Hypofractionated radiotherapy for localised prostate cancer. Review of clinical trials

Hybrid Tomo-Helical and Tomo-Direct radiotherapy for localized prostate cancer

PURPOSE

The aim of the study is to present a new planning approach to provide better planning target volume (PTV) coverage and reduce bladder and rectum dose with hybrid Tomo-Helical (TH)/Tomo-Direct (TD) radiotherapy (RT) for localized prostate cancer (LPC).

METHODS

Twenty-five LPC patients were included in this retrospective study. TH plans, TD plans, and hybrid TH/TD plans were created. Lateral beams were used for the hybrid TD plan and the prescribed dose was 70 Gy in 28 fractions (hybrid plans were combined 45 Gy/ 18 fxs for TH and 25 Gy/10 fxs for TD). Doses of PTV (D2%, D98%, D50%, homogeneity index (HI), conformity index (CI), coverage) and organs at risk (OARs) (V50%, V35%, V25%, V5%, and V95%) were analyzed. The Wilcoxon signed-rank test was used to analyze the difference in dosimetric parameters. p-Value < 0.05 was considered statistically significant.

RESULTS

TH plans showed better CI, and target coverage (p < 0.01) than TD and hybrid plans in all patient plan evaluations. However, TD plans D2%, D98%, and D50% doses were better than TH and hybrid plans. The HI values were similar between the three plans. Significant reductions in bladder and rectum V50%, V35%, and V25% doses (p < 0.001) were observed with hybrid plans compared to TH and TD. Penile bulb V95% and bowel V5% doses were better in the hybrid plans. Left and right femoral head V5% doses were higher in the hybrid plan compared to others (p < 0.001).

CONCLUSION

Concurrently hybrid TH/TD RT plan can be a good option to reduce the doses of the rectum and bladder in the RT of LPC.

Cost-containment in hypofractionated radiation therapy: a literature review

Recent technological advances in radiation therapy have allowed for greater accuracy in planning and treatment delivery. The development of hypofractionated radiation treatment regimens is an example, and has the potential to decrease the cost per episode of care, relative to conventional treatments. Our aim was to analyse published literature on the cost-effectiveness and budgetary implications of hypofractionated radiation therapy. As such, this article will quantify the projected health care cost savings and address the optimal means of treatment delivery, associated patient outcomes, and implications arising from an increased use of hypofractionated regimens.

Hypofractionated image guided radiation therapy followed by prostate seed implant boost for men with newly diagnosed intermediate and high risk adenocarcinoma of the prostate: Preliminary results of a phase 2 prospective study

PURPOSE

A phase 2 protocol was designed and implemented to assess the toxicity and efficacy of hypofractionated image guided intensity modulated radiation therapy (IG-IMRT) combined with low-dose rate 103Pd prostate seed implant for treatment of localized intermediate- and high-risk adenocarcinoma of the prostate.

METHODS AND MATERIALS

This is a report of an interim analysis on 24 patients enrolled on an institutional review board-approved phase 2 single-institution study of patients with intermediate- and high-risk adenocarcinoma of the prostate. The median pretreatment prostate-specific antigen level was 8.15 ng/mL. The median Gleason score was 4 + 3 = 7 (range, 3 + 4 = 7 - 4 + 4 = 8), and the median T stage was T2a. Of the 24 patients, 4 (17%) were high-risk patients as defined by the National Comprehensive Cancer Network criteria, version 2016. The treatment consisted of 2465 cGy in 493 cGy/fraction of IG-IMRT to the prostate and seminal vesicles. This was followed by a 103Pd transperineal prostate implant boost (prescribed dose to 90% of the prostate volume of 100 Gy) using intraoperative planning. Five patients received neoadjuvant, concurrent, and adjuvant androgen deprivation therapy.

RESULTS

The median follow-up was 18 months (range, 1-42 months). The median nadir prostate-specific antigen was 0.5 ng/mL and time to nadir was 16 months. There was 1 biochemical failure associated with distant metastatic disease without local failure. Toxicity (acute or late) higher than grade 3 was not observed. There was a single instance of late grade 3 genitourinary toxicity secondary to hematuria 2 years and 7 months after radiation treatment. There were no other grade 3 gastrointestinal or genitourinary toxicities.

CONCLUSIONS

Early results on the toxicity and efficacy of the combination of hypofractionated IG-IMRT and low-dose-rate brachytherapy boost are favorable. Longer follow-up is needed to confirm safety and effectiveness.

Different outcomes among favourable and unfavourable intermediate-risk prostate cancer patients treated with hypofractionated radiotherapy and androgen deprivation therapy

Background

to evaluate the role of a risk stratification system in intermediate-risk prostate cancer (PCa) treated with hypofractionated radiotherapy (HyRT).

Methods

131 patients affected by intermediate-risk PCa were treated with HyRT at the total dose of 54,75 Gy in 15 fraction plus 9 months of androgen deprivation therapy (ADT). Patients were classified as favourable risk (FIR) if they had a single NCCN intermediate-risk factor (IRF), a Gleason score ≤3 + 4 = 7, and <50 % of biopsy cores containing cancer (PBCC). If these criteria were not met were classified as unfavourable risk (UIR). Univariate and multivariate analyses using Cox proportional hazards model were calculated for biochemical recurrence-free survival (bRFS), the risk of local recurrence and metastasis-free survival (MFS).

Results

After a median follow-up of 56.7 months (range 9.8 to 93.7 months), 11 patients (8.4 %) died, of whom 2 (1.5 %) for PCa. In the univariate analysis, Gleason score, PPBCs, IRFs and PSA at first follow-up were prognostic factors for bRFS and LF while Gleason score, PPBCs and PSA at first follow-up were significant predictor for MFS. In the multivariate analysis only the PSA at first follow-up resulted a prognostic factor for bRFS and MFS. Patients with a value of PSA at first follow-up <0.7 ng/mL respect to those with PSA ≥0,7 ng/mL had a 5y-bRFS of 93.3 % vs. 57.5 %, 5y-MFS of 99.0 % vs. 78.9 % and 5y-LF of 5.8 % vs. 38.3 %. Patients in the UIR PCa group with a PSA value <0.7 ng/mL at first follow-up had significant better bRFS, LF and MFS.

Conclusions

Risk factors currently not included in the guidelines are useful to stratify patients with intermediate-risk PCa in two groups of different prognosis even when HyRT is delivered. PSA at first follow-up is useful in UIR PCa to guide the overall length of ADT.

SHARP hypofractionated stereotactic radiotherapy is well tolerated in prostate cancer : Toxicity and quality of life assessment

BACKGROUND

Quality of life (QoL) is one of the most significant issues in prostate cancer treatment decisions. This study aimed to investigate the toxicity of hypofractionated stereotactic radiotherapy (SBRT) and QoL after treatment in localized prostate cancer patients.

MATERIALS AND METHODS

A prospective single-center clinical study was performed in low- and intermediate-risk prostate cancer patients. Patients received 33.5 Gy in 5 fractions (SHARP regimen). Acute and late toxicity was assessed according to RTOG/EORTC score. Patients filled out EORTC QLQ-C30 and prostate cancer-specific QLQ-PR25 questionnaires.

RESULTS

The analysis included 68 prostate cancer patients (55-83 years, median 73) with clinical stage T1c-T2cN0M0, median combined Gleason score of 6 (3-8), and median prostate-specific antigen (PSA) level of 10 ng/mL (4-20 ng/mL). Neoadjuvant androgen deprivation therapy was given to 52 patients (76.5 %), and stopped in 31 patients (45.5 %) after 6 months; in 21 patients (31 %) after 2-3 years. Average and median follow-up was 24 months (18-45). Median nadir PSA level was 0.03 ng/mL for all patients and 0.6 ng/mL for patients without hormone treatment. No patients had PSA failure. There were no acute grade IV toxicities. One patient (1.5 %) developed grade III and 24 patients (35.3 %) grade II acute bladder toxicity. No one developed grade III and 7 patients (10.3 %) grade II acute rectal toxicity. No grade III or IV late gastrointestinal or genitourinary toxicities were reported. Grade II late urinary symptoms were observed in 8 patients (11.8 %) and gastrointestinal symptoms in 3 patients (4.4 %). Global health status/QoL was good and improved during the observational period.

CONCLUSION

SBRT for prostate cancer patients is a well-tolerated treatment in terms of toxicity and QoL, has no negative impact on functioning and everyday life, with the important benefit of a short treatment period. However, long-term follow-up data are needed.

Stereotactic body radiation therapy for prostate cancer patients with old age or medical comorbidity: a 5-year follow-up of an investigational study

We evaluated 5-year follow-up of stereotactic body radiation therapy (SBRT) with Cyberknife for prostate cancer patients. Forty-five men with prostate adenocarcinoma who received SBRT using Cyberknife from May 2006 to November 2012 were enrolled in this study. They were prostate cancer patients with old age and medical comorbidities who received a total of 36 Gy to the prostate in 5 fractions with either everyday or every other day schedule. Prostate-specific antigen (PSA) levels at initial diagnosis and after radiation were traced. Primary endpoints were biochemical relapse-free survival (bRFS), progression-free survival (PFS), and overall survival (OS). The definition of biochemical relapse was a PSA level of nadir+2 ng/mL. Progression was defined as biochemically or clinically detected disease and the start of salvage therapy. After median follow-up of 63 months, the 5-year bRFS for all patients was estimated at 89.7%. The 5-year PFS was estimated at 71%. Four cases of biochemical relapse were observed, including two patients who experienced locoregional failure and one patient who had distant metastasis with biochemical relapse. The 5-year OS was estimated at 94.3%. There were five deaths, all of which were unrelated to prostate cancer. There was no grade 3 or higher acute complication. Grade 3 or higher late urinary toxicity was reported in 2 (4.4%) of 45 patients. The 5-year survival and toxicity outcome of SBRT using Cyberknife on prostate cancer patients with old age or comorbidities were favorable and safe in an investigational study.

[New methods in the treatment of localized prostate cancer: use of dynamic arc therapy and kV cone-beam CT positioning]

INTRODUCTION

Prostate cancer is a common disease among elderly male patients in developed countries. In addition to prostatectomy, definitive irradiation plays an increasing role in the treatment of localized disease.

AIM

The authors wanted to share their experience obtained with the use of the Novalis TX linear accelerator for the application of dose-escalation, dynamic, intensity modulated arc therapy with the routine usage of cone-beam computer tomography based or image guided radiotherapy in patients with prostate cancer.

METHOD

Between 2011, December and 2013, February the authors performed 102 treatments. In 10 low risk and 10 high risk prostate cancer patients (median age: 72.5 years) three-dimensional conformal plans with the same target volume coverage were created and tolerance doses of organs at risk (OAR) were compared.

RESULTS

Compared to three-dimensional conformal techniques, intensity modulated arc therapy treatments produced a significantly lower dose at organ at risk that led to a more favorable early toxicity rate.

CONCLUSIONS

The intensity modulated arc therapy with image guided radiotherapy proved to be a safe standard treatment mode in the daily routine in the institute of the authors. Late toxicity and local control rates need to be further examined.

Toxicity and efficacy of three dose-fractionation regimens of intensity-modulated radiation therapy for localized prostate cancer

Outcomes of three protocols of intensity-modulated radiation therapy (IMRT) for localized prostate cancer were evaluated. A total of 259 patients treated with 5-field IMRT between 2005 and 2011 were analyzed. First, 74 patients were treated with a daily fraction of 2.0 Gy to a total of 74 Gy (low risk) or 78 Gy (intermediate or high risk). Then, 101 patients were treated with a 2.1-Gy daily fraction to 73.5 or 77.7 Gy. More recently, 84 patients were treated with a 2.2-Gy fraction to 72.6 or 74.8 Gy. The median patient age was 70 years (range, 54-82) and the follow-up period for living patients was 47 months (range, 18-97). Androgen deprivation therapy was given according to patient risk. The overall and biochemical failure-free survival rates were, respectively, 96 and 82% at 6 years in the 2.0-Gy group, 99 and 96% at 4 years in the 2.1-Gy group, and 99 and 96% at 2 years in the 2.2-Gy group. The biochemical failure-free rate for high-risk patients in all groups was 89% at 4 years. Incidences of Grade ≥ 2 acute genitourinary toxicities were 9.5% in the 2.0-Gy group, 18% in the 2.1-Gy group, and 15% in the 2.2-Gy group (P = 0.29). Cumulative incidences of Grade ≥ 2 late gastrointestinal toxicity were 13% in the 2.0-Gy group at 6 years, 12% in the 2.1-Gy group at 4 years, and 3.7% in the 2.2-Gy group at 2 years (P = 0.23). So far, this stepwise shortening of treatment periods seems to be successful.

On the sensitivity of α/β prediction to dose calculation methodology in prostate brachytherapy

PURPOSE

To study the relationship between the accuracy of the dose calculation in brachytherapy and the estimations of the radiosensitivity parameter, α/β, for prostate cancer.

METHODS AND MATERIALS

In this study, Monte Carlo methods and more specifically the code ALGEBRA was used to produce accurate dose calculations in the case of prostate brachytherapy. Equivalent uniform biologically effective dose was calculated for these dose distributions and was used in an iso-effectiveness relationship with external beam radiation therapy.

RESULTS

By considering different levels of detail in the calculations, the estimation for the α/β parameter varied from 1.9 to 6.3 Gy, compared with a value of 3.0 Gy suggested by the American Association of Physicists in Medicine Task Group 137.

CONCLUSIONS

Large variations of the α/β show the sensitivity of this parameter to dose calculation modality. The use of accurate dose calculation engines is critical for better evaluating the biological outcomes of treatments.

Transformation of physical DVHs to radiobiologically equivalent ones in hypofractionated radiotherapy analyzing dosimetric and clinical parameters: a practical approach for routine clinical practice in radiation oncology

Purpose. The purpose of this study was to transform DVHs from physical to radiobiological ones as well as to evaluate their reliability by correlations of dosimetric and clinical parameters for 50 patients with prostate cancer and 50 patients with breast cancer, who were submitted to Hypofractionated Radiotherapy. Methods and Materials. To achieve this transformation, we used both the linear-quadratic model (LQ model) and the Niemierko model. The outcome of radiobiological DVHs was correlated with acute toxicity score according to EORTC/RTOG criteria. Results. Concerning the prostate radiotherapy, there was a significant correlation between RTOG acute rectal toxicity and D₅₀ (P < 0.001) and V₆₀ (P = 0.001) dosimetric parameters, calculated for α/β = 10 Gy. Moreover, concerning the breast radiotherapy there was a significant correlation between RTOG skin toxicity and V_≥60 dosimetric parameter, calculated for both α/β = 2.3 Gy (P < 0.001) and α/β = 10 Gy (P < 0.001). The new tool seems reliable and user-friendly. Conclusions. Our proposed model seems user-friendly. Its reliability in terms of agreement with the presented acute radiation induced toxicity was satisfactory. However, more patients are needed to extract safe conclusions.

Radiation treatment for patients with intermediate-risk prostate cancer

Around 70% of men presenting with prostate cancer will have organ-confined disease, with the majority presenting with low- or intermediate-risk prostate cancer. This article reviews the evidence supporting the current standard of care in radiation oncology for the evaluation and management of men with intermediate-risk prostate cancer. Dose escalation, hormonal therapy, combined modality therapy, and modern techniques for the delivery of radiation therapy are reviewed.

Dose-escalated hypofractionated intensity-modulated radiotherapy in high-risk carcinoma of the prostate: outcome and late toxicity

Background. The benefit of dose-escalated hypofractionated radiotherapy using intensity-modulated radiotherapy (IMRT) in prostate cancer is not established. We report 5-year outcome and long-term toxicity data within a phase II clinical trial. Materials and Methods. 60 men with predominantly high-risk prostate cancer were treated. All patients received neoadjuvant hormone therapy, completing up to 6 months in total. Thirty patients were treated with 57 Gy in 19 fractions and 30 patients with 60 Gy in 20 fractions. Acute and 2-year toxicities were reported and patients followed longitudinally to assess 5 year outcomes and long-term toxicity. Toxicity was measured using RTOG criteria and LENT/SOMA questionnaire. Results. Median followup was 84 months. Five-year overall survival (OS) was 83% and biochemical progression-free survival (bPFS) was 50% for 57 Gy. Five-year OS was 75% and bPFS 58% for 60 Gy. At 7 years, toxicity by RTOG criteria was acceptable with no grade 3 or above toxicity. Compared with baseline, there was no significant change in urinary symptoms at 2 or 7 years. Bowel symptoms were stable between 2 and 7 years. All patients continued to have significant sexual dysfunction. Conclusion. In high-risk prostate cancer, dose-escalated hypofractionated radiotherapy using IMRT results in encouraging outcomes and acceptable late toxicity.

Carbon-ion radiation therapy for prostate cancer

In 1994, carbon-ion radiotherapy was started at the National Institute of Radiological Sciences using the Heavy-Ion Medical Accelerator in Chiba. Between June 1995 and March 2000, two phase I/II dose escalation studies (protocols 9402 and 9703) of hypofractionated carbon-ion radiotherapy for both early- and advance-stage prostate cancer patients had been carried out to establish radiotherapy technique and to determine the optimal radiation dose. To validate the feasibility and efficacy of hypofractionated carbon-ion radiotherapy, a phase II study (9904) was initiated in April 2000 using the shrinking field technique and the recommended dose fractionation (66 gray equivalents in 20 fractions over 5 weeks) obtained from the phase I/II studies, and was successfully completed in October 2003. The data from 175 patients in the phase II study showed the importance of an appropriate use of androgen deprivation therapy according to tumor risk group. Since November 2003, carbon-ion radiotherapy for prostate cancer was approved as "Highly Advanced Medical Technology" from the Ministry of Health, Labor, and Welfare, and since then approximately 1100 patients have received carbon-ion radiotherapy as of July 2011. In this review, we introduce our steps thorough three clinical trials carried out at National Institute of Radiological Sciences, and show the updated data of carbon-ion radiotherapy obtained from approximately 1000 prostate cancer patients. In addition, our recent challenge and future direction will be also described.

Evaluation of EBT radiochromic film using a multiple exposure technique

Radiochromic film is a self developing two-dimensional dosimeter system that is widely used in radiotherapy. Since its development some 40 years ago many improvements have been made; however the sensitivity can vary across the film and a non-linear dose response remains. The former can be addressed using a double exposure technique; however this technique assumes that the response is linear so that the dose distribution is incorrectly measured. We are proposing the use of two homogenous exposures; one performed prior, the other after the irradiation to be measured. In this 'multiple exposure technique' (MET), the first homogenous exposure can be used to correct for variations in response in different parts of the film, while the second homogenous exposure allows correction for non-linearity of response with dose. The MET was tested with a 60° wedged field and an Intensity Modulated Radiation Therapy fluence map produced by a computerised treatment planning system. In the wedge field measurements, the MET profile showed agreement within 0.6 cGy for 80% of the field compared to ionisation chamber dose values. A comparison of a TPS generated fluence map dose distribution with one measured using conventionally calibrated EBT, and another measured with MET calibrated EBT, showed similar agreement. The MET would be particularly useful for the assessment of highly inhomogenous dose distributions with high maximum dose such as encountered in hypofractionated radiation therapy.

Stereotactic body radiotherapy for low-risk prostate cancer: five-year outcomes

Purpose

Hypofractionated, stereotactic body radiotherapy (SBRT) is an emerging treatment approach for prostate cancer. We present the outcomes for low-risk prostate cancer patients with a median follow-up of 5 years after SBRT.

Method and Materials

Between Dec. 2003 and Dec. 2005, a pooled cohort of 41 consecutive patients from Stanford, CA and Naples, FL received SBRT with CyberKnife for clinically localized, low-risk prostate cancer. Prescribed dose was 35-36.25 Gy in five fractions. No patient received hormone therapy. Kaplan-Meier biochemical progression-free survival (defined using the Phoenix method) and RTOG toxicity outcomes were assessed.

Results

At a median follow-up of 5 years, the biochemical progression-free survival was 93% (95% CI = 84.7% to 100%). Acute side effects resolved within 1-3 months of treatment completion. There were no grade 4 toxicities. No late grade 3 rectal toxicity occurred, and only one late grade 3 genitourinary toxicity occurred following repeated urologic instrumentation.

Conclusion

Five-year results of SBRT for localized prostate cancer demonstrate the efficacy and safety of shorter courses of high dose per fraction radiation delivered with SBRT technique. Ongoing clinical trials are underway to further explore this treatment approach.

Stereotactic body radiotherapy as monotherapy or post-external beam radiotherapy boost for prostate cancer: technique, early toxicity, and PSA response

PURPOSE

High dose rate (HDR) brachytherapy has been established as an excellent monotherapy or after external-beam radiotherapy (EBRT) boost treatment for prostate cancer (PCa). Recently, dosimetric studies have demonstrated the potential for achieving similar dosimetry with stereotactic body radiotherapy (SBRT) compared with HDR brachytherapy. Here, we report our technique, PSA nadir, and acute and late toxicity with SBRT as monotherapy and post-EBRT boost for PCa using HDR brachytherapy fractionation.

PATIENTS AND METHODS

To date, 38 patients have been treated with SBRT at the University of California-San Francisco with a minimum follow-up of 12 months. Twenty of 38 patients were treated with SBRT monotherapy (9.5 Gy × 4 fractions), and 18 were treated with SBRT boost (9.5 Gy × 2 fractions) post-EBRT and androgen deprivation therapy. PSA nadir to date for 44 HDR brachytherapy boost patients with disease characteristics similar to the SBRT boost cohort was also analyzed as a descriptive comparison.

RESULTS

SBRT was well tolerated. With a median follow-up of 18.3 months (range, 12.6-43.5), 42% and 11% of patients had acute Grade 2 gastrourinary and gastrointestinal toxicity, respectively, with no Grade 3 or higher acute toxicity to date. Two patients experienced late Grade 3 GU toxicity. All patients are without evidence of biochemical or clinical progression to date, and favorably low PSA nadirs have been observed with a current median PSA nadir of 0.35 ng/mL (range, <0.01-2.1) for all patients (0.47 ng/mL, range, 0.2-2.1 for the monotherapy cohort; 0.10 ng/mL, range, 0.01-0.5 for the boost cohort). With a median follow-up of 48.6 months (range, 16.4-87.8), the comparable HDR brachytherapy boost cohort has achieved a median PSA nadir of 0.09 ng/mL (range, 0.0-3.3).

CONCLUSIONS

Early results with SBRT monotherapy and post-EBRT boost for PCa demonstrate acceptable PSA response and minimal toxicity. PSA nadir with SBRT boost appears comparable to those achieved with HDR brachytherapy boost.

Is there an optimal management for localized prostate cancer?

Widespread screening with prostate-specific antigen (PSA) has led to a significant increase in the detection of early stage, clinically localized prostate cancer (CaP). Various treatment options for localized CaP are discussed in this review article including active surveillance, radical prostatectomy, radiation therapy, and cryotherapy. The paucity of high-level evidence adds a considerable amount of controversy when choosing the "optimal" intervention, for both the treating physician and the patient. The long time course of CaP intervention outcomes, combined with continuing modifications in treatments, further complicate the matter. Lacking randomized trials that compare treatment options, this review article attempts to summarize the different treatment options and associated side-effects, including effects on health-related quality of life, from current published literature.

Hypofractionated radiotherapy has the potential for second cancer reduction

Background and Purpose

A model for carcinoma and sarcoma induction was used to study the dependence of carcinogenesis after radiotherapy on fractionation.

Materials and methods

A cancer induction model for radiotherapy doses including fractionation was used to model carcinoma and sarcoma induction after a radiation treatment. For different fractionation schemes the dose response relationships were obtained. Tumor induction was studied as a function of dose per fraction.

Results

If it is assumed that the tumor is treated up to the same biologically equivalent dose it was found that large dose fractions could decrease second cancer induction. The risk decreases approximately linear with increasing fraction size and is more pronounced for sarcoma induction. Carcinoma induction decreases by around 10% per 1 Gy increase in fraction dose. Sarcoma risk is decreased by about 15% per 1 Gy increase in fractionation. It is also found that tissue which is irradiated using large dose fractions to dose levels lower than 10% of the target dose potentially develop less sarcomas when compared to tissues irradiated to all dose levels. This is not observed for carcinoma induction.

Conclusions

It was found that carcinoma as well as sarcoma risk decreases with increasing fractionation dose. The reduction of sarcoma risk is even more pronounced than carcinoma risk. Hypofractionation is potentially beneficial with regard to second cancer induction.