Functional imaging guided stereotactic ablative body radiotherapy (SABR) with focal dose escalation and bladder trigone sparing for intermediate and high-risk prostate cancer: study protocol for phase II safo trial

BACKGROUND

Stereotactic ablative body radiotherapy (SABR) is an emerging treatment alternative for patients with localized low and intermediate risk prostate cancer patients. As already explored by some authors in the context of conventional moderate hypofractionated radiotherapy, focal boost of the index lesion defined by magnetic resonance imaging (MRI) is associated with an improved biochemical outcome. The objective of this phase II trial is to determine the effectiveness (in terms of biochemical, morphological and functional control), the safety and impact on quality of life, of prostate SABR with MRI guided focal dose intensification in males with intermediate and high-risk localized prostate cancer.

METHODS

Patients with intermediate and high-risk prostate cancer according to NCCN definition will be treated with SABR 36.25 Gy in 5 fractions to the whole prostate gland with MRI guided simultaneous integrated focal boost (SIB) to the index lesion (IL) up to 50 Gy in 5 fractions, using a protocol of bladder trigone and urethra sparing. Intra-fractional motion will be monitored with daily cone beam computed tomography (CBCT) and intra-fractional tracking with intraprostatic gold fiducials. Androgen deprivation therapy (ADT) will be allowed. The primary endpoint will be efficacy in terms of biochemical and local control assessed by Phoenix criteria and post-treatment MRI respectively. The secondary endpoints will encompass acute and late toxicity, quality of life (QoL) and progression-free survival. Finally, the subgroup of high-risk patients will be involved in a prospective study focused on immuno-phenotyping.

DISCUSSION

To the best of our knowledge, this is the first trial to evaluate the impact of post-treatment MRI on local control among patients with intermediate and high-risk prostate cancer undergoing SABR and MRI guided focal intensification. The results of this trial will enhance our understanding of treatment focal intensification through the employment of the SABR technique within this specific patient subgroup, particularly among those with high-risk disease, and will help to clarify the significance of MRI in monitoring local responses. Hopefully will also help to design more personalized biomarker-based phase III trials in this specific context. Additionally, this trial is expected to be incorporated into a prospective radiomics study focused on localized prostate cancer treated with radiotherapy.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT05919524; Registered 17 July 2023.

TRIAL SPONSOR

IRAD/SEOR (Instituto de Investigación de Oncología Radioterápica / Sociedad Española de Oncología Radioterápica).

STUDY SETTING

Clinicaltrials.gov identifier: NCT05919524; Registered 17 July 2023.

TRIAL STATUS

Protocol version number and date: v. 5/ 17 May-2023. Date of recruitment start: August 8, 2023. Date of recruitment completion: July 1, 2024.

Predictive Factors for Toxicity After Primary Chemoradiation for Locally Advanced Cervical Cancer: A Systematic Review

PURPOSE

Women with locally advanced cervical cancer (LACC) undergoing primary platinum-based chemoradiotherapy and brachytherapy often experience toxicities. Normal-tissue complication probability (NTCP) models quantify toxicity risk and aid in optimizing radiation therapy to minimize side effects. However, it is unclear which predictors to include in an NTCP model. The aim of this systematic review was to provide an overview of the identified predictors contributing to gastrointestinal (GI), genitourinary (GU), and vaginal toxicities and insufficiency fractures for LACC.

METHODS AND MATERIALS

A systematic search was performed and articles evaluating the relationship between predictors and toxicities in women with LACC treated with primary chemoradiation were included. The Quality In Prognosis Studies tool was used to assess risk of bias, with high-risk studies being excluded from further analysis. Relationships between dose-volume parameters, patient and treatment characteristics, and toxicity endpoints were analyzed.

RESULTS

Seventy-three studies were identified. Twenty-six had a low or moderate risk of bias and were therefore included. Brachytherapy-related dose-volume parameters of the GI tract, including rectum and bowel equivalent dose in 2 Gy fractions (EQD2) D2 cm3, were frequently related to toxicities, unlike GU dose-volume parameters. Furthermore, (recto)vaginal point doses predicted toxicities. Few studies evaluated external beam radiation therapy dose-volume parameters and identified rectum EQD2 V30 Gy, V40 Gy, and V55 Gy, bowel and bladder EQD2 V40 Gy as toxicity predictors. Also, total reference air kerma and vaginal reference length were associated with toxicities. Relationships between patient characteristics and GI toxicity were inconsistent. The extent of vaginal involvement at diagnosis, baseline symptoms, and obesity predicted GU or vaginal toxicities. Only 1 study evaluated insufficiency fractures and demonstrated lower pretreatment bone densities to be associated.

CONCLUSIONS

This review detected multiple candidate predictors of toxicity. Larger studies should consider insufficiency fractures, assess dose levels from external beam radiation therapy, and quantify the relationship between the predictors and treatment-related toxicities in women with LACC to further facilitate NTCP model development for clinical use.

Impact of Interfractional Bladder and Trigone Displacement and Deformation on Radiation Exposure and Subsequent Acute Genitourinary Toxicity: A Post Hoc Analysis of Patients Treated with Magnetic Resonance Imaging-Guided Prostate Stereotactic Body Radiation Therapy in a Phase 3 Randomized Trial

PURPOSE

Emerging data suggest that trigone dosimetry may be more associated with poststereotactic body radiation therapy (SBRT) urinary toxicity than whole bladder dosimetry. We quantify the dosimetric effect of interfractional displacement and deformation of the whole bladder and trigone during prostate SBRT using on-board, pretreatment 0.35T magnetic resonance images (MRI).

METHODS AND MATERIALS

Seventy-seven patients treated with MRI-guided prostate SBRT (40 Gy/5 fractions) on the MRI arm of a phase 3 single-center randomized trial were included. Bladder and trigone structures were contoured on images obtained from a 0.35T simulation MRI and 5 on-board pretreatment MRIs. Dice similarity coefficient (DSC) scores and changes in volume between simulation and daily treatments were calculated. Dosimetric parameters including Dmax, D0.03 cc, Dmean, V40 Gy, V39 Gy, V38 Gy, and V20 Gy for the bladder and trigone for the simulation and daily treatments were collected. Both physician-scored (Common Terminology Criteria for Adverse Events, version 4.03 scale) as well as patient-reported (International Prostate Symptom Scores and the Expanded Prostate Cancer Index Composite-26 scores) acute genitourinary (GU) toxicity outcomes were collected and analyzed.

RESULTS

The average treatment bladder volume was about 30% smaller than the simulation bladder volume; however, the trigone volume remained fairly consistent despite being positively correlated with total bladder volume. Overall, the trigone accounted for <2% of the bladder volume. Median DSC for the bladder was 0.79, whereas the median DSC of the trigone was only 0.33. No statistically significant associations between our selected bladder and trigonal dosimetric parameters and grade ≥2 GU toxicity were identified, although numerically, patients with GU toxicity (grade ≥2) had higher intermediate doses to the bladder (V20 Gy and Dmean) and larger volumes exposed to higher doses in the trigone (V40 Gy, V39 Gy, and V38 Gy).

CONCLUSIONS

The trigone exhibits little volume change, but considerable interfractional displacement/deformation. As a result, the relative volume of the trigone receiving high doses during prostate SBRT varies substantially between fractions, which could influence GU toxicity and may not be predicted by radiation planning dosimetry.

The effects of radiation on myeloid lineage immune cells within the rodent urinary bladder: a systematic review

PURPOSE

Radiotherapy is a prominent therapy for many malignant and non-malignant disorders, though it can cause side effects such as radiation-induced cystitis. Current research has highlighted a role for mast cells and macrophages in the prognosis of such radiation-induced toxicities. However, the prognostic value of these immune cells in the pathophysiology of radiation-induced cystitis is not clear. As such, a systematic review was conducted to assess myeloid-lineage immune cells for their prognostic value in radiation-induced cystitis to address this gap in literature.

METHODS

The protocol was registered in PROSPERO, and searches were performed in PubMed, Embase and Web of Science databases for pre-clinical rodent studies on radiation-induced cystitis.

RESULTS

After de-duplication, 153 articles were screened for relevancy by title and abstract. Title and abstract screening deemed 64 studies irrelevant. The remaining 85 studies were full-text screened, yielding seven unique articles for data extraction. Most included studies had an unclear risk of bias. The findings of this systematic review suggest that the prognostic value of myeloid-lineage immune cells in radiation-induced cystitis is still unclear, indicating a need for further research in this field.

CONCLUSION

Although the studies reviewed provide some insight into the role of these immune cells in disease pathology, the limited number of studies and unclear risk of bias further highlights a need for additional, high-quality research in this area. In summary, this systematic review highlights a need to understand the involvement of immune cells in radiation-induced cystitis pathophysiology and lay the groundwork for further research in this area.

TRIAL REGISTRATION

PROSPERO registration: CRD42022345960.

Differences in Quality of Life and Toxicity for Male and Female Patients following Chemo(radiotherapy) for Bladder Cancer

AIMS

BC2001, a randomised trial of treatment for muscle-invasive bladder cancer, demonstrated no difference in health-related quality of life (HRQoL) or late toxicity between patients receiving radical radiotherapy with and without chemotherapy. This secondary analysis explored sex-based differences in HRQoL and toxicity.

MATERIALS AND METHODS

Participants completed the Functional Assessment of Cancer Therapy Bladder (FACT-BL) HRQoL questionnaires at baseline, end of treatment, 6 months and annually until 5 years. Clinicians assessed toxicity with the Radiation Therapy Oncology Group (RTOG) and Late Effects in Normal Tissues Subjective, Objective and Management (LENT/SOM) scoring systems at the same timepoints. The impact of sex on patient-reported HRQoL was evaluated using multivariate analyses of change in FACT-BL subscores from baseline to the timepoints of interest. For clinician-reported toxicity, differences were compared by calculating the proportion of patients with grade 3-4 toxicities occurring over the follow-up period.

RESULTS

For both males and females, all FACT-BL subscores had a reduction in HRQoL at the end of treatment. For males, the mean bladder cancer subscale (BLCS) score remained stable through to year 5. For females, there was a decline in BLCS from baseline at years 2 and 3 with a return to baseline at year 5. At year 3, females had a statistically significant and clinically meaningful worsening of mean BLCS score (-5.18; 95% confidence interval -8.37 to -1.99), which was not seen in males (0.24; -0.76 to 1.23). RTOG toxicity was more frequent in females than males (27% versus 16%, P = 0.027).

CONCLUSION

Results suggest that female patients treated with radiotherapy ± chemotherapy for localised bladder cancer report worse treatment-related toxicity in post-treatment years 2 and 3 than males.

LATE RADIATION TOXICITY AFTER RADICAL RADIOTHERAPY FOR GENITAL CANCER

Radiation therapy for malignant tumors of the female genital area, even with the use of modern radiotherapy equipment and dosimetric planning, causes the development of local radiation changes. An approach involving methodsof general and local exposure is used in their treatment. One of the most promising directions is the creation of optimal combinations of medicines (in the form of ointments, gels, aerosols, suppositories, etc.), which have a therapeutic effect on the inflammatory process. The article reflects the clinical course and stage of occurrence of late radiation reactions of the skin, vaginal/cervix mucosa, bladder, and intestines, as well as the features of their treatment.Literary data and own practical experience in the treatment of radiation complications are presented. Whenreviewing the topic under study, it could be concluded that the leading cause of the development of local radiationdamage is the errors in the planning and implementation of radiation therapy, when high absorbed doses thatexceed the tolerance of healthy tissues are used. Another reason for this is the poor accounting for dose distribution of ionizing radiation in tissues, the presence of concomitant diseases in patients, and the underestimation ofthe long-term effects of radiation.

A role for phosphodiesterase type 5 inhibitors in remodelling the urinary bladder after radiation exposure

Minimizing the toxicity of radiotherapy is challenging. We investigated the effects of a phosphodiesterase type-5 inhibitor (PDE5I) on the urinary bladder after pelvic radiotherapy. Eight rats were assigned to each group (group 1: control; group 2: radiation; group 3: radiation plus PDE5I). Radiation dose was 10 Gy/one fraction. Udenafil (20 mg/kg, daily for 4 weeks) was administered in group 3. Cystometry was performed 4 weeks after treatment, followed by real-time PCR for PDE5, vascular endothelial growth factor (VEGF), and endothelial nitric oxide synthase (eNOS) mRNA, western blotting for PDE5, cyclic GMP-dependent protein kinase (PRKG), VEGF₁₆₄, Akt, eNOS and NADPH oxidase (NOX)-2 proteins, and immunohistochemistry for eNOS. The expression of both VEGF mRNA and eNOS mRNA was higher in group 3 than in group 2. VEGF and eNOS protein expression improved with PDE5I treatment. Akt protein phosphorylation was higher in group 3 than in group 2, but NOX-2 protein expression was lower in group 3 than in group 2. Immunohistochemistry showed that the mean density of arterioles expressing eNOS was higher in group 3 than in group 2. Cystometry revealed that the intercontraction interval was remarkably longer in group 3 than in group 2 but that the maximal voiding pressure was higher in group 2 than in group 3. Daily treatment with a PDE5I after radiotherapy may prevent bladder storage dysfunction, potentially due to its effects on vasodilation and angiogenesis and through minimizing tissue oxidative damage by means of the VEGF/Akt/eNOS pathway.

At-Home Transvaginal Device Following Fractional Carbon Dioxide Laser Treatment for Genitourinary Syndrome of Menopause

BACKGROUND

Device-based therapeutic approaches have been developed to treat women&rsquo;s genitourinary post-menopausal symptoms. Fractional carbon dioxide laser resurfacing (FxCO2) has been demonstrated to be safe and effective in the treatment of GSM symptoms, however the results begin to wane by 12-months post-treatment.

OBJECTIVE

This study aims at assessing the application of an at-home transvaginal red and infrared light device as a maintenance treatment commencing 12 months following FxCO2 laser treatment for genitourinary syndrome of menopause (GSM).

STUDY DESIGN

Subjects completing 12-month follow-up after three fractional CO2 laser vulvovaginal treatments received an at-home device and monitored for GSM symptoms with long-term follow-up to 12 months (2 years post-laser).

METHODS

10 post-menopausal subjects completing 12-months follow-up after three FxCO2 vulvovaginal treatments for GSM were treated with an at-home red and infrared LED device. Treatment consisted of intravaginal application three times per week, and subjects were followed to 1, 3, 6, and 12 months. Subjects completed the vaginal assessment scale subject satisfaction, and QUID to assess for vulvovaginal and stress urinary incontinence (SUI) symptoms.

RESULTS

Vulvovaginal symptoms measured by VAS were mean 89% improved at 12-month follow-up after FxCO2 and maintained at 73% improved over baseline (2 years post-laser) following an additional 12 months of at-home transvaginal light therapy (P&lt;0.05). VAS symptoms gradually increased over the 12 months maintenance period by a mean of 17% (P&lt;0.05). Mean subject satisfaction was 0 at baseline, 1.86 at 1 year following FxCO2, and 1.00 after an additional 1 year of at-home light therapy. SUI symptoms as measured by QUID were mean 81% improved at 12-month follow-up after FxCO2and maintained at 38% improved over baseline (2 years post-laser) following an additional 12-months of at-home light therapy (P&lt;0.05). SUI symptoms gradually increased by a mean of 43% over the 12-month maintenance period (P&lt;0.05).

CONCLUSIONS

At-home transvaginal red and near infrared light therapy commencing at 12 months post-FxCO2 vulvovaginal treatment in a post-menopausal population maintained statistically significant improvements in vulvovaginal and SUI symptoms over the additional12-month period (2 years post-laser); however, a gradual return of symptoms suggests that laser re-treatment or combination withhormone therapy may be necessary to maintain optimal outcomes.J Drugs Dermatol. 2020;19(11):1076-1079. doi:10.36849/JDD.2020.1012.

Dosimetric effects of adaptive prostate cancer radiotherapy in an MR-linac workflow

BACKGROUND

The purpose was to evaluate the dosimetric effects in prostate cancer treatment caused by anatomical changes occurring during the time frame of adaptive replanning in a magnetic resonance linear accelerator (MR-linac) workflow.

METHODS

Two MR images (MR1 and MR2) were acquired with 30 min apart for each of the 35 patients enrolled in this study. The clinical target volume (CTV) and organs at risk (OARs) were delineated based on MR1. Using a synthetic CT (sCT), ultra-hypofractionated VMAT treatment plans were created for MR1, with three different planning target volume (PTV) margins of 7 mm, 5 mm and 3 mm. The three treatment plans of MR1, were recalculated onto MR2 using its corresponding sCT. The dose distribution of MR2 represented delivered dose to the patient after 30 min of adaptive replanning, omitting motion correction before beam on. MR2 was registered to MR1, using deformable registration. Using the inverse deformation, the structures of MR1 was deformed to fit MR2 and anatomical changes were quantified. For dose distribution comparison the dose distribution of MR2 was warped to the geometry MR1.

RESULTS

The mean center of mass vector offset for the CTV was 1.92 mm [0.13 - 9.79 mm]. Bladder volume increase ranged from 12.4 to 133.0% and rectum volume difference varied between -10.9 and 38.8%. Using the conventional 7 mm planning target volume (PTV) margin the dose reduction to the CTV was 1.1%. Corresponding values for 5 mm and 3 mm PTV margin were 2.0% and 4.2% respectively. The dose to the PTV and OARs also decreased from D1 to D2, for all PTV margins evaluated. Statistically significant difference was found for CTV Dmin between D1 and D2 for the 3 mm PTV margin (p < 0.01).

CONCLUSIONS

A target underdosage caused by anatomical changes occurring during the reported time frame for adaptive replanning MR-linac workflows was found. Volume changes in both bladder and rectum caused large prostate displacements. This indicates the importance of thorough position verification before treatment delivery and that the workflow needs to speed up before introducing margin reduction.

Radiation of the urinary bladder attenuates the development of lipopolysaccharide-induced cystitis

In the present study we assessed how ionizing radiation affects TLR4-stimulated immune activation in lipopolysaccharide (LPS)-induced cystitis. LPS or saline was administered intravesically to female rats followed by urinary bladder irradiation (20 Gy) 24 h later or sham treatment. Presence in the urinary bladder of inflammatory cells (mast cells, CD3+, ionized calcium-binding adapter molecule 1 (Iba-1)+, CD68+, CD40+, CD80+, CD11c + and CD206 + cells) and expression of oxidative stress (8-OHdG), hypoxia (HIF1α) and anti-oxidative responses (NRF2, HO-1, SOD1, SOD2, catalase) were assessed 14 days later with western blot, qPCR and/or immunohistochemistry. LPS stimulation resulted in a decrease of Iba-1 + cells in the urothelium, an increase in mast cells in the submucosa and a decrease in the bladder protein expression of HO-1, while no changes in the bladder expression of 8-OHdG, NRF2, SOD1, SOD2, catalase and HIF1α were observed. Bladder irradiation inhibited the LPS-driven increase in mast cells and the decrease in Iba1 + cells. Combining LPS and radiation increased the expression of 8-OHdG and number of CD3-positive cells in the urothelium and led to a decrease in NRF2α gene expression in the urinary bladder. In conclusion, irradiation may attenuate LPS-induced immune responses in the urinary bladder but potentiates LPS-induced oxidative stress, which as a consequence may have an impact on the urinary bladder immune sensing of pathogens and danger signals.

Does muscle invasive bladder cancer following pelvic radiotherapy portend worse prognosis? A seer-based study

BACKGROUND

Although emerging evidence demonstrates increased risk of secondary bladder cancer following pelvic radiotherapy, the aggressiveness of these tumors is not well-characterized.

MATERIALS AND METHODS

A search of the Surveillance, Epidemiology, and End Results (SEER) 18 Database, identified 25,734 patients diagnosed with bladder cancer following definitive therapy for previous pelvic malignancy. Kaplan-Meier curve analyses were utilized to determine overall survival with significance set at p<0.05.

RESULTS

Of the 25,734 patients, 11,376 (44.2%) received radiation treatment for their first cancer. Overall survival of bladder cancer was found to be 80%, 69.5%, and 49.2% at 1,2 and 5 years, respectively. There was no significant survival difference between groups whose first cancer was treated with or without radiation (p=0.8). A survival advantage was seen for the bladder cancer patients not treated with radiation for cervical (p=0.004), uterine (p=0.0006), and vaginal cancers (p<0.0001). Bladder cancer patients treated with radiation for prostate cancer showed a survival advantage (p=0.002). The average time to second cancer diagnosis was 6.5±6.1 years. Patients treated with radiation for first primary cancer showed a longer time to second cancer (7.2±6.0 years) compared to those treated without radiation (5.9±6.0 years) (p<0.01).

CONCLUSION

Patients with prior history of female cancers treated without radiation demonstrated significant survival advantage in second primary bladder cancer. A small significant survival advantage was seen in bladder cancer patients previously treated for prostate cancer with radiation. This data suggests that second primary bladder cancer following pelvic radiotherapy has similar biologic aggressiveness to urothelial carcinoma developing without a history of radiotherapy.

MICROABSTRACT

The overall survival of 25,734 patients diagnosed with bladder cancer following definitive therapy for a previous pelvic malignancy was 49.2% at 5 years. There was no significant survival difference between groups whose first cancer was treated with or without radiation. Second primary bladder cancer following pelvic radiotherapy has similar biologic aggressiveness to urothelial carcinoma developing without a history of radiotherapy.

Dosimetric impact of organ at risk daily variation during prostate stereotactic ablative radiotherapy

OBJECTIVE

Prostate stereotactic ablative radiotherapy (SABR) delivers large doses using a fast dose rate. This amplifies the effect geometric uncertainties have on normal tissue dose. The aim of this study was to determine whether the treatment dose-volume histogram (DVH) agrees with the planned dose to organs at risk (OAR).

METHODS

41 low-intermediate risk prostate cancer patients were treated with SABR using a linac based technique. Dose prescribed was 35 Gy in five fractions delivered on alternate days, planned using volumetric modulated arc therapy (VMAT) with 10X flattening filter free (FFF). On treatment, prostate was matched to fiducial markers on cone beam CT (CBCT). OAR were retrospectively delineated on 205 pre-treatment CBCT images. Daily CBCT contours were overlaid on the planning CT for dosimetric analysis. Verification plan used to evaluate the daily DVH for each structure. The daily doses received by OAR were recorded using the D%.

RESULTS

The median rectum and bladder volumes at planning were 67.1 cm3 (interquartile range 56.4-78.2) and 164.4 cm3 (interquartile range 120.3-213.4) respectively. There was no statistically significant difference in median rectal volume at each of the five treatment scans compared to the planning scan (p = 0.99). This was also the case for median bladder volume (p = 0.79). The median dose received by rectum and bladder at each fraction was higher than planned, at the majority of dose levels. For rectum the increase ranged from 0.78-1.64Gy and for bladder 0.14-1.07Gy. The percentage of patients failing for rectum D35% < 18 Gy (p = 0.016), D10% < 28 Gy (p = 0.004), D5% < 32 Gy (p = 0.0001), D1% < 35 Gy (p = 0.0001) and bladder D1% < 35 Gy (p = 0.001) at treatment were all statistically significant.

CONCLUSION

In this cohort of prostate SABR patients, we estimate the OAR treatment DVH was higher than planned. This was due to rectal and bladder organ variation.

ADVANCES IN KNOWLEDGE

OAR variation in prostate SABR using a FFF technique, may cause the treatment DVH to be higher than planned.

[Comparison between Stump Cylinder and custom mold, effect of the shape of the applicator on the dose distribution]

PURPOSE

The purpose of this study was to compare the efficacy of two applicators used in high dose rate vaginal brachytherapy. The first is the Stump Cylinder used in the "brachycenter" department at the Middle East Institute of Health in Lebanon and the second is the custom mold used in the radiotherapy department at Tenon Hospital in France.

MATERIALS AND METHOD

A comparison of the clinical target volume and the doses received by the rectum and bladder was performed in order to determine the best method of treatment and to optimize the dose distribution. 95 patients were treated in both departments.

RESULTS

The average values of the D95% dose received by the CTV were respectively 89.43% for the Stump Cylinder and 110.16% for the custom mold. The conformity index was 0.84 for the Stump Cylinder while it was 0.97 for the custom mold, which ensures a better dose distribution. For the rectum, the maximum dose D2cc taken by volume was 71.23% for the Stump Cylinder and 79.51% for the custom mold. The bladder was better protected with Stump Cylinder with a D2cc value of 65.81% against 94.88% for the custom mold.

CONCLUSION

The underdosing obtained using the Stump Cylinder was due to the shape of upper part of the cylinder which was not conform with the shape of the vaginal vault in women. A better protection of the organs at risk was observed with the Stump Cylinder since the dose taken by the rectum and bladder using a custom mold can reach the tolerance limits.

The importance of mesorectum motion in determining PTV margins in rectal cancer patients treated with neoadjuvant radiotherapy

New precision radiotherapy (RT) techniques reduce the uncertainties in localizing soft and moving tumors. However, there are still many uncontrollable internal organ movements. In our study, patients who underwent neoadjuvant chemoradiotherapy (NA-CRT) for rectal cancer were evaluated to determine inter-fraction mesorectum motion and dosimetric changes. Fourteen patients treated with NA-CRT for rectal cancer between 2014 and 2016 were included in the analysis. The mesorectum and clinical target volume (CTV) were delineated on planning computed tomography (CT) and cone-beam CT (CB-CT) scans. After planning with a volumetric modulated arc therapy (VMAT) plan, re-planning was performed on all CB-CTs. Finally, the volumetric and dosimetric changes of PTV and mesorectum were evaluated in all CB-CTs compared with the initial CT and VMAT plans. The geometrical center of mesorectum volume in CB-CTs had moved 1 (0.2-6.6), 1.6 (0.2-3.8) and 1.6 (0-4.9) mm in the x, y and z-axis respectively compared with the initial CT. The dosimetric parameters of PTV including D2, D95 and D98 on CB-CT showed a median 47.19 (46.70-47.80), 45.05 (44.18-45.68) and 44.69 (43.83-45.48) Gy and median 1% (1-2), 0% (0-2) and 1% (0-2) dosimetric change compared with the initial VMAT plan. In our study, we have shown that the mesorectum has moved up to 20 mm in the lateral and anterior-posterior direction and almost 10 mm in the superior/inferior direction during RT, causing a median of ~2% change in dosimetric parameters. Therefore, these movements must be considered in determining PTV margins to avoid dosimetric changes.

Moderately HRT vs. CRT for localized prostate cancer using image-guided VMAT with SIB: evaluation of acute and late toxicities

Purpose

This retrospective study aims at investigating the effects of moderately hypofractionated radiation therapy (HRT) on acute and late toxicities as well as on early biochemical control and therapeutic efficiency compared to conventional radiation therapy (CRT) in prostate cancer.

Patients and methods

We analyzed 55 HRT patients irradiated with the total dose of 60 Gy in 20 fractions delivered over 4 weeks. These patients were compared to a control group of 55 patients who received CRT with a total of <78 Gy in 37–39 fractions delivered over circa 8 weeks. External beam radiation therapy (EBRT) was conducted using daily image-guided (cone beam CT) volumetric modulated arc therapy (VMAT) and a simultaneously integrated boost (SIB) for both groups to protect the rectum. Acute toxicities were evaluated according to Common Terminology Criteria for Adverse Events (CTCAE) v5, whereas chronic toxicities were assessed in accordance with LENT-SOMA. Patient traits were compared by implementing t‑tests and Wilcoxon–Whitney tests for continuous variables, whereas discrete characteristics were evaluated by applying two-tailed Fisher’s exact tests. In addition, we calculated average treatment effects (ATE). Thereby, propensity score matching (PSM) based on nearest-neighbor matching considering age, comorbidities, and risk stratification as covariates was applied. The statistical analysis was conducted using Stata 14.2 (StataCorp LLC, TX, USA).

Results

As confirmed by the descriptive tests, the ATE revealed that the intensity and occurrence of urinary frequency (p = 0.034) and proctitis (p = 0.027) significantly decreased for the HRT group, whereas all other acute toxicities did not differ significantly between the HRT and CRT groups. For late toxicities, neither statistical tests nor ATE estimation showed significant differences. Also, no significant difference was found regarding the decrease in prostate specific antigen (PSA) after a median follow-up of 13 months (range 2–28 months), which indicates biochemical freedom from progression.

Conclusion

HRT offers several medical and economic advantages and should therefore be considered as a useful alternative to CRT.

Radiation cystitis modeling: A comparative study of bladder fibrosis radio-sensitivity in C57BL/6, C3H, and BALB/c mice

A subset of patients receiving radiation therapy for pelvic cancer develop radiation cystitis, a complication characterized by mucosal cell death, inflammation, hematuria, and bladder fibrosis. Radiation cystitis can reduce bladder capacity, cause incontinence, and impair voiding function so severely that patients require surgical intervention. Factors influencing onset and severity of radiation cystitis are not fully known. We tested the hypothesis that genetic background is a contributing factor. We irradiated bladders of female C57BL/6, C3H, and BALB/c mice and evaluated urinary voiding function, bladder shape, histology, collagen composition, and distribution of collagen-producing cells. We found that the genetic background profoundly affects the severity of radiation-induced bladder fibrosis and urinary voiding dysfunction. C57BL/6 mice are most susceptible and C3H mice are most resistant. Irradiated C57BL/6 mouse bladders are misshapen and express more abundant collagen I and III proteins than irradiated C3H and BALB/c bladders. We localized Col1a1 and Col3a1 mRNAs to FSP1-negative stromal cells in the bladder lamina propria and detrusor. The number of collagen I and collagen III-producing cells can predict the average voided volume of a mouse. Collectively, we show that genetic factors confer sensitivity to radiation cystitis, establish C57BL/6 mice as a sensitive preclinical model, and identify a potential role for FSP1-negative stromal cells in radiation-induced bladder fibrosis.

Experimental study of the difference in deformation between normal and pathological, renal and bladder, cells induced by acoustic radiation force

Previous studies have shown that alterations in the mechanical properties of cells may be associated with the onset and progression of some forms of pathology. In this paper, an experimental study of two types of cells, renal (cancer) and bladder (cancer) cells, is described which used acoustic radiation force (ARF) generated by a high-frequency ultrasound focusing transducer and performed on the operating platform of an inverted light microscope. Comparing images of cancer cells with those of normal cells of the same kind, we find that the cancer cells are more prone to deform than normal cells of the same kind under the same ARF. In addition, cancer cells with higher malignancy are more deformable than those with lower malignancy. This means that the deformability of cells may be used to distinguish diseased cells from normal ones, and more aggressive cells from less aggressive ones, which may provide a more rapid and accurate method for clinical diagnosis of urological disease in the future.

Is one brachytherapy fraction of 7 Gy similar to more fractions after external beam irradiation in postoperative endometrial carcinoma?

PURPOSE

To determine whether brachytherapy with a single hypofractionated dose of 7 Gy provides the similar vaginal-cuff relapses and safety profile in terms of complications compared to schedules of 2 or 3 fractions of lower doses in patients treated previously with external beam irradiation in postoperative endometrial carcinoma.

METHODS/MATERIAL

From June 2003 to December 2016, 325 patients were treated with 3 different schedules of high-dose-rate brachytherapy after external beam irradiation for postoperative endometrial carcinoma. The patients were divided into 3 groups: Group-1: 125 patients were treated with 3 fractions of 4-6 Gy per fraction (3 fractions/week) between 2003 and 2008; Group-2: 93 patients were treated with 2 consecutive daily fractions of 5-6 Gy between 2008 and 2011; Group-3: 107 patients received a single fraction of 7 Gy between 2011 and 2016. Bladder and rectum complications were assessed using RTOG scores and with the objective scores of LENT-SOMA for the vagina.

STATISTICS

the chi-square test.

RESULTS

The mean follow-up of Groups 1, 2 and 3 was 95, 67 and 51 months, respectively. Three patients in Group-1, 2 in Group-2, 1 in Group-3 developed vaginal-cuff relapse (p = 0.68). No differences were found in late toxicity among the three groups.

CONCLUSIONS

One single dose of 7 Gy is safe and effective and may be the best treatment schedule with a similar incidence of vaginal-cuff relapses, complications and patient comfort with less hospital attendance.

The Influence of Aerosol Density and Shape Factor on the Assessment of Internal Exposure to 239Pu

Internal exposure due to inhalation of aerosols depends on the ratio of aerodynamic shape factor (χ) to aerosol mass density (ρ). Inhaled aerosol parameters may differ from the default ρ and χ values provided by the International Commission on Radiological Protection, which are adopted for the assessment of internal exposures. This paper focuses on the influences of χ/ρ on the assessment of internal exposure to Pu for reference workers. Regional deposition fractions are found to decrease with increasing χ/ρ, and larger decreases are observed with smaller activity median aerodynamic diameter aerosols, while the slow clearance fractions (fs) in the tracheobronchial region are more sensitive for larger activity median aerodynamic diameter aerosols. Results from biokinetics calculations reveal that both the time-dependent content (excretion) and cumulative activities are determined mainly for particles initially deposited in the alveolar-interstitial region, while fs affects the local cumulative activities in the tracheobronchial region. χ/ρ is proven to have different influences for aerosols with different activity median aerodynamic diameters. The default χ/ρ values can be used when activity median aerodynamic diameters are greater than 1 μm, while one should pay attention to the value of χ/ρ when activity median aerodynamic diameters are less than 1 μm, where significant influence may be anticipated.

Implementation of intensity-modulated radiotherapy and comparison with three-dimensional conformal radiotherapy in the postoperative treatment of cervical cancer

PURPOSE

Within implementation of intensity-modulated radiotherapy (IMRT) in the postoperative irradiation of cervical cancer we evaluated and compared IMRT and three-dimensional conformal radiotherapy (3DCRT) dosimetric parameters for target volumes and organs at risk (OAR).

METHODS

We randomized 95 patients with cervical cancer, UICC stage I-III, in groups depending of the type of external beam postoperative radiotherapy. Forty-five patients were treated with IMRT and 50 with 3DCRT. All patients underwent brachytherapy, and according to risk factors some of the patients had concomitant cisplatin chemotherapy. The study was done in a period of three years from December 2015. Analysis of dosimetric parameters for target volume coverage and OARs was performed.

RESULTS

IMRT plans showed better conformity compared to 3DCRT plans, represented with homogenity index and conformity index, with higher maximum dose (PTV105 and D2). Both plans achieved adequate planning target volume coverage described with PTV95. Statistically significant difference between groups was found for bladder, rectum and bowel high dose regions: bladder V45 (p=0.000), rectum V40 (p=0.043) and V45 (p=0.000), bowel V45 (p=0.000), and bone marrow dosimetric parameters V20-V45; all were better in IMRT plans. Significant difference was found for volume of patient body normal tissue receiving dose of 20Gy, which was higher in IMRT.

CONCLUSION

IMRT is a highly conformal technique. Satisfactory target volume coverage was achieved with both techniques, with better sparing of OARs in the IMRT group. With this technique improvement, we expect better quality of life in cervical cancer patients with good prognosis.

Hyaluronate gel injection for rectum dose reduction in gynecologic high-dose-rate brachytherapy: initial Japanese experience

Perirectal hyaluronate gel injection (HGI) appears to be a promising technique for healthy tissue dose sparing in pelvic radiotherapy. In this analysis, we report our initial experience of HGI in gynecologic brachytherapy, focusing on its safety and effectiveness for dose reduction to the rectum. Between July 2013 and May 2014, 36 patients received HGI for primary/salvage gynecologic brachytherapy. Dosimetric effect analysis was based on pre- and post-HGI computed tomography dataset registration with corresponding dose-volume histogram evaluation. The maximum dose to the most exposed 0.1 cm3 (D0.1cm3) and 2.0 cm3 (D2.0cm3) were used as index values for rectum and bladder dose evaluation. The dose indexes for target volume (TV) coverage were TV D90/V100. In all cases, HGI was well tolerated, with no acute or late adverse events documented at a median follow-up of 220 days (range, 18-1046 days). Rectum D2.0cm3 and D0.1cm3 were significantly decreased by HGI (P < 0.001 and P = 0.003, respectively), with no significant impact on dosimetric parameters of bladder and TV coverage. Factors correlating negatively with the dosimetric effect of HGI were an increasing number of interstitial catheters (P = 0.003) as well as Lcranial100% (P = 0.014) and Lcranial80% (P = 0.001) [i.e. the length from the anal verge to the most cranial point at which the 100% and 80% isodose lines, respectively, crossed the rectum]. The concept of HGI for gynecologic brachytherapy is plausible, and our initial experience indicates it to be an effective technique for rectal dose reduction in radiotherapy of intrapelvic tumours.

Organ-preserving approach via radiotherapy for small cell carcinoma of the bladder: an analysis based on the Japanese Radiation Oncology Study Group (JROSG) survey

Small cell carcinoma of the bladder is extremely rare, accounting for <1% of all malignant tumours in the urinary tract. Thus, no standard therapy modality for this malignancy has been established. This study aimed to retrospectively analyse the clinical outcomes associated with definitive radiotherapy for small cell carcinoma of the bladder. A questionnaire-based survey of patients with pathologically proven small cell carcinoma of the bladder treated with definitive radiation therapy between 1990 and 2010 was conducted by the Japanese Radiation Oncology Study Group. The clinical records of 12 eligible patients were collected from nine institutions. The median age of the patients was 70.5 years (range: 44-87 years), and the median follow-up period was 27.3 months (range: 3.3-117.8 months). The median prescribed dose was 60 Gy (range: 50.0-61.0 Gy), and a median of 2.0 Gy (range: 1.2-2.0 Gy) was administered per fraction. Systemic chemotherapy combined with radiotherapy was performed in eight cases (66.7%). The 3- and 5-year overall survival rates were 50.0% and 33.3%, respectively. And the 3- and 5-year local control rates were 66.7% and 55.6%, respectively. Chemotherapy significantly improved overall survival and relapse-free survival (P = 0.006 and 0.001, respectively). No serious adverse events occurred in the observation period. All patients who achieved local control maintained functional bladders. In conclusion, radiotherapy is a potential local treatment option and has an important role in maintaining quality of life. Systemic chemotherapy combined with local radiotherapy seems to be effective in improving survival.

CT male pelvic organ segmentation using fully convolutional networks with boundary sensitive representation

Accurate segmentation of the prostate and organs at risk (e.g., bladder and rectum) in CT images is a crucial step for radiation therapy in the treatment of prostate cancer. However, it is a very challenging task due to unclear boundaries, large intra- and inter-patient shape variability, and uncertain existence of bowel gases and fiducial markers. In this paper, we propose a novel automatic segmentation framework using fully convolutional networks with boundary sensitive representation to address this challenging problem. Our novel segmentation framework contains three modules. First, an organ localization model is designed to focus on the candidate segmentation region of each organ for better performance. Then, a boundary sensitive representation model based on multi-task learning is proposed to represent the semantic boundary information in a more robust and accurate manner. Finally, a multi-label cross-entropy loss function combining boundary sensitive representation is introduced to train a fully convolutional network for the organ segmentation. The proposed method is evaluated on a large and diverse planning CT dataset with 313 images from 313 prostate cancer patients. Experimental results show that the performance of our proposed method outperforms the baseline fully convolutional networks, as well as other state-of-the-art methods in CT male pelvic organ segmentation.

Dual benefit of supplementary oral 5-aminolevulinic acid to pelvic radiotherapy in a syngenic prostate cancer model

BACKGROUND

Normal tissue damage caused by radiotherapy remains the largest dose-limiting factor in radiotherapy for cancer. Therefore, the aim of this study was to investigate the supplementary oral 5-aminolevulinic acid (ALA) to standard radiation therapy as a novel radioprotective approach that would not compromise the antitumor effect of radiation in normal rectal and bladder mucosa in a syngenic prostate cancer (PCa) model.

METHODS

To evaluate the radiosensitizing effect of ALA in vitro, clonogenic survival assays were performed in DU145, PC3, and MyC-CaP cell lines. To evaluate the effect of ALA in vivo a single dose (25 Gy) of radiation with or without ALA was given to healthy mice. Next, a syngenic PCa model of MyC-CaP cells in FVB mice was created, and multiple doses (12 Gy total) of radiation were administered to the mouse pelvic area with or without ALA administration. Resected tumors, recta, and urinary bladders were immunostained with antibodies against Ki-67, γ-H2AX, CD204, and uroplakin-III. Total RNA levels in recta and urinary bladders were analyzed via RT2 Profiler polymerase chain reaction (PCR) arrays related to "Stress & Toxicity PathwayFinder," "Mitochondria," and "Inflammasomes."

RESULTS

The addition of in vitro single or in vivo repeated administration of exogenous ALA acted as a radiosensitizer for PCa cells. Rectal toxicity was characterized by histological changes including loss of surface epithelium, fibrosis, severe DNA damage, and the aggregation of M2 macrophages. Urinary bladder toxicity was characterized by bladder wall thickening and urothelium denuding. The higher dose (300 mg/kg/day) of ALA exerted a better radioprotective profile than the lower dose (30 mg/kg/day) in normal recta and urinary bladders. Out of the 252 genes tested, 35 (13.4%) were detected as relevant genes which may be involved in the radioprotective role of ALA administration. These included interleukin-1a (IL-1a), IL-1b, IL-12, chemokine (C-X-C motif) ligand 1 (CXCL1), CXCL3, and NLRP3.

CONCLUSIONS

Our study provides novel and comprehensive insights into the dual benefits including radiosensitizing PCa tumor tissues and radioprotection of normal pelvic organs from radiation therapy. Knowledge of the underlying mechanism will facilitate the search for optimal treatment parameters for supplemental oral ALA during radiotherapy for PCa.

A multi-institutional study of bladder-preserving therapy for stage II-IV bladder cancer: A Korean Radiation Oncology Group Study (KROG 14-16)

Background

Although radical cystectomy is a standard treatment in muscle-invasive bladder cancer, bladder preservation therapy including transurethral resection of bladder tumor, radiotherapy, and concurrent chemotherapy has been widely adopted, recently. This retrospective analysis was performed to evaluate the survival rates and prognostic factors related to treatment outcomes following bladder-preserving therapy including radiotherapy (RT) in bladder cancer with a curative intent.

Materials and methods

We conducted a multi-institutional retrospective study of 152 patients with stage II-IV bladder cancer treated with curative RT between 2000 and 2010. There were 72 patients in stage II, 49 in stage III, and 31 in stage IV. Ninety-seven patients were treated with concurrent chemoradiotherapy and fifty-five with RT alone. Radiation was delivered to the pelvis (median 63 Gy), mainly with cisplatin. The median follow-up time was 35.5 months.

Results

Sixty-nine patients (45.4%) showed a complete response to RT. The 5-year overall survival (OS) rate was 45.8%, the 5-year cause-specific survival (CSS) rate was 48.9%, and the 5-year disease-free survival (DFS) rate was 20.8%. Univariate analysis revealed significant differences in the following factors according to the survival rates: patient age, initial hemoglobin level, clinical T stage, clinical N stage, clinical stage group, tumor response to RT, hydronephrosis, and concurrent chemotherapy. Multivariate analysis also revealed a significant difference in patient age (p = 0.003 in OS, p<0.017 in CSS) and tumor response to RT (p = 0.002 in OS, p<0.001 in CSS). Concurrent chemotherapy was significantly different in the DFS rates (p = 0.046).

Conclusions

The survival rates reported herein are comparable to those from other studies, and tumor response and concurrent chemoradiotherapy were significant prognostic factors for better survival rates. Further randomized studies are needed to elucidate the impact of RT in bladder cancer.

Hematologic Toxicity of Conformal Radiotherapy and Intensity Modulated Radiotherapy in Prostate and Bladder Cancer Patients

Background: The purpose of this study was to compare hematologic adverse effects and hematologic toxicity (HT) of pelvic irradiation in patients treated with conformal radiotherapy (CRT) and intensity modulated radiotherapy (IMRT) for radical treatment of prostate and bladder cancer. Methods: A group of 115 patients with prostate or bladder cancer treated with definitive radical radiotherapy was evaluated retrospectively. Blood test were taken before and after treatment comprising of following indices: white blood cells (WBC) hemoglobin (HGB), red blood cell (RBC), lymphocyte (LC), neutrophil (NC) and platelet (PLT) count. Patients were divided into several subgroups and the data was evaluated statistically using absolute and relative values. Results: There was a statistically significant difference in WBC (p=0.007), NC (p=0.031) and PLT (p=0.026) count decrease (absolute values) after treatment, between two treatment methods (CRT and IMRT), all in favor of IMRT. The relationship still proves to be significant regarding WBC (p=0,02) and (NC) (p=0,049) after presenting the data as relative percentage loss of starting value. However using Common Terminology Criteria for Adverse Effects (CTCAE), PLT count toxicity was more common in IMRT group (p=0.045). Conclusion: IMRT in comparison to CRT in bladder and prostate cancer patients is associated with a lesser absolute and relative decrease of hematologic indices. The hematologic effect of radiation was observed mainly regarding LC. Patients treated with IMRT suffered from significantly lesser decrease in relative and absolute values of WBC and NC. The mean of absolute PLT decrease count was lower in IMRT group; however, toxicity according to CTCAE was slightly more prevalent in IMRT group.

An Investigation of Dosimetric Correlates of Acute Toxicity in Prostate Stereotactic Body Radiotherapy: Dose to Urinary Trigone is Associated with Acute Urinary Toxicity

AIMS

There are limited data on dosimetric correlates of toxicity in stereotactic body radiotherapy (SBRT) for prostate cancer. We aimed to identify potential relationships between dose and toxicity using conventional dose-volume histograms (DVHs) and dose-surface maps (DSMs).

MATERIALS AND METHODS

Urinary bladder trigone and rectum DSMs were produced for a single-institution service evaluation cohort of 50 patients receiving SBRT for localised prostate cancer, together with conventional DVHs for bladder and rectum. Patients had been prospectively recruited to this cohort and treated according to a pre-defined protocol to a dose of 36.25 Gy in five fractions. Radiation Therapy Oncology Group (RTOG) and International Prostate Symptom Score (IPSS) toxicity data were recorded prospectively. Logistic regression was used to identify dosimetric predictors of acute IPSS+10 (rise of 10 points or more above baseline) and grade 2+ RTOG toxicity.

RESULTS

On univariate analysis, trigone area receiving 40 Gy and trigone Dmax were associated with IPSS+10 (odds ratio 1.06 [1.02-1.11], P = 0.007 and odds ratio 1.54 [1.06-2.25], P = 0.024, respectively). These two variables were highly correlated. In a multivariate model, including all baseline variables, trigone Dmax remained associated with IPSS+10 (odds ratio 1.91 [1.13-3.22], P = 0.016). These findings were not significant with Holm-Bonferroni correction for multiple testing (corrected P value threshold 0.006). No associations were seen between rectal toxicity and DVH or DSM parameters.

CONCLUSIONS

Our study suggests a potential relationship between high doses to the urinary bladder trigone and patient-reported urinary toxicity in prostate SBRT, and is consistent with previous studies in conventionally fractionated radiotherapy, justifying further evaluation in larger cohorts.

Dose-limiting Urinary Toxicity With Pembrolizumab Combined With Weekly Hypofractionated Radiation Therapy in Bladder Cancer

There is currently significant interest in the potential benefits of combining radiation and immune checkpoint blockade (ICB) to stimulate both regional and distant abscopal immune responses. In melanoma and lung cancer, patients who have received radiation therapy during ICB appear to have prolonged survival. The PLUMMB trial (Pembrolizumab in Muscle-invasive/Metastatic Bladder cancer) (NCT02560636) is a phase I study to test the tolerability of a combination of weekly radiation therapy with pembrolizumab in patients with metastatic or locally advanced urothelial cancer of the bladder. In the first dose-cohort, patients received pembrolizumab 100 mg 3-weekly, starting 2 weeks before commencing weekly adaptive bladder radiation therapy to a dose of 36 Gy in 6 fractions. The first dose-cohort was stopped after 5 patients, having met the predefined definition of dose-limiting toxicity. Three patients experienced grade 3 urinary toxicities, 2 of which were attributable to therapy. One patient experienced a grade 4 rectal perforation. In view of these findings, the trial has been paused and the protocol will be amended to reduce radiation therapy dose per fraction. The authors advise caution to those combining radiation therapy and ICB, particularly when radiation therapy is given at high dose per fraction for pelvic tumours. The PLUMMB trial met the protocol-defined definition of dose-limiting toxicity and will be amended to reduce radiation therapy dose.

Automatic replanning of VMAT plans for different treatment machines: A template-based approach using constrained optimization

PURPOSE

To investigate a new automatic template-based replanning approach combined with constrained optimization, which may be highly useful for a rapid plan transfer for planned or unplanned machine breakdowns. This approach was tested for prostate cancer (PC) and head-and-neck cancer (HNC) cases.

METHODS

The constraints of a previously optimized volumetric modulated arc therapy (VMAT) plan were used as a template for automatic plan reoptimization for different accelerator head models. All plans were generated using the treatment planning system (TPS) Hyperion. Automatic replanning was performed for 16 PC cases, initially planned for MLC1 (4 mm MLC) and reoptimized for MLC2 (5 mm) and MLC3 (10 mm) and for 19 HNC cases, replanned from MLC2 to MLC3. EUD, D_mean, D_2%, and D_98% were evaluated for targets; for OARs EUD and D_2% were analyzed. Replanning was considered successful if both plans fulfilled equal constraints.

RESULTS

All prostate cases were successfully replanned. The mean relative target EUD deviation was -0.15% and -0.57% for replanning to MLC2 and MLC3, respectively. OAR sparing was successful in all cases. Replanning of HNC cases from MLC2 to MLC3 was successful in 16/19 patients with a mean decrease of -0.64% in PTV60 EUD. In three cases target doses were substantially decreased by up to -2.58% (PTV60) and -3.44% (PTV54), respectively. Nevertheless, OAR sparing was always achieved as planned.

CONCLUSIONS

Automatic replanning of VMAT plans for a different treatment machine by using pre-existing constraints as a template for a reoptimization is feasible and successful in terms of equal constraints.

Physician assessed and patient reported urinary morbidity after radio-chemotherapy and image guided adaptive brachytherapy for locally advanced cervical cancer

BACKGROUND AND PURPOSE

The EMBRACE study is a prospective multi-institutional study on MRI guided adaptive brachytherapy (IGABT) in locally advanced cervix cancer (LACC). This analysis describes early to late urinary morbidity assessed by physicians and patients (PRO).

MATERIAL AND METHODS

A total of 1176 patients were analysed. Median follow up (FU) was 27 (1-83) months. Morbidity (CTCAE v.3) and PRO (EORTC QLQ-C30&CX24) was prospectively assessed at baseline (BL), and during FU.

RESULTS

The most frequent symptoms were frequency/urgency, incontinence, and cystitis with grade 2-4 prevalence rates of 4.3%, 5.0% and 1.7% and grade 1-4 prevalence rates of 24.5%, 16.1% and 5.8% at 3-years. The most frequent PRO endpoints were "urinary frequency" and "leaking of urine". Prevalence of "Quite a bit" or "very much" bother fluctuated from 14.0% to 21.5% for "frequency", while "leaking of urine" increased from 4.6% at BL to 9.3% at 3-years. Actuarial 3-year incidence of grade 3-4 urinary morbidity was 5.3% with most events being urinary frequency, incontinence and ureteral strictures. Grade 3-4 fistula, bleeding, spasm and cystitis were all <1.0% at 3/5-years. No grade 5 toxicity occurred.

CONCLUSION

Urinary grade 3-4 morbidity with IGABT was limited. Urinary morbidity grade 2-4 comprises mainly frequency/urgency, incontinence and cystitis and has considerable prevalence in PRO. Various urinary morbidity endpoints have different patterns of manifestation and time course.

Analysis of Motion-dependent Clinical Outcome of Tumor Tracking Stereotactic Body Radiotherapy for Prostate Cancer

BACKGROUND

To analyze clinical outcome of CyberKnife (CK) tumor-tracking stereotactic body radiotherapy (SBRT) for prostate cancer (Pca) according to the magnitude of intra-fractional prostate motion.

METHODS

Medical records and daily treatment logs for 71 patients who received CK tumor-tracking SBRT were retrospectively analyzed. Statistical relationships between prostate motion and various outcome results, including local recurrence (LR), biochemical failure (BF), and treatment-related toxicity, were investigated in order to evaluate motion-dependent efficacy of tumor-tracking SBRT for Pca.

RESULTS

In a total 71 patients, 3 (4.2%) patients with LR, 12 (16.9%) patients with BF, and 22 (31%) patients with grade-II or worse toxicities to rectal or bladder (22 to rectal, 22 to bladder and 8 patients to both) were observed in a median follow-up of 47 months. Magnitudes of intra-fractional tumor motion along superior-inferior, right-left, and anterior-posterior (AP) axes were 0.15 ± 0.31, 0.12 ± 0.19, and 0.73 ± 0.32 mm, respectively. Radial magnitude was estimated to be 1.0 ± 0.35 mm. Intra-fractional movement was not significantly correlated with tumor control. However, it was significant correlated with the incidence of grade-II or worse toxicity to rectum or bladder particularly when tumor motion was in the AP axis.

CONCLUSION

Our quantitative results revealed that toxicity related to SBRT treatment was highly sensitive to intra-fractional prostate movements, although local-tumor control was not affected by such movements. Our results demonstrate that precise motion correction is essential in prostate SBRT, even if it seems to be small.

The Efficacy and Safety of Conventional and Hypofractionated High-Dose Radiation Therapy for Prostate Cancer in an Elderly Population: A Subgroup Analysis of the CHHiP Trial

PURPOSE

Outcome data on radiation therapy for prostate cancer in an elderly population are sparse. The CHHiP (Conventional or Hypofractionated High Dose Intensity Modulated Radiotherapy in Prostate Cancer) trial provides a large, prospectively collected, contemporary dataset in which to explore outcomes by age.

METHODS AND MATERIALS

CHHiP participants received 3 to 6 months of androgen deprivation therapy and were randomly assigned (1:1:1) to receive 74 Gy in 37 fractions (conventional fractionation), 60 Gy in 20 fractions, or 57 Gy in 19 fractions. Toxicity was assessed using clinician-reported outcome (CRO) and patient-reported outcome questionnaires. Participants were categorized as aged < 75 years or ≥ 75 years. Outcomes were compared by age group.

RESULTS

Of 3216 patients, 491 (15%) were aged ≥ 75 years. There was no difference in biochemical or clinical failure rates between the groups aged < 75 years and ≥ 75 years for any of the fractionation schedules. In the group aged ≥ 75 years, biochemical or clinical failure-free rates favored hypofractionation, and at 5 years, they were 84.7% for 74 Gy, 91% for 60 Gy, and 87.7% for 57 Gy. The incidence of CRO (grade 3) acute bowel toxicity was 2% in both age groups. The incidence of grade 3 acute bladder toxicity was 8% in patients aged < 75 years and 7% in those aged ≥ 75 years. The 5-year cumulative incidence of CRO grade ≥ 2 late bowel side effects was similar in both age groups. However, in the group aged ≥ 75 years, there was a suggestion of a higher cumulative incidence of bowel bother (small or greater) with 60 Gy compared with 74 Gy and 57 Gy. Patient-reported bladder bother was slightly higher in the group aged ≥ 75 years than the group aged < 75 years, and there was a suggestion of a lower cumulative incidence of bladder bother with 57 Gy compared with 74 Gy and 60 Gy in patients aged ≥ 75 years, which was not evident in those aged < 75 years.

CONCLUSIONS

Hypofractionated radiation therapy appears to be well tolerated and effective in men aged ≥ 75 years. The 57-Gy schedule has potential advantages in that it may moderate long-term side effects without compromising treatment efficacy in this group.

Fitting NTCP models to bladder doses and acute urinary symptoms during post-prostatectomy radiotherapy

BACKGROUND

To estimate the radiobiological parameters of three popular normal tissue complication probability (NTCP) models, which describe the dose-response relations of bladder regarding different acute urinary symptoms during post-prostatectomy radiotherapy (RT). To evaluate the goodness-of-fit and the correlation of those models with those symptoms.

METHODS

Ninety-three consecutive patients treated from 2010 to 2015 with post-prostatectomy image-guided intensity modulated radiotherapy (IMRT) were included in this study. Patient-reported urinary symptoms were collected pre-RT and weekly during treatment using the validated Prostate Cancer Symptom Indices (PCSI). The assessed symptoms were flow, dysuria, urgency, incontinence, frequency and nocturia using a Likert scale of 1 to 4 or 5. For this analysis, an increase by ≥2 levels in a symptom at any time during treatment compared to baseline was considered clinically significant. The dose volume histograms of the bladder were calculated. The Lyman-Kutcher-Burman (LKB), Relative Seriality (RS) and Logit NTCP models were used to fit the clinical data. The fitting of the different models was assessed through the area under the receiver operating characteristic curve (AUC), Akaike information criterion (AIC) and Odds Ratio methods.

RESULTS

For the symptoms of urinary urgency, leakage, frequency and nocturia, the derived LKB model parameters were: 1) D50 = 64.2Gy, m = 0.50, n = 1.0; 2) D50 = 95.0Gy, m = 0.45, n = 0.50; 3) D50 = 83.1Gy, m = 0.56, n = 1.00; and 4) D50 = 85.4Gy, m = 0.60, n = 1.00, respectively. The AUC values for those symptoms were 0.66, 0.58, 0.64 and 0.64, respectively. The differences in AIC between the different models were less than 2 and ranged within 0.1 and 1.3.

CONCLUSIONS

Different dose metrics were correlated with the symptoms of urgency, incontinence, frequency and nocturia. The symptoms of urinary flow and dysuria were poorly associated with dose. The values of the parameters of three NTCP models were determined for bladder regarding four acute urinary symptoms. All the models could fit the clinical data equally well. The NTCP predictions of urgency showed the best correlation with the patient reported outcomes.

Vaginal packing volume impact on dose parameters during radiography and computed tomography based postoperative brachytherapy of cervical carcinoma

PURPOSE

To investigate the influence of the vaginal packing volume on the registered dose parameters evaluated by radiography (2D) and computed tomography (CT) (3D) based brachytherapy planning in cervical cancer patients treated with postoperative radiotherapy.

METHODS

The postoperative radiotherapy was performed in 40 cervical cancer patients with increased risk for disease relapse. Both, radiography and CT based brachytherapy planning were done in all patients. Vaginal packing volume was evaluated by clinical target volume (CTV)uk, assessed on CT scans and analyzed according to the registered dose parameters: doses delivered to the organs at risk (OAR) and the defined CTV, using both planning methods.

RESULTS

CTVuk volume had statistically significant influence on CTV coverage with the prescribed brachytherapy doses D90 (p<0.01) and D100 (p<0.01), revealing a CTVuk cut-off value of 25.6 cm3. Dividing the patients into two groups according to the cutoff value, we found a statistical significance in the registered doses to the rectal wall and no significance in the bladder wall doses between the groups. Also, a statistically significant, negative correlation was found between CTVuk and following doses: Rmax (rho= -0.34, p<0.05), D0.1cc (rho= -0.76, p<0.01), D1cc (rho= -0.74, p<0.01) and D2cc (rho= -0.72, p<0.01), D90 (rho= -0.80, p<0.01), D100 (rho= -0.7, p<0.01).

CONCLUSION

If the brachytherapy vaginal packing is of a large volume (more than 25.6 cm3), an asymmetric deformation of the proximal part of the vaginal cavity might appear, leading to inappropriate dose coverage of the CTV part of the vaginal mucosa. Also, making a vaginal packing volume larger than 25.6 cm3 made no further reduction in the bladder dose, but it made a statistically significant further reduction in the rectal doses.

Evaluation of rectum and bladder dose accumulation from external beam radiotherapy and brachytherapy for cervical cancer using two different deformable image registration techniques

We evaluated dose-volume histogram (DVH) parameters based on deformable image registration (DIR) between brachytherapy (BT) and external beam radiotherapy (EBRT) that included a center-shielded (CS) plan. Eleven cervical cancer patients were treated with BT, and their pelvic and CS EBRT were studied. Planning CT images for EBRT and BT (except for the first BT, used as the reference image) were deformed with DIR to reference image. We used two DIR parameter settings: intensity-based and hybrid. Mean Dice similarity coefficients (DSCs) comparing EBRT with the reference for the uterus, rectum and bladder were 0.81, 0.77 and 0.83, respectively, for hybrid DIR and 0.47, 0.37 and 0.42, respectively, for intensity-based DIR (P < 0.05). D1 cm3 for hybrid DIR, intensity-based DIR and DVH addition were 75.1, 81.2 and 78.2 Gy, respectively, for the rectum, whereas they were 93.5, 92.3 and 94.3 Gy, respectively, for the bladder. D2 cm3 for hybrid DIR, intensity-based DIR and DVH addition were 70.1, 74.0 and 71.4 Gy, respectively, for the rectum, whereas they were 85.4, 82.8 and 85.4 Gy, respectively, for the bladder. Overall, hybrid DIR obtained higher DSCs than intensity-based DIR, and there were moderate differences in DVH parameters between the two DIR methods, although the results varied among patients. DIR is only experimental, and extra care should be taken when comparing DIR-based dose values with dose-effect curves established using DVH addition. Also, a true evaluation of DIR-based dose accumulation would require ground truth data (e.g. measurement with physical phantom).

Comparative results of three short brachytherapy schedules as exclusive treatment in postoperative endometrial carcinoma

PURPOSE

To compare vaginal control and treatment toxicity of three different high-dose-rate brachytherapy schedules as exclusive treatment in postoperative endometrial carcinoma.

METHODS AND MATERIALS

From 2003 to 2015, three different schedules were used as postoperative treatment for 146 patients (p) with intermediate-risk endometrial carcinoma. Group 1 (41 p): six fractions of 4-6 Gy, 3-4 fractions per week; Group 2 (59 p): four fractions of 5-6 Gy administered daily; Group 3 (46 p): 6 Gy × 3 fractions in three consecutive days. The dose was prescribed at 5 mm of applicator surface using an active treatment length of 2.5 cm. Toxicity scores were evaluated using the Radiation Therapy Oncology Group scores for bladder and rectum and the objective criteria of late effects of normal tissues-subjective, objective, management, analytic for vagina. Statistics used were group descriptions calculating their means, medians, and ranges. Bivariate analysis was evaluated using variance models and χ² tests.

RESULTS

The mean followup was as follows: Group 1: 88 months, Group 2: 75 months, and 41 months in Group 3. No vaginal relapses were found. Late toxicity ≥ G2: rectum: 0 p in the three groups (0%). Bladder: Group 1: 1 p (2.4%), Group 2: 0%, and Group 3: 0%. Vagina: Group 1: 4 p (9.5%); Group 2: 9 p (15.3%); and Group 3:10 p (21.8%). There were no differences in late toxicity among the three groups of patients for rectum (p = 0.83), bladder (p = 0.58), and vagina (p = 0.67); the expected global risk of complications for rectum, bladder, and vagina is 0.8%, 0.8%, and 28.8%, respectively.

CONCLUSIONS

Similar results in vaginal control and complications were achieved with the three schedules. The use of three fractions of 6 Gy administered daily is the best option for patient comfort and convenience and use of resources. Nonetheless, specific studies are needed to demonstrate the best cost-efficacy regime.

Clinical Outcomes of Image Guided Adaptive Hypofractionated Weekly Radiation Therapy for Bladder Cancer in Patients Unsuitable for Radical Treatment

PURPOSE AND OBJECTIVES

We report on the clinical outcomes of a phase 2 study assessing image guided hypofractionated weekly radiation therapy in bladder cancer patients unsuitable for radical treatment.

METHODS AND MATERIALS

Fifty-five patients with T2-T4aNx-2M0-1 bladder cancer not suitable for cystectomy or daily radiation therapy treatment were recruited. A "plan of the day" radiation therapy approach was used, treating the whole (empty) bladder to 36 Gy in 6 weekly fractions. Acute toxicity was assessed weekly during radiation therapy, at 6 and 12 weeks using the Common Terminology Criteria for Adverse Events version 3.0. Late toxicity was assessed at 6 months and 12 months using Radiation Therapy Oncology Group grading. Cystoscopy was used to assess local control at 3 months. Cumulative incidence function was used to determine local progression at 1 at 2 years. Death without local progression was treated as a competing risk. Overall survival was estimated using the Kaplan-Meier method.

RESULTS

Median age was 86 years (range, 68-97 years). Eighty-seven percent of patients completed their prescribed course of radiation therapy. Genitourinary and gastrointestinal grade 3 acute toxicity was seen in 18% (10/55) and 4% (2/55) of patients, respectively. No grade 4 genitourinary or gastrointestinal toxicity was seen. Grade ≥3 late toxicity (any) at 6 and 12 months was seen in 6.5% (2/31) and 4.3% (1/23) of patients, respectively. Local control after radiation therapy was 92% of assessed patients (60% total population). Cumulative incidence of local progression at 1 year and 2 years for all patients was 7% (95% confidence interval [CI] 2%-17%) and 17% (95% CI 8%-29%), respectively. Overall survival at 1 year was 63% (95% CI 48%-74%).

CONCLUSION

Hypofractionated radiation therapy delivered weekly with a plan of the day approach offers good local control with acceptable toxicity in a patient population not suitable for radical bladder treatment.

Hyperbaric oxygen treatment reverses radiation induced pro-fibrotic and oxidative stress responses in a rat model

PURPOSE

Radiotherapy is effective in the treatment of tumors in the pelvic area but is associated with side effects such as cystitis and proctitis. Hyperbaric Oxygen Therapy (HBOT) has emerged as a treatment modality for radiation-induced side effects. In a rat model for radiation cystitis, we studied the effects of HBOT on oxidative stress and pro-fibrotic factors.

MATERIALS AND METHODS

Sedated Sprague-Dawley rats underwent bladder irradiation of 20Gy with and without 20 sessions of HBOT during a fortnight. Control animals were treated with and without HBOT. All four groups of animals were euthanized 28 days later. Histopathological examinations, immunohistochemistry and quantitative polymerase chain reaction (qPCR) were used to analyze changes in oxidative stress (8-OHdG), anti-oxidative responses (SOD-1, SOD2, HO-1 and NRFα) and a panel of Th1-type and Th2-type cytokines (IL-1β, IL-4, IL-5, IL-6, IL-10, IL-13, TNF-α, TGF-β, IFN-γ) in the urinary bladder.

RESULTS

Bladder irradiation increased the expression of 8-OHdG, SOD2, HO-1, NRFα, IL-10, TNF-α and tended to increase TGF-β. These changes were completely reversed by HBOT while HBOT in control animals had no effects on the studied markers for oxidative stress, anti-oxidative responses and Th1-type and Th2-type cytokines.

CONCLUSIONS

Radiation induced a significant elevation of oxidative stress, antioxidants and pro-fibrotic factors in our animal model for radiation cystitis that were completely reversed and normalized by HBOT. Our findings indicate that HBOT may prevent radiation-induced changes by affecting oxidative stress and inflammatory cascades induced by radiation.

SUMMARY

Radiotherapy may cause the development of chronic inflammation and fibrosis, significantly impairing organ function. We hypothesized that bladder irradiation induces an oxidative stress reaction, thereby triggering the redox system and thus initiating an inflammatory and pro-fibrotic response. We aimed to assess whether these changes would be reversed by hyperbaric oxygen using an animal model for radiation cystitis. Our study show that hyperbaric oxygen therapy may reverse oxidative stress and pro-inflammatory factors induced by radiation.

Causes, Timing, Hospital Costs and Perioperative Outcomes of Index vs Nonindex Hospital Readmissions after Radical Cystectomy: Implications for Regionalization of Care

PURPOSE

We compared the timing, causes, hospital costs and perioperative outcomes of index vs nonindex hospital readmissions after radical cystectomy.

MATERIALS AND METHODS

The 2013 Nationwide Readmissions Database was queried for patients with bladder cancer undergoing cystectomy. Sociodemographic characteristics, hospital costs and causes of readmission were compared among index and nonindex readmitted patients. Univariable and multivariable logistic regression models were used to identify predictors of nonindex readmissions, mortality during the first readmission and subsequent readmission.

RESULTS

Among 4,991 patients identified 29% (1,447) and 11% (571) experienced an index and nonindex readmission, respectively. Compared to index readmissions, nonindex readmissions were more likely late readmissions (p <0.001) of older patients (p=0.047) who underwent cystectomy at higher volume hospitals (p=0.02) and were readmitted to hospitals located in less populated areas (p <0.001). Compared to index readmissions the percentage of nonindex readmissions for cardiovascular complications was higher (7.6% vs 2.9%, p=0.003), while the percentage of nonindex readmissions for gastrointestinal (6.0% vs 11.0%, p=0.04) and wound (5.3% vs 16.7%, p=0.0001) complications was lower. Predictors of nonindex readmission included longer length of stay (OR 1.02; 95% CI 1.001, 1.04), patient location in less populated areas, nonteaching hospital (OR 0.52; 95% CI 0.31, 0.86) and discharge to facility (OR 2.82; 95% CI 1.75, 4.55) or with home health (OR 1.49; 95% CI 1.05, 2.10). Nonindex readmissions had comparable mean readmission hospital costs ($14,147 vs $15,102, p=0.7), in-hospital mortality (OR 1.11; 95% CI 0.42, 2.87) and subsequent readmission (OR 1.32; 95% CI 0.87, 2.00) to index readmissions.

CONCLUSIONS

This nationally representative study of patients undergoing radical cystectomy demonstrated comparable perioperative outcomes and hospital costs between index and nonindex readmitted patients, which supports the continued regionalization of cystectomy care.

Rectal dose to prostate cancer patients treated with proton therapy with or without rectal spacer

The purpose of this study was to evaluate whether a spacer inserted in the prerectal space could reduce modeled rectal dose and toxicity rates for patients with prostate cancer treated in silico with pencil beam scanning (PBS) proton therapy. A total of 20 patients were included in this study who received photon therapy (12 with rectal spacer (DuraSeal™ gel) and 8 without). Two PBS treatment plans were retrospectively created for each patient using the following beam arrangements: (1) lateral-opposed (LAT) fields and (2) left and right anterior oblique (LAO/RAO) fields. Dose volume histograms (DVH) were generated for the prostate, rectum, bladder, and right and left femoral heads. The normal tissue complication probability (NTCP) for ≥grade 2 rectal toxicity was calculated using the Lyman-Kutcher-Burman model and compared between patients with and without the rectal spacer. A significantly lower mean rectal DVH was achieved in patients with rectal spacer compared to those without. For LAT plans, the mean rectal V70 with and without rectal spacer was 4.19 and 13.5%, respectively. For LAO/RAO plans, the mean rectal V70 with and without rectal spacer was 5.07 and 13.5%, respectively. No significant differences were found in any rectal dosimetric parameters between the LAT and the LAO/RAO plans generated with the rectal spacers. We found that ≥ 9 mm space resulted in a significant decrease in NTCP modeled for ≥grade 2 rectal toxicity. Rectal spacers can significantly decrease modeled rectal dose and predicted ≥grade 2 rectal toxicity in prostate cancer patients treated in silico with PBS. A minimum of 9 mm separation between the prostate and anterior rectal wall yields the largest benefit.

Investigation of Abscopal and Bystander Effects in Immunocompromised Mice After Exposure to Pencilbeam and Microbeam Synchrotron Radiation

Out-of-field effects are of considerable interest in radiotherapy. The mechanisms are poorly understood but are thought to involve signaling processes, which induce responses in non-targeted cells and tissues. The immune response is thought to play a role. The goal of this research was to study the induction of abscopal effects in the bladders of NU-Foxn1 mice after irradiating their brains using Pencil Beam (PB) or microbeam (MRT) irradiation at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Athymic nude mice injected with F98 glioma cells into their right cerebral hemisphere 7 d earlier were treated with either MRT or PB. After recovery times of 2, 12, and 48 h, the urinary bladders were extracted and cultured as tissue explants for 24 h. The growth medium containing the potential signaling factors was harvested, filtered, and transferred to HaCaT reporter cells to assess their clonogenic survival and calcium signaling potential. The results show that in the tumor-free mice, both treatment modalities produce strong bystander/abscopal signals using the clonogenic reporter assay; however, the calcium data do not support a calcium channel mediated mechanism. The presence of a tumor reduces or reverses the effect. PB produced significantly stronger effects in the bladders of tumor-bearing animals. The authors conclude that immunocompromised mice produce signals, which can alter the response of unirradiated reporter cells; however, a novel mechanism appears to be involved.

Changes in Rectal Dose Due to Alterations in Beam Angles for Setup Uncertainty and Range Uncertainty in Carbon-Ion Radiotherapy for Prostate Cancer

Background and Purpose

Carbon-ion radiotherapy of prostate cancer is challenging in patients with metal implants in one or both hips. Problems can be circumvented by using fields at oblique angles. To evaluate the influence of setup and range uncertainties accompanying oblique field angles, we calculated rectal dose changes with oblique orthogonal field angles, using a device with fixed fields at 0° and 90° and a rotating patient couch.

Material and Methods

Dose distributions were calculated at the standard angles of 0° and 90°, and then at 30° and 60°. Setup uncertainty was simulated with changes from −2 mm to +2 mm for fields in the anterior-posterior, left-right, and cranial-caudal directions, and dose changes from range uncertainty were calculated with a 1 mm water-equivalent path length added to the target isocenter in each angle. The dose distributions regarding the passive irradiation method were calculated using the K2 dose algorithm.

Results

The rectal volumes with 0°, 30°, 60°, and 90° field angles at 95% of the prescription dose were 3.4±0.9 cm³, 2.8±1.1 cm³, 2.2±0.8 cm³, and 3.8±1.1 cm³, respectively. As compared with 90° fields, 30° and 60° fields had significant advantages regarding setup uncertainty and significant disadvantages regarding range uncertainty, but were not significantly different from the 90° field setup and range uncertainties.

Conclusions

The setup and range uncertainties calculated at 30° and 60° field angles were not associated with a significant change in rectal dose relative to those at 90°.

Prospective Study Delivering Simultaneous Integrated High-dose Tumor Boost (≤70 Gy) With Image Guided Adaptive Radiation Therapy for Radical Treatment of Localized Muscle-Invasive Bladder Cancer

PURPOSE

Image guided adaptive radiation therapy offers individualized solutions to improve target coverage and reduce normal tissue irradiation, allowing the opportunity to increase the radiation tumor dose and spare normal bladder tissue.

METHODS AND MATERIALS

A library of 3 intensity modulated radiation therapy plans were created (small, medium, and large) from planning computed tomography (CT) scans performed at 30 and 60 minutes; treating the whole bladder to 52 Gy and the tumor to 70 Gy in 32 fractions. A "plan of the day" approach was used for treatment delivery. A post-treatment cone beam CT (CBCT) scan was acquired weekly to assess intrafraction filling and coverage.

RESULTS

A total of 18 patients completed treatment to 70 Gy. The plan and treatment for 1 patient was to 68 Gy. Also, 1 patient's plan was to 70 Gy but the patient was treated to a total dose of 65.6 Gy because dose-limiting toxicity occurred before dose escalation. A total of 734 CBCT scans were evaluated. Small, medium, and large plans were used in 36%, 48%, and 16% of cases, respectively. The mean ± standard deviation rate of intrafraction filling at the start of treatment (ie, week 1) was 4.0 ± 4.8 mL/min (range 0.1-19.4) and at end of radiation therapy (ie, week 5 or 6) was 1.1 ± 1.6 mL/min (range 0.01-7.5; P=.002). The mean D98 (dose received by 98% volume) of the tumor boost and bladder as assessed on the post-treatment CBCT scan was 97.07% ± 2.10% (range 89.0%-104%) and 99.97% ± 2.62% (range 96.4%-112.0%). At a median follow-up period of 19 months (range 4-33), no muscle-invasive recurrences had developed. Two patients experienced late toxicity (both grade 3 cystitis) at 5.3 months (now resolved) and 18 months after radiation therapy.

CONCLUSIONS

Image guided adaptive radiation therapy using intensity modulated radiation therapy to deliver a simultaneous integrated tumor boost to 70 Gy is feasible, with acceptable toxicity, and will be evaluated in a randomized trial.

Cystectomy and Urinary Diversion for the Management of a Devastated Lower Urinary Tract Following Prostatic Cryotherapy and/or Radiotherapy

INTRODUCTION

We investigated the outcomes and quality of life measures in men who underwent cystectomy and urinary diversion for devastating lower urinary tract toxicity after prostatic radiotherapy and/or cryotherapy for the treatment of prostate cancer.

METHODS

Records of patients who underwent cystectomy and urinary diversion for the management of a devastated lower urinary tract following prostatic radiotherapy or cryotherapy were reviewed retrospectively. A postoperative, retrospective quality of life (QOL) survey was designed specific to this patient subset and obtained by telephone interview.

RESULTS

Extirpative surgery with urinary diversion for management of a devastated lower urinary tract was performed on 15 patients with a mean age of 72 years (range 63-82). Toxicities leading to bladder removal included bladder neck contractures, prostatic necrosis, incontinence, osteomyelitis, bladder calculi, fistulae, urethral strictures, abscesses, necrotizing fasciitis, and radiation/hemorrhagic cystitis. The mean number of failed conservative, minimally invasive interventions per patients prior to cystectomy was 3.7 (range 1-12). The average time period from major complication following radiotherapy/cryotherapy to cystectomy was 29.1 months (range 5-65). The QOL survey showed all of the patients who completed the survey (n = 13) would undergo the procedure again and 11 (85%) would have undergone the procedure an average of 13.2 months sooner (range 5-36).

CONCLUSION

Toxicities secondary to prostatic radiotherapy or cryotherapy may be debilitating. Our results demonstrate that cystectomy with urinary diversion can improve QOL in patients with a devastated lower urinary tract.

Effects of Cyclooxygenase on the Urothelium of the Urinary Bladder of Mice Exposed to Pelvic Radiation

OBJECTIVE

To determine the role of cyclooxygenase (COX) expression in the urothelium of the urinary bladder during radiation injury caused by pelvic radiotherapy for cancer therapy.

STUDY DESIGN

Twenty-four male Swiss Albino mice were separated into 4 groups. The first group was the control group (Group 1) and the second, third, and fourth groups were euthanized after 24 hours (Group 2), 48 hours (Group 3), and 7 days (Group 4), respectively. A single-fractioned 10 Gy of ionizing radiation was applied to all mice's pelvic zone with Co-60. Bladders were removed completely from the pelvic region. Histochemical analysis using hematoxylin and eosin and immunohistochemical analysis using anti-COX-1 and COX-2 antibodies were performed on tissue samples. The immunoreactivities of the urinary bladder were quantified using H-score measurement, and statistical comparison was performed.

RESULTS

In the immunohistochemical examination the COX-1 immunoreactivities were found to be higher in the urothelium of the bladder in the radiation exposed groups than in the normal control group (group 1) (p < 0.005). Additionally, high immunoreactivity of COX-2 molecule was established in groups 2, 3, and 4 of radiation groups as compared to group 1 (p < 0.005) in examination of the urothelium. COX-1 and COX-2 immunoreactivities in the submucosa were detected higher in group 4 than in the other groups (p < 0.005).

CONCLUSION

COX-1 and COX-2 expressions in the urothelium and subepithelium of the urinary bladder were investigated in mice during the acute radiation response. The expression of COX-1 and COX-2 in the urothelium seems to prevent bladder damage from radiation, supplying differentiation and restoration of the urothelium.

Influence of Radiation Exposure During Radiotherapy. Evidence for the Increase of Versican and Heparin-Binding EGF-like Growth Factor Concentrations

OBJECTIVE

To investigate the reaction of versican and heparin-binding EGF-like growth factor (HB-EGF) molecule concentrations to acute radiation exposure in normal bladder and rectal tissue samples in order to gain more insight into the effects of cancer radiotherapy.

STUDY DESIGN

Four groups with 6 male adult Swiss Albino mice per group were investigated. The mice bladder and rectum tissue samples were subjected to a 10-Gy single-dose radiation exposure in the pelvic region with a Co-60 teletherapy device and investigated 1, 2, and 7 days after radiation exposure, with 1 reference group which was not exposed to radiation.

RESULTS

In the immunohistochemical examination of the tissue samples with anti-versican and anti-HB-EGF primary antibodies was observed a statistically significant increase 7 days after radiation exposure.

CONCLUSION

The observed increase of versican and HB-EGF concentrations in the normal tissue matrix after radiation exposure may play a role in the side effects of radiotherapy.

[Long-term adverse effects on bladder filling phase in males submitted to the pelvic radiotherapy]

OBJECTIVE

To describe and quantify the long-term adverse effects on filling phase of lower urinary tract function in males submitted to radiotherapy.

METHODS

We performed a retrospective comparative study on a cohort of 99 men undergoing EBRT a mean of 4.7 years before for clinically localized prostate, rectum or colon neoplasia, and another cohort formed by 97 men over 50 years who did not undergo radiotherapy.

RESULTS

Cystometric bladder capacity and bladder capacity at first voiding desire were significantly lower in the radiotherapy group. Univariate analysis showed that the radiotherapy group evinced a risk to present a diminished compliance of 3.5 times more and 9.3 times more to find stress urinary incontinence, but we did not found increased risk for detrusor overactivity. In multivariate analysis the history of radical surgery acted as a confounding factor in the risk of stress urinary incontinence, but not to suffer diminished bladder compliance.

CONCLUSIONS

The main long-term adverse effect of pelvic radiotherapy on male bladder function during filling is the increased risk of low bladder compliance.

Does radio frequency radiation induce micronuclei frequency in exfoliated bladder cells of diabetic rats?

OBJECTIVE

For many years there has been a discussion among both experts and the general public regarding the effects of radio frequency (RF) radiation on the human organism. The purpose of the present study was to evaluate the relationship of micronucleui (MN) frequency and RF radiation in exfoliated bladder cells of non-diabetic and diabetic rats.

METHODS

Three groups were used in the experiment: Group I (n=6): diabetic group without RF exposure; Group II (n=6): diabetic group exposed 2100 MHz RF radiation and Group III (n=6): control animals (non-diabetic group, no RF exposure). RF exposure in the experiment resulted in a whole body average SAR of 0.24 W/kg with an ERMS field of 17.5 V/m in non-thermal levels.

RESULT

Results showed that there was no statistically important differences between non-RF exposed diabetes group and control group; Group I and Group III (p>0.05). There was no statistically important differences between diabetes group and diabetes+RF exposed group (Group I and Group II) (p>0.05). RF exposure did not result in increased MN frequencies in exfoliated bladder cells of diabetic rats with respect to control animals (Group II and Group III), either and this result found no statistically important (p>0.05).

CONCLUSIONS

This study suggested no possible genotoxic effects of RF radiation among human beings especially with chronic disorders, such as diabetes.

Anterior-oriented proton beams for prostate cancer: A multi-institutional experience

BACKGROUND

Proton beam therapy (PBT) for prostate cancer generally involves the use of two lateral beams that transverse the hips. In patients with hip replacements or a previously irradiated hip, this arrangement is contraindicated. The use of non-lateral beams is possible, but not well described. Here we report a multi-institutional experience for patients treated with at least one non-lateral proton beam for prostate cancer.

MATERIAL AND METHODS

Between 2010 and 2014, 20 patients with organ-confined prostate cancer and a history of hip prosthesis underwent proton therapy utilizing at least one anterior oblique beam (defined as between 10° and 85° from vertical) at one of three proton centers.

RESULTS

The median follow-up was 6.4 months. No patients have developed PSA failure or distant metastases. The median planning target volume (PTV) D95 was 79.2 Gy (RBE) (range 69.7-79.9). The median rectal V70 was 9.2% (2.5-15.4). The median bladder V50, V80, and mean dose were 12.4% (3.7-27.1), 3.5 cm3 (0-7.1), and 14.9 Gy (RBE) (4.6-37.8), respectively. The median contralateral femur head V45 and max dose were 0.01 cm3 (0-16.6) and 43.7 Gy (RBE) (15.6-52.5), respectively. The incidence of acute Grade 2 urinary toxicity was 40%. There were no Grade≥3 urinary toxicities. There was one patient who developed late Grade 2 rectal proctitis, with no other cases of acute or late ≥Grade 2 gastrointestinal toxicity. Grade 2 erectile dysfunction occurred in two patients (11.1%). Mild hip pain was experienced by five patients (25%). There were no cases of hip fracture.

CONCLUSION

PBT for prostate cancer utilizing anterior oblique beam trajectories is feasible with favorable dosimetry and acceptable toxicity. Further follow-up is needed to assess for long-term outcomes and toxicities.