994 to 1999 (n = 828), and 2000 to 2007 (n = 1125). To help adjust for stage migration, patients were stratified according to risk group as defined by the National Comprehensive Cancer Network. Biochemical (Phoenix definition), local, distant, and any clinical failure, prostate-cancer specific survival, and overall survival were analyzed according to the Kaplan-Meier method.

RESULTS

Median age was 68.5 years and median follow-up was 6.4 years. Fewer men in the most recent era had high-risk disease, and a higher proportion received 72 Gy or higher (99% vs 4%) and androgen deprivation therapy (60% vs 6%) than the earliest era. All risk groups treated in the modern era experienced improved rates of biochemical, local, and distant failure. In high-risk patients, decreased rates of distant failure and clinical failure led to improved prostate cancer-specific survival and overall survival. Local control was improved for intermediate- and high-risk patients, with a trend toward improvement in low-risk patients. On multivariate analysis, recent treatment era was closely correlated with a dose of 72 Gy or higher and treatment with androgen deprivation therapy and predicted for lower rates of biochemical, local, and distant failure. Androgen deprivation therapy, higher dose, and more recent treatment era predicted for improved prostate cancer-specific survival.

DISCUSSION

During the last 20 years of prostate cancer irradiation, disease control outcomes have improved in all patients, leading to improved prostate cancer-specific survival and overall survival for men with high-risk disease. This may reflect advances in workup, staging accuracy, and prostate cancer treatment in the modern era.

Phase I/II trial of single-fraction high-dose-rate brachytherapy-boosted hypofractionated intensity-modulated radiation therapy for localized adenocarcinoma of the prostate

PURPOSE

A Phase I/II protocol was conducted to examine the toxicity and efficacy of the combination of intensity-modulated radiation therapy (IMRT) with a single-fraction high-dose-rate (HDR) brachytherapy implant.

METHODS AND MATERIALS

From 2001 through 2006, 26 consecutive patients were treated on the trial. The primary objective was to demonstrate a high rate of completion without experiencing a treatment-limiting toxicity. Eligibility was limited to patients with T stage ≤2b, prostate-specific antigen (PSA) ≤20, and Gleason score ≤7. Treatment began with a single HDR fraction of 6Gy to the entire prostate and 9Gy to the peripheral zone, followed by IMRT optimized to deliver in 28 fractions with a normalized total dose of 70Gy. Patients received 50.4Gy to the pelvic lymph node. The prostate dose (IMRT and HDR) resulted in an average biologic equivalent dose >128Gy (α/β=3). Patients whose pretreatment PSA was ≥10ng/mL, Gleason score 7, or stage ≥T2b received short-term androgen ablation.

RESULTS

Median followup was 53 months (9-68 months). There were no biochemical failures by either the American Society of Therapeutic Radiology and Oncology or the Phoenix definitions. The median nadir PSA was 0.32ng/mL. All the 26 patients completed the treatment as prescribed. The rate of Grade 3 late genitourinary toxicity was 3.8% consisting of a urethral stricture. There was no other Grade 3 or 4 genitourinary or gastrointestinal toxicities.

CONCLUSIONS

Single-fraction HDR-boosted IMRT is a safe effective method of dose escalation for localized prostate cancer.

Long-term biochemical results after high-dose-rate intensity modulated brachytherapy with external beam radiotherapy for high risk prostate cancer

Background

Biochemical control from series in which radical prostatectomy is performed for patients with unfavorable prostate cancer and/or low dose external beam radiation therapy are given remains suboptimal.

The treatment regimen of HDR brachytherapy and external beam radiotherapy is a safe and very effective treatment for patients with high risk localized prostate cancer with excellent biochemical control and low toxicity.

Conventional versus hypofractionated high-dose intensity-modulated radiotherapy for prostate cancer: preliminary safety results from the CHHiP randomised controlled trial

BACKGROUND

Prostate cancer might have high radiation-fraction sensitivity, implying a therapeutic advantage of hypofractionated treatment. We present a pre-planned preliminary safety analysis of side-effects in stages 1 and 2 of a randomised trial comparing standard and hypofractionated radiotherapy.

METHODS

We did a multicentre, randomised study and recruited men with localised prostate cancer between Oct 18, 2002, and Aug 12, 2006, at 11 UK centres. Patients were randomly assigned in a 1:1:1 ratio to receive conventional or hypofractionated high-dose intensity-modulated radiotherapy, and all were given with 3-6 months of neoadjuvant androgen suppression. Computer-generated random permuted blocks were used, with risk of seminal vesicle involvement and radiotherapy-treatment centre as stratification factors. The conventional schedule was 37 fractions of 2 Gy to a total of 74 Gy. The two hypofractionated schedules involved 3 Gy treatments given in either 20 fractions to a total of 60 Gy, or 19 fractions to a total of 57 Gy. The primary endpoint was proportion of patients with grade 2 or worse toxicity at 2 years on the Radiation Therapy Oncology Group (RTOG) scale. The primary analysis included all patients who had received at least one fraction of radiotherapy and completed a 2 year assessment. Treatment allocation was not masked and clinicians were not blinded. Stage 3 of this trial completed the planned recruitment in June, 2011. This study is registered, number ISRCTN97182923.

FINDINGS

153 men recruited to stages 1 and 2 were randomly assigned to receive conventional treatment of 74 Gy, 153 to receive 60 Gy, and 151 to receive 57 Gy. With 50·5 months median follow-up (IQR 43·5-61·3), six (4·3%; 95% CI 1·6-9·2) of 138 men in the 74 Gy group had bowel toxicity of grade 2 or worse on the RTOG scale at 2 years, as did five (3·6%; 1·2-8·3) of 137 men in the 60 Gy group, and two (1·4%; 0·2-5·0) of 143 men in the 57 Gy group. For bladder toxicities, three (2·2%; 0·5-6·2) of 138 men, three (2·2%; 0·5-6·3) of 137, and none (0·0%; 97·5% CI 0·0-2·6) of 143 had scores of grade 2 or worse on the RTOG scale at 2 years.

INTERPRETATION

Hypofractionated high-dose radiotherapy seems equally well tolerated as conventionally fractionated treatment at 2 years.

FUNDING

Stage 1 was funded by the Academic Radiotherapy Unit, Cancer Research UK programme grant; stage 2 was funded by the Department of Health and Cancer Research UK.

A comparison of imaging schedules for prostate radiotherapy including online tracking techniques

Background and purpose: Repeat imaging protocols, specifying imaging frequency and action levels for movement correction, can be used to achieve more accurate targeting of the prostate gland during radiotherapy. We have carried out a study comparing the accuracies of online versus off-line correction strategies which use implanted marker seeds to localize the prostate.

Material and methods: Data have been analysed for 60 prostate patients, verified using an online imaging technique. Systematic and random errors have been calculated for a daily imaging protocol and for other common imaging schedules. Resource requirements have been assessed for the daily imaging technique by analysing the in-room timings performed on 10 patients.

Results: Daily imaging is beneficial for the majority of patients, an online imaging schedule with a 2 mm action level significantly reducing systematic and random errors. The online imaging can be performed with a 2-minute increase in the standard treatment slot.

Conclusions: Online imaging tracking techniques can facilitate margin reduction, which may help to reduce rectal toxicities. The impact on departmental time and resource requirements is modest for the online daily tracking technique with marker seeds and kilovoltage planar imaging.

Acute toxicity in prostate cancer patients treated with and without image-guided radiotherapy

BACKGROUND

Image-guided radiotherapy (IGRT) increases the accuracy of treatment delivery through daily target localisation. We report on toxicity symptoms experienced during radiotherapy treatment, with and without IGRT in prostate cancer patients treated radically.

METHODS

Between 2006 and 2009, acute toxicity data for ten symptoms were collected prospectively onto standardized assessment forms. Toxicity was scored during radiotherapy, according to the Common Terminology Criteria Adverse Events V3.0, for 275 prostate cancer patients before and after the implementation of a fiducial marker IGRT program and dose escalation from 74 Gy in 37 fractions, to 78 Gy in 39 fractions. Margins and planning constraints were maintained the same during the study period. The symptoms scored were urinary frequency, cystitis, bladder spasm, urinary incontinence, urinary retention, diarrhoea, haemorrhoids, proctitis, anal skin discomfort and fatigue. Analysis was conducted for the maximum grade of toxicity and the median number of days from the onset of that toxicity to the end of treatment.

RESULTS

In the IGRT group, 14228 toxicity scores were analysed from 249 patients. In the non-IGRT group, 1893 toxicity scores were analysed from 26 patients. Urinary frequency ≥G3 affected 23% and 7% in the non-IGRT and IGRT group respectively (p = 0.0188). Diarrhoea ≥G2 affected 15% and 3% of patients in the non-IGRT and IGRT groups (p = 0.0174). Fatigue ≥G2 affected 23% and 8% of patients in the non-IGRT and IGRT groups (p = 0.0271). The median number of days with a toxicity was higher for ≥G2 (p = 0.0179) and ≥G3 frequency (p = 0.0027), ≥G2 diarrhoea (p = 0.0033) and ≥G2 fatigue (p = 0.0088) in the non-IGRT group compared to the IGRT group. Other toxicities were not of significant statistical difference.

CONCLUSIONS

In this study, prostate cancer patients treated radically with IGRT had less severe urinary frequency, diarrhoea and fatigue during treatment compared to patients treated with non-IGRT. Onset of these symptoms was earlier in the non-IGRT group. IGRT results in less acute toxicity during radiotherapy in prostate cancer.

Biochemical outcome after high-dose-rate intensity modulated brachytherapy with external beam radiotherapy: 12 years of experience

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Biochemical control from series in which radical prostatectomy is performed for patients with unfavorable prostate cancer and/or low dose external beam radiation therapy are given remains suboptimal. The treatment regimen of HDR brachytherapy and external beam radiotherapy is a safe and very effective treatment for patients with high risk localized prostate cancer with excellent biochemical control and low toxicity.

OBJECTIVE

• To investigate the long-term oncological outcome, during the PSA era, of patients with prostate cancer who were treated using high-dose-rate (HDR) brachy therapy (BT) combined with external beam radiation therapy (EBRT).

PATIENTS AND METHODS

• From June 1998 to April 2007, 313 patients with localized prostate cancer were treated with 46 Gy of EBRT to the pelvis with a HDR-BT boost. • The mean (median) follow-up was 71 (68) months. • Toxicity was reported according to the Common Toxicity Criteria for Adverse Event, V.4.

RESULTS

• The 10-year actuarial biochemical control was 100% for patients with no high-risk criteria, 88% for patients with two intermediate-risk criteria, 91% with one high-risk criterion and 79% for patients with two to three high-risk criteria (P= 0.004). • The 10-year cancer-specific survival was 97% (standard deviation ± 1%). • The multivariate Cox regression analyses identified, Gleason score and T stage as independent prognostic factors for biochemical failure. • Gleason score was the only factor to significantly affect distant metastases. • Grade ≥ 3 late toxicity was not detected.

CONCLUSION

• The 10-year results confirm the feasibility and effectiveness of EBRT with conformal HDR-BT boost for patients with localised prostate cancer.

MAGE-C2/CT10 protein expression is an independent predictor of recurrence in prostate cancer

The cancer-testis (CT) family of antigens is expressed in a variety of malignant neoplasms. In most cases, no CT antigen is found in normal tissues, except in testis, making them ideal targets for cancer immunotherapy. A comprehensive analysis of CT antigen expression has not yet been reported in prostate cancer. MAGE-C2/CT-10 is a novel CT antigen. The objective of this study was to analyze extent and prognostic significance of MAGE-C2/CT10 protein expression in prostate cancer. 348 prostate carcinomas from consecutive radical prostatectomies, 29 castration-refractory prostate cancer, 46 metastases, and 45 benign hyperplasias were immunohistochemically analyzed for MAGE-C2/CT10 expression using tissue microarrays. Nuclear MAGE-C2/CT10 expression was identified in only 3.3% primary prostate carcinomas. MAGE-C2/CT10 protein expression was significantly more frequent in metastatic (16.3% positivity) and castration-resistant prostate cancer (17% positivity; p<0.001). Nuclear MAGE-C2/CT10 expression was identified as predictor of biochemical recurrence after radical prostatectomy (p = 0.015), which was independent of preoperative PSA, Gleason score, tumor stage, and surgical margin status in multivariate analysis (p<0.05). MAGE-C2/CT10 expression in prostate cancer correlates with the degree of malignancy and indicates a higher risk for biochemical recurrence after radical prostatectomy. Further, the results suggest MAGE-C2/CT10 as a potential target for adjuvant and palliative immunotherapy in patients with prostate cancer.

Toxicity analysis of dose escalation from 75.6 gy to 81.0 gy in prostate cancer

OBJECTIVE

Several randomized trials have demonstrated a biochemical control advantage to an increase from the "conventional" 66 to 70 Gy range to the "high-dose" 75 to 81 Gy range; these trials have also, however, demonstrated a toxicity disadvantage. Our objective was to perform a toxicity analysis of a minor dose escalation (from 75.6 to 81.0 Gy) within this "high-dose" range.

METHODS

A total of 189 patients comprised the study population-119 received 75.6 Gy and 70 received 81.0 Gy. Acute, late, and final (at most recent follow-up) gastrointestinal (GI) and genitourinary (GU) toxicity were charted for each group and compared using the χ test. Ordered logit regression analyses were performed on each toxicity end point, using all major demographic, disease, and treatment factors as covariates.

RESULTS

The 81.0 Gy group had higher rates of grade 2 acute GU (P < 0.001), late GU (P = 0.001), and late GI (P = 0.082) toxicity, a lower rate of acute GI toxicity (P = 0.002) and no notable differences in final GU (P = 0.551) or final GI (P = 0.194) toxicity compared with the 75.6 Gy group. The ordered logit regression analyses showed that only age (P = 0.019) and radiotherapy dose (P = 0.016) correlated with acute GU toxicity and only radiotherapy dose (P = 0.018) correlated with late GU toxicity. Only intensity modulated radiotherapy use (P = 0.001) correlated with acute GI toxicity; no factors correlated with late GI toxicity or final GU or GI toxicity.

CONCLUSIONS

Although some increases in acute and late toxicity rates were observed with even a minor dose escalation from 75.6 to 81.0 Gy, notably no increases in final late GI or GU toxicity rates were observed.

VMAT vs. 7-field-IMRT: assessing the dosimetric parameters of prostate cancer treatment with a 292-patient sample

We compared normal tissue radiation dose for the treatment of prostate cancer using 2 different radiation therapy delivery methods: volumetric modulated arc therapy (VMAT) vs. fixed-field intensity-modulated radiation therapy (IMRT). Radiotherapy plans for 292 prostate cancer patients treated with VMAT to a total dose of 7740 cGy were analyzed retrospectively. Fixed-angle, 7-field IMRT plans were created using the same computed tomography datasets and contours. Radiation doses to the planning target volume (PTV) and organs at risk (bladder, rectum, penile bulb, and femoral heads) were measured, means were calculated for both treatment methods, and dose-volume comparisons were made with 2-tailed, paired t-tests. The mean dose to the bladder was lower with VMAT at all measured volumes: 5, 10, 15, 25, 35, and 50% (p < 0.05). The mean doses to 5 and 10% of the rectum, the high-dose regions, were lower with VMAT (p < 0.05). The mean dose to 15% of the rectal volume was not significantly different (p = 0.95). VMAT exposed larger rectal volumes (25, 35, and 50%) to more radiation than fixed-field IMRT (p < 0.05). Average mean dose to the penile bulb (p < 0.05) and mean dose to 10% of the femoral heads (p < 0.05) were lower with VMAT. VMAT therapy for prostate cancer has dosimetric advantages for critical structures, notably for high-dose regions compared with fixed-field IMRT, without compromising PTV coverage. This may translate into reduced acute and chronic toxicity.

Dose escalation improves cancer-related events at 10 years for intermediate- and high-risk prostate cancer patients treated with hypofractionated high-dose-rate boost and external beam radiotherapy

PURPOSE

To evaluate the 10-year outcomes of intermediate- and high-risk prostate cancer patients treated with a prospective dose escalation hypofractionated trial of pelvic external beam radiation therapy (P-EBRT) with a high-dose-rate (HDR) brachytherapy boost.

METHODS AND MATERIALS

From 1992 to 2007, 472 patients were treated with a HDR boost at William Beaumont Hospital. They had at least one of the following: a prostate-specific antigen (PSA) level of >10 ng/ml, a Gleason score of ≥7, or clinical stage ≥T2b. Patients received 46-Gy P-EBRT and an HDR boost. The HDR dose fractionation was divided into two dose levels. The prostate biologically equivalent dose (BED) low-dose-level group received <268 Gy, and the high-dose group received >268 Gy . Phoenix biochemical failure (BF) definition was used.

RESULTS

Median follow-up was 8.2 years (range, 0.4-17 years). The 10-year biochemical failure rate of 43.1% vs. 18.9%, (p < 0.001), the clinical failure rate of 23.4% vs. 7.7%, (p < 0.001), and the distant metastasis of 12.4% vs. 5.7%, (p = 0.028) were all significantly better for the high-dose level group. On Cox multivariate analysis, higher BED levels (p = 0.017; hazard ratio [HR] = 0.586), pretreatment PSA assays (p < 0.001, HR = 1.022), and Gleason scores (p = 0.004) were significant variables for reduced biochemical failure. Higher dose levels (p, 0.002; HR, 0.397) and Gleason scores (p < 0.001) were significant for clinical failure. Grade 3 genitourinary complications were 2% and 3%, respectively, and grade 3 gastrointestinal complication was <0.5%.

CONCLUSIONS

This prospective trial using P-EBRT with HDR boost and hypofractionated dose escalation demonstrates a strong dose-response relationship for intermediate- and high-risk prostate cancer patients. The improvement at 10 years for locoregional control with higher radiation doses (BED, > 268 Gy) has significantly decreased biochemical and clinical failures as well as distant metastasis.

Comparison of acute and late toxicities for three modern high-dose radiation treatment techniques for localized prostate cancer

PURPOSE

We compared acute and late genitourinary (GU) and gastrointestinal (GI) toxicities in prostate cancer patients treated with three different high-dose radiation techniques.

METHODS AND MATERIALS

A total of 1,903 patients with localized prostate cancer were treated with definitive RT at William Beaumont Hospital from 1992 to 2006: 22% with brachytherapy alone (BT), 55% with image-guided external beam (EB-IGRT), and 23% external beam with high-dose-rate brachytherapy boost (EBRT+HDR). Median dose with BT was 120 Gy for LDR and 38 Gy for HDR (9.5 Gy × 4). Median dose with EB-IGRT was 75.6 Gy (PTV) to prostate with or without seminal vesicles. For EBRT+HDR, the pelvis was treated to 46 Gy with an additional 19 Gy (9.5 Gy × 2) delivered via HDR. GI and GU toxicity was evaluated utilizing the NCI-CTC criteria (v.3.0). Median follow-up was 4.8 years.

RESULTS

The incidences of any acute ≥ Grade 2 GI or GU toxicities were 35%, 49%, and 55% for BT, EB-IGRT, and EBRT+HDR (p < 0.001). Any late GU toxicities ≥ Grade 2 were present in 22%, 21%, and 28% for BT, EB-IGRT, and EBRT+HDR (p = 0.01), respectively. Patients receiving EBRT+HDR had a higher incidence of urethral stricture and retention, whereas dysuria was most common in patients receiving BT. Any Grade ≥ 2 late GI toxicities were 2%, 20%, and 9% for BT, EB-IGRT, and EBRT+HDR (p < 0.001). Differences were most pronounced for rectal bleeding, with 3-year rates of 0.9%, 20%, and 6% (p < 0.001) for BT, EB-IGRT, and EBRT+HDR respectively.

CONCLUSIONS

Each of the three modern high-dose radiation techniques for localized prostate cancer offers a different toxicity profile. These data can help patients and physicians to make informed decisions regarding radiotherapy for prostate andenocarcinoma.

70 Gy versus 80 Gy in localized prostate cancer: 5-year results of GETUG 06 randomized trial

PURPOSE

To perform a randomized trial comparing 70 and 80 Gy radiotherapy for prostate cancer.

PATIENTS AND METHODS

A total of 306 patients with localized prostate cancer were randomized. No androgen deprivation was allowed. The primary endpoint was biochemical relapse according to the modified 1997-American Society for Therapeutic Radiology and Oncology and Phoenix definitions. Toxicity was graded using the Radiation Therapy Oncology Group 1991 criteria and the late effects on normal tissues-subjective, objective, management, analytic scales (LENT-SOMA) scales. The patients' quality of life was scored using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire 30-item cancer-specific and 25-item prostate-specific modules.

RESULTS

The median follow-up was 61 months. According to the 1997-American Society for Therapeutic Radiology and Oncology definition, the 5-year biochemical relapse rate was 39% and 28% in the 70- and 80-Gy arms, respectively (p = .036). Using the Phoenix definition, the 5-year biochemical relapse rate was 32% and 23.5%, respectively (p = .09). The subgroup analysis showed a better biochemical outcome for the higher dose group with an initial prostate-specific antigen level >15 ng/mL. At the last follow-up date, 26 patients had died, 10 of their disease and none of toxicity, with no differences between the two arms. According to the Radiation Therapy Oncology Group scale, the Grade 2 or greater rectal toxicity rate was 14% and 19.5% for the 70- and 80-Gy arms (p = .22), respectively. The Grade 2 or greater urinary toxicity was 10% at 70 Gy and 17.5% at 80 Gy (p = .046). Similar results were observed using the LENT-SOMA scale. Bladder toxicity was more frequent at 80 Gy than at 70 Gy (p = .039). The quality-of-life questionnaire results before and 5 years after treatment were available for 103 patients with no differences found between the 70- and 80-Gy arms.

CONCLUSION

High-dose radiotherapy provided a better 5-year biochemical outcome with slightly greater toxicity.

Current clinical evidence for proton therapy

Proton beam therapy provides the opportunity for more localized delivery of ionizing radiation with the potential for improved normal tissue avoidance to reduce treatment related morbidity and to allow for dose escalation to improve disease control and survival without increased toxicity. However, a systematic review of published peer-reviewed literature reported previously and updated here is devoid of any clinical data demonstrating benefit in terms of survival, tumor control, or toxicity in comparison with best conventional treatment for any of the tumors so far treated including skull base and ocular tumors, prostate cancer and childhood malignancies. The current lack of evidence for benefit of protons should provide a stimulus for continued research. Well designed in silico clinical trials using validated normal tissue complication probability-models are important to predict the magnitude of benefit for individual tumor sites but the future use of protons should be guided by clear evidence of benefit demonstrated in well-designed prospective studies, away from commercial influence, and this is likely to require international collaboration. Any complex and expensive technology, including proton therapy, should not be employed on the basis of belief alone and requires testing to avoid inappropriate use of potential detriment to future patients.

Treatment strategies for high-risk locally advanced prostate cancer

High-risk prostate cancer can be defined by the assessment of pretreatment prognostic factors such as clinical stage, Gleason score, and PSA level. High-risk features include PSA >20 ng/ml, Gleason score 8-10, and stage T3 tumors. Patients with adverse prognostic factors have historically fared poorly with monotherapeutic approaches. Multimodal treatment utilizing combined androgen suppression and radiotherapy has improved survival rates for patients with high-risk prostate cancer. In addition, multiple randomized trials in patients treated with primary radical prostatectomy have demonstrated improved outcomes with the addition of adjuvant radiotherapy. Improved radiotherapy techniques that allow for dose escalation, and new systemic therapy approaches such as adjuvant chemotherapy, present promising future therapeutic alternatives for patients with high-risk prostate cancer.

A review of the clinical evidence for intensity-modulated radiotherapy

AIMS

Intensity-modulated radiotherapy (IMRT) is a development of three-dimensional conformal radiotherapy that offers improvements in dosimetry in many clinical scenarios. Here we review the clinical evidence for IMRT and present ongoing or unpublished randomised controlled trials (RCTs).

METHODS

We identified randomised and non-randomised comparative studies of IMRT and conventional radiotherapy using MEDLINE, hand-searching Radiotherapy and Oncology and the International Journal of Radiation Oncology, Biology and Physics and the proceedings of the American Society for Therapeutic Radiology and Oncology and the European Society for Therapeutic Radiology and Oncology annual meetings. The metaRegister of Controlled Trials was searched to identify completed-unpublished, ongoing and planned RCTs.

RESULTS

Sixty-one studies comparing IMRT and conventional radiotherapy were identified. These included three RCTs in head and neck cancer (205 patients) and three in breast cancer (664 patients) that had reported clinical outcomes; these were all powered for toxicity-related end points, which were significantly better with IMRT in each trial. There were 27 additional non-randomised studies in head and neck (1119 patients), 26 in prostate cancer (>5000 patients), four in breast cancer (875 patients) and nine in other tumour sites. The results of these studies supported those of the RCTs with benefits reported in acute and late toxicity, health-related quality of life and tumour control end points. Twenty-eight completed-unpublished, ongoing or planned RCTs incorporating IMRT were identified, including at least 12,310 patients, of which 15 compared conventional radiotherapy within IMRT as a randomisation or pre-planned stratification.

DISCUSSION

Inverse-planned IMRT maintains parotid saliva production and reduces acute and late xerostomia during radiotherapy for locally advanced head and neck cancer, reduces late rectal toxicity in prostate cancer patients allowing safe dose escalation and seems to reduce toxicity in several other tumour sites. Forward-planned IMRT reduces acute toxicity and improves late clinician-assessed cosmesis compared with conventional tangential breast radiotherapy.

Adaptive radiation therapy for prostate cancer

Adaptive radiotherapy has been introduced to manage an individual's treatment by, including patient-specific treatment variation identified and quantified during the course of radiotherapy in the treatment planning and delivering optimization. Early studies have demonstrated that this technique could significantly improve the therapeutic ratio by safely reducing the large target margin that has to be used in conventional radiotherapy for prostate cancer treatment. Clinical application of off-line image-guided adaptive radiotherapy for prostate cancer has demonstrated encouraging clinical outcome. Long-term clinical follow-up has shown significant improvement in terms of tumor control and low toxicity profile, emphasizing the beneficial effect of image-guidance and adaptive treatment. Continuous development in adaptive radiotherapy has made possible additional increases in target dose by further reducing target margin when using online image-guided adaptive intensity-modulated radiation therapy. However, clinical implementation of new techniques should be explored cautiously and should include a comprehensive management strategy to address uncertainties in target definition and delineation in the preclinical implementation studies.

Dose Escalation Study with Two Different Hypofractionated Intensity Modulated Radiotherapy Techniques for Localized Prostate Cancer: Acute Toxicity

To assess acute gastrointestinal (GI) and genitourinary (GU) toxicities in patients with localized prostate cancer treated with a sequential dose escalation hypofractionated intensity-modulated radiotherapy (IMRT) study using two different delivery methods. Since 2003, 88 and 48 patients were sequentially treated to 56 Gy and to 60 Gy (4 Gy/fraction twice weekly), respectively. IMRT with 6 MV beams was delivered with five fields in Geneva and with nine in Barcelona. Acute GI and GU side effects were scored weekly during treatment and 6 weeks after treatment completion using the Radiation Therapy Oncology Group (RTOG) toxicity scale. Clinical, technical, and dosimetric parameters were analyzed in order to assess for a potential correlation with toxicity.

Grade 1–2, GU and GI toxicities during and 6 weeks after treatment completion were 64%, and 24%, and 35% and 12%, respectively. Only one Grade 4 GU toxicity, consisting of transitory urinary obstruction, was observed. Patients treated to 60 Gy in Geneva presented a higher rate of Grade 1–2 GU toxicity ( p = 0.01), while patients treated to both 56 and 60 Gy in Barcelona presented a higher Grade 1–2 GI toxicity ( p = 0.02). A lower rate of rectal toxicity was observed in the subgroup of 22 patients treated with a rectal balloon ( p = 0.02). The use of androgen deprivation therapy was associated with a higher rate of Grade 1–2 GU toxicity after the end of the treatment ( p = 0.02). Dose escalation with either 14 × 4 Gy or 15 × 4 Gy delivered with two different IMRT techniques is feasible and is associated with a tolerable acute toxicity.

Dose-volume constraints to reduce rectal side effects from prostate radiotherapy: evidence from MRC RT01 Trial ISRCTN 47772397

PURPOSE

Radical radiotherapy for prostate cancer is effective but dose limited because of the proximity of normal tissues. Comprehensive dose-volume analysis of the incidence of clinically relevant late rectal toxicities could indicate how the dose to the rectum should be constrained. Previous emphasis has been on constraining the mid-to-high dose range (>/=50 Gy). Evidence is emerging that lower doses could also be important.

METHODS AND MATERIALS

Data from a large multicenter randomized trial were used to investigate the correlation between seven clinically relevant rectal toxicity endpoints (including patient- and clinician-reported outcomes) and an absolute 5% increase in the volume of rectum receiving the specified doses. The results were quantified using odds ratios. Rectal dose-volume constraints were applied retrospectively to investigate the association of constraints with the incidence of late rectal toxicity.

RESULTS

A statistically significant dose-volume response was observed for six of the seven endpoints for at least one of the dose levels tested in the range of 30-70 Gy. Statistically significant reductions in the incidence of these late rectal toxicities were observed for the group of patients whose treatment plans met specific proposed dose-volume constraints. The incidence of moderate/severe toxicity (any endpoint) decreased incrementally for patients whose treatment plans met increasing numbers of dose-volume constraints from the set of V30

CONCLUSION

Considering the entire dose distribution to the rectum by applying dose-volume constraints such as those tested here in the present will reduce the incidence of late rectal toxicity.

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Key Words Collapse

MESH Headings

• Dose-Response Relationship, Radiation
• Gastrointestinal Hemorrhage/etiology
• Humans
• Male
• Odds Ratio
• Prostatic Neoplasms/radiotherapy
• Radiation Injuries/complications
• Radiation Injuries/prevention & control
• Radiotherapy Dosage
• Rectal Diseases/etiology
• Rectum/pathology
• Rectum/radiation effects

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Grants

• G0501019 Medical Research Council
• MC_U122861330 Medical Research Council
• C46/A2131 Cancer Research UK

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Affiliation(s)

Sarah L Gulliford Joint Department of Physics, Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, United Kingdom
Kerwyn Foo
Rachel C Morgan
Edwin G Aird
A Margaret Bidmead
Helen Critchley
Philip M Evans
Stefano Gianolini
W Philip Mayles
A Rollo Moore
Beatriz Sánchez-Nieto
Mike Partridge
Matthew R Sydes
Steve Webb
David P Dearnaley

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Expression of Bcl-2, p53, and MDM2 in localized prostate cancer with respect to the outcome of radical radiotherapy dose escalation

PURPOSE

Established prognostic factors in localized prostate cancer explain only a moderate proportion of variation in outcome. We analyzed tumor expression of apoptotic markers with respect to outcome in men with localized prostate cancer in two randomized controlled trials of radiotherapy dose escalation.

METHODS AND MATERIALS

Between 1995 and 2001, 308 patients with localized prostate cancer received neoadjuvant androgen deprivation and radical radiotherapy at our institution in one of two dose-escalation trials. The biopsy specimens in 201 cases were used to make a biopsy tissue microarray. We evaluated tumor expression of Bcl-2, p53, and MDM2 by immunohistochemistry with respect to outcome.

RESULTS

Median follow-up was 7 years, and 5-year freedom from biochemical failure (FFBF) was 70.4% (95% CI, 63.5-76.3%). On univariate analysis, expression of Bcl-2 (p < 0.001) and p53 (p = 0.017), but not MDM2 (p = 0.224), was significantly associated with FFBF. Expression of Bcl-2 remained significantly associated with FFBF (p = 0.001) on multivariate analysis, independently of T stage, Gleason score, initial prostate-specific antigen level, and radiotherapy dose. Seven-year biochemical control was 61% vs. 41% (p = 0.0122) for 74 Gy vs. 64 Gy, respectively, among patients with Bcl-2-positive tumors and 87% vs. 81% (p = 0.423) for 74 Gy vs. 64 Gy, respectively, among patients with Bcl-2-negative tumors. There was no statistically significant interaction between dose and Bcl-2 expression.

CONCLUSIONS

Bcl-2 expression was a significant, independent determinant of biochemical control after neoadjuvant androgen deprivation and radical radiotherapy for prostate cancer. These data generate the hypothesis that Bcl-2 expression could be used to inform the choice of radiotherapy dose in individual patients.

No impairment of quality of life 18 months after high-dose intensity-modulated radiotherapy for localized prostate cancer: a prospective study

PURPOSE

To determine prospectively intermediate-term toxicity and quality of life (QoL) of prostate cancer patients after intensity-modulated radiotherapy (IMRT).

PATIENTS AND METHODS

Fifty-five patients with localized prostate adenocarcinoma were treated by IMRT (76 Gy). Physicians scored acute and late toxicity using the Common Terminology Criteria for Adverse Events version 3.0. Patients assessed general and prostate-specific QoL before IMRT (baseline) and at 2, 6, and 18 months using European Organization for Research and Treatment of Cancer questionnaires QLQ-C30(+3) and QLQ-PR25.

RESULTS

Median age was 73 years (range, 54-80 years). Risk categories were 18% low risk, 60% intermediate risk, and 22% high risk; 45% of patients received hormonal therapy (median duration, 6 months). The incidence of urinary and bowel toxicity immediately after IMRT was, respectively, 38% and 13% (Grade 2) and 2% and none (Grade 3); at 18 months it was 15% and 11% (Grade 2) and none (Grade 3). Significant worsening of QoL was reported at 2 months with regard to fatigue (+11.31, p = 1.10(-7)), urinary symptoms (+9.07, p = 3.10(-11)), dyspnea (+7.27, p = 0.008), and emotional (-7.02, p = 0.002), social (-6.36, p = 0.003), cognitive (-4.85, p = 0.004), and physical (-3.39, p = 0.007) functioning. Only fatigue (+5.86, p = 0.003) and urinary symptoms (+5.86, p = 0.0004) had not improved by 6 months. By 18 months all QoL scores except those for dyspnea (+8.02, p = 0.01) and treatment-related symptoms (+4.24, p = 0.01) had returned to baseline. These adverse effects were exacerbated by hormonal therapy.

CONCLUSION

High-dose IMRT with accurate positioning induces only a temporary worsening of QoL.

Late gastrointestinal toxicity after dose-escalated conformal radiotherapy for early prostate cancer: results from the UK Medical Research Council RT01 trial (ISRCTN47772397)

Purpose

In men with localized prostate cancer, dose-escalated conformal radiotherapy (CFRT) improves efficacy outcomes at the cost of increased toxicity. We present a detailed analysis to provide further information about the incidence and prevalence of late gastrointestinal side effects.

Methods and Materials

The UK Medical Research Council RT01 trial included 843 men with localized prostate cancer, who were treated for 6 months with neoadjuvant radiotherapy and were randomly assigned to either 64-Gy or 74-Gy CFRT. Toxicity was evaluated before CFRT and during long-term follow-up using Radiation Therapy Oncology Group (RTOG) grading, the Late Effects on Normal Tissue: Subjective, Objective, Management (LENT/SOM) scale, and Royal Marsden Hospital assessment scores. Patients regularly completed Functional Assessment of Cancer Therapy--Prostate (FACT-P) and University of California, Los Angeles, Prostate Cancer Index (UCLA-PCI) questionnaires.

Results

In the dose-escalated group, the hazard ratio (HR) for rectal bleeding (LENT/SOM grade ≥2) was 1.55 (95% CI, 1.17–2.04); for diarrhea (LENT/SOM grade ≥2), the HR was 1.79 (95% CI, 1.10–2.94); and for proctitis (RTOG grade ≥2), the HR was 1.64 (95% CI, 1.20–2.25). Compared to baseline scores, the prevalence of moderate and severe toxicities generally increased up to 3 years and than lessened. At 5 years, the cumulative incidence of patient-reported severe bowel problems was 6% vs. 8% (standard vs. escalated, respectively) and severe distress was 4% vs. 5%, respectively.

Conclusions

There is a statistically significant increased risk of various adverse gastrointestinal events with dose-escalated CFRT. This remains at clinically acceptable levels, and overall prevalence ultimately decreases with duration of follow-up.

Stakeholder Insights into Autonomous Setup Correction by Radiation Therapists during High-Dose Prostate Radiotherapy

Although online setup correction is beneficial during high-dose radiotherapy, little is known about the attitudes and concerns of stakeholders directly involved in this process. Therefore, the purpose of this research was to explore radiation oncologists' and therapists' insights on changes in workload, procedures, and professional practice resulting from involvement in therapist-autonomous online setup correction for patients receiving radiotherapy for prostate cancer. This was a single-center study with a qualitative design. All 10 radiation oncologists and 20 therapists involved in the online-autonomous process for prostate radiotherapy were approached for participation. Two specifically designed questionnaires were developed (one for therapists and one for oncologists) using a standard interview-to-pilot process. These were distributed to the participants both by hand and by e-mail. Content analysis methods and descriptive statistics were used to summarize the qualitative responses. Twenty-eight responses to the questionnaire were received. According to the results, the online-autonomous process was considered efficient when left solely in the hands of therapists (27 of 28 responses). Participant confidence with the process was influenced by communication (8/8), education (23/28), and documentation (20/20). Stakeholder perceptions indicated that the process was implemented exclusively to improve patient outcomes (28/28). The respondents experienced no professional resentment or resistance to change (20/20). The assumption of responsibility for online setup correction improved the therapists' perceptions of their role and themselves as professionals. Despite limited generalizability, this study confirms that within a well-established process, radiation oncologists are willing to cede responsibility for autonomous image approval and setup correction to therapists. Despite increases in professional accountability, radiation therapists are prepared to accept that responsibility for the benefit of their patients.