Prostate cancer radiation dose response: results of the M. D. Anderson phase III randomized trial

Moderate hypofractionation and simultaneous integrated boost by helical tomotherapy in prostate cancer: monoinstitutional report of acute tolerability assessment with different toxicity scales

INTRODUCTION

Based on radiobiology evidence, hypofractionated radiotherapy has the potential of improving treatment outcome in prostate cancer patients. In this study, we evaluated the safety, in terms of acutetoxicity, of using moderate hypofractionated radiotherapy delivered with Helical Tomotherapy (HT) to treat prostate cancer patients.

MATERIALS AND METHODS

Between December 2012 and April 2014, 42 consecutive patients were treated with hypofractionated radiotherapy using HT. All patients received 70 Gy in 28 fractions to PTV1, which included the prostate. In the intermediate risk group, 61.6 Gy were delivered to PTV2, which included the seminal vesicles. In high risk patients, the pelvic nodes were added (PTV3) and received 50.4 Gy. Acute toxicity was recorded prospectively with RTOG and Common Terminology Criteria for Adverse Events 3.0, retrospectively with CTCAE 4.0. Expanded Prostate Cancer Index Composite (EPIC) was measured at baseline and 3 months after end of treatment, to investigate health related quality of life with regards to bladder and gastrointestinal function.

RESULTS

Acute toxicity was acceptable, independently from the system used to score side effects. Moderate genitourinary toxicity was more frequent than gastrointestinal toxicity. No correlation between acute side effects and patients' characteristics or physical dose parameters was registered. EPIC evaluation showed a negligible difference in urinary and bowel function post-treatment, that did not reach statistical significance.

CONCLUSIONS

Our experience confirms the safety of moderate hypofractionation delivered with HT in prostate cancer patients with low, intermediate and high risk.

Contouring variability of human- and deformable-generated contours in radiotherapy for prostate cancer

This study was designed to evaluate contouring variability of human-and deformable-generated contours on planning CT (PCT) and CBCT for ten patients with low-or intermediate-risk prostate cancer. For each patient in this study, five radiation oncologists contoured the prostate, bladder, and rectum, on one PCT dataset and five CBCT datasets. Consensus contours were generated using the STAPLE method in the CERR software package. Observer contours were compared to consensus contour, and contour metrics (Dice coefficient, Hausdorff distance, Contour Distance, Center-of-Mass [COM] Deviation) were calculated. In addition, the first day CBCT was registered to subsequent CBCT fractions (CBCTn: CBCT2-CBCT5) via B-spline Deformable Image Registration (DIR). Contours were transferred from CBCT1 to CBCTn via the deformation field, and contour metrics were calculated through comparison with consensus contours generated from human contour set. The average contour metrics for prostate contours on PCT and CBCT were as follows: Dice coefficient-0.892 (PCT), 0.872 (CBCT-Human), 0.824 (CBCT-Deformed); Hausdorff distance-4.75 mm (PCT), 5.22 mm (CBCT-Human), 5.94 mm (CBCT-Deformed); Contour Distance (overall contour)-1.41 mm (PCT), 1.66 mm (CBCT-Human), 2.30 mm (CBCT-Deformed); COM Deviation-2.01 mm (PCT), 2.78 mm (CBCT-Human), 3.45 mm (CBCT-Deformed). For human contours on PCT and CBCT, the difference in average Dice coefficient between PCT and CBCT (approx. 2%) and Hausdorff distance (approx. 0.5 mm) was small compared to the variation between observers for each patient (standard deviation in Dice coefficient of 5% and Hausdorff distance of 2.0 mm). However, additional contouring variation was found for the deformable-generated contours (approximately 5.0% decrease in Dice coefficient and 0.7 mm increase in Hausdorff distance relative to human-generated contours on CBCT). Though deformable contours provide a reasonable starting point for contouring on CBCT, we conclude that contours generated with B-Spline DIR require physician review and editing if they are to be used in the clinic.

Pre-Chemoradiotherapy FDG PET/CT cannot Identify Residual Metabolically-Active Volumes within Individual Esophageal Tumors

OBJECTIVE

To study whether subvolumes with a high pre-chemoradiotherapy (CRT) FDG uptake could identify residual metabolically-active volumes (MAVs) post-CRT within individual esophageal tumors. Accurate identification will allow simultaneous integrated boost to these subvolumes at higher risk to improve clinical outcomes.

METHODS

Twenty patients with esophageal cancer were treated with CRT plus surgery and underwent FDG PET/CT scans before and after CRT. The two scans were rigidly registered. Seven MAVs pre-CRT and four MAVs post-CRT within a tumor were defined with various SUV thresholds. The similarity and proximity between the MAVs pre-CRT and post-CRT were quantified with three metrics: fraction of post-CRT MAV included in pre-CRT MAV, volume overlap and centroid distance.

RESULTS

Eight patients had no residual MAV. Six patients had local residual MAV (SUV ≥2.5 post-CRT) within or adjoining the original MAV (SUV ≥2.5 pre-CRT). On average, less than 65% of any post-CRT MAVs was included in any pre-CRT MAVs, with a low volume overlap <45%, and large centroid distance >8.6 mm. In general, subvolumes with higher FDG-uptake pre-CRT or post-CRT had lower volume overlap and larger centroid distance. Six patients had new distant MAVs that were determined to be inflammation from radiation therapy.

CONCLUSIONS

Pre-CRT PET/CT cannot reliably identify the residual MAVs within individual esophageal tumors. Simultaneous integrated boost to subvolumes with high FDG uptake pre-CRT may not be feasible.

Timing of High-Dose Rate Brachytherapy With External Beam Radiotherapy in Intermediate and High-Risk Localized Prostate CAncer (THEPCA) Patients and Its Effects on Toxicity and Quality of Life: Protocol of a Randomized Feasibility Trial

Background

Prostate cancer is the most common cancer in males in the UK and affects around 105 men for every 100,000. The role of radiotherapy in the management of prostate cancer significantly changed over the last few decades with developments in brachytherapy, external beam radiotherapy (EBRT), intensity-modulated radiotherapy (IMRT), and image-guided radiotherapy (IGRT). One of the challenging factors of radiotherapy treatment of localized prostate cancer is the development of acute and late genitourinary and gastrointestinal toxicities. The recent European guidelines suggest that there is no consensus regarding the timing of high-dose rate (HDR) brachytherapy and EBRT. The schedules vary in different institutions where an HDR boost can be given either before or after EBRT. Few centers deliver HDR in between the fractions of EBRT.

Objective

Assessment of acute genitourinary and gastrointestinal toxicities at various time points to better understand if the order in which treatment modality is delivered (ie, HDR brachytherapy or EBRT first) has an effect on the toxicity profile.

Methods

Timing of HDR brachytherapy with EBRT in Prostate CAncer (THEPCA) is a single-center, open, randomized controlled feasibility trial in patients with intermediate and high-risk localized prostate cancer. A group of 50 patients aged 18 years old and over with histological diagnosis of prostate cancer (stages T1b-T3BNOMO), will be randomized to one of two treatment arms (ratio 1:1), following explanation of the study and informed consent. Patients in both arms of the study will be treated with HDR brachytherapy and EBRT, however, the order in which they receive the treatments will vary. In Arm A, patients will receive HDR brachytherapy before EBRT. In Arm B (control arm), patients will receive EBRT before HDR brachytherapy. Study outcomes will look at prospective assessment of genitourinary and gastrointestinal toxicities. The primary endpoint will be grade 3 genitourinary toxicity and the secondary endpoints will be all other grades of genitourinary toxicities (grades 1 and 2), gastrointestinal toxicities (grades 1 to 4), prostate-specific antigen (PSA) recurrence-free survival, overall survival, and quality of life.

Results

Results from this feasibility trial will be available in mid-2016.

Conclusions

If the results from this feasibility trial show evidence that the sequence of treatment modality does affect the patients’ toxicity profiles, then funding would be sought to conduct a large, multicenter, randomized controlled trial.

Trial Registration

International Standard Randomized Controlled Trial Number (ISRCTN): 15835424; http://www.isrctn.com/ISRCTN15835424 (Archived by WebCite at http://www.webcitation.org/6Xz7jfg1u).

Acute toxicity of hypofractionated intensity-modulated radiotherapy for prostate cancer

BACKGROUND

Dose-escalated hypofractionated radiotherapy (hfrt) using intensity-modulated radiotherapy (imrt), with inclusion of the pelvic lymph nodes (plns), plus androgen suppression therapy (ast) in high-risk prostate cancer patients should improve patient outcomes, but acute toxicity could limit its feasibility.

METHODS

Our single-centre phase ii prospective study enrolled 40 high-risk prostate cancer patients. All patients received hfrt using imrt with daily mega-voltage computed tomography imaging guidance, with 95% of planning target volumes (ptv68 and ptv50) receiving 68 Gy and 50 Gy (respectively) in 25 daily fractions. The boost volume was targeted to the involved plns and the prostate (minus the urethra plus 3 mm and minus 3 mm from adjacent rectal wall) and totalled up to 75 Gy in 25 fractions. Acute toxicity scores were recorded weekly during and 3 months after radiotherapy (rt) administration.

RESULTS

For the 37 patients who completed rt and the 3-month follow-up, median age was 65.5 years (range: 50-76 years). Disease was organ-confined (T1c-T2c) in 23 patients (62.1%), and node-positive in 5 patients (13.5%). All patients received long-term ast. Maximum acute genitourinary (gu) and gastrointestinal (gi) toxicity peaked at grade 2 in 6 of 36 evaluated patients (16.6%) and in 4 of 31 evaluated patients (12.9%) respectively. Diarrhea and urinary frequency were the chief complaints. Dose-volume parameters demonstrated no correlation with toxicity. The ptv treatment objectives were met in 36 of the 37 patients.

CONCLUSIONS

This hfrt dose-escalation trial in high-risk prostate cancer has demonstrated the feasibility of administering 75 Gy in 25 fractions with minimal acute gi and gu toxicities. Further follow-up will report late toxicities and outcomes.

A comparative assessment of prostate positioning guided by three-dimensional ultrasound and cone beam CT

Background

The accuracy of the Elekta Clarity™ three-dimensional ultrasound system (3DUS) was assessed for prostate positioning and compared to seed- and bone-based positioning in kilo-voltage cone-beam computed tomography (CBCT) during a definitive radiotherapy.

Methods

The prostate positioning of 6 patients, with fiducial markers implanted into the prostate, was controlled by 3DUS and CBCT. In total, 78 ultrasound scans were performed trans-abdominally and compared to bone-matches and seed-matches in CBCT scans. Setup errors detected by the different modalities were compared. Systematic and random errors were analysed, and optimal setup margins were calculated.

Results

The discrepancy between 3DUS and seed-match in CBCT was −0.2 ± 2.7 mm laterally, −1.9 ± 2.3 mm longitudinally and 0.0 ± 3.0 mm vertically and significant only in longitudinal direction. Using seed-match as reference, systematic errors of 3DUS were 1.3 mm laterally, 0.8 mm longitudinally and 1.4 mm vertically, and random errors were 2.5 mm laterally, 2.3 mm longitudinally, and 2.7 mm vertically. No significant difference could be detected for 3DUS in comparison to bone-match in CBCT.

Conclusions

3DUS is feasible for image guidance for patients with prostate cancer and appears comparable to CBCT based image guidance in the retrospective study. While 3DUS offers some distinct advantages such as no need of invasive fiducial implantation and avoidance of extra radiation, its disadvantages include the operator dependence of the technique and dependence on sufficient bladder filling. Further study of 3DUS for image guidance in a large patient cohort is warranted.

Dose-Escalated Robotic SBRT for Stage I-II Prostate Cancer

Stereotactic body radiotherapy (SBRT) is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I) dose-escalation should yield improved rates of cancer control; (II) the unique radiobiology of prostate cancer favors hypofractionation; and (III) the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent organs, potentially reducing complications. This approach is also more convenient for patients, and is cheaper than intensity-modulated radiotherapy (IMRT). Several external beam platforms are capable of delivering SBRT for early-stage prostate cancer, although most of the mature reported series have employed a robotic non-coplanar platform (i.e., CyberKnife). Several large studies report 5-year biochemical relapse rates which compare favorably to IMRT. Rates of late GU toxicity are similar to those seen with IMRT, and rates of late rectal toxicity may be less than with IMRT and low-dose rate brachytherapy. Patient-reported quality of life (QOL) outcomes appear similar to IMRT in the urinary domain. Bowel QOL may be less adversely affected by SBRT than with other radiation modalities. After 5 years of follow-up, SBRT delivered on a robotic platform is yielding outcomes at least as favorable as IMRT, and may be considered appropriate therapy for stage I–II prostate cancer.

The role of androgen deprivation therapy on biochemical failure and distant metastasis in intermediate-risk prostate cancer: effects of radiation dose escalation

BACKGROUND

To determine whether the effect of androgen deprivation therapy (ADT) on the risk of biochemical failure varies at different doses of radiation in patients treated with definitive external beam radiation for intermediate risk prostate cancer (IRPC).

METHODS

This study included 1218 IRPC patients treated with definitive external beam radiation therapy to the prostate and seminal vesicles from June 1987 to January 2009 at our institution. Patient, treatment, and tumor information was collected, including age, race, Gleason score, radiation dose, PSA, T-stage, and months on ADT.

RESULTS

The median follow-up was 6 years. A total of 421(34.6%) patients received ADT, 211 (17.3%) patients experienced a biochemical failure, and 38 (3.1%) developed distant metastasis. On univariable analyses, higher PSA, earlier year of diagnosis, higher T-stage, lower doses of radiation, and the lack of ADT were associated with an increased risk of biochemical failure. No difference in biochemical failure was seen among different racial groups or with the use of greater than 6 months of ADT compared with less than 6 months. On multivariate analysis, the use of ADT was associated with a lower risk of biochemical failure than no ADT (HR, 0.599; 95% CI, 0.367-0.978; P<0.04) and lower risk of distant metastasis (HR, 0.114; 95% CI, 0.014-0.905; P=0.04).

CONCLUSIONS

ADT reduced the risk of biochemical failure and distant metastasis in both low- and high dose radiation groups among men with intermediate-risk PCa. Increasing the duration of ADT beyond 6 months did not reduce the risk of biochemical failures. Better understanding the benefit of ADT in the era of dose escalation will require a randomized clinical trial.

Dose-volume histogram comparison between static 5-field IMRT with 18-MV X-rays and helical tomotherapy with 6-MV X-rays

We treated prostate cancer patients with static 5-field intensity-modulated radiation therapy (IMRT) using linac 18-MV X-rays or tomotherapy with 6-MV X-rays. As X-ray energies differ, we hypothesized that 18-MV photon IMRT may be better for large patients and tomotherapy may be more suitable for small patients. Thus, we compared dose-volume parameters for the planning target volume (PTV) and organs at risk (OARs) in 59 patients with T1-3 N0M0 prostate cancer who had been treated using 5-field IMRT. For these same patients, tomotherapy plans were also prepared for comparison. In addition, plans of 18 patients who were actually treated with tomotherapy were analyzed. The evaluated parameters were homogeneity indicies and a conformity index for the PTVs, and D2 (dose received by 2% of the PTV in Gy), D98, Dmean and V10-70 Gy (%) for OARs. To evaluate differences by body size, patients with a known body mass index were grouped by that index ( <21; 21-25; and >25 kg/m(2)). For the PTV, all parameters were higher in the tomotherapy plans compared with the 5-field IMRT plans. For the rectum, V10 Gy and V60 Gy were higher, whereas V20 Gy and V30 Gy were lower in the tomotherapy plans. For the bladder, all parameters were higher in the tomotherapy plans. However, both plans were considered clinically acceptable. Similar trends were observed in 18 patients treated with tomotherapy. Obvious trends were not observed for body size. Tomotherapy provides equivalent dose distributions for PTVs and OARs compared with 18-MV 5-field IMRT. Tomotherapy could be used as a substitute for high-energy photon IMRT for prostate cancer regardless of body size.

Therapeutic outcomes of neoadjuvant and concurrent androgen-deprivation therapy and intensity-modulated radiation therapy with gold marker implantation for intermediate-risk and high-risk prostate cancer

OBJECTIVES

To investigate the therapeutic outcomes of neoadjuvant and concurrent androgen-deprivation therapy and intensity-modulated radiation therapy with gold marker implantation for intermediate- and high-risk prostate cancer.

METHODS

This was a retrospective study of 325 patients with intermediate- or high-risk prostate cancer according to the National Comprehensive Cancer Network guidelines who underwent androgen-deprivation therapy and intensity-modulated radiation therapy (76 Gy) after gold marker implantation between 2001 and 2010.

RESULTS

The 5-year distant metastasis-free survival rate was significantly lower for very high-risk patients than for intermediate- and high-risk patients (82.6% vs 99.4% and 96.5%, respectively; P  <  0.01). The 5-year biochemical relapse-free survival rates significantly declined with increasing prostate cancer risk (P  <  0.01), and were 95.9%, 87.2%, and 73.1% for the intermediate-risk, high-risk and very high-risk patients, respectively. Acute genitourinary and gastrointestinal toxicity grade ≥3 were not observed in any of the patients. Late grade 3 genitourinary toxicity occurred in 0.3% of patients.

CONCLUSION

Combination androgen-deprivation therapy and 76-Gy intensity-modulated radiation therapy with gold marker implantation offers good therapeutic outcomes with few serious complications in patients with intermediate- and high-risk prostate cancer.

From whole gland to hemigland to ultra-focal high-dose-rate prostate brachytherapy: A dosimetric analysis

PURPOSE

To assess the magnitude of dosimetric reductions of a focal and ultra-focal high-dose-rate (HDR) prostate brachytherapy treatment strategy relative to standard whole gland (WG) treatment.

METHODS AND MATERIALS

HDR brachytherapy plans for five patients treated with WG HDR monotherapy were optimized to assess different treatment strategies. Plans were generated to treat the hemigland (HG), one-third gland (1/3G), and one-sixth gland (1/6G), as well as to assess treating the WG with a boost to one of those sub-volumes (WG + HG, WG + 1/3G, WG + 1/6G). Dosimetric parameters analyzed included Target D90%, V100%, V150%, Bladder (B), Rectal (R), Urethral (U) D0.1, 1 and 2cc, Urethral V75%, and the V50% to the contralateral HG. Two-tailed t tests were used for comparison of means, and p-values less than 0.05 were considered statistically significant.

RESULTS

Target objectives (D90 > 100% and V100 > 97%) were met in all cases. Significant organs at risk dose reductions were achieved for all approaches compared with WG plans. 1/6G vs WG plans resulted in the greatest reduction in dose with a mean bladder D2cc 24.7 vs 64.8%, rectal D2cc 32.8 vs 65.3%, urethral D1cc 52.1 vs 103.8%, and V75 14.5 vs 75% (p < 0.05 for all comparisons).

CONCLUSION

Significant dose reductions to organs at risk can be achieved using HDR focal brachytherapy. The magnitude of the reductions achievable with treating progressively smaller sub-volumes suggests the potential to reduce morbidity, but the clinical impact on morbidity and tumor control remain to be investigated.

Hypofractionated versus conventionally fractionated radiotherapy for patients with prostate cancer (HYPRO): acute toxicity results from a randomised non-inferiority phase 3 trial

BACKGROUND

In 2007, we began the randomised phase 3 multicentre HYPRO trial to investigate the effect of hypofractionated radiotherapy compared with conventionally fractionated radiotherapy on relapse-free survival in patients with prostate cancer. Here, we examine whether patients experience differences in acute gastrointestinal and genitourinary adverse effects.

METHODS

In this randomised non-inferiority phase 3 trial, done in seven radiotherapy centres in the Netherlands, we enrolled intermediate-risk or high-risk patients aged between 44 and 85 years with histologically confirmed stage T1b-T4 NX-0MX-0 prostate cancer, a PSA concentration of 60 ng/mL or lower, and WHO performance status of 0-2. A web-based application was used to randomly assign (1:1) patients to receive either standard fractionation with 39 fractions of 2 Gy in 8 weeks (five fractions per week) or hypofractionation with 19 fractions of 3·4 Gy in 6·5 weeks (three fractions per week). Randomisation was done with minimisation procedure, stratified by treatment centre and risk group. The primary endpoint is 5-year relapse-free survival. Here we report data for the acute toxicity outcomes: the cumulative incidence of grade 2 or worse acute and late genitourinary and gastrointestinal toxicity. Non-inferiority of hypofractionation was tested separately for genitourinary and gastrointestinal acute toxic effects, with a null hypothesis that cumulative incidences of each type of adverse event were not more than 8% higher in the hypofractionation group than in the standard fractionation group. We scored acute genitourinary and gastrointestinal toxic effects according to RTOG-EORTC criteria from both case report forms and patients' self-assessment questionnaires, at baseline, twice during radiotherapy, and 3 months after completion of radiotherapy. Analyses were done in the intention-to-treat population. Patient recruitment has been completed. This study is registered with www.controlled-trials.com, number ISRCTN85138529.

FINDINGS

Between March 19, 2007, and Dec 3, 2010, 820 patients were randomly assigned to treatment with standard fractionation (n=410) or hypofractionation (n=410). 3 months after radiotherapy, 73 (22%) patients in the standard fractionation group and 75 (23%) patients in the hypofractionation group reported grade 2 or worse genitourinary toxicity; grade 2 or worse gastrointestinal toxicity was noted in 43 (13%) patients in the standard fractionation group and in 42 (13%) in the hypofractionation group. Grade 4 acute genitourinary toxicity was reported for two patients, one (<1%) in each group. No grade 4 acute gastrointestinal toxicities were observed. We noted no significant difference in cumulative incidence by 120 days after radiotherapy of grade 2 or worse acute genitourinary toxicity (57·8% [95% CI 52·9-62·7] in the standard fractionation group vs 60·5% (55·8-65·3) in the hypofractionation group; difference 2·7%, 90% CI -2·99 to 8·48; odds ratio [OR] 1·12, 95% CI 0·84-1·49; p=0·43). The cumulative incidence of grade 2 or worse acute gastrointestinal toxicity by 120 days after radiotherapy was higher in patients given hypofractionation (31·2% [95% CI 26·6-35·8] in the standard fractionation group vs 42·0% [37·2-46·9] in the hypofractionation group; difference 10·8%, 90% CI 5·25-16·43; OR 1·6; p=0·0015; non-inferiority not confirmed).

INTERPRETATION

Hypofractionated radiotherapy was not non-inferior to standard fractionated radiotherapy in terms of acute genitourinary and gastrointestinal toxicity for men with intermediate-risk and high-risk prostate cancer. In fact, the cumulative incidence of grade 2 or worse acute gastrointestinal toxicity was significantly higher in patients given hypofractionation than in those given standard fractionated radiotherapy. Patients remain in follow-up for efficacy endpoints.

FUNDING

The Dutch Cancer Society.

Results and DVH analysis of late rectal bleeding in patients treated with 3D-CRT or IMRT for localized prostate cancer

In patients undergoing radiotherapy for localized prostate cancer, dose-volume histograms and clinical variables were examined to search for correlations between radiation treatment planning parameters and late rectal bleeding. We analyzed 129 patients with localized prostate cancer who were managed from 2002 to 2010 at our institution. They were treated with 3D conformal radiation therapy (3D-CRT, 70 Gy/35 fractions, 55 patients) or intensity-modulated radiation therapy (IMRT, 76 Gy/38 fractions, 74 patients). All radiation treatment plans were retrospectively reconstructed, dose-volume histograms of the rectum were generated, and the doses delivered to the rectum were calculated. Time to rectal bleeding ranged from 9-53 months, with a median of 18.7 months. Of the 129 patients, 33 patients had Grade 1 bleeding and were treated with steroid suppositories, while 25 patients with Grade 2 bleeding received argon plasma laser coagulation therapy (APC). Three patients with Grade 3 bleeding required both APC and blood transfusion. The 5-year incidence rate of Grade 2 or 3 rectal bleeding was 21.8% for the 3D-CRT group and 21.6% for the IMRT group. Univariate analysis showed significant differences in the average values from V65 to V10 between Grades 0-1 and Grades 2-3. Multivariate analysis demonstrated that patients with V65 ≥ 17% had a significantly increased risk (P = 0.032) of Grade 2 or 3 rectal bleeding. Of the 28 patients of Grade 2 or 3 rectal bleeding, 17 patients (60.7%) were cured by a single session of APC, while the other 11 patients required two sessions. Thus, none of the patients had any further rectal bleeding after the second APC session.

Focal radiotherapy as focal therapy of prostate cancer

PURPOSE OF REVIEW

Focal radiotherapy treatment procedures play an increasingly important role in function-preservation and organ-preservation treatment techniques. As an alternative to traditional whole-gland radiotherapy regimes, focal prostate radiotherapy may be of benefit for both primary tumor as well as locally recurrent disease. This is a review of the current literature on the topic, including patient selection, preliminary toxicity, and outcome data as well as a technical overview on treatment delivery techniques.

RECENT FINDINGS

Partial organ treatment in early prostate cancer (PCa) is now technically feasible with both newer external-beam and brachytherapy technology. To date, only small and generally monoinstitutional series have been published in the literature. Early feasibility and toxicity data are encouraging, and demonstrate potential advantages for the role of focal brachytherapy in early PCa. Although some advanced external-beam techniques can also be used to deliver focal therapy within the prostate, there is no relevant publication in the literature.

SUMMARY

Radiotherapy, especially interventional radiotherapy (brachytherapy), is a technically feasible treatment technique to deliver focal radiotherapy for PCa. To date, only preliminary results are available for all forms of interventional radiotherapy (high dose rate, low dose rate, and pulsed dose rate) for focal PCa treatment and no large cohort comparative results are published. As interventional radiotherapy (brachytherapy) as yet lacks any such long-term studies, comparative outcome data are not available to suggest differences in efficacy for one form of brachytherapy or another.

Automatic CT simulation optimization for radiation therapy: A general strategy

PURPOSE

In radiation therapy, x-ray computed tomography (CT) simulation protocol specifications should be driven by the treatment planning requirements in lieu of duplicating diagnostic CT screening protocols. The purpose of this study was to develop a general strategy that allows for automatically, prospectively, and objectively determining the optimal patient-specific CT simulation protocols based on radiation-therapy goals, namely, maintenance of contouring quality and integrity while minimizing patient CT simulation dose.

METHODS

The authors proposed a general prediction strategy that provides automatic optimal CT simulation protocol selection as a function of patient size and treatment planning task. The optimal protocol is the one that delivers the minimum dose required to provide a CT simulation scan that yields accurate contours. Accurate treatment plans depend on accurate contours in order to conform the dose to actual tumor and normal organ positions. An image quality index, defined to characterize how simulation scan quality affects contour delineation, was developed and used to benchmark the contouring accuracy and treatment plan quality within the predication strategy. A clinical workflow was developed to select the optimal CT simulation protocols incorporating patient size, target delineation, and radiation dose efficiency. An experimental study using an anthropomorphic pelvis phantom with added-bolus layers was used to demonstrate how the proposed prediction strategy could be implemented and how the optimal CT simulation protocols could be selected for prostate cancer patients based on patient size and treatment planning task. Clinical IMRT prostate treatment plans for seven CT scans with varied image quality indices were separately optimized and compared to verify the trace of target and organ dosimetry coverage.

RESULTS

Based on the phantom study, the optimal image quality index for accurate manual prostate contouring was 4.4. The optimal tube potentials for patient sizes of 38, 43, 48, 53, and 58 cm were 120, 140, 140, 140, and 140 kVp, respectively, and the corresponding minimum CTDIvol for achieving the optimal image quality index 4.4 were 9.8, 32.2, 100.9, 241.4, and 274.1 mGy, respectively. For patients with lateral sizes of 43-58 cm, 120-kVp scan protocols yielded up to 165% greater radiation dose relative to 140-kVp protocols, and 140-kVp protocols always yielded a greater image quality index compared to the same dose-level 120-kVp protocols. The trace of target and organ dosimetry coverage and the γ passing rates of seven IMRT dose distribution pairs indicated the feasibility of the proposed image quality index for the predication strategy.

CONCLUSIONS

A general strategy to predict the optimal CT simulation protocols in a flexible and quantitative way was developed that takes into account patient size, treatment planning task, and radiation dose. The experimental study indicated that the optimal CT simulation protocol and the corresponding radiation dose varied significantly for different patient sizes, contouring accuracy, and radiation treatment planning tasks.

Quality indicators for prostate radiotherapy: are patients disadvantaged by receiving treatment in a 'generalist' centre?

INTRODUCTION

The purpose of this retrospective review was to evaluate concordance with evidence-based quality indicator guidelines for prostate cancer patients treated radically in a 'generalist' (as distinct from 'sub-specialist') centre. We were concerned that the quality of treatment may be lower in a generalist centre. If so, the findings could have relevance for many radiotherapy departments that treat prostate cancer.

METHODS

Two hundred fifteen consecutive patients received external beam radiotherapy (EBRT) and/or brachytherapy between 1.10.11 and 30.9.12. Treatment was deemed to be in line with evidence-based guidelines if the dose was: (i) 73.8-81 Gy at 1.8-2.0 Gy/fraction for EBRT alone (eviQ guidelines); (ii) 40-50 Gy (EBRT) for EBRT plus high-dose rate (HDR) brachytherapy boost (National Comprehensive Cancer Network (NCCN) guidelines); and (iii) 145 Gy for low dose rate (LDR) I-125 monotherapy (NCCN). Additionally, EBRT beam energy should be ≥6 MV using three-dimensional conformal RT (3D-CRT) or intensity-modulated RT (IMRT), and high-risk patients should receive neo-adjuvant androgen-deprivation therapy (ADT) (eviQ/NCCN). Treatment of pelvic nodes was also assessed.

RESULTS

One hundred four high-risk, 84 intermediate-risk and 27 low-risk patients (NCCN criteria) were managed by eight of nine radiation oncologists. Concordance with guideline doses was confirmed in: (i) 125 of 136 patients (92%) treated with EBRT alone; (ii) 32 of 34 patients (94%) treated with EBRT + HDR BRT boost; and (iii) 45 of 45 patients (100%) treated with LDR BRT alone. All EBRT patients were treated with ≥6 MV beams using 3D-CRT (78%) or IMRT (22%). 84%, 21% and 0% of high-risk, intermediate-risk and low-risk patients received ADT, respectively. Overall treatment modality choice (including ADT use and duration where assessable) was concordant with guidelines for 176/207 (85%) of patients.

CONCLUSION

The vast majority of patients were treated concordant with evidence-based guidelines suggesting that, within the limits of the selected criteria, prostate cancer patients are unlikely to be disadvantaged by receiving radiotherapy in this 'generalist' centre.

Simultaneous modulated accelerated radiation therapy for esophageal cancer: A feasibility study

AIM: To establish the feasibility of simultaneous modulated accelerated radiation therapy (SMART) in esophageal cancer (EC).

METHODS: Computed tomography (CT) datasets of 10 patients with upper or middle thoracic squamous cell EC undergoing chemoradiotherapy were used to generate SMART, conventionally-fractionated three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiation therapy (cf-IMRT) plans, respectively. The gross target volume (GTV) of the esophagus, positive regional lymph nodes (LN), and suspected lymph nodes (LN±) were contoured for each patient. The clinical target volume (CTV) was delineated with 2-cm longitudinal and 0.5- to 1.0-cm radial margins with respect to the GTV and with 0.5-cm uniform margins for LN and LN(±). For the SMART plans, there were two planning target volumes (PTVs): PTV66 = (GTV + LN) + 0.5 cm and PTV54 = CTV + 0.5 cm. For the 3DCRT and cf-IMRT plans, there was only a single PTV: PTV60 = CTV + 0.5 cm. The prescribed dose for the SMART plans was 66 Gy/30 F to PTV66 and 54 Gy/30 F to PTV54. The dose prescription to the PTV60 for both the 3DCRT and cf-IMRT plans was set to 60 Gy/30 F. All the plans were generated on the Eclipse 10.0 treatment planning system. Fulfillment of the dose criteria for the PTVs received the highest priority, followed by the spinal cord, heart, and lungs. The dose-volume histograms were compared.

RESULTS: Clinically acceptable plans were achieved for all the SMART, cf-IMRT, and 3DCRT plans. Compared with the 3DCRT plans, the SMART plans increased the dose delivered to the primary tumor (66 Gy vs 60 Gy), with improved sparing of normal tissues in all patients. The D_max of the spinal cord, V₂₀ of the lungs, and D_mean and V₅₀ of the heart for the SMART and 3DCRT plans were as follows: 38.5 ± 2.0 vs 44.7 ± 0.8 (P = 0.002), 17.1 ± 4.0 vs 25.8 ± 5.0 (P = 0.000), 14.4 ± 7.5 vs 21.4 ± 11.1 (P = 0.000), and 4.9 ± 3.4 vs 12.9 ± 7.6 (P = 0.000), respectively. In contrast to the cf-IMRT plans, the SMART plans permitted a simultaneous dose escalation (6 Gy) to the primary tumor while demonstrating a significant trend of a lower irradiation dose to all organs at risk except the spinal cord, for which no significant difference was found.

CONCLUSION: SMART offers the potential for a 6 Gy simultaneous escalation in the irradiation dose delivered to the primary tumor of EC and improves the sparing of normal tissues.

Management of post-radiation therapy complications among prostate cancer patients: A case series

INTRODUCTION

Treating prostate cancer with radiation therapy (RT) is a viable option, albeit with its own profile of complications. We describe a unique Canadian report of a single surgeon (RJB) experience in the management of complex post-prostate cancer RT complications.

METHODS

We retrospectively analyzed patients who had previously received external beam radiation (XRT) or brachytherapy (BT) for prostate cancer referred to a single surgeon for persistent urologic related difficulties between 2005 and 2010. We used the Radiation Therapy Oncology Group (RTOG) morbidity grading system to assign each patient a 1 to 5 grade for their greatest complication.

RESULTS

In total, 15 patients were identified with a total of 43 RT-related complications. Of these 43 complications, 19 presented with obstruction, 8 with radiation failure or new bladder cancer, 6 with hematuria, 5 with intractable incontinence, and 5 with urinary tract infections. These patients required several investigations prior to treatment. Treatment of these complications used surgical, local and medical approaches. In the end, 1 patient had total incontinence, 3 improved their incontinence, 3 had self-catheterization and dilation, 1 voided well, 3 underwent cystectomy with ileo-conduits, 2 had chronic hematuria, and 2 passed away.

CONCLUSION

These patients are heavily investigated and require significant resources, including patient visits, diagnostics and treatment modalities to optimize their condition. Cure is not always possible, but the aim to improve quality of life should guide management.

Saudi oncology society and Saudi urology association combined clinical management guidelines for prostate cancer

In this report, updated guidelines for the evaluation, medical, and surgical management of prostate cancer are presented. They are categorized according the stage of the disease using the tumor node metastasis staging system 7(th) edition. The recommendations are presented with supporting evidence level.

[What is the level of evidence of new techniques in prostate cancer radiotherapy?]

Prostate cancer radiotherapy has evolved from the old 2D technique to conformal, and then to intensity-modulated radiation therapy (IMRT) and stereotactic radiotherapy. At the same time, image-guidance (IGRT) is routinely used. New techniques such as protontherapy or carbontherapy are being developed with the objective of increased efficacy, decreased treatment duration, toxicity or cost. This review summarizes the evidence-based medicine of new technologies in the treatment of prostate cancer.

Systematic review of the cost effectiveness of radiation therapy for prostate cancer from 2003 to 2013

BACKGROUND

Prostate cancer remains a prevalent diagnosis with a spectrum of treatment choices that offer similar oncologic outcomes but differing side effect profiles and associated costs. As the technology for prostate radiation therapy has advanced, its associated costs have escalated, thus making cost-effectiveness analyses critical to assess the value of competing treatment options, including watchful waiting, surgery, brachytherapy, intensity-modulated radiation therapy (IMRT), 3D-conformal radiation therapy (3D-CRT), proton beam therapy (PBT), and stereotactic body radiation therapy (SBRT).

OBJECTIVE

The aim of this systematic review was to identify articles that performed a cost-effectiveness analysis on different radiation treatment options for localized prostate cancer, summarize their findings, and highlight the main drivers of cost effectiveness.

METHODS

A literature search was performed on two databases, PubMed and the Cost-Effectiveness Analysis Registry ( https://research.tufts-nemc.org/cear4 ), using search terms that included 'prostate', 'cost effectiveness prostate radiation' and 'cost analysis comparative effectiveness prostate radiation'. Studies were included in this review if the cost data were from 2002 or later, and outcomes reported both cost and effectiveness, preferably including a cost-utility analysis with the outcome of an incremental cost-effectiveness ratio with quality-adjusted life-year (QALY) as the effectiveness measure.

RESULTS

There were 14 articles between 2003 and 2013 that discussed cost effectiveness of prostate radiotherapy in men over the age of 65. All but four of the papers were from the US; the others were from Canada and the UK. The majority of the papers used Markov decision analysis and estimated cost from a payer's perspective, usually from Medicare reimbursement data. Assumptions for the model and utilities to calculate QALYs were estimated using published literature at the time of the analysis. Each analysis had a sensitivity analysis to compensate for the uncertainty of the model inputs. The main drivers of cost effectiveness were the cost of the radiation treatment and the differential QALYs accrued because of different treatment-related morbidities. Brachytherapy was consistently found to be more cost effective when compared with surgery and other radiation treatment options. IMRT was cost effective when compared with 3D-CRT. PBT was not found to be cost effective in any of the analyses, mostly due to the high costs of PBT. SBRT was the newest technology that was analyzed, and it was also found to be cost effective compared with IMRT and PBT.

CONCLUSIONS

Cost-effectiveness research of prostate radiation treatments allows patients, providers, and payers to better understand the true value of each treatment choice. Due to the variation in each of these analyses (e.g., costing, and disease and complication assumptions, etc.), it is difficult to generalize the results. One must be careful in drawing conclusions from these studies and extrapolating to individual patients, particularly with the clear utility dependence seen in the majority of these studies.

Significance of image guidance to clinical outcomes for localized prostate cancer

Purpose. To compare toxicity profiles and biochemical tumor control outcomes between patients treated with image-guided intensity-modulated radiotherapy (IG-IMRT) and non-IGRT intensity-modulated radiotherapy (IMRT) for clinically localized prostate cancer. Materials and Methods. Between 2009 and 2012, 65 patients with localized prostate cancer were treated with IG-IMRT. This group of patients was retrospectively compared with a similar cohort of 62 patients who were treated between 2004 and 2009 with IMRT to the same dose without image guidance. Results. The median follow-up time was 4.8 years. The rectal volume receiving ≥40 and ≥70 Gy was significantly lower in the IG-IMRT group. Grade 2 and higher acute and late GI and GU toxicity rates were lower in IG-IMRT group, but there was no statistical difference. No significant improvement in biochemical control at 5 years was observed in two groups. In a Cox regression analysis identifying predictors for PSA relapse-free survival, only preradiotherapy PSA was significantly associated with biochemical control; IG-IMRT was not a statistically significant indicator. Conclusions. The use of image guidance in the radiation of prostate cancer at our institute did not show significant reduction in the rates of GI and GU toxicity and did not improve the biochemical control compared with IMRT.

Comparing four volumetric modulated arc therapy beam arrangements for the treatment of early-stage prostate cancer

INTRODUCTION

This study compared four different volumetric modulated arc therapy (VMAT) beam arrangements for the treatment of early-stage prostate cancer examining plan quality and the impact on a radiotherapy department's resources.

METHODS

Twenty prostate cases were retrospectively planned using four VMAT beam arrangements (1) a partial arc (PA), (2) one arc (1A), (3) one arc plus a partial arc (1A + PA) and (4) two arcs (2A). The quality of the dose distributions generated were compared by examining the overall plan quality, the homogeneity and conformity to the planning target volume (PTV), the number of monitor units and the dose delivered to the organs at risk. Departmental resources were considered by recording the planning time and beam delivery time.

RESULTS

Each technique produced a plan of similar quality that was considered adequate for treatment; though some differences were noted. The 1A, 1A + PA and 2A plans demonstrated a better conformity to the PTV which correlated to improved sparing of the rectum in the 60-70 Gy range for the 1A + PA and 2A techniques. The time needed to generate the plans was different for each technique ranging from 13.1 min for 1A + PA to 17.8 min for 1A. The PA beam delivery time was fastest with a mean time of 0.9 min. Beam-on times then increased with an increase in the number of arcs up to an average of 2.2 min for the 2A technique.

CONCLUSION

Which VMAT technique is best suited for clinical implementation for the treatment of prostate cancer may be dictated by the individual patient and the availability of departmental resources.

Early stage prostate cancer: biochemical recurrence after treatment

OBJECTIVES

To identify retrospectively through chart analysis the biochemical recurrence frequency of localized prostate cancer at diagnosis of patients submitted to surgery or radiotherapy; to correlate diagnostic characteristics associated with higher risk of biochemical recurrence.

MATERIALS AND METHODS

Retrospective analysis of 483 patients treated in a single center, from March 2000 to December 2009 in order to verify factors associated with biochemical recurrence.

RESULTS

Biochemical recurrence was more frequent in patients with higher initial PSA levels and those with higher risk disease. Recurrence was more frequent in patients with high risk (25.9%) than those with intermediate risk (10.7%)) and low risk (5.5%). There was no significant statistical difference of biochemical recurrence between patients submitted to radiotherapy or radical prostatectomy. Biochemical recurrence was diagnosed in only 11 of 73 patients (15%)) submitted to conformal radiotherapy using tridimensional technique.

CONCLUSION

Radiotherapy and radical prostatectomy have similar treatment results. Tridimensional conformal radiotherapy used nowadays is more efficient than earlier forms of radiation therapy (cobalt therapy and bidimensional linear accelerator therapy).

Increasing use of dose-escalated external beam radiation therapy for men with nonmetastatic prostate cancer

PURPOSE

To examine recent practice patterns, using a large national cancer registry, to understand the extent to which dose-escalated external beam radiation therapy (EBRT) has been incorporated into routine clinical practice for men with prostate cancer.

METHODS AND MATERIALS

We conducted a retrospective observational cohort study using the National Cancer Data Base, a nationwide oncology outcomes database in the United States. We identified 98,755 men diagnosed with nonmetastatic prostate cancer between 2006 and 2011 who received definitive EBRT and classified patients into National Comprehensive Cancer Network (NCCN) risk groups. We defined dose-escalated EBRT as total prescribed dose of ≥75.6 Gy. Using multivariable logistic regression, we examined the association of patient, clinical, and demographic characteristics with the use of dose-escalated EBRT.

RESULTS

Overall, 81.6% of men received dose-escalated EBRT during the study period. The use of dose-escalated EBRT did not vary substantially by NCCN risk group. Use of dose-escalated EBRT increased from 70.7% of patients receiving treatment in 2006 to 89.8% of patients receiving treatment in 2011. On multivariable analysis, year of diagnosis and use of intensity modulated radiation therapy were significantly associated with receipt of dose-escalated EBRT.

CONCLUSIONS

Our study results indicate that dose-escalated EBRT has been widely adopted by radiation oncologists treating prostate cancer in the United States. The proportion of patients receiving dose-escalated EBRT increased nearly 20% between 2006 and 2011. We observed high utilization rates of dose-escalated EBRT within all disease risk groups. Adoption of intensity modulated radiation therapy was strongly associated with use of dose-escalated treatment.

Comparative efficacy and safety of treatments for localised prostate cancer: an application of network meta-analysis

CONTEXT

There is ongoing uncertainty about the optimal management of patients with localised prostate cancer.

OBJECTIVE

To evaluate the comparative efficacy and safety of different treatments for patients with localised prostate cancer.

DESIGN

Systematic review with Bayesian network meta-analysis to estimate comparative ORs, and a score (0-100%) that, for a given outcome, reflects average rank order of superiority of each treatment compared against all others, using the Surface Under the Cumulative RAnking curve (SUCRA) statistic.

DATA SOURCES

Electronic searches of MEDLINE without language restriction.

STUDY SELECTION

Randomised trials comparing the efficacy and safety of different primary treatments (48 papers from 21 randomised trials included 7350 men).

DATA EXTRACTION

2 reviewers independently extracted data and assessed risk of bias.

RESULTS

Comparative efficacy and safety evidence was available for prostatectomy, external beam radiotherapy (different types and regimens), observational management and cryotherapy, but not high-intensity focused ultrasound. There was no evidence of superiority for any of the compared treatments in respect of all-cause mortality after 5 years. Cryotherapy was associated with less gastrointestinal and genitourinary toxicity than radiotherapy (SUCRA: 99% and 77% for gastrointestinal and genitourinary toxicity, respectively).

CONCLUSIONS

The limited available evidence suggests that different treatments may be optimal for different efficacy and safety outcomes. These findings highlight the importance of informed patient choice and shared decision-making about treatment modality and acceptable trade-offs between different outcomes. More trial evidence is required to reduce uncertainty. Network meta-analysis may be useful to optimise the power of evidence synthesis studies once data from new randomised controlled studies in this field are published in the future.

Practice patterns of photon and proton pediatric image guided radiation treatment: results from an International Pediatric Research consortium

PURPOSE

Image guided radiation therapy (IGRT) has become common practice for both photon and proton radiation therapy, but there is little consensus regarding its application in the pediatric population. We evaluated clinical patterns of pediatric IGRT practice through an international pediatrics consortium comprised of institutions using either photon or proton radiation therapy.

METHODS AND MATERIALS

Seven international institutions with dedicated pediatric expertise completed a 53-item survey evaluating patterns of IGRT use in definitive radiation therapy for patients ≤21 years old. Two institutions use proton therapy for children and all others use IG photon therapy. Descriptive statistics including frequencies of IGRT use and means and standard deviations for planning target volume (PTV) margins by institution and treatment site were calculated.

RESULTS

Approximately 750 pediatric patients were treated annually across the 7 institutions. IGRT was used in tumors of the central nervous system (98%), abdomen or pelvis (73%), head and neck (100%), lung (83%), and liver (69%). Photon institutions used kV cone beam computed tomography and kV- and MV-based planar imaging for IGRT, and all proton institutions used kV-based planar imaging; 57% of photon institutions used a specialized pediatric protocol for IGRT that delivers lower dose than standard adult protocols. Immobilization techniques varied by treatment site and institution. IGRT was utilized daily in 45% and weekly in 35% of cases. The PTV margin with use of IGRT ranged from 2 cm to 1 cm across treatment sites and institution.

CONCLUSIONS

Use of IGRT in children was prevalent at all consortium institutions. There was treatment site-specific variability in IGRT use and technique across institutions, although practices varied less at proton facilities. Despite use of IGRT, there was no consensus of optimum PTV margin by treatment site. Given the desire to restrict any additional radiation exposure in children to instances where the exposure is associated with measureable benefit, prospective studies are warranted to optimize IGRT protocols by modality and treatment site.

Efficacy and toxicity of external-beam radiation therapy for localised prostate cancer: a network meta-analysis

BACKGROUND

Many radiation regimens for treating prostate cancer have been used over the years, but which regimen is optimal for localised or locally advanced prostate cancer lacks consensus. We performed a network meta-analysis to identify the optimal radiation regimen.

METHODS

We systematically reviewed data from 27 randomised controlled trials and could group seven radiation regimens as follows: low- and high-dose radiation therapy (LDRT and HDRT), LDRT+ short- or long-term androgen deprivation therapy (LDRT+SADT and LDRT+LADT), HDRT+SADT, hypofractionated radiotherapy (HFRT), and HFRT+SADT. The main outcomes were overall mortality (OM), prostate-specific antigen (PSA) failure, cancer-specific mortality, and adverse events.

RESULTS

For the network meta-analysis of 27 trials, LDRT+LADT and LDRT+SADT were associated with decreased risk of OM as compared with LDRT alone as was LDRT+LADT compared with HDRT. Apart from HFRT, all other treatments were associated with decreased risk of PSA failure as compared with LDRT. HFRT+SADT was associated with decreased risk of cancer-specific mortality as compared with HFRT, LDRT+SADT, HDRT, and LDRT.

CONCLUSIONS

HFRT+SADT therapy might be the most efficacious treatment but with worst toxicity for localised or locally advanced prostate cancer, and HDRT showed excellent efficacy but more adverse events.

Late toxicity and quality of life after definitive treatment of prostate cancer: redefining optimal rectal sparing constraints for intensity-modulated radiation therapy

The objective of this study was to assess late toxicity and quality of life (QOL) for patients receiving definitive intensity-modulated radiotherapy (IMRT) and image-guided radiation therapy (IGRT) with regard to normal tissue sparing objectives. Three hundred and seventy-two consecutive men treated with definitive IMRT for prostate adenocarcinoma. Toxicity was graded by CTC v3.0 genitourinary (GU) and gastrointestinal (GI) toxicity at each follow-up visit. Patient-reported QOL (EPIC-26) was prospectively collected for a subset of men. Dosimetric data for bladder and rectum were compared to toxicity and QOL global domain scores, specifically analyzing outcomes for men who met ideal rectal constraints (V70 <10%, V65 <20%, V40 <40%). The median age and prescription dose was 69 years and 76 Gy, respectively. Median follow-up was 47 months. At 4 years, freedom from Grade 2 (FFG2) GI toxicity was 92% and FFG2 GU toxicity was 76%. On univariate analysis, current smoking, larger bladder volume, and higher RT dose were associated with decreased FFG2 GU toxicity, while use of anticoagulation, increasing age, and not meeting ideal rectal constraints were associated with decreased FFG2 GI toxicity (all P ≤ 0.05). Bowel QOL remained stable over the 2-year follow-up period and was higher for patients who met ideal rectal constraints (P = 0.05). IMRT with IGRT is associated with low rates of severe toxicity and a high GI and GU QOL. The use of strict rectal constraints can further improve GI QOL and reduce GI toxicity.

Effect on therapeutic ratio of planning a boosted radiotherapy dose to the dominant intraprostatic tumour lesion within the prostate based on multifunctional MR parameters

OBJECTIVE

To demonstrate the feasibility of an 8-Gy focal radiation boost to a dominant intraprostatic lesion (DIL), identified using multiparametric MRI (mpMRI), and to assess the potential outcome compared with a uniform 74-Gy prostate dose.

METHODS

The DIL location was predicted in 23 patients using a histopathologically verified model combining diffusion-weighted imaging, dynamic contrast-enhanced imaging, T2 maps and three-dimensional MR spectroscopic imaging. The DIL defined prior to neoadjuvant hormone downregulation was firstly registered to MRI-acquired post-hormone therapy and subsequently to CT radiotherapy scans. Intensity-modulated radiotherapy (IMRT) treatment was planned for an 8-Gy focal boost with 74-Gy dose to the remaining prostate. Areas under the dose-volume histograms (DVHs) for prostate, bladder and rectum, the tumour control probability (TCP) and normal tissue complication probabilities (NTCPs) were compared with those of the uniform 74-Gy IMRT plan.

RESULTS

Deliverable IMRT plans were feasible for all patients with identifiable DILs (20/23). Areas under the DVHs were increased for the prostate (75.1 ± 0.6 vs 72.7 ± 0.3 Gy; p < 0.001) and decreased for the rectum (38.2 ± 2.5 vs 43.5 ± 2.5 Gy; p < 0.001) and the bladder (29.1 ± 9.0 vs 36.9 ± 9.3 Gy; p < 0.001) for the boosted plan. The prostate TCP was increased (80.1 ± 1.3 vs 75.3 ± 0.9 Gy; p < 0.001) and rectal NTCP lowered (3.84 ± 3.65 vs 9.70 ± 5.68 Gy; p = 0.04) in the boosted plan. The bladder NTCP was negligible for both plans.

CONCLUSION

Delivery of a focal boost to an mpMRI-defined DIL is feasible, and significant increases in TCP and therapeutic ratio were found.

ADVANCES IN KNOWLEDGE

The delivery of a focal boost to an mpMRI-defined DIL demonstrates statistically significant increases in TCP and therapeutic ratio.

Hypofractionation in prostate cancer: radiobiological basis and clinical appliance

External beam radiation therapy with conventional fractionation to a total dose of 76–80 Gy represents the most adopted treatment modality for prostate cancer. Dose escalation in this setting has been demonstrated to improve biochemical control with acceptable toxicity using contemporary radiotherapy techniques. Hypofractionated radiotherapy and stereotactic body radiation therapy have gained an increasing interest in recent years and they have the potential to become the standard of care even if long-term data about their efficacy and safety are not well established. Strong radiobiological basis supports the use of high dose for fraction in prostate cancer, due to the demonstrated exceptionally low values of α/β. Clinical experiences with hypofractionated and stereotactic radiotherapy (with an adequate biologically equivalent dose) demonstrated good tolerance, a PSA control comparable to conventional fractionation, and the advantage of shorter time period of treatment. This paper reviews the radiobiological findings that have led to the increasing use of hypofractionation in the management of prostate cancer and briefly analyzes the clinical experience in this setting.

Radiobiological impact of planning techniques for prostate cancer in terms of tumor control probability and normal tissue complication probability

Background:

The radiobiological models describe the effects of the radiation treatment on cancer and healthy cells, and the radiobiological effects are generally characterized by the tumor control probability (TCP) and normal tissue complication probability (NTCP).

Aim:

The purpose of this study was to assess the radiobiological impact of RapidArc planning techniques for prostate cancer in terms of TCP and normal NTCP.

Subjects and Methods:

A computed tomography data set of ten cases involving low-risk prostate cancer was selected for this retrospective study. For each case, two RapidArc plans were created in Eclipse treatment planning system. The double arc (DA) plan was created using two full arcs and the single arc (SA) plan was created using one full arc. All treatment plans were calculated with anisotropic analytical algorithm. Radiobiological modeling response evaluation was performed by calculating Niemierko's equivalent uniform dose (EUD)-based Tumor TCP and NTCP values.

Results:

For prostate tumor, the average EUD in the SA plans was slightly higher than in the DA plans (78.10 Gy vs. 77.77 Gy; P = 0.01), but the average TCP was comparable (98.3% vs. 98.3%; P = 0.01). In comparison to the DA plans, the SA plans produced higher average EUD to bladder (40.71 Gy vs. 40.46 Gy; P = 0.03) and femoral heads (10.39 Gy vs. 9.40 Gy; P = 0.03), whereas both techniques produced NTCP well below 0.1% for bladder (P = 0.14) and femoral heads (P = 0.26). In contrast, the SA plans produced higher average NTCP compared to the DA plans (2.2% vs. 1.9%; P = 0.01). Furthermore, the EUD to rectum was slightly higher in the SA plans (62.88 Gy vs. 62.22 Gy; P = 0.01).

Conclusion:

The SA and DA techniques produced similar TCP for low-risk prostate cancer. The NTCP for femoral heads and bladder was comparable in the SA and DA plans; however, the SA technique resulted in higher NTCP for rectum in comparison with the DA technique.

[Prostate-rectum spacers: optimization of prostate cancer irradiation]

In the curative radiotherapy of localized prostate cancer, improvements in biochemical control observed with dose escalation have been counterbalanced by an increase in radiation-induced toxicity. The injection of biodegradable spacers between prostate and rectum represents a new frontier in the optimization of radiotherapy treatments for patients with localized disease. Transperineal injection of different types of spacers under transrectal ultrasound guidance allows creating a 7-to-20 mm additional space between the prostate and the anterior rectal wall lasting 3 to 12 months. Dosimetrically, a relative reduction in the rectal volume receiving at least 70 Gy (V70) in the order of 43% to 84% is observed with all types of spacers, regardless of the radiotherapy technique used. Preliminary clinical results show for all spacers a good tolerance and a possible reduction in the acute side effects rate. The aim of the present systematic review of the literature is to report on indications as well as dosimetric and clinical advantages of the different types of prostate-rectum spacers commercially available (hydrogel, hyaluronic acid, collagen, biodegradable balloon).

Phase I/II trial of definitive carbon ion radiotherapy for prostate cancer: evaluation of shortening of treatment period to 3 weeks

BACKGROUND

The purpose of this study was to evaluate the feasibility of a new shortened 3-week treatment schedule of carbon ion radiotherapy (CIRT) for prostate cancer.

METHODS

Beginning in May 2010, patients with T1b-T3bN0M0, histologically proven prostate adenocarcinoma were enrolled in the phase II trial of CIRT. Patients received 51.6 GyE in 12 fractions over 3 weeks (protocol 1002). The primary end point was defined as the incidence of late adverse events that were evaluated based on the Common Terminology Criteria for Adverse Events version 4.0. Biochemical failure was determined using the Phoenix definition (nadir +2.0 ng ml(-1)).

RESULTS

Forty-six patients were enrolled, and all patients were included in the analysis. The number of low-, intermediate-, and high-risk patients was 12 (26%), 9 (20%), and 25 (54%), respectively. The median follow-up period of surviving patients was 32.3 months. Two patients had intercurrent death without recurrence, and the remaining 44 patients were alive at the time of this analysis. In the analysis of late toxicities, grade 1 (G1) rectal haemorrhage was observed in 3 (7%) patients. The incidence of G1 haematuria was observed in 6 (13%) patients, and G1 urinary frequency was observed in 17 (37%) patients. No ⩾G2 late toxicities were observed. In the analysis of acute toxicities, 2 (4%) patients showed G2 urinary frequency, and no other G2 acute toxicities were observed.

CONCLUSIONS

The new shortened CIRT schedule over 3 weeks was considered as feasible. The analysis of long-term outcome is warranted.

Red bone marrow dose calculations in radiotherapy of prostate cancer based on the updated VCH adult male phantom

Red bone marrow (RBM) is an important dose-limiting tissue that has high radiosensitivity but is difficult to identify on clinical medical images. In this study, we investigated dose distribution in RBM for prostate cancer radiotherapy. Four suborgans were identified in the skeleton of the visible Chinese human phantom: cortical bone (CB), trabecular bone (TB), RBM, and yellow bone marrow (YBM). Dose distributions in the phantom were evaluated by the Monte Carlo method. When the left os coxae was taken as the organ-at-risk (OAR), the difference in absorbed dose between RBM and each CB and TB was up to 20%, but was much less (≤3.1%) between RBM and YBM. When the left os coxae and entire bone were both taken as OARs, RBM dose also increased with increasing planning target volume size. The results indicate the validity of using dose to homogeneous bone marrow mixture for estimating dose to RBM when RBM is not available in computational phantoms. In addition, the human skeletal system developed in this study provides a model for considering RBM dose in radiotherapy planning.

Comparison of IMRT and VMAT plans with different energy levels using Monte-Carlo algorithm for prostate cancer

PURPOSE

To make dosimetric comparisons of volumetric-modulated arc therapy (VMAT) and 7-field intensity-modulated radiotherapy (IMRT) with dynamic MLCs using the Monaco treatment planning system with Monte Carlo algorithm.

MATERIALS AND METHODS

Single-arc VMAT and 7-field IMRT treatment plans were compared for 12 intermediate risk prostate cancer patients treated with prostate and seminal vesicle radiotherapy. For all patients, the prescribed dose was 78 Gy delivered in 39 fractions. The dosimetric data of IMRT and VMAT plans with 6, 10 and 15 MV energies were compared. The comparison was made for target volume, organs at risk (OAR) doses, and for monitor units (MU).

RESULTS

The normal tissue surrounding the target were lower in VMAT plans compared to IMRT plans. VMAT plans achieved lower doses to all OARs for nearly all dosimetric endpoints. VMAT plans achieved 9.4, 9.0 and 7.0 % relative decrease in MUs required for RT delivery, for 6, 10 and 15 MV energy levels, respectively. The target volume and OAR dosimetric values did not differ significantly between 6, 10 and 15 MV photon energies.

CONCLUSION

VMAT plans were found to be dosimetrically equivalent to IMRT plans for prostate cancer patients, with better rectum and bladder sparing and fewer MUs required.

Ion Prostate Irradiation (IPI) - a pilot study to establish the safety and feasibility of primary hypofractionated irradiation of the prostate with protons and carbon ions in a raster scan technique

BACKGROUND

Due to physical characteristics, ions like protons or carbon ions can administer the dose to the target volume more efficiently than photons since the dose can be lowered at the surrounding normal tissue. Radiation biological considerations are based on the assumption that the α/β value for prostate cancer cells is 1.5 Gy, so that a biologically more effective dose could be administered due to hypofractionation without increasing risks of late effects of bladder (α/β = 4.0) and rectum (α/β = 3.9).

METHODS/DESIGN

The IPI study is a prospective randomized phase II study exploring the safety and feasibility of primary hypofractionated irradiation of the prostate with protons and carbon ions in a raster scan technique. The study is designed to enroll 92 patients with localized prostate cancer. Primary aim is the assessment of the safety and feasibility of the study treatment on the basis of incidence grade III and IV NCI-CTC-AE (v. 4.02) toxicity and/or the dropout of the patient from the planned therapy due to any reason. Secondary endpoints are PSA-progression free survival (PSA-PFS), overall survival (OS) and quality-of-life (QoL).

DISCUSSION

This pilot study aims at the evaluation of the safety and feasibility of hypofractionated irradiation of the prostate with protons and carbon ions in prostate cancer patients in an active beam technique. Additionally, the safety results will be compared with Japanese results recently published for carbon ion irradiation. Due to the missing data of protons in this hypofractionated scheme, an in depth evaluation of the toxicity will be created to gain basic data for a following comparison study with carbon ion irradiation.

TRIAL REGISTRATION

Clinical Trial Identifier: NCT01641185 (clinicaltrials.gov).

Famotidine as a radioprotector for rectal mucosa in prostate cancer patients treated with radiotherapy: phase I/II randomized placebo-controlled trial

BACKGROUND AND PURPOSE

Acute bowel toxicity significantly affects the quality of life of patients treated with pelvic radiotherapy. This study was performed to assess whether pretreatment with famotidine can reduce acute radiation toxicities in patients undergoing radiotherapy for prostate cancer.

PATIENTS AND METHODS

Between April 2012 and February 2013, 36 patients undergoing radiotherapy for prostate cancer were enrolled to receive either placebo or famotidine. The patients received external-beam radiotherapy up to 70 Gy at daily fractions of 1.8-2 Gy (5 days/week). Oral famotidine 40 mg (80 mg/day) or placebo was administered twice daily (4 and 3 h prior to each radiotherapy fraction). Bowel and bladder acute toxicities were evaluated weekly during radiotherapy and once thereafter according to RTOG grading criteria.

RESULTS

Famotidine was well tolerated. No grade III or higher acute toxicities were noted in the two groups. Grade II rectal toxicity developed significantly more often in patients receiving placebo than in patients receiving famotidine (10/18 vs. 2/16, p=0.009). Moreover, no rectal bleeding occurred in the famotidine group, while 5 patients in the placebo group experienced rectal bleeding during treatment (p=0.046). The duration of rectal toxicity in the radiotherapy course was also reduced in the famotidine group (15.7 vs. 25.2 days, p=0.027). No significant difference between the two groups was observed in terms of urinary toxicity.

CONCLUSION

We demonstrated for the first time that famotidine significantly reduces radiation-induced injury on rectal mucosa representing a suitable radioprotector for patients treated with radiotherapy for prostate cancer.

Feasibility of and rectal dosimetry improvement with the use of SpaceOAR® hydrogel for dose-escalated prostate cancer radiotherapy

INTRODUCTION

The aim of this study was to investigate the feasibility of injecting a temporary spacer between the rectum and the prostate and to quantify the degree of rectal dosimetric improvement that might result.

METHODS

Ten patients underwent CT and MRI before and after injection of 10 cc of hydrogel and at completion of radiotherapy. Hydrogel was injected under general anaesthetic using a transperineal approach. The primary endpoints were perioperative toxicity and rectal dosimetry (V80, V75, V70, V65, V40 and V30). Secondary endpoints were acute gastrointestinal toxicity during and 3 months following radiotherapy and the stability of the hydrogel. Treatment for all patients was planned incorporating volumetric modulated arc therapy with a D95 of 80 Gy in 40 fractions to the prostate and proximal seminal vesicles on both the pre- and post-hydrogel scans. Toxicity was scored with the Common Terminology Criteria, v. 3.0.

RESULTS

In the first 24 h, two patients described an increase in bowel movement frequency. The comparison plans had identical prescription doses. Rectal doses were significantly lower for all hydrogel patients for all dose endpoints (V80 = 7% vs. 0.1%, V75 = 10.3% vs. 1.1%, V70 = 13.2% vs. 2.7%, V65 = 15.8% vs. 4.6%, V40 = 35.2% vs. 23.3%, V30 = 52.6% vs. 38.5%; P < 0.001). Post-treatment MRI showed gel stability. Grade 1 bowel toxicity was reported in six patients during radiotherapy and two patients at 3 months' follow-up. No Grade 2 or Grade 3 acute bowel toxicity was reported.

CONCLUSION

SpaceOAR hydrogel was successfully injected in 10 patients with minimal side effects. Rectal dosimetry was significantly improved in all patients. This study has been extended to 30 patients with longer follow-up planned.

Prognostic factors for newly diagnosed prostate cancer and their role in treatment selection

Adenocarcinoma of the prostate is extremely heterogeneous, ranging from an indolent chronic illness to an aggressive rapidly fatal systemic malignancy. The classic prognostic factors of tumor stage, prostate specific antigen level, and Gleason score have been used for over a decade to categorize patients at the time of diagnosis into broad risk groups that help to determine appropriate management. Although the grouping of patients into favorable, intermediate, and high-risk categories has become standard, and the categories continue to define distinct prognostic subgroups, considerable heterogeneity exists within each risk group. As a range of management options are available, additional prognostic factors can be considered when determining the treatment approach for an individual patient. We review these additional prognostic variables under the headings of patient-related, tumor-related, and treatment-related. The influence of each of these factors may vary depending on treatment factors such as dose, the radiation modality, or the use of concomitant androgen ablation.

Management of prostate cancer in elderly men

Elderly men comprise a large percentage of men diagnosed with prostate cancer (PrCa). Although localized PrCa is often indolent, older men tend to be diagnosed with higher-stage disease and are more likely to die from PrCa than younger men. Multiple factors other than age play an important role in determining who will benefit from active treatment, such as comorbid conditions, life expectancy, and tumor characteristics. Careful consideration of such factors can help prevent the overtreatment of elderly men with low-risk disease and undertreatment of elderly men with high-risk disease. Management decisions should be individualized by weighing the benefits of treatment against potential risks and side effects pertinent to the elderly population, whether evaluating for surgery, radiation, or androgen deprivation.