Significant reduction of acute toxicity following pelvic irradiation with Helical Tomotherapy in patients with localized prostate cancer

The top 100 most cited articles in helical tomotherapy: a scoping review

Objective

The purpose of this scoping review was to explore the top 100 most cited articles in helical tomotherapy (HT) through bibliometric analysis and visualization tools, help researchers comprehensively understand the research hotspots of HT, and provide clear and intuitive network visualization.

Methods

The Web of Science Core Collection and the search strategy of "Title (TI)=(tomotherapy)" were used to search for articles related to HT as of 27 May 2023. The top 100 most cited articles were obtained by sorting "citations: highest first". From these top 100 most cited articles, the following information was extracted: journals, years and months, countries, authors, types of tumor treated, and topics. The VOSviewer software was introduced for visualizing all the articles related to HT.

Results

The top 100 most cited articles in HT were published between 1999 and 2019. The citation counts of these articles ranges from 326 to 45, with a total of 8,422 citations at the time of searching. The index of citations per year (CPY) ranges from 22.32 to 2.45. These articles originated from 17 countries, with most publications from the United States (n=50), followed by Canada (n=12), Italy (n=10), Germany (n=7) and Belgium (n=5). The International Journal of Radiation Oncology, Biology, Physics published the highest number of articles (n=31), followed by Radiotherapy and Oncology (n=20), Medical Physics (n=13) and Strahlentherapie und Onkologie (n=12). In terms of specific tumor types, head and neck cancer (n=15) is the most common disease, followed by cancers with complex target structures (n=14), breast cancer (n=12), prostate cancer (n=10) and lung cancer (n=8). The most common research topics also include dosimetric comparison (n = 44), quality assurance (n = 12) and Megavoltage CT (n = 8).

Conclusion

This scoping review provides a comprehensive list of the 100 most cited articles in HT. This analysis offers valuable insights into the current research directions of HT that can be utilized by researchers, clinicians, and policy-makers.

Incidence of genitourinary complications following radiation therapy for localised prostate cancer

Purpose

Studies of genitourinary toxicity following radiotherapy for prostate cancer are mainly from high volume single institutions and the incidence and burden of treatment remain uncertain. Hence we determine the cumulative incidence of treatment-related genitourinary toxicity in patients with localised prostate cancer treated with primary external beam radiotherapy (EBRT) at a state population level.

Methods

We analysed data from a prospective population-based cohort, including hospital admission and cancer registry data, for men with localised prostate cancer who underwent primary EBRT without nodal irradiation between 1998 and 2019 in South Australia. The 10-year cumulative incidence of genitourinary toxicity requiring hospitalisation or procedures was determined. Clinical predictors of toxicity and the volume of admissions, non-operative, minor operative and major operative procedures were determined.

Results

All the included patients (n = 3350) had EBRT, with a median (IQR) of 74 Gy (70–78) in 37 fractions (35–39). The 10-year cumulative incidence of was 28.4% (95% CI 26.3–30.6) with a total of 2545 hospital admissions, including 1040 (41%) emergency and 1893 (74%) readmissions. The 10-year cumulative incidence of patients in this cohort requiring a urological operative procedure was 18% (95% CI 16.1–19.9), with a total of 106 (4.2%) non-operative, 1044 (41%) minor operative and 57 (2.2%) major operative urological procedures.

Conclusions

Genitourinary toxicity after radiotherapy for prostate cancer is common. Although there continue to be advancements in radiotherapy techniques, patients and physicians should be aware of the risk of late toxicity when considering EBRT.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-022-04124-x.

Ten Year Results of Extensive Nodal Radiotherapy and Moderately Hypofractionated Simultaneous Integrated Boost in Unfavorable Intermediate-, High-, and Very High-Risk Prostate Cancer

Simple Summary

Several phase III randomized trials of moderate hypofractionation, including a higher proportion of high-risk prostate cancer patients treated only to the prostate, failed to demonstrate the superiority of hypofractionated regimens. There is only one randomized phase III trial, of moderately hypofractionated high-dose radiotherapy to the prostate-only versus pelvic irradiation and prostate boost, with a sufficiently long follow-up. It demonstrated better biochemical and disease-free survival when lymph nodal radiotherapy was added. Here we present the 10-year results of our experience based on an Institutional protocol adopted after a phase I–II study, on patients with unfavorable intermediate- (UIR), high- (HR), and very high-risk (VHR) prostate cancer (PCa) treated with pelvic lymph nodal irradiation (WPRT) and moderately hypofractionated high-dose (HD) simultaneous integrated boost (SIB) to the prostate. Prognostic factors for relapse, as well as acute and late gastro-intestinal (GI) and genito-urinary (GU) toxicity were also analyzed.

Abstract

Aims: To report 10-year outcomes of WPRT and HD moderately hypofractionated SIB to the prostate in UIR, HR, and VHR PCa. Methods: From 11/2005 to 12/2015, 224 UIR, HR, and VHR PCa patients underwent WPRT at 51.8 Gy/28 fractions and SIB at 74.2 Gy (EQD2 88 Gy) to the prostate. Androgen deprivation therapy (ADT) was prescribed in up to 86.2% of patients. Results: Median follow-up was 96.3 months (IQR: 71–124.7). Median age was 75 years (IQR: 71.3–78.1). At last follow up, G3 GI–GU toxicity was 3.1% and 8%, respectively. Ten-year biochemical relapse-free survival (bRFS) was 79.8% (95% CI: 72.3–88.1%), disease-free survival (DFS) 87.8% (95% CI: 81.7–94.3%), overall survival (OS) 65.7% (95% CI: 58.2–74.1%), and prostate cancer-specific survival (PCSS) 94.9% (95% CI: 91.0–99.0%). Only two patients presented local relapse. At univariate analysis, VHR vs. UIR was found to be a significant risk factor for biochemical relapse (HR: 2.8, 95% CI: 1.17–6.67, p = 0.021). After model selection, only Gleason Score ≥ 8 emerged as a significant factor for biochemical relapse (HR = 2.3, 95% CI: 1.12–4.9, p = 0.023). Previous TURP (HR = 3.5, 95% CI: 1.62–7.54, p = 0.001) and acute toxicity ≥ G2 (HR = 3.1, 95% CI = 1.45–6.52, p = 0.003) were significant risk factors for GU toxicity ≥ G3. Hypertension was a significant factor for GI toxicity ≥ G3 (HR = 3.63, 95% CI: 1.06–12.46, p = 0.041). ADT (HR = 0.31, 95% CI: 0.12–0.8, p = 0.015) and iPsa (HR = 0.37, 95% CI: 0.16–0.83, p = 0.0164) played a protective role. Conclusions: WPRT and HD SIB to the prostate combined with long-term ADT, in HR PCa, determine good outcomes with acceptable toxicity.

Effective Organs-at-Risk Dose Sparing in Volumetric Modulated Arc Therapy Using a Half-Beam Technique in Whole Pelvic Irradiation

BACKGROUND

Although there are some controversies regarding whole pelvic radiation therapy (WPRT) due to its gastrointestinal and hematologic toxicities, it is considered for patients with gynecological, rectal, and prostate cancer. To effectively spare organs-at-risk (OAR) doses using multi-leaf collimator (MLC)'s optimal segments, potential dosimetric benefits in volumetric modulated arc therapy (VMAT) using a half-beam technique (HF) were investigated for WPRT.

METHODS

While the size of a fully opened field (FF) was decided to entirely include a planning target volume in all beam's eye view across arc angles, the HF was designed to use half the FF from the isocenter for dose optimization. The left or the right half of the FF was alternatively opened in VMAT-HF using a pair of arcs rotating clockwise and counterclockwise. Dosimetric benefits of VMAT-HF, presented with dose conformity, homogeneity, and dose-volume parameters in terms of modulation complex score, were compared to VMAT optimized using the FF (VMAT-FF). Consequent normal tissue complication probability (NTCP) by reducing the irradiated volumes was evaluated as well as dose-volume parameters with statistical analysis for OAR. Moreover, beam-on time and MLC position precision were analyzed with log files to assess plan deliverability and clinical applicability of VMAT-HF as compared to VMAT-FF.

RESULTS

While VMAT-HF used 60%-70% less intensity modulation complexity than VMAT-FF, it showed superior dose conformity. The small intestine and colon in VMAT-HF showed a noticeable reduction in the irradiated volumes of up to 35% and 15%, respectively, at an intermediate dose of 20-45 Gy. The small intestine showed statistically significant dose sparing at the volumes that received a dose from 15 to 45 Gy. Such a dose reduction for the small intestine and colon in VMAT-HF presented a significant NTCP reduction from that in VMAT-FF. Without sacrificing the beam delivery efficiency, VMAT-HF achieved effective OAR dose reduction in dose-volume histograms.

CONCLUSIONS

VMAT-HF led to deliver conformal doses with effective gastrointestinal-OAR dose sparing despite using less modulation complexity. The dose of VMAT-HF was delivered with the same beam-on time with VMAT-FF but precise MLC leaf motions. The VMAT-HF potentially can play a valuable role in reducing OAR toxicities associated with WPRT.

Intensity-Modulated Radiation Therapy with Simultaneous Integrated Boost for Clinically Node-Positive Prostate Cancer: A Single-Institutional Retrospective Study

Simple Summary

Recently, it has been shown that radiation therapy (RT) together with androgen-depletion therapy (ADT) might be more beneficial compared with ADT alone for clinically node-positive (cN1) prostate cancer. However, there are a limited number of studies that have addressed specific RT techniques and analyzed their clinical results. The present study was a retrospective analysis of cN1 prostate cancer patients treated with intensity-modulated radiation therapy with simultaneous integrated boost (SIB-IMRT), in addition to ADT, in our hospital. The present study suggests that ADT plus SIB-IMRT for cN1 prostate cancer treatment was safe and effective, was well tolerated, and had acceptable rates of late toxicity. Further prospective multicenter studies would be required to confirm the robustness of the present results.

Abstract

This study aimed to evaluate clinical outcomes and the toxicity of intensity-modulated radiation therapy with simultaneous integrated boost (SIB-IMRT) combined with androgen-deprivation therapy for clinically node-positive (cN1) prostate cancer. We retrospectively analyzed 97 patients with cN1 prostate cancer who received SIB-IMRT between June 2008 and October 2017 at our hospital. The prescribed dosages delivered to the prostate and seminal vesicle, elective node area, and residual lymph nodes were 69, 54, and 60 Gy in 30 fractions, respectively. Kaplan–Meier analysis was used to determine 5-year biochemical relapse-free survival (bRFS), relapse-free survival (RFS), overall survival (OS), and prostate cancer-specific survival (PCSS). Toxicity was evaluated using the Common Terminology Criteria for Adverse Events ver. 4.0. Over a median follow-up duration of 60 months, the 5-year bRFS, RFS, OS, and PCSS were 85.1%, 88.1%, 92.7% and 95.0%, respectively. Acute Grade 2 genito-urinary (GU) and gastro-intestinal (GI) toxicities were observed in 10.2% and 2.1%, respectively, with no grade ≥3 toxicities being detected. The cumulative incidence rates of 5-year Grade ≥2 late GU and GI toxicities were 4.7% and 7.4%, respectively, with no Grade 4 toxicities being detected. SIB-IMRT for cN1 prostate cancer demonstrated favorable 5-year outcomes with low incidences of toxicity.

Evaluating the predictive value of quantec rectum tolerance dose suggestions on acute rectal toxicity in prostate carcinoma patients treated with IMRT

Aim

To investigate the predictive value of convenience of rectum dosimetry with Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) dose limits, maximum rectum dose (Dmax), total rectal volume (TVrectum), rectal volume included in PTV (VrectumPTV) on Grade 2-3 acute rectal toxicity for utilization in clinical practice.

Background

Numerous previous data have reported frequent acute proctitis after external-beam RT of prostate cancer. Predicting toxicity limited with dose information is inadequate in clinical practice due to comorbidities and medications used.

Materials and Method

Sixty-four non-metastatic prostate cancer patients treated with IMRT were enrolled. Patients were treated to a total dose of 70-76 Gy. Rectal dose volume histograms (DVH) of all patients were evaluated retrospectively, and a QUANTEC Score between 0 and 5 was calculated for each patient. The correlation between the rectal DVH data, QUANTEC score, TVrectum, VrectumPTV, rectum Dmax and Grade 2-3 rectal toxicity was investigated.

Results

In the whole group grade 1, 2 and 3 acute rectal toxicities were 25%, 18.8% and 3.1%, respectively. In the DVH data, rectum doses of all patients were under RTOG dose limits. Statistically significant correlation was found between grade 2-3 rectal toxicity and TVrectum (p = 0,043); however. It was not correlated with QUANTEC score, VrectumPTV and Dmax.

Conclusion

Our results were not able to show any significant correlation between increasing convenience with QUANTEC limits and lower rectal toxicity. Conclusively, new dosimetric definitions are warranted to predict acute rectal toxicity more accurately in prostate cancer patients during IMRT treatment.

[Prophylactic nodal radiotherapy in prostate cancer]

The risk of lymph node invasion, in case of prostate cancer, increases with the clinical stage of the disease, the Gleason score of prostate biopsies and the value of PSA at diagnosis. Historically, beyond 15% risk of lymph node involvement, irradiation of the pelvic areas was performed with prostate radiotherapy (RT) to take into account the risk of occult lymph node metastasis in patients at risk, but the benefit of this therapeutic approach remains to be demonstrated. The data from surgical lymph node dissection seem to question the risk levels, the escalation of the dose on the prostate increases the survival without relapse, the contribution of image-guided radiotherapy, (IGRT) and modulation of intensity (IMRT), decreases the toxicity of pelvic RT. This article reviews the principles of prophylactic ganglion irradiation for prostate cancer and discusses its relevance, current uncertainties, and prospective trials.

Acute and Late Toxicity after Moderate Hypofractionation with Simultaneous Integrated Boost (SIB) Radiation Therapy for Prostate Cancer. A Single Institution, Prospective Study

ASBTRACT

To evaluate the acute and late toxicity using moderately hypofractionated, intensity-modulated radiotherapy (IMRT) with a simultaneous integrated boost (SIB) to prostate for patients with intermediate and high risk prostate cancer. From 2015 to 2017, 162 patients were treated with IMRT with SIB to the prostate. IMRT plans were designed to deliver 50.4Gy in 28 fractions (1.8 Gy/fraction) to the pelvic lymph nodes (whole pelvis radiotherapy, WPRT) while simultaneously delivering 57.4 Gy in 28 fractions (2.05 Gy/fraction) to the seminal vesicles and 70 Gy in 28 fractions (2.5 Gy/fraction) to the prostate for high risk patients. For intermediate risk patients the same technique was applied, without WPRT. Acute and cumulative late genitourinary (GU) and gastrointestinal (GI) toxicities were scored according to the Radiation Therapy Oncology Group (RTOG) scoring system. Of the 162 patients enrolled, 156 (96%) completed the treatment as planned. The median follow-up time was 30 months. Seventy-eight patients (48.2%) were treated with WPRT. The rate of acute grade ≥ 2 GI and GU toxicities in all patients were 22% and 58%, respectively. The rate of cumulative late grade ≥ 2 GI and GU toxicities were 11% and 17%, respectively. Acute grade 3 GI and GU toxicities occurred in 1% and 1%. Late grade 3 GI and GU side effects occurred in 5% and 4%, respectively. None of the patients developed grade ≥ 4 toxicity. IMRT with SIB technique using moderate hypofractionation to the prostate is feasible treatment option for intermediate and high risk patients, associated with low rate of severe GU and GI toxicities.

Dosimetric and volumetric effects in clinical target volume and organs at risk during postprostatectomy radiotherapy

PURPOSE

To assess the reproducibility of the dose-volume distribution of the initial simulation CT, generated using volumetric modulated arc therapy (VMAT) planning, during the radiotherapy of the prostatic bed based on weekly cone beam CTs (CBCT).

METHODS

Twenty-three patients, after radical prostatectomy were treated with adjuvant or salvage radiotherapy between July and December 2016 and considered for this evaluation. Weekly CBCT scans (n = 138) were imported into the treatment planning system, and the clinical tumor volume (CTV), the rectum and the bladder were contoured. The initially calculated dose distribution and the dose-volume histograms generated from weekly CBCTs were compared. The prostatic fossa dose coverage was assessed by the proportion of the CTV fully encompassed by the 95% and 98% isodose lines. Rectal and bladder volumes receiving 50, 60 and 65 Gy during the treatment were compared to the initial plan, with statistical significance determined using the one-sample t‑test.

RESULTS

Marked variations in the total organ volume of the rectum and the bladder were observed. The correlation between rectum volume and V₅₀ was not significant (p = 0.487), while the bladder volume and V₅₀ demonstrated a significant correlation. There was no correlation between urinary bladder volume and CTV. The change in rectal volume correlated significantly with CTV. The dose coverage (D_98% and D_95%) to the prostatic bed could be achieved for all patients due to the ventral shift in the volume differences of the rectum.

CONCLUSION

Weekly CBCTs can be considered as adequate verification tools to assess the interfractional variability of the CTV and organs at risk. The proven volume changes in the urinary bladder and the rectum do not compromise the final delivered dose in the CTV.

Postoperative Radiotherapy in Prostate Cancer: Acquired Certainties and Still Open Issues. A Review of Recent Literature

It is recognized that radiation therapy can eradicate microscopic tumor disease, even in postoperative prostate cancer patients, when extracapsular extension, positive surgical margins or increased prostate-specific antigen is found in surgical specimens. This review of recent literature analyzes and discusses acquired certainties and still open questions regarding type, timing, doses, techniques, toxicities, and associated hormonal therapies of radiotherapy prescribed after radical prostatectomy. Free full text available at www.tumorionline.it

Prostate cancer treated with reduced-volume intensity-modulated radiation therapy: Report on the 5-year outcome of a prospective series

How to define a clinical target volume (CTV) as small as possible for prostate cancer to reduce the dose received by normal organs is an interesting study. We conduct a research to analyze the clinical efficacy of intensity modulated radiotherapy (IMRT) using reduced CTV in the treatment of prostate cancer. From January 2006 to June 2010, 78 patients with prostate cancer were treated with IMRT according to this institutional protocol. Of them, 18 had stage II tumors, 39 had stage III tumors, and 21 had stage IVa tumors. Clinical outcomes included overall survival, biochemical recurrence, recurrence-free survival, and acute and chronic injuries caused by radiotherapy. Risk factors were evaluated using the Cox regression model. As of December 31, 2014, all patients completed radiotherapy as planned. Myelosuppression was mostly grade 1, acute urinary injury was mostly grades 1 and 2, and intestinal injury was mostly grade 1. The 5-year follow-up rate was 91.0%. The overall, progression-free, biochemical recurrence-free, and distant metastasis-free survival rates were 82.1%, 79.4%, 84.6%, and 94.9%, respectively. Tumor volumes defined by small target volumes and Radiation Therapy Oncology Group were 274.21 ± 92.64 and 600.68 ± 113.72, respectively, representing a significant difference (P < .05). Age, prostate-specific antigen level, eastern cooperative oncology Group score, Gleason score, and volume of CTV were independent risk factors for mortality and disease progression. Our findings indicated that IMRT with reduced CTV have less acute and chronic injuries caused by radiation, particularly grade 3 or higher urinary and intestinal injuries, while ensuring survival benefits and protecting the hematopoietic function.

[Expected benefit of lymph node and seminal vesical dissection to decrease high-risk prostate cancer radiotherapy]

PURPOSE

In case of pelvic lymph node and seminal vesicle dissection followed by prostate cancer intensity-modulated radiotherapy, the objective of the study was to evaluate the dosimetric benefit of reducing the target volume.

PATIENTS AND METHODS

A total of 25 patients with high-risk prostate cancer had surgery first followed by intensity-modulated radiotherapy and androgen deprivation. Four treatment planning were simulated for each patient, based on two CT scans performed before and after surgery. The target volumes were: prostate-seminal vesicles-lymph nodes, prostate-lymph nodes, prostate-seminal vesicles and prostate only. The total dose was 46Gy in the seminal vesicles and lymph nodes, and 80Gy in the prostate.

RESULTS

Compared to prostate target volume only, the addition of seminal vesicles and lymph nodes multiplied by a factor of 1.6 and 6.5 the target volume, respectively. Decreasing the target volume from prostate-seminal vesicles-lymph nodes to prostate-seminal vesicles, to prostate only decreased the rectal wall mean dose from 49Gy to 42Gy, to 36Gy, and the risk of late rectal bleeding from 4.4% to 3.2%, to 2.4% (P<0.05), respectively. The bladder wall mean dose decreased from 51Gy to 40Gy, to 35Gy (P<0,05), respectively. Not irradiating the lymph nodes decreased the absolute risk of diarrhea by 11%.

CONCLUSION

Lymph node and seminal vesicle dissection before prostate cancer intensity-modulated radiotherapy allows decreasing moderately the risk of digestive toxicity.

Impact of 18F-Choline PET/CT in the Decision-Making Strategy of Treatment Volumes in Definitive Prostate Cancer Volumetric Modulated Radiation Therapy

INTRODUCTION

Aim of the study is to evaluate the impact of Cho-PET/CT in decision-making strategy of patients with localized prostate cancer (PC) eligible to definitive radiotherapy (RT).

MATERIALS AND METHODS

Sixty patients Cho-PET/CT before RT were prospectively enrolled. All patients were treated with volumetric modulated arc therapy with simultaneous integrated boost in 28 fractions. Androgen deprivation therapy was prescribed according to National Comprehensive Cancer Network (NCCN) risk classification. Therapeutic strategy based on the Cho-PET/CT evaluation was compared with the strategy that would have been proposed in case of PET not available and/or not strictly indicated, according to international and national PC guidelines.

RESULTS

Cho-PET/CT was positive in 57 cases (95%): T in 45 (79%); T in combination with N in 8 (14%); and M (bone) in combination with T or N, or both, in 4 (7%). After Cho-PET/CT, patients were stratified as follows: 26 (43%) low risk, 10 (16%) intermediate risk, and 24 (41%) high risk. Cho-PET/CT shifted treatment indication in 13 cases (21%). The changes regarding radiation treatment volumes were as follows: 6 intermediate risk (10%) shifted to high risk and consequently were irradiated on prostate, seminal vesicles, and pelvic nodes PTVs; in 7 high risk (11%), the Cho-PET/CT showed bone and/or N uptake, and consequently, a simultaneous integrated boost on PET positive sites was prescribed.

CONCLUSIONS

Cho-PET/CT seems to be a promising diagnostic tool in patients who are candidates for radical RT and supporting the decision making in treatment planning, in particular in intermediate-high risk.

Radiation-induced erectile dysfunction: Recent advances and future directions

Prostate cancer is one of the most prevalent cancers and the second leading cause of cancer-related deaths in men in the United States. A large number of patients undergo radiation therapy (RT) as a standard care of treatment; however, RT causes erectile dysfunction (radiation-induced erectile dysfunction; RiED) because of late side effects after RT that significantly affects quality of life of prostate cancer patients. Within 5 years of RT, approximately 50% of patients could develop RiED. Based on the past and current research findings and number of publications from our group, the precise mechanism of RiED is under exploration in detail. Recent investigations have shown prostate RT induces significant morphologic arterial damage with aberrant alterations in internal pudendal arterial tone. Prostatic RT also reduces motor function in the cavernous nerve which may attribute to axonal degeneration may contributing to RiED. Furthermore, the advances in radiogenomics such as radiation induced somatic mutation identification, copy number variation and genome-wide association studies has significantly facilitated identification of biomarkers that could be used to monitoring radiation-induced late toxicity and damage to the nerves; thus, genomic- and proteomic-based biomarkers could greatly improve treatment and minimize arterial tissue and nerve damage. Further, advanced technologies such as proton beam therapy that precisely target tumor and significantly reduce off-target damage to vital organs and healthy tissues. In this review, we summarize recent advances in RiED research and novel treatment modalities for RiED. We also discuss the possible molecular mechanism involved in the development of RiED in prostate cancer patients. Further, we discuss various readily available methods as well as novel strategies such as stem cell therapies, shockwave therapy, nerve grafting with tissue engineering, and nutritional supplementations might be used to mitigate or cure sexual dysfunction following radiation treatment.

Urinary adverse effects of pelvic radiotherapy

Objective

Radiation is an integral part of the treatment of many pelvic tumors. The cellular death induced by radiotherapy (RT) benefits cancer control but can also result in adverse effects (AEs) on the organ being treated or those adjacent to it. RT for cancers of the pelvis (bladder, prostate, rectum, uterus or cervix) can result in AEs in the urinary tract. While the acute urinary AEs of pelvic RT are well described, late AEs are less well characterized. The burden of treatment for late AEs may be large given the prevalence of tumors in the pelvis and the high utilization of RT to treat them.

Review

For prostate cancer, grade 1 and 2 urinary AEs following external beam radiation therapy (EBRT) are reported to occur in 20-43% and 7-19%, respectively, with a follow up of 10 years. Three-year cumulative risk for grade ≥2 urinary AEs is 28-30%. Following brachytherapy (BT), rates of urinary AEs at 5 years are reported to be 36%, 24%, 6.2% and 0.1% for Radiation Therapy Oncology Group (RTOG) grade 1, 2, 3, and 4, respectively. For bladder cancer, with a median follow-up of 5 years, 7-12% of patients who receive RT experience urinary AEs of grade 3 or more. For cervical cancer, there remains a 0.25% per year risk of severe AEs for at least 25 years following RT, and ureteral stricture is a well-described AE. For endometrial cancer, severe urinary AEs are rare, but at 13 years of follow up, patients report a significantly worse quality of life with respect to urinary function. In rectal cancer, preoperative RT has a lower risk of AEs than postoperative RT, and few urinary AEs are reported in the literature.

Conclusions

Urinary AEs can manifest long after RT, and there is a paucity of studies describing rates of these long-term AEs. It is important that the possible complications of RT are recognized by providers and properly communicated to patients so that they are able to make informed decisions about their cancer treatment.

Dose-volume effects for pelvic bone marrow in predicting hematological toxicity in prostate cancer radiotherapy with pelvic node irradiation

PURPOSE

To prospectively identify clinical/dosimetric predictors of acute/late hematologic toxicity (HT) in chemo-naÏve patients treated with whole-pelvis radiotherapy (WPRT) for prostate cancer.

MATERIAL AND METHODS

Data of 121 patients treated with adjuvant/salvage WPRT were analyzed (static-field IMRT n=19; VMAT/Rapidarc n=57; Tomotherapy n=45). Pelvic bone marrow (BM) was delineated as ilium (IL), lumbosacral, lower and whole pelvis (WP), and the relative DVHs were calculated. HT was graded both according to CTCAE v4.03 and as variation in percentage relative to baseline. Logistic regression was used to analyze association between HT and clinical/DVHs factors.

RESULTS

Significant differences (p<0.005) in the DVH of BM volumes between different techniques were found: Tomotherapy was associated with larger volumes receiving low doses (3-20 Gy) and smaller receiving 40-50 Gy. Lower baseline absolute values of WBC, neutrophils and lymphocytes (ALC) predicted acute/late HT (p ⩽ 0.001). Higher BM V40 was associated with higher risk of acute Grade3 (OR=1.018) or late Grade2 lymphopenia (OR=1.005). Two models predicting lymphopenia were developed, both including baseline ALC, and BM WP-V40 (AUC=0.73) and IL-V40+smoking (AUC=0.904) for acute/late respectively.

CONCLUSIONS

Specific regions of pelvic BM predicting acute/late lymphopenia, a risk factor for viral infections, were identified. The 2-variable models including specific constraints to BM may help reduce HT.

Incorporating Genetic Biomarkers into Predictive Models of Normal Tissue Toxicity

There is considerable variation in the level of toxicity patients experience for a given dose of radiotherapy, which is associated with differences in underlying individual normal tissue radiosensitivity. A number of syndromes have a large effect on clinical radiosensitivity, but these are rare. Among non-syndromic patients, variation is less extreme, but equivalent to a ±20% variation in dose. Thus, if individual normal tissue radiosensitivity could be measured, it should be possible to optimise schedules for individual patients. Early investigations of in vitro cellular radiosensitivity supported a link with tissue response, but individual studies were equivocal. A lymphocyte apoptosis assay has potential, and is currently under prospective validation. The investigation of underlying genetic variation also has potential. Although early candidate gene studies were inconclusive, more recent genome-wide association studies are revealing definite associations between genotype and toxicity and highlighting the potential for future genetic testing. Genetic testing and individualised dose prescriptions could reduce toxicity in radiosensitive patients, and permit isotoxic dose escalation to increase local control in radioresistant individuals. The approach could improve outcomes for half the patients requiring radical radiotherapy. As a number of patient- and treatment-related factors also affect the risk of toxicity for a given dose, genetic testing data will need to be incorporated into models that combine patient, treatment and genetic data.

Exploiting biological and physical determinants of radiotherapy toxicity to individualize treatment

The recent advances in radiation delivery can improve tumour control probability (TCP) and reduce treatment-related toxicity. The use of intensity-modulated radiotherapy (IMRT) in particular can reduce normal tissue toxicity, an objective in its own right, and can allow safe dose escalation in selected cases. Ideally, IMRT should be combined with image guidance to verify the position of the target, since patients, target and organs at risk can move day to day. Daily image guidance scans can be used to identify the position of normal tissue structures and potentially to compute the daily delivered dose. Fundamentally, it is still the tolerance of the normal tissues that limits radiotherapy (RT) dose and therefore tumour control. However, the dose-response relationships for both tumour and normal tissues are relatively steep, meaning that small dose differences can translate into clinically relevant improvements. Differences exist between individuals in the severity of toxicity experienced for a given dose of RT. Some of this difference may be the result of differences between the planned dose and the accumulated dose (DA). However, some may be owing to intrinsic differences in radiosensitivity of the normal tissues between individuals. This field has been developing rapidly, with the demonstration of definite associations between genetic polymorphisms and variation in toxicity recently described. It might be possible to identify more resistant patients who would be suitable for dose escalation, as well as more sensitive patients for whom toxicity could be reduced or avoided. Daily differences in delivered dose have been investigated within the VoxTox research programme, using the rectum as an example organ at risk. In patients with prostate cancer receiving curative RT, considerable daily variation in rectal position and dose can be demonstrated, although the median position matches the planning scan well. Overall, in 10 patients, the mean difference between planned and accumulated rectal equivalent uniform doses was -2.7 Gy (5%), and a dose reduction was seen in 7 of the 10 cases. If dose escalation was performed to take rectal dose back to the planned level, this should increase the mean TCP (as biochemical progression-free survival) by 5%. Combining radiogenomics with individual estimates of DA might identify almost half of patients undergoing radical RT who might benefit from either dose escalation, suggesting improved tumour cure or reduced toxicity or both.

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.

Pelvic nodal dosing with registration to the prostate: implications for high-risk prostate cancer patients receiving stereotactic body radiation therapy

PURPOSE

To determine whether image guidance with rigid registration (RR) to intraprostatic markers (IPMs) yields acceptable coverage of the pelvic lymph nodes in the context of a stereotactic body radiation therapy (SBRT) regimen.

METHODS AND MATERIALS

Four to seven kilovoltage cone-beam CTs (CBCTs) from 12 patients with high-risk prostate cancer were analyzed, allowing approximation of an SBRT regimen. The nodal clinical target volume (CTV(N)) and bladder were contoured on all kilovoltage CBCTs. The V100 CTV(N), expressed as a ratio to the same parameter on the initial plan, and the magnitude of translational shift between RR to the IPMs versus RR to the pelvic bones, were computed. The ability of a multimodality bladder filling protocol to minimize bladder height variation was assessed in a separate cohort of 4 patients.

RESULTS

Sixty-five CBCTs were assessed. The average V100 CTV(N) was 92.6%, but for a subset of 3 patients the average was 80.0%, compared with 97.8% for the others (P<.0001). The average overall and superior-inferior axis magnitudes of the bony-to-fiducial translations were significantly larger in the subgroup with suboptimal nodal coverage (8.1 vs 3.9 mm and 5.8 vs 2.4 mm, respectively; P<.0001). Relative bladder height changes were also significantly larger in the subgroup with suboptimal nodal coverage (42.9% vs 18.5%; P<.05). Use of a multimodality bladder-filling protocol minimized bladder height variation (P<.001).

CONCLUSION

A majority of patients had acceptable nodal coverage after RR to IPMs, even when approximating SBRT. However, a subset of patients had suboptimal nodal coverage. These patients had large bony-to-fiducial translations and large variations in bladder height. Nodal coverage should be excellent if the superior-inferior axis bony-to-fiducial translation and the relative bladder height change (both easily measured on CBCT) are kept to a minimum. Implementation of a strict bladder filling protocol may achieve this goal.

Toxicity of tomotherapy-based simultaneous integrated boost in whole-pelvis radiation for prostate cancer

PURPOSE

The validity of tomotherapy-based simultaneous integrated boost (TOMOSIB) was assessed in terms of acute intestinal/urinary toxicity by comparing with 3-dimensional conformal radiotherapy (3DCRT) in cases of whole-pelvis radiation therapy (WPRT) for prostate cancer.

MATERIALS AND METHODS

Thirty-eight consecutive patients who underwent curative WPRT were retrospectively reviewed. Twenty six (68.4%) received 3DCRT and the others (31.6%) were treated with TOMOSIB. A local boost to the prostate circumferential area was added to WPRT sequentially for 3DCRT and concomitantly for TOMOSIB. The total median prostate or prostatic bed dose was 64.8 Gy including median 45.0 Gy of WPRT. Acute toxicities were assessed according to RTOG criteria.

RESULTS

Overall intestinal toxicity was lower in TOMOSIB group than 3DCRT group (p=0.008). When it was divided into rectum and non-rectum intestine (NRI), TOMOSIB showed borderline superiority only in NRI toxicity (p=0.047). For the urinary toxicity, there was no significant difference between two groups (p=0.796). On dosimetric analysis for the rectum and bladder, dose delivered to 80% (p<0.001) and volume receiving 25-40 Gy (p<0.001) were remarkably higher in 3DCRT. For the NRI, only maximum dose showed significant results between two groups (p<0.001).

CONCLUSION

Intestinal toxicity should be verified with more detailed anatomic categorization such as rectum and NRI. TOMOSIB could not reduce urinary toxicity because of inevitably high dose exposure to the prostatic urethra. Current dosimetry system did not properly reflect intestinal/urinary toxicity, and suitable dosimetric guidelines are needed in TOMOSIB.

Offline multiple adaptive planning strategy for concurrent irradiation of the prostate and pelvic lymph nodes

PURPOSE

Concurrent irradiation of the prostate and pelvic lymph nodes (PLNs) can be challenging due to the independent motion of the two target volumes. To address this challenge, the authors have proposed a strategy referred to as Multiple Adaptive Planning (MAP). To minimize the number of MAP plans, the authors' previous work only considered the prostate motion in one major direction. After analyzing the pattern of the prostate motion, the authors investigated a practical number of intensity-modulated radiotherapy (IMRT) plans needed to accommodate the prostate motion in two major directions simultaneously.

METHODS

Six patients, who received concurrent irradiation of the prostate and PLNs, were selected for this study. Nine MAP-IMRT plans were created for each patient with nine prostate contours that represented the prostate at nine locations with respect to the PLNs, including the original prostate contour and eight contours shifted either 5 mm in a single anterior-posterior (A-P), or superior-inferior (S-I) direction, or 5 mm in both A-P and S-I directions simultaneously. From archived megavoltage cone beam CT (MV-CBCT) and a dual imaging registration, 17 MV-CBCTs from 33 available MV-CBCT from these patients showed large prostate displacements (>3 mm in any direction) with respect to the pelvic bones. For each of these 17 fractions, one of nine MAP-IMRT plans was retrospectively selected and applied to the MV-CBCT for dose calculation. For comparison, a simulated isocenter-shifting plan and a reoptimized plan were also created for each of these 17 fractions. The doses to 95% (D95) of the prostate and PLNs, and the doses to 5% (D5) of the rectum and bladder were calculated and analyzed.

RESULTS

For the prostate, D95 > 97% of the prescription dose was observed in 16, 16, and 17 of 17 fractions for the MAP, isocenter-shifted, and reoptimized plans, respectively. For PLNs, D95 > 97% of the prescription doses was observed in 10, 3, and 17 of 17 fractions for the three types of verification plans, respectively. The D5 (mean ± SD) of the rectum was 45.78 ± 5.75, 45.44 ± 4.64, and 44.64 ± 2.71 Gy, and the D5 (mean ± SD) of the bladder was 45.18 ± 2.70, 46.91 ± 3.04, and 45.67 ± 3.61 Gy for three types of verification plans, respectively.

CONCLUSIONS

The MAP strategy with nine IMRT plans to accommodate the prostate motions in two major directions achieved good dose coverage to the prostate and PLNs. The MAP approach can be immediately used in clinical practice without requiring extra hardware and software.

Helical tomotherapy for cancer treatment: a rapid health technology assessment

OBJECTIVES

Helical tomotherapy (HT) can be applied to treat complex malignant cancer with high-precise radiotherapy, and it can reduce the damage to normal tissues and improve treatment effects. But the procurement of HT must be approved by relevant departments of administration affairs. This study, appointed by the National Health and Family Planning Commission of China and undertook by the National Health Development Research Center and the Chinese Evidence-Based Medicine Centre, was aimed to rapidly assess the effectiveness, safety, costs, and applicability of HT, so as to provide currently available best evidence for decision-makers of health policies.

METHODS

We electronically searched databases including PubMed, EMbase, The Cochrane Library, CNKI, WanFang Data, VIP, CBM, and other professional websites. Two reviewer independently screened literature according to the inclusion and exclusion criteria, extracted data, assessed quality, and then performed descriptive analysis.

RESULTS

(i) We finally included 150 studies, encompassing 5 HTAs, 18 CCTs, and 127 observational studies. (ii) The included HTAs were published during 2006-2009, providing fairly less evidence of low quality and the results of 145 primary studies showed that: HT had been used mainly in the treatments of 14 kinds of cancer, with low total toxicity and high survival rates. Although the quality of the included studies was poor, there was much evidence about prostate cancer, head and neck cancer, nasopharynx cancer, cervical cancer, lung cancer and liver cancer, with enough sample and fairly reliable results in HT efficacy and safety. And (iii) a total of 56 clinical trials were registered in Clinicaltrials.gov, most of which were registered by the occident. Among them, 9 were completed but the results had not been published yet.

CONCLUSIONS

The evidence of this study showed that, HT is safe and effective in clinic. But the abovementioned conclusion needs to be verified by conducting more high-quality studies with long-term follow-up. The costs of HT in procurement, maintenance, and application are high; and the skills, training, and qualification of operators are required. We suggest that the procurement of HT should be reduced; it should be allocated rationally and effectively used after comprehensive assessment in China's cancer epidemiology characteristics, health resource allocation, disease burden, medical service level, etc.; and also high-quality studies with long-term follow-up should be financially supported on the basis of establishing projects, so as to provide local evidence and consistently guide and improve scientific decision-making.

Higher-than-expected severe (Grade 3-4) late urinary toxicity after postprostatectomy hypofractionated radiotherapy: a single-institution analysis of 1176 patients

BACKGROUND

Dose escalation and hypofractionation may have a role in postprostatectomy radiotherapy (RT), but at the risk of increasing urinary toxicity.

OBJECTIVE

To address predictors of severe (Grade ≥3) late urinary toxicities (LGUTOX3) after postoperative irradiation.

DESIGN, SETTING, AND PARTICIPANTS

A single-institution cohort of 1176 patients treated between 1993 and 2010 with adjuvant or salvage RT was analyzed. A total of 929 patients underwent conventionally fractionated (CF) RT (1.8 Gy per fraction; median dose to the prostatic bed: 70.2 Gy) with nonconformal RT (n=169), three-dimensional conformal RT (n=657), or intensity-modulated RT (n=103) technique, while 247 patients received hypofractionated helical TomoTherapy (median: 2.50 Gy per fraction) at the following doses: 117 patients at 65.8 Gy (2.35 Gy in 28 fractions), 80 patients at a median of 71.4 Gy (2.5-2.6 Gy in 28 fractions), and 50 patients at 58 Gy in 20 fractions. Total doses were converted into 2 Gy-equivalent doses (EQD2) following the linear quadratic model taking α/β=5.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariable and multivariable Cox regression models tested the relationship between clinicodosimetric variables and the risk of LGUTOX3 retrospectively, graded according to Common Terminology Criteria for Adverse Events v.4.0.

RESULTS AND LIMITATIONS

After a median follow-up of 98 mo, the 5-yr risk of LGUTOX3 was 6.9% and 18.1% in the CF and hypofractionated cohorts, respectively. At univariable analysis, the risk of LGUTOX3 was predicted by dose per fraction (hazard ratio [HR]: 2.96), acute Grade ≥2 toxicity (HR: 2.37), EQD2, pT4, and year of irradiation. At multivariable analyses, acute Grade ≥2 toxicity and dose per fraction independently predicted LGUTOX3 in the population, while an interaction analysis indicated a predictive role of hypertension in the hypofractionated cohort only. These findings are limited by their retrospective nature.

CONCLUSIONS

In the postprostatectomy setting, the logistic convenience of hypofractionation should be carefully balanced against the risk of severe late urinary sequelae.

PATIENT SUMMARY

This study investigated the causes of urinary adverse effects after postprostatectomy radiotherapy. Hypofractionation resulted in an increased risk of severe urinary toxicities.

Long-term quality of life outcomes in patients with locally advanced prostate cancer after intensity-modulated radiotherapy combined with androgen deprivation

With great improvements in survival in patients with locally advanced prostate cancer, quality of life (QOL) is becoming an important factor in the selection of treatment. The aim of this study was to evaluate changes in health-related QOL in patients with locally advanced prostate cancer after intensity-modulated radiotherapy (IMRT) combined with androgen deprivation therapy. Patients were treated with IMRT combined with androgen deprivation. Total dose to the prostate was 68.2 Gy (2.2 Gy per fraction), and patients received 50 mg of oral Casodex once daily and 3.6 mg of subcutaneous Zoladex once every 28 days for 2.5 years. QOL was measured using the Expanded Prostate Cancer Index Composite. The time points were baseline, end of radiotherapy, and 3, 12, 36, 48, and 60 months after radiotherapy. From 2002 to 2007, a total of 87 patients were enrolled. Median follow-up time was 76.8 months. Compared with baseline, all four domain summary scores were decreased to varying degrees. Statistically significant changes in the urinary, bowel, and hormonal domain scores were observed (P < 0.05). The changes in scores for urinary incontinence and dysuria were -13.0 ± 8.3 and -6.12 ± 3.9, respectively (P < 0.05). QOL was decreased in patients with locally advanced prostate cancer after IMRT combined with androgen deprivation therapy in all four primary domains, especially in urinary, bowel, and hormonal domains. Nevertheless, the treatment was well tolerated in most patients during the 5 years of follow-up.

Intensity-modulated radiotherapy combined with endocrine therapy for intermediate and advanced prostate cancer: long-term outcome of Chinese patients

AIM

The aim of this study was to evaluate acute adverse events and efficacy of three-dimensional intensity- modulated radiotherapy (IMRT) combined with endocrine therapy for intermediate and advanced prostate cancer.

METHODS

Sixty-seven patients were treated with three-dimensional IMRT combined with maximum androgen blockade. The correlation between radiation-induced rectal injury and clinical factors was further analyzed.

RESULTS

After treatment, 21 patients had complete remission (CR), 37 had partial remission (PR), and nine had stable disease (SD), with an overall response rate of 86.5%. The follow-up period ranged from 12.5 to 99.6 months. Thirty-nine patients had a follow-up time of ≥ five years. In this group, three-year and five-year overall survival rates were 89% and 89.5%, respectively; three-year and five-year progression-free survival rates were 72% and 63%. In univariate analyses, gross tumor volume was found to be prognostic for survival (χ2 = 5.70, P = 0.037). Rates of leucopenia and anemia were 91.1% and 89.5%, respectively. Two patients developed acute liver injury, and a majority of patients developed acute radiation proctitis and cystitis, mainly grade 1/2. Tumor volume before treatment was the only prognostic factor influencing the severity of acute radiation proctitis (P < 0.05).

CONCLUSIONS

IMRT combined with endocrine therapy demonstrated promising efficacy and was well tolerated in patients with intermediate and advanced prostate cancer.

Image-guided radiation therapy based on helical tomotherapy in prostate cancer: minimizing toxicity

BACKGROUND

We report the clinical results and prognostic factors of image-guided radiation therapy (RT) with helical tomotherapy (HT) for localized and recurrent prostate cancer (PC).

PATIENTS AND METHODS

We evaluated 70 patients with PC (primary diagnosis, n = 48; adjuvant, n = 5; salvage, n = 17) treated with HT from May 2006 through January 2011. The dose prescribed to the prostate/surgical bed ranged between 60 and 78 Gy. Potential risk factors for genitourinary (GU) and gastrointestinal (GI) toxicity were assessed.

RESULTS

The median age was 68 years (range 51-87 years). The median follow-up was 37 months (range 3-74 months). The rates of acute grade 2 GI and GU toxicities were 10 and 13%, respectively. Only 1 patient experienced acute grade 3 GU toxicity. The rates of late grade ≥ 2 GI and GU toxicities were 1% each. Multivariate analysis showed an association between rectum mean dose > median (39 Gy) and bladder median dose > median (46 Gy) with a higher grade of acute GI (p = 0.017) and GU (p = 0.019) toxicity, respectively. Additionally, older age was associated with late GU toxicity (p = 0.026).

CONCLUSION

Toxicity with HT is low and is associated with higher median/mean doses in organs at risk as well as with older age. A prospective validation would be necessary to confirm these results.

(11)C-Choline PET/CT as a guide to radiation treatment planning of lymph-node relapses in prostate cancer patients

PURPOSE

To evaluate, in prostate cancer (PCa) patients the potential of (11)C-choline PET/CT as a guide to helical tomotherapy (HTT) of lymph-node (LN) relapses with simultaneous integrated boost (SIB). The efficacy and feasibility of HTT in terms of acute toxicity were assessed.

METHODS

We enrolled 83 PCa patients (mean age 68 years, range 51 - 82 years) with biochemical recurrence after radical primary treatment (mean serum PSA 7.61 ng/ml, range 0.37 - 187.00 ng/ml; PSA0) who showed pathological findings on (11)C-choline PET/CT only at the LN site. (11)C-Choline PET/CT was performed for restaging and then for radiation treatment planning (PET/CT0). Of the 83 patients, 8 experienced further LN relapse, of whom 5 were retreated once and 3 were retreated twice (total 94 radiotherapy treatments). All pelvic and/or abdominal LNs positive on PET/CT0 were treated with high doses using SIB. Doses were in the range 36 - 74 Gy administered in 28 fractions. After the end of HTT (mean 83 days, range 16 - 365 days), serum PSA was measured in all patients (PSA1) and compared with PSA0 to evaluate early biochemical response. In 47 patients PET/CT was repeated (PET/CT1) to assess metabolic responses at the treated areas. Toxicity criteria of the Radiation Therapy Oncology Group (RTOG) were used to assess acute toxicity.

RESULTS

PET/CT0 revealed pathological LNs in the pelvis in 49 patients, pathological LNs in the abdomen in 15 patients pathological LNs in both the pelvis and abdomen in 18 patients, and pathological LNs in the pelvis or abdomen and other sites in 12 patients. All these sites were treated with HTT. With respect to PSA0, PSA1 (mean 6.28 ng/ml, range 0.00 - 220.46 ng/ml) showed a complete biochemical response after 66 of the 94 HTT treatments, a partial response after 12 treatments, stable disease after 1 treatment and progression of disease after 15 treatments. Of the 47 patients receiving PET/CT1, 20 showed a complete metabolic response at the treated area, 22 a partial metabolic response, 3 progression of disease and 2 stable disease. HTT with SIB was well tolerated in all patients. Grade 3 acute toxicity in the genitourinary tract was observed in two patients.

CONCLUSION

(11)C-Choline PET/CT is a valuable tool for planning and monitoring HTT in LN relapse after primary treatment. High-dose hypofractionated (11)C-choline PET/CT-guided HTT with SIB is well tolerated and is associated with a high early biochemical response rate.

Small bowel toxicity after high dose spot scanning-based proton beam therapy for paraspinal/retroperitoneal neoplasms

PURPOSE

Mesenchymal tumours require high-dose radiation therapy (RT). Small bowel (SB) dose constraints have historically limited dose delivery to paraspinal and retroperitoneal targets. This retrospective study correlated SB dose-volume histograms with side-effects after proton radiation therapy (PT).

PATIENTS AND METHODS

Between 1997 and 2008, 31 patients (mean age 52.1 years) underwent spot scanning-based PT for paraspinal/retroperitoneal chordomas (81%), sarcomas (16%) and meningiom (3%). Mean total prescribed dose was 72.3 Gy (relative biologic effectiveness, RBE) delivered in 1.8-2 Gy (RBE) fractions. Mean follow-up was 3.8 years. Based on the pretreatment planning CT, SB dose distributions were reanalysed.

RESULTS

Planning target volume (PTV) was defined as gross tumour volume (GTV) plus 5-7 mm margins. Mean PTV was 560.22 cm(3). A mean of 93.2% of the PTV was covered by at least 90% of the prescribed dose. SB volumes (cm(3)) receiving doses of 5, 20, 30, 40, 50, 60, 70, 75 and 80 Gy (RBE) were calculated to give V5, V20, V30, V40, V50, V60, V70, V75 and V80 respectively. In 7/31 patients, PT was accomplished without any significant SB irradiation (V5=0). In 24/31 patients, mean maximum dose (Dmax) to SB was 64.1 Gy (RBE). Despite target doses of >70 Gy (RBE), SB received >50 and >60 Gy (RBE) in only 61 and 54% of patients, respectively. Mean SB volumes (cm(3)) covered by different dose levels (Gy, RBE) were: V20 (n=24): 45.1, V50 (n=19): 17.7, V60 (n=17): 7.6 and V70 (n=12): 2.4. No acute toxicity ≥ grade 2 or late SB sequelae were observed.

CONCLUSION

Small noncircumferential volumes of SB tolerated doses in excess of 60 Gy (RBE) without any clinically-significant late adverse effects. This small retrospective study has limited statistical power but encourages further efforts with higher patient numbers to define and establish high-dose threshold models for SB toxicity in modern radiation oncology.

Tomotherapy: implications on daily workload and scheduling patients based on three years' institutional experience

Helical tomotherapy (HT) was introduced at the Greater Poland Cancer Centre (GPCC) in April 2009. Retrospective analysis included data from the treatments performed for the first 656 patients treated with HT between May 2009 and May 2012 at the GPCC. In order to evaluate the implications on daily workload and scheduling of patients, stepwise regression and time analysis for each component of the overall treatment time, such as positioning, imaging, registration, and irradiation were performed. A detailed analysis included: (1) learning curves and optimized time needed for positioning and registration; (2) relation between irradiation time and parameters used for plan creation; and (3) average time of daily imaging. The irradiation component has the highest influence on the overall treatment time (R = 0.911). The lowest influence was observed for the imaging (R = 0.670). The learning curve for positioning was 7 months while the reduction of the average daily time needed for registration was observed even after two years. The irradiation time strongly depends on the planning parameters. Changing the pitch from 0.215 to 0.287 for pelvic cancer cases decreased the average daily beam-on time per patient by about 2 minutes. Similar changes for head and neck reduced this time by 1.3 minutes. The limitation in the usage of 1 cm field width only for complex cases, lower than 10 cm in the cranio-caudal direction, reduced the beam-on time per patient by 2 minutes. The average overall treatment time decreased from 21.5 minutes per patient in the first year of the HT usage to 13.8 minutes per patient in current practice. Our current practice shows that for a group of patients including mainly those with pelvis and head and neck cancers, the HT treatment takes approximately 15 minutes per patient allowing 40 patients to be treated within 10 hours.

Dosimetric consequences of prostate-based couch shifts on the precision of dose delivery during simultaneous IMRT irradiation of the prostate, seminal vesicles and pelvic lymph nodes

INTRODUCTION

To evaluate the impact interfraction prostate (CTV1) motion corrections on doses delivered to seminal vesicles (CTV2) and lymph nodes (CTV3), and to determine ideal planning target volume (PTV) margins for these targets with prostate-based position verification.

MATERIAL AND METHODS

Retrospective analysis based on 253 cone beam computed tomography (CBCT) studies of 28 patients. The isocenter-shift method was used to estimate the interfraction prostate and bony shift effects on the original plan coverage. Friedman's test was used to assess statistical significance between dose-volume histogram (DVH) parameters which were calculated for prostate-based sum plans, bony-based sum plans and original treatment plans. The van Herk formula was used to determine the set-up margin size for prostate-based verification.

RESULTS

The tracked shifts influenced the minimum, maximum and mean CTV2 and CTV3 doses, with a range differential of 0.17%-2.63% (prostate shifts) and 0.13%-1.92% (bony shifts) compared to the corresponding original parameters. Friedman's test revealed significant differences in the minimum doses to the CTV3 and maximum doses to both the CTV2 and CTV3. The calculated set-up margins of 1.22 cm (vertical), 0.19 cm (longitudinal) and 0.39 cm (lateral) should be added to CTV3 while performing prostate-based positioning.

CONCLUSION

To avoid geographical miss during simultaneous irradiation of independently moving targets (CTV1-3) appropriate margins should be used in accordance with the position verification method used. Based on our findings the following margin sizes should be used: 0.7 cm for the CTV1, 0.8-0.9 cm for the CTV2 , and asymmetric 1.0 cm (vertically) and 0.5 cm (other axes) for the CTV3.

A criterion-based audit of the technical quality of external beam radiotherapy for prostate cancer

PURPOSE

To evaluate the technical quality of external beam radiotherapy for prostate cancer in Canada.

METHODS

This was a multi-institution, retrospective study of a random sample of patients undergoing radiotherapy (RT) for prostate cancer in Canada. Patterns of care were determined by abstracting details of the patients' management from original records. The quality of patient's technical care was measured against a previously published, comprehensive suite of quality indicators.

RESULTS

32 of the 37 RT centres participated. The total study population of 810 patients included 25% low-risk, 44% intermediate-risk, and 28% high-risk cases. 649 received external beam RT (EBRT) only, for whom compliance with 12 indicators of the quality of pre-treatment assessment ranged from 56% (sexual function documented) to 96% (staging bone scan obtained in high-risk patients). Compliance with treatment-related indicators ranged from 78% (dose to prostate ≥74 Gy in intermediate risk patients not receiving hormone therapy) to 100% (3DCRT or IMRT plan). Compliance varied among centres; no centre demonstrated 100% compliance on all indicators and every centre was 100% compliant on at least some indicators. The number of assessment-related indicators (n=13) with which a given centre was 100% compliant ranged from 4 to 11 (median 7) and the number of the treatment-specific indicators (n=8) with which a given centre was 100% compliant ranged from 6 to 8 (median 8). ADT therapy was utilised in most high-risk cases (191, 92.3%).

CONCLUSIONS

While patterns of prostate cancer care in Canada vary somewhat, compliance on the majority of quality indicators is very high. However, all centres showed room for improvement on several indicators and few individual patients received care that met target benchmarks on all quality measures. This variation is particularly important for indicators such as delivered dose where impact on disease outcome is known to exist, and suggests that quality improvement programmes have the potential to further improve quality of care.

The PROCAINA (PROstate CAncer INdication Attitudes) Project (Part I): a survey among Italian radiation oncologists on postoperative radiotherapy in prostate cancer

PURPOSE

Radiotherapy (RT) has an established role in the postoperative treatment of prostate cancer patients with extracapsular extension, positive surgical margins or a detectable post-operative prostate-specific antigen (PSA). Despite the large number of patients treated with postoperative RT, some issues about optimal technique, doses, volumes, timing and association with androgen deprivation are still subject of debate. The aim of this survey was to determine the patterns of choice of Italian radiation oncologists in two different clinical cases of postoperative prostate cancer patients.

STUDY DESIGN

During the 2010 National Congress of the Italian Association of Radiation Oncology (AIRO), four clinical cases were presented to the attending radiation oncologists. Two of them were cases of postoperative prostate cancer, differing in T stage of the primary tumour according to the TNM classification, preoperative staging procedures, preoperative PSA (iPSA), Gleason score of biopsies and definitive pathological specimen after surgery and postoperative PSA. For each clinical case, the radiation oncologists were asked to: (a) give indication to new pre-treatment procedures for staging; b) give indication to postoperative treatment; (c) to define specifically, where indicated, the total dose, type of fractionation, treatment volumes, type of technique, type of image-guided setup control; (d) indicate whether adjuvant hormonal therapy should be prescribed; (e) define criteria that mostly influenced the prescription. A descriptive statistical analysis was then performed.

RESULTS

A total of 300 questionnaires were distributed amongst radiation oncologists attending the congress; 128 were completed and considered for this analysis (41%). Some important differences were shown in prescribing and performing postoperative radiotherapy, and some significant differences with international guidelines and data available from the literature were also reviewed and discussed.

CONCLUSIONS

Despite the results of clinical trials, significant differences still exist among Italian radiation oncologists in deciding postoperative treatment in prostate cancer patients. These patients probably deserve a more uniform approach based on updated, detailed and evidence-based recommendations.

Toxicity and Long-Term Outcomes of Dose-Escalated Intensity Modulated Radiation Therapy to 74Gy for Localised Prostate Cancer in a Single Australian Centre

Purpose

To report the toxicity and long-term outcomes of dose-escalated intensity-modulated radiation therapy (IMRT) for patients with localised prostate cancer.

Methods and Materials

From 2001 to 2005, a total of 125 patients with histologically confirmed T1-3N0M0 prostate cancer were treated with IMRT to 74Gy at the Austin Health Radiation Oncology Centre. The median follow-up was 5.5 years (range 0.5–8.9 years). Biochemical prostate specific antigen (bPSA) failure was defined according to the Phoenix consensus definition (absolute nadir + 2ng/mL). Toxicity was scored according to the RTOG/EORTC criteria. Kaplan-Meier analysis was used to calculate toxicity rates, as well as the risks of bPSA failure, distant metastases, disease-specific and overall survival, at 5 and 8-years post treatment.

Results

All patients completed radiotherapy without any treatment breaks. The 8-year risks of ≥ Grade 2 genitourinary (GU) and gastrointestinal (GI) toxicity were 6.4% and 5.8% respectively, and the 8-year risks of ≥ Grade 3 GU and GI toxicity were both < 0.05%. The 5 and 8-year freedom from bPSA failure were 76% and 58% respectively. Disease-specific survival at 5 and 8 years were 95% and 91%, respectively, and overall survival at 5 and 8 years were 90% and 71%, respectively.

Conclusions

These results confirm existing international data regarding the safety and efficacy of dose-escalated intensity-modulated radiation therapy for localised prostate cancer within an Australian setting.