Five Year Results of a Randomized External Beam Radiotherapy Hypofractionation Trial for Prostate Cancer

Moderately Hypofractionated Radiotherapy and Androgen Deprivation Therapy for High-risk Localised Prostate Cancer: Predictors of Long-term Biochemical Control and Toxicity

AIMS

There is a paucity of long-term data on outcomes of high-risk prostatic adenocarcinoma after moderately hypofractionated radiotherapy with elective nodal treatment and long-term androgen deprivation therapy (ADT). We report long-term control and toxicity outcomes and analyse the predictors of failure and toxicity.

MATERIALS AND METHODS

The records of 120 consecutive high-risk prostate cancer patients treated in a single institution between February 2012 and December 2016 were retrospectively analysed. A moderately hypofractionted radiotherapy (HypoRT) regimen of 60 Gy in 20 fractions over 4 weeks with simultaneous elective pelvic irradiation to 44 Gy in 20 fractions with intensity-modulated radiotherapy was used, together with long-term ADT with either orchiectomy or medical castration for a total duration of 2-3 years. We analysed biochemical control, metastasis-free survival and late toxicities and their predictive factors using survival analysis.

RESULTS

Patients had locally advanced cancers (cT3 77.5%, median pretreatment prostate-specific antigen 30 ng/ml, Gleason score 8-10 in 45.8%). The median follow-up time was 70 months. The 3- and 5-year probability of freedom from biochemical progression was 93% and 80%, respectively. The 5-year probability of freedom from local relapse/intra-pelvic nodal relapse/distant metastases as the site of first failure was 96%/97%/86%, respectively. Gleason score 8-10 and medical ADT for 2-3 years (as opposed to orchidectomy) were independent risk factors for distant metastases. A total of 18 grade 2 and above late gastrointestinal toxicity events and a total of 23 grade 2 and above late genitourinary toxicity events were documented. Patients who underwent a transurethral resection of prostate prior to radiotherapy had worse urological toxicity.

CONCLUSIONS

HypoRT with elective nodal treatment results in excellent pelvic control. Distant metastases are the primary mode of failure. Risk of metastases is associated with Gleason score and the duration of ADT. Late urinary toxicities are more common in those with prior transurethral resection of prostate.

Prostate SBRT using O-Ring Halcyon Linac - Plan quality, delivery efficiency, and accuracy

Cone beam CT‐guided prostate stereotactic body radiotherapy (SBRT) treatment on the recently installed novel O‐ring coplanar geometry Halcyon Linac with a single energy 6MV‐flattening filter free (FFF) beam and volumetric modulated arc therapy (VMAT) is a fast, safe, and feasible treatment modality for early stage low‐ and intermediate‐risk prostate cancer patients. Following the RTOG‐0938 compliance criteria and utilizing two‐full arc geometry, VMAT prostate SBRT plans were generated for ten consecutive patients using advanced Acuros‐based algorithm for heterogeneity corrections with Halcyon couch insert. Halcyon VMAT plans with the stacked and staggered multileaf collimators (MLC) produced highly conformal SBRT dose distributions to the prostate, lower intermediate dose spillage and similar dose to adjacent organs‐at‐risks (OARs) compared to SBRT‐dedicated Truebeam VMAT plans. Due to lower monitor units per fraction and less MLC modulation through the target, the Halcyon VMAT plan can deliver prostate SBRT fractions in and overall treatment time of less than 10 minutes (for 36.25 Gy in five fractions), significantly improving patient compliance and clinic workflow. Pretreatment quality assurance results were similar to Truebeam VMAT plans. We have implemented Halcyon Linac for prostate SBRT treatment in our institution. We recommend that others use Halcyon for prostate SBRT treatments to expand the access of curative hypofractionated treatments to other clinics only equipped with a Halcyon Linac. Clinical follow‐up results for patients who underwent prostate SBRT treatment on our Halcyon Linac is underway.

Margin verification for hypofractionated prostate radiotherapy using a novel dose accumulation workflow and iterative CBCT

PURPOSE

Hypofractionated radiotherapy for prostate cancer reduces the inconvenience of an extended treatment course but the appropriate treatment margin to ensure tumor control while minimizing toxicity is not standardized. Using a novel dose accumulation workflow with iterative CBCT (iCBCT) images, we were able to validate treatment margins.

METHODS

Sixteen patients treated to the prostate on a hypofractionated clinical trial were selected. Prescription dose was 3625 cGy to > 95% of the PTV in 5 fractions with a boost to 4000 cGy to the high risk GTV (if applicable). PTV margin expansion was 5 mm isotropic except 3 mm posterior, no margin for the GTV. Daily iCBCT images were obtained while practicing strict bladder and rectal filling protocols. Using a novel adaptive dose accumulation workflow, synthetic CTs were created and the daily delivered dose was recalculated. The daily dose distributions were accumulated and target coverage and organ dose were assessed.

RESULTS

Although the PTV coverage dropped for the accumulated dose, the prostate coverage was not compromised. The differences in bladder and anorectum dose were not significantly different. Four patients received a boost to the GTV and a significant decrease in coverage was noted in the accumulated dose.

CONCLUSIONS

The novel dose accumulation workflow demonstrated that daily iCBCT images can be used for dose accumulation. We found that our clinical treatment margins resulted in adequate dose to the prostate while sparing OARs. If the goal is to deliver the full dose to an intra-prostatic GTV, a margin may be appropriate.

Hypofractionation for clinically localized prostate cancer

BACKGROUND

Using hypofractionation (fewer, larger doses of daily radiation) to treat localized prostate cancer may improve convenience and resource use. For hypofractionation to be feasible, it must be at least as effective for cancer-related outcomes and have comparable toxicity and quality of life outcomes as conventionally fractionated radiation therapy.

OBJECTIVES

To assess the effects of hypofractionated external beam radiation therapy compared to conventionally fractionated external beam radiation therapy for men with clinically localized prostate cancer.

SEARCH METHODS

We searched CENTRAL, MEDLINE (Ovid), Embase (Ovid) and trials registries from 1946 to 15 March 2019 with reference checking, citation searching and contact with study authors. Searches were not limited by language or publication status. We reran all searches within three months (15th March 2019) prior to publication.

SELECTION CRITERIA

Randomized controlled comparisons which included men with clinically localized prostate adenocarcinoma where hypofractionated radiation therapy (external beam radiation therapy) to the prostate using hypofractionation (greater than 2 Gy per fraction) compared with conventionally fractionated radiation therapy to the prostate delivered using standard fractionation (1.8 Gy to 2 Gy per fraction).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. Two authors independently assessed trial quality and extracted data. We used Review Manager 5 for data analysis and meta-analysis. We used the inverse variance method and random-effects model for data synthesis of time-to-event data with hazard ratios (HR) and 95% confidence intervals (CI) reported. For dichotomous data, we used the Mantel-Haenzel method and random-effects model to present risk ratios (RR) and 95% CI. We used GRADE to assess evidence quality for each outcome.

MAIN RESULTS

We included 10 studies with 8278 men in our analysis comparing hypofractionation with conventional fractionation to treat prostate cancer.Primary outcomesHypofractionation may result in little or no difference in prostate cancer-specific survival [PC-SS] (HR 1.00, 95% CI 0.72 to 1.39; studies = 8, participants = 7946; median follow-up 72 months; low-certainty evidence). For men in the intermediate-risk group undergoing conventional fractionation this corresponds to 976 per 1000 men alive after 6 years and 0 more (44 fewer to 18 more) alive per 1000 men undergoing hypofractionation.We are uncertain about the effect of hypofractionation on late radiation therapy gastrointestinal (GI) toxicity (RR 1.10, 95% CI 0.68 to 1.78; studies = 4, participants = 3843; very low-certainty evidence).Hypofractionation probably results in little or no difference to late radiation therapy genitourinary (GU) toxicity (RR 1.05, 95% CI 0.93 to 1.18; studies = 4, participants = 3843; moderate-certainty evidence). This corresponds to 262 per 1000 late GU radiation therapy toxicity events with conventional fractionation and 13 more (18 fewer to 47 more) per 1000 men when undergoing hypofractionation.Secondary outcomesHypofractionation results in little or no difference in overall survival (HR 0.94, 95% CI 0.83 to 1.07; 10 studies, 8243 participants; high-certainty evidence). For men in the intermediate-risk group undergoing conventional fractionation this corresponds to 869 per 1000 men alive after 6 years and 17 fewer (54 fewer to 17 more) participants alive per 1000 men when undergoing hypofractionation.Hypofractionation may result in little to no difference in metastasis-free survival (HR 1.07, 95% CI 0.65 to 1.76; 5 studies, 4985 participants; low-certainty evidence). This corresponds to 981 men per 1000 men metastasis-free at 6 years when undergoing conventional fractionation and 5 more (58 fewer to 19 more) metastasis-free per 1000 when undergoing hypofractionation.Hypofractionation likely results in a small, possibly unimportant reduction in biochemical recurrence-free survival based on Phoenix criteria (HR 0.88, 95% CI 0.68 to 1.13; studies = 5, participants = 2889; median follow-up 90 months to 108 months; moderate-certainty evidence). In men of the intermediate-risk group, this corresponds to 804 biochemical-recurrence free men per 1000 participants at six years with conventional fractionation and 42 fewer (134 fewer to 37 more) recurrence-free men per 1000 participants with hypofractionationHypofractionation likely results in little to no difference to acute GU radiation therapy toxicity (RR 1.03, 95% CI 0.95 to 1.11; 4 studies, 4174 participants at 12 to 18 weeks' follow-up; moderate-certainty evidence). This corresponds to 360 episodes of toxicity per 1000 participants with conventional fractionation and 11 more (18 fewer to 40 more) per 1000 when undergoing hypofractionation.

AUTHORS' CONCLUSIONS

These findings suggest that moderate hypofractionation (up to a fraction size of 3.4 Gy) results in similar oncologic outcomes in terms of disease-specific, metastasis-free and overall survival. There appears to be little to no increase in both acute and late toxicity.

Prostate cancer as a paradigm of multidisciplinary approach? Highlights from the Italian young radiation oncologist meeting

Aims and background

The diagnostic and therapeutic approach to prostate cancer has evolved rapidly in last decades. Young professionals need an update about these recent developments in order to improve the care of patients treated in their daily clinical practice.

Methods

On May 18, 2013, AIRO Giovani (the young section of the Italian Association of Radiation Oncology) organized a multidisciplinary meeting involving, as speakers, several young physicians from many parts of Italy actively involved in the diagnostic and therapeutic approach to prostate cancer. The meeting was specifically addressed to young physicians (radio-oncologists, urologists, medical oncologists) and presented the state-of-the-art of the diagnostic/therapeutic approach based on the latest evidence on the issue. Highlights of the congress are summarized and presented in this report.

Results

The large participation in the meeting (more than 120 participants were present) confirmed the interest of young radiation oncologists in improving their skills in prostate cancer management. The contributions of the speakers confirmed the need for regular updates, considering the promising results of recently published studies and the many new ongoing trials, on the diagnostic and therapeutic approaches to prostate cancer.

Conclusions

Multidisciplinary meetings are helpful to improve the skills of young professionals.

Proton beam therapy for the treatment of prostate cancer

Through unique physical dose deposition properties, proton beam therapy (PBT) potentiates radiation dose escalation to target tissue while minimizing radiation exposure to nontarget organs. Proton beam therapy has been used to treat prostate cancer for several decades; however, access to proton centers has been restricted to the limited number of proton centers. Because of recent enhancements in availability and treatment delivery systems, interest in PBT has been burgeoning among oncologists, industry experts, and prostate cancer patients. As a result, the importance of understanding the collective experience to date and technical aspects of PBT delivery has become increasingly important in cancer medicine. This review article is intended to discuss the fundamentals of PBT treatment, critically review the literature on PBT for localized prostate cancer, and describe the continued development of proton beam technology for the treatment of prostate cancer.

Long-term results of a study using individualized planning target volumes for hypofractionated intensity-modulated radiotherapy boost for prostate cancer

Background

This is the final report of a prospective phase I study which evaluated the feasibility, toxicities, and biochemical control in prostate cancer patients treated with a hypofractionated boost utilizing a fiducial marker-based daily image guidance strategy and small patient-specific PTV margins.

Methods

Low- and intermediate-risk prostate cancer patients underwent transperineal ultrasound-guided implantation of three gold fiducial markers and were treated with three-dimensional conformal radiotherapy to 42 Gy (2 Gy/day). During the first nine fractions of treatment, pre- and post-treatment electronic portal imaging was performed to calculate intrafraction prostate motion. Patient-specific PTV margins were derived and a 30 Gy (3 Gy/day) intensity modulated radiotherapy boost was delivered (Total dose = 72 Gy in 31 fractions; EQD2 = 81 Gy, α/β = 1.4).

Results

Thirty-three patients completed treatment and were followed for a median of 7.2 years (range, 1.2 – 9.5). Seven patients (21%) developed Radiation Therapy Oncology Group (RTOG) late grade 2 GI toxicity and 1 patient (3%) developed late grade 2 GU toxicity. No patients developed late grade 3 GI or GU toxicity. To date, nine patients developed PSA relapse according to the Phoenix criteria. The actuarial five, seven and nine year biochemical control (BC) rates were 87% (95% confidence interval: 69–95), 77% (95% confidence interval: 56–89) and 66% (95% confidence interval: 42–82).

Conclusions

Our study demonstrates that the use of prostate fiducial markers in combination with a daily online image guidance protocol permits reduced, patient-specific PTV margins in a hypofractionated treatment scheme. This treatment planning and delivery strategy was well tolerated in the intermediate time frame. The use of very small PTV margins did not result in excessive failures when compared to other radiation regimens of similar radiobiological intensity.

The effectiveness and side effects of conformal external beam radiotherapy combined with high-dose-rate brachytherapy boost compared to conformal external beam radiotherapy alone in patients with prostate cancer

Background

Clinical data that compare external-beam radiotherapy (EBRT) combined with high-dose-rate brachytherapy (HDR-BT) boost versus EBRT alone are scarce. The analysis of published studies suggest that biochemical relapse-free survival in combined EBRT and HDR-BT may be superior compared to EBRT alone. We retrospectively examined the effectiveness and tolerance of both schemes in a single center study.

Methods

Between March 2003 and December 2004, 229 patients were treated for localized T1-T2N0M0 prostate cancer. Median age was 66 years (range, 49 – 83 years). PSA level ranged from 0.34 to 64 ng/ml (median 12.3 ng/ml) and Gleason score ranged from 2 to 10. The analysis included 99 patients who underwent EBRT with HDR-BT (group A) and 130 patients who were treated with EBRT alone (group B).

Results

Median follow-up was 6 years. Biochemical relapses occurred in 34% vs. 22% (p = 0.002), local recurrences in 17% vs. 5% (p = 0.002), and distant metastases in 11% vs. 6% (p = 0.179) of patients in groups A and B, respectively. Five-year biochemical relapse-free survival was 67% vs. 81% (p = 0.005), local recurrence-free survival 95% vs. 99% (p = 0.002), metastases-free survival 95% vs. 94% (p = 0.302) for groups A and B, respectively. Five-year overall survival was 85% in both groups (p = 0.596). Grade 2/3 late GI complications appeared in 9.2% and 24.8% (p = 0.003), respectively. Grade 2/3 late GU symptoms occurred in 12% in both groups.

Conclusions

Although because of the retrospective character of the study and nonrandomized selection of fractionation schedule the present conclusions had limitations EBRT alone appeared more effective than EBRT combined with HDR-BT. It was likely the result of the less frequent use of androgen deprivation therapy (ADT) for combined scheme group, too low dose in a single BT fraction or inadequate assumptions regarding fractionation sensitivity of prostate cancer.

SBRT and extreme hypofractionation: A new era in prostate cancer treatments?

AIM

Radiation therapy (RT) is a standard therapeutic option for prostate cancer (PC). In the last decades, several innovative technology applications have been introduced. 3-Dimensional conformal RT, volumetric/rotational intensity modulated RT associated or not with image-guided RT, are becoming largely diffused in the treatment of PC.

BACKGROUND

Considering that PC could have a low α/β ratio, similar to late-reacting normal tissues, it could also be highly responsive to fraction size. Thus, the reduction of the number of fractions and the increase of the dose/fraction seem to be reasonable choices in the treatment of this cancer. This review reported the technology evolution, the radiobiological and the clinical data about the role of extreme hypofractionated RT in the treatment approach of PC patients.

MATERIALS AND METHODS

Medline search and analysis of published studies containing key words: prostate cancer, radiotherapy, stereotactic radiotherapy.

RESULTS

Recent technological developments, combined with an improved knowledge of the radiobiological models in favor of a high sensitivity of PC to larger fraction sizes are opening a new scenario in its treatment, reporting favorable efficacy and acceptable toxicity, despite short follow-up.

CONCLUSION

Thus, thanks to technological improvement and the recent radiobiological data, "extreme hypofractionated RT" has been strongly introduced in the last years as a potential solid treatment option for PC.

Early closure of phase II prospective study on acute and late tolerance of hypofractionated radiotherapy in low-risk prostate cancer patients

AIM

To assess acute and late toxicity of hypofractionated radiotherapy, its efficacy and impact on quality of life in patients with low-risk prostate cancer.

MATERIALS AND METHODS

Since August 2006 to October 2007, 15 prostate cancer patients with favorable clinical features, aged 54-74 years (mean 67 years) entered the study. Tumor stage in the majority (73%) of patients was T2a, the mean pretreatment PSA value was 7.2 ng/ml (range 5-10.9 ng/ml). The study group was treated 3 times a week with 4 Gy per fraction to the total dose of 60 Gy within 5 weeks. 3D conformal treatment planning was used with no fiducial markers. Acute and late toxicity was evaluated using modified EORTC/RTOG/LENT scoring systems. Patients regularly filled the EORTC QLQ-PR25 questionnaires.

RESULTS

All patients completed radiotherapy according to the plan. During radiotherapy, 26% of patients had grade 1-2 rectal symptoms. The incidence of acute urinary toxicity score was 26%, 60%, and 14% for grade 0-1, 2 and 3, respectively. One year after RT, the incidence of grade 2 GI toxicity was 27%, which was the reason for an early closure of the accrual. Grade 2 late urinary toxicity was noted in 20% of patients. The mean PSA level was 0.61 ng/ml after 24 months and 0.47 ng/ml after 36 months (range: 0.06-1.54 ng/ml).

CONCLUSIONS

Low number of patients does not allow to determine the influence of hypofractionation on unsatisfactory tolerance of this regimen. Suboptimal (from the present day's perspective) target localization (no fiducial markers) could potentially explain higher than expected late GI reactions in our series.

A single-center study of 100 consecutive patients with localized prostate cancer treated with stereotactic body radiotherapy

BACKGROUND

Radiotherapy is an increasingly preferred treatment option for localized prostate cancer, and stereotactic body radiation therapy (SBRT) a relatively established modality of therapeutic irradiation. The present study analyzes the toxicity and biochemical efficacy of SBRT in 100 consecutive prostate cancer patients treated with CyberKnife Robotic Radiosurgery System.

METHODS

One hundred patients were treated with SBRT at the Radiation Oncology department of San Bortolo Hospital, Vicenza, Italy. All patients included in this IRB-approved protocol-driven prospective study had biopsy-proven prostate cancer. Risk category was low in 41, intermediate in 42, and high in 17 patients. The patients were treated with CyberKnife-SBRT (CK-SBRT), the prescription dose was 35 Gy in five fractions, corresponding to 92 Gy in 2-Gy fractions (α/β =1.5 Gy); 29 patients also received androgen deprivation therapy (ADT).

RESULTS

Median follow-up was 36 months (range, 6-76 months). Acute Grade 2 genitourinary and gastrointestinal toxicity occurred in respectively 12% and 18% of the patients; there were no Grade 3 or higher acute toxicities. Late Grade 1, 2, and 3 genitourinary toxicities occurred in 4%, 3%, and 1% of the patients, respectively; late Grade 1 gastrointestinal toxicity occurred in two patients and Grade 2 toxicity in one patient; no late gastrointestinal toxicities of grade 3 or 4 were observed. Median PSA nadir was 0.45 ng/ml at 36 months for all patients. In the SBRT-monotherapy group, the median PSA nadir at 36 months was 0.62 ng/ml; in the ADT-SBRT group, it was 0.18 ng/ml. Four patients had clinical recurrence: one local, two lymph nodes, and one to the bone. Ninety-six patients had no evidence of biochemical or clinical recurrence. A benign PSA bounce of median 1.08 ng/ml occurred in 12% of the 71 SBRT monotherapy patients at a mean 23 months (range, 18-30 months).

CONCLUSIONS

In this study CK-SBRT has provided promising outcomes in localized prostate cancer with good PSA response, minimal toxicity and patient inconvenience.

[Hypofractionated radiotherapy in prostate cancer]

Radiotherapy plays a central role in the management of localized prostate cancer, but the total duration of treatment of nearly 2 months poses not only problems of fatigue related to repetitive transports, especially for older patients, but also increases the overall cost of treatment including linear accelerators occupancy and patient transportation. To address this problem, various teams have developed hypofractionated radiotherapy protocols seeking to maintain the same efficacy and toxicity while reducing the total duration of treatment. These hypofractionated protocols require recent techniques such as image-guided radiation therapy (IGRT) and intensity-modulated radiation therapy (IMRT). Single centre series have validated the feasibility of "light" hypofractionation schemes at doses per fraction less than 6 Gy Similarly, different teams have shown the possibility of stereotactic irradiation for delivering "severe" hypofractionation schemes at doses greater than 6 Gy per fraction. Whatever the dose per fraction, the current clinical data support the conclusion that hypofractionated radiotherapy does not increase mid-term toxicity and could even improve biochemical control. Studies with the objective of demonstrating non-inferiority are expected to definitively validate the role of hypofractionated irradiation in the treatment of prostate cancer.

Efficacy and toxicity of conventionally fractionated pelvic radiation with a hypofractionated simultaneous versus conventionally fractionated sequential boost for patients with high-risk prostate cancer

PURPOSE

To determine if high-risk prostate cancer responds differently to hypofractionation.

MATERIAL AND METHODS

One hundred and fifty-seven men with NCCN high-risk (T3, PSA > 20, or Gleason ≥ 8) clinically localized prostate cancer treated between 1998 and 2010 met the inclusion criteria for the analysis. Eighty-two were treated with conventional WPRT with a conventionally fractionated sequential boost to the prostate (cRT), with the prostate receiving 75-77 Gy in 1.8-2.0 Gy fractions. Seventy-five were treated with pelvic IMRT with a hypofractionated simultaneous boost to the prostate (hRT), with the prostate receiving 70 Gy in 2.5 Gy fractions. The dose to the pelvic lymph nodes was 45 Gy in the cRT group and 50.4 Gy in the hRT group, both at 1.8 Gy per fraction. Ninety-two percent received neoadjuvant hormonal ablation therapy, typically beginning two months prior to the start of RT.

RESULTS

Median follow-up was 6.5 years for men receiving cRT and 3.7 years for those receiving hRT. The actuarial rate of biochemical control at four years was 88% for cRT and 94% for hRT (p = 0.82). The rates of early rectal and urinary grade ≥ 2 toxicities were 35% (29 of 82) and 49% (40 of 82) for the cRT group and 36% (27 of 75) and 44% (33 of 75) for the hRT group. The actuarial rate of late grade ≥ 2 rectal toxicity at four years was 25% for the cRT group and 13% for the hRT group (p = 0.037). The rate of late grade 3 rectal complications was 4% (3 of 82) for patients receiving cRT and 1% (1 of 75) for patients receiving hRT.

CONCLUSION

Initial follow-up indicates equivalent biochemical control between regimens. Patients receiving hRT experienced fewer late rectal complications.

Linac based SBRT for prostate cancer in 5 fractions with VMAT and flattening filter free beams: preliminary report of a phase II study

Background

To evaluate the feasibility and early side effects of a short course hypo-fractionated SBRT programme with Volumetric Modulated Arc Therapy (VMAT) and Flattening Filter Free (FFF) beams.

Methods

A prospective phase I-II study, started on February 2012. Inclusion criteria were: age ≤ 80 years, WHO-PS ≤ 2, PSA ≤ 20 ng/ml, histologically proven prostate adenocarcinoma, T1-T2 stage, no distant metastases, no previous surgery other than TURP, no malignant tumours in the previous 5 years, IPSS 0–7. The schedule was 35 Gy in 5 alternative days. SBRT was delivered with RapidArc VMAT, with 10MV FFF photons. Toxicity assessment was performed according to CTCAE v4.0 scale. EPIC questionnaires assessed Quality-of-Life. Neo-adjuvant/concomitant hormonal-therapy was prescribed according to risk classification. SpaceOAR™ gel was optionally implanted to increase the separation space between the prostate and the rectal wall.

Results

Median follow-up was 11 months (range: 5–16); 40 patients were recruited in the protocol and treated. According to NCCN criteria, 26/40 patients were low-risk and 14/40 were intermediate risk. Median age was 70 years (56–80), median initial PSA was 6.25 ng/ml (0.50-13.43 ng/ml). Median Gleason score was 6 (6–7). All patients completed the treatment as programmed (median 11.8 days (9–22). Acute Toxicities were as follow: Rectum G0: 30/40 cases (75%); G1: 6/40 (15%); G2: 4/40 (10%). Genito-urinary: G0: 16/40 (40%); G1: 8/40 (20%); G2: 16/34 (40%). In two G2 urinary retention cases, intermittent catheter was needed. No acute G3 or greater toxicity was found. Median treatment time was 126 sec (120–136). SpaceOAR™ was implanted in 8 patients. PSA reduction from the pre-treatment value of the marker was documented in all patients.

Conclusions

Early findings suggest that SBRT with RapidArc and FFF beams for prostate cancer in 5 fractions is feasible and tolerated in acute setting. Longer follow-up is needed for assessment of late toxicity and outcome.

Current standards and future directions for prostate cancer radiation therapy

Definitive radiation therapy is a well-recognized curative treatment option for localized prostate cancer. A suitable technique, dose, target volume and the option of a combination with androgen deprivation therapy need to be considered. An optimal standard external beam radiotherapy currently includes intensity-modulated and image-guided radiotherapy techniques with total doses of ≥76-78 Gy in conventional fractionation. Protons or carbon ions are alternatives available only in specific centers. Data from several randomized studies increasingly support the rationale for hypofractionated radiotherapy. A simultaneous integrated boost with dose escalation focused on a computed tomography/PET- or MRI/magnetic resonance spectroscopy-detected malignant lesion is one option to increase tumor control, with potentially no additional toxicity. The application of a spacer is a promising concept for optimal protection of the rectal wall.

Toxicity after external beam radiotherapy for prostate cancer: an analysis of late morbidity in men with diabetes mellitus

OBJECTIVE

To investigate the influence of diabetes mellitus (DM) on late genitourinary (GU) and gastrointestinal (GI) toxicity in patients treated with external beam radiotherapy (RT) for prostate cancer.

MATERIALS AND METHODS

A total of 626 men were treated with curative-intent RT for prostate cancer from 1988 to 2008. Using the National Comprehensive Cancer Network risk category, the patients were considered to have low-risk (30%), intermediate-risk (42%), or high-risk (28%) prostate cancer. The median radiation dose was 74 Gy; 45% received androgen deprivation therapy for a median of 4 months. Late GU and GI Radiation Therapy Oncology Group toxicity was recorded prospectively at each visit after external beam RT. The median follow-up period was 55 months.

RESULTS

Of the 626 men, 102 (16%) had DM that was controlled by diet (8%), oral medications (52%), or insulin (39%). The patients with DM were more likely to receive intensity-modulated RT and androgen deprivation therapy and to have a shorter follow-up duration (P ≤.05 for all). Univariate analyses demonstrated that greater radiation dose, baseline urinary dysfunction, intensity-modulated RT, and DM were associated with grade 2 or greater GU toxicity, and transurethral resection of the prostate and DM were associated with grade 3 or greater GU toxicity. In addition, androgen deprivation therapy use, age ≥70 years, and anticoagulation were associated with grade 2 or greater GI toxicity, and age ≥70 years and anticoagulation were associated with grade 3 or greater GI toxicity. The multivariate analyses for late toxicity demonstrated a greater risk of grade 2 or greater (relative risk 1.36, P = .10) and grade 3 or greater GU toxicity (relative risk 2.74, P = .04) with DM.

CONCLUSION

A greater incidence of late GU toxicity was seen in patients with DM treated for prostate cancer. This relationship might be useful when considering the treatment of patients with DM, especially those receiving dose-escalated RT or with a history of transurethral resection of the prostate.

Whole-pelvic nodal radiation therapy in the context of hypofractionation for high-risk prostate cancer patients: a step forward

Given the low α/β ratio of prostate cancer, prostate hypofractionation has been tested through numerous clinical studies. There is a growing body of literature suggesting that with high conformal radiation therapy and even with more sophisticated radiation techniques, such as high-dose-rate brachytherapy or image-guided intensity modulated radiation therapy, morbidity associated with shortening overall treatment time with higher doses per fraction remains low when compared with protracted conventional radiation therapy to the prostate only. In high-risk prostate cancer patients, there is accumulating evidence that either dose escalation to the prostate or hypofractionation may improve outcome. Nevertheless, selected patients who have a high risk of lymph node involvement may benefit from whole-pelvic radiation therapy (WPRT). Although combining WPRT with hypofractionated prostate radiation therapy is feasible, it remains investigational. By combining modern advances in radiation oncology (high-dose-rate prostate brachytherapy, intensity modulated radiation therapy with an improved image guidance for soft-tissue sparing), it is hypothesized that WPRT could take advantage of recent results from hypofractionation trials. Moreover, the results from hypofractionation trials raise questions as to whether hypofractionation to pelvic lymph nodes with a high risk of occult involvement might improve the outcomes in WPRT. Although investigational, this review discusses the challenging idea of WPRT in the context of hypofractionation for patients with high-risk prostate cancer.

Systematic review of hypofractionated radiation therapy for prostate cancer

Prostate cancer is the second most prevalent solid tumor diagnosed in men in the United States and Western Europe. Conventionally fractionated external beam radiation therapy (1.8-2.0 Gy/fraction) is an established treatment modality for men in all disease risk groups. Emerging evidence from experimental and clinical studies suggests that the α/β ratio for prostate cancer may be as low as 1.5 Gy, which has prompted investigators around the world to explore moderately hypofractionated radiation therapy (2.1-3.5 Gy/fraction). We review the impetus behind moderate hypofractionation and the current clinical evidence supporting moderate hypofractionated radiation therapy for prostate cancer. Although hypofractionated radiation therapy has many theoretical advantages, there is no clear evidence from prospective, randomized, controlled trials showing that hypofractionated schedules have improved outcomes or lower toxicity than conventionally fractionated regimens. Currently, hypofractionated schedules should only be used in the context of clinical trials. High dose rate brachytherapy and stereotactic body radiation therapy (fraction size 3.5 Gy and greater) are alternative approaches to hypofractionation, but are beyond the scope of this report.

Intensity-modulated radiation therapy for prostate cancer is cost effective and improves therapeutic ratio

Radiation therapy is one of the standard treatment options for many prostate cancer patients. Intensity-modulated radiation therapy (IMRT) allows for more conformal dose distributions that can reduce normal tissue toxicity compared with older external beam techniques. There has been a rapid adoption of IMRT between 2001 and 2007 for prostate cancer patients regardless of the patients' race, socioeconomic status or disease risk classification. IMRT is more expensive than older radiation techniques and has an impact on healthcare spending for prostate cancer.

Stereotactic body radiation therapy for prostate cancer: is the technology ready to be the standard of care?

Prostate cancer is the second most prevalent solid tumor diagnosed in men in the United States and Western Europe. Stereotactic body radiation therapy (SBRT) is touted as a superior type of external beam radiation therapy (EBRT) for the treatment of various tumors. SBRT developed from the theory that high doses of radiation from brachytherapy implant seeds could be recapitulated from advanced technology of radiation treatment planning and delivery. Moreover, SBRT has been theorized to be advantageous compared to other RT techniques because it has a treatment course shorter than that of conventionally fractionated EBRT (a single session, five days per week, for about two weeks vs. eight weeks), is non-invasive, is more effective at killing tumor cells, and is less likely to cause damage to normal tissue. In areas of the US and Europe where there is limited access to RT centers, SBRT is frequently being used to treat prostate cancer, even though long-term data about its efficacy and safety are not well established. We review the impetus behind SBRT and the current clinical evidence supporting its use for prostate cancer, thus providing oncologists and primary care physicians with an understanding of the continually evolving field of prostate radiation therapy. Studies of SBRT provide encouraging results of biochemical control and late toxicity. However, they are limited by a number of factors, including short follow-up, exclusion of intermediate- and high-risk patients, and relatively small number of patients treated. Currently, SBRT regimens should only be used in the context of clinical trials.

[Role of hypofractionated radiotherapy in the treatment of prostate cancer: a review]

BACKGROUND

Radiotherapy of prostate cancers, over the last few years, has been an alternative choice to radical prostatectomy in the case of localised cancers as well as being the preferred treatment in both advanced localised cancers and those of the elderly. A conventional course of prostate radiotherapy consisting of four to five sessions a week, lasts between 7 and 8 weeks plus about one week of preparation.

MATERIALS AND METHODS

A systematic review of the scientific literature based on Pubmed, along with an exhaustive review of randomised studies presented at international congresses, have made it possible to analyse the numerous therapeutic regimens available other than the conventional normofractioned one (i.e. with doses per session ranging between 1.8 and 2.2 grays).

RESULTS

Five randomised trials reported since 2005, plus several thousand patients treated by stereotaxic radiotherapy, have given rise to numerous scientific questions; these alternative hypofractioned courses (dose per fraction higher than 2.2 grays) have a potentially enhanced antitumoral efficacity along with the practical advantages of a shortened duration of radiotherapy.

CONCLUSION

The aim of this analysis of the scientific literature on hypofractioning in prostate cancer radiotherapy is to gather all the scientific evidence we currently have at our disposal. Further mature results of future randomised trials will have to be examined before modifying current practice.