A randomized trial comparing bladder volume consistency during fractionated prostate radiation therapy

Adaptive radiotherapy for muscle invasive bladder cancer: a retrospective audit of two bladder filling protocols

BACKGROUND

Radical radiotherapy for muscle-invasive bladder cancer (MIBC) is challenging due to large variations in bladder shape, size and volume during treatment, with drinking protocols often employed to mitigate geometric uncertainties. Utilising adaptive radiotherapy together with CBCT imaging to select a treatment plan that best fits the bladder target and reduce normal tissue irradiation is an attractive option to compensate for anatomical changes. The aim of this retrospective study was to compare a bladder empty (BE) protocol to a bladder filling (BF) protocol with regards to variations in target volumes, plan of the day (PoD) selection and plan dosimetry throughout treatment.

METHODS

Forty patients were included in the study; twenty were treated with a BE protocol and twenty with a BF protocol to a total prescribed dose of 55 Gy in 20 fractions. Small, medium and large bladder plans were generated using three different CTV to PTV margins. Bladder (CTV) volumes were delineated on planning CTs and online pre-treatment CBCTs. Differences in CTV volumes throughout treatment, plan selection, PTV volumes and resulting dose metrics were compared for both protocols.

RESULTS

Mean bladder volume differed significantly on both the planning CTs and online pre-treatment CBCTs between the protocols (p < 0.05). Significant differences in bladder volumes were observed between the planning CT and pre-treatment CBCTs for BF (p < 0.05) but not for BE (p = 0.11). Both protocols saw a significant decrease in bladder volume between first and final treatment fractions (p < 0.05). Medium plans were preferentially selected for BE whilst when using the BF protocol the small plan was chosen most frequently. With no significant change to PTV coverage between the protocols, the volume of body receiving 25.0-45.8 Gy was found to be significantly smaller for BE patients (p < 0.05).

CONCLUSIONS

This work provides evidence in favour of a BE protocol compared to a BF protocol for radical radiotherapy for MIBC. The smaller treatment volumes observed in the BE protocol led to reduced OAR and total body doses and were also observed to be more consistent throughout the treatment course. These results highlight improvements in dosimetry for patients who undergo a BE protocol for MIBC.

Does a patient-specific bladder-filling protocol affect bladder volume and dose in postprostatectomy radiotherapy?

PURPOSE

Our aim is to develop a patient-specific bladder-filling protocol (PSP) using an ultrasound-based bladder scanner (BS) and compare the volumetric and dosimetric parameters with those of the standard filling protocol (SP) in postprostatectomy patients.

METHODS

Twenty postprostatectomy patients who received salvage radiotherapy (72 Gy/36 fx) were included. For PSP, the patient was asked to drink 500 mL of water after emptying his bladder. Bladder volume was measured using BS every 10 min. Each patient's unique time to reach a 150-200 cc volume was used for simulation and treatment. For the SP, the patient was asked about the feeling of having a full bladder. Organs at risk (OAR) were contoured on cone-beam computed tomography (CBCT) scans that were transferred to the treatment planning system (TPS). Treatment plans were applied to CBCTs. Changes in bladder volume and doses for planning computed tomography (PCT) and CBCT were determined.

RESULTS

In the SP, there was no significant difference in mean bladder volume for PCT and CBCT (p = 0.139); however, there was a trend for significance in the mean bladder dose (p = 0.074). In PSP, there was no significant difference in the mean bladder volume or dose for PCT and CBCT (p = 0.139 and p = 0.799, respectively). There was a significant difference in terms of mean CBCT bladder volume between the two protocols (p = 0.007), whereas no significant difference was detected in terms of bladder dose (p = 0.130).

CONCLUSION

With PSP, optimal bladder filling was obtained and maintained throughout the whole treatment course, and it was reproducible in every fraction.

Optimal Bladder Condition in Volumetric Modulated Arc Therapy for Prostate Cancer: The Role of Superior-Inferior Lengths of the Bladder and Dose Constraints

Background Optimal bladder conditions based on dose constraints in prostate cancer radiation therapy (RT) are important. In this study, the superior-inferior (SI) lengths of the bladder were assessed to define the ideal bladder state for RT. Materials and methods In this study, 50 prostate cancer cases treated with three-dimensional conformal radiation therapy between January and December 2021 were retrospectively analyzed. Using their CT data, a volumetric modulated arc therapy (VMAT) plan was simulated. Bladder dose constraints and dimensions, including SI, right-left (RL), and anterior-posterior (AP) lengths, were assessed. In total, 28 cases met the dose constraints and 22 cases did not meet the dose constraints.  Results Median bladder volumes (BVs) for compliant and non-compliant cases were 163.6 ml and 88.5 ml, respectively (p<0.0001). For compliant plans, median bladder dimensions were RL: 78 mm, AP: 89 mm, and SI: 51 mm. Non-compliant plans showed RL: 72 mm, AP: 84 mm, and SI: 42 mm, with significant differences (SI: p=0.0004, RL: p=0.0065, AP: p=0.037). Established thresholds were SI: 46 mm, RL: 92 mm, AP: 75 mm, and BV: 142.8 ml. SI showed the strongest correlation with BV (coefficient: 0.78). Conclusions This study analyzed the SI lengths of the bladder concerning dose constraints in VMAT for prostate cancer. It was concluded that smooth treatment planning could be achieved with proper consideration of the bladder's SI distance. Further case collection and prospective studies are warranted.

Advances in the management of radiation-induced cystitis in patients with pelvic malignancies

OBJECTIVE

Radiotherapy plays a vital role as a treatment for malignant pelvic tumors, in which the bladder represents a significant organ at risk involved during tumor radiotherapy. Exposing the bladder wall to high doses of ionizing radiation is unavoidable and will lead to radiation cystitis (RC) because of its central position in the pelvic cavity. Radiation cystitis will result in several complications (e.g. frequent micturition, urgent urination, and nocturia) that can significantly reduce the patient's quality of life and in very severe cases become life-threatening.

METHODS

Existing studies on the pathophysiology, prevention, and management of radiation-induced cystitis from January 1990 to December 2021 were reviewed. PubMed was used as the main search engine. Besides the reviewed studies, citations to those studies were also included.

RESULTS AND DISCUSSIONS

In this review, the symptoms of radiation cystitis and the mainstream grading scales employed in clinical situations are presented. Next, preclinical and clinical research on preventing and treating radiation cystitis are summarized, and an overview of currently available prevention and treatment strategies as guidelines for clinicians is provided. Treatment options involve symptomatic treatment, vascular interventional therapy, surgery, hyperbaric oxygen therapy (HBOT), bladder irrigation, and electrocoagulation. Prevention includes filling up the bladder to remove it from the radiation field and delivering radiation based on helical tomotherapy and CT-guided 3D intracavitary brachytherapy techniques.

Prostate Volume Changes during Extreme and Moderately Hypofractionated Magnetic Resonance Image-guided Radiotherapy

AIMS

Prostate morphological changes during external beam radiotherapy are poorly understood. Excellent soft-tissue visualisation offered by magnetic resonance image-guided radiotherapy (MRIgRT) provides an opportunity to better understand such changes. The aim of this study was to quantify prostate volume and dimension changes occurring during extreme and moderately hypofractionated schedules.

MATERIALS AND METHODS

Forty prostate cancer patients treated on the Unity 1.5 Tesla magnetic resonance linear accelerator (MRL) were retrospectively reviewed. The cohort comprised patients treated with 36.25 Gy in five fractions (n = 20) and 60 Gy in 20 fractions (n = 20). The volume of the delineated prostates on reference planning computed tomography (fused with MRI) and daily T2-weighted 2-min session images acquired on Unity were charted. Forty planning computed tomography and 500 MRL prostate volumes were evaluated. The mean absolute and relative change in prostate volume during radiotherapy was compared using a paired t-test (P value <0.01 considered significant to control for multiple comparisons). The maximum dimension of the delineated prostate was measured in three isocentric planes.

RESULTS

Significant prostate volume changes, relative to MRL imaging fraction 1 (MRL#1), were seen at all time points for the five-fraction group. The peak mean relative volume increase was 21% (P < 0.001), occurring at MRL#3 and MRL#4 after 14.5 and 21.75 Gy, respectively. Prostate expansion was greatest in the superior-inferior direction; the peak mean maximal extension was 5.9 mm. The maximal extension in the left-right and anterior-posterior directions measured 1.1 and 2.2 mm, respectively. For the 20-fraction group, prostate volume increased relative to MRL#1, for all treatment time points. The mean relative volume increase was 11% (P < 0.001) at MRL#5 after 12 Gy, it then fluctuated between 8 and 13%. From MRL#5 to MRL#20, the volume increase was significant (P < 0.01) for 12 of 16 time points calculated. The peak mean maximal extension in the superior-inferior direction was 3.1 mm. The maximal extension in the left-right and anterior-posterior directions measured 1.7 and 3.7 mm, respectively.

CONCLUSION

Significant prostate volume and dimension changes occur during extreme and moderately hypofractionated radiotherapy. The extent of change was greater during extreme hypofractionation. MRIgRT offers the opportunity to reveal, quantify and correct for this deformation.

Bladder filling in patients undergoing prostate radiotherapy on a MR-linac: The dosimetric impact

The implementation of adaptive radiotherapy for prostate cancer compensates for inter-fraction motion, at the penalty of increased time in room. The subsequent increase in bladder filling may impact dosimetry, which we have investigated on ten patients treated on the MR-linac. Patients drank water before treatment, to achieve a bladder volume of 200-300 cm3. Bladder and bowel were re-outlined offline on 140 images and plans recalculated. All mandatory bladder dose constraints and 99.1% of bowel constraints were achieved at time of treatment, despite varying bladder volumes and varying adherence to original bladder filling guidance.

Bowel and bladder reproducibility in image guided radiation therapy for prostate cancer: Results of a patterns of practice survey

Purpose

Optimal management of patients with prostate cancer (PCa) to achieve bowel and bladder reproducibility for radiation therapy (RT) and the appropriate planning target volume (PTV) expansions for use with modern image guidance is uncertain. We surveyed American Society of Radiation Oncology radiation oncologists to ascertain practice patterns for definitive PCa RT with respect to patient instructions and set up, daily image guidance, and subsequent PTV expansions.

Methods and Materials

A pattern of practice survey was sent to American Society of Radiation Oncology radiation oncologists who self-identified as specializing in PCa. Respondents identified the fractionation regimens routinely used, and their practices regarding diet, bowel, and bladder instructions for patients with PCa before RT simulation and throughout treatment. Questions regarding PTV margins, daily set up practices, and use of image guidance were included.

Results

Of 190 respondents, 158 reported using conventional fractionation (CFx), 49 moderate hypofractionation (MHFx), and 61 stereotactic body radiation therapy (SBRT). Diet modifications during RT were advised by 84% of respondents, treatment with full bladder by 96%, and bowel instructions by 78%. Prescription of bowel medication was higher for respondents using SBRT (95.1%) versus those using CFx/MHFx (55.1%; 34.7%). The most common implantable device reported was fiducial markers, with increased use in SBRT (86.0%; 68.9%) versus CFx/MHFx. Cone beam computed tomography was the most common daily imaging technique across fractionation regimens. SBRT showed correlation between PTV margin expansions, fiducial marker use, and image guidance.

Conclusions

Survey results indicate heterogeneity in treatment modality, dose, patient instructions, and PTV expansions used by radiation oncologists in the treatment of patients with PCa. Further investigation to define appropriate patient instructions on bowel preparation to maximize target reproducibility in PCa is needed, as is continued guidance on evidence-based approaches for image guidance and PTV margin selection.

A model to guide the management and decision of re-planning during radiotherapy for cervical cancer

BACKGROUND

To establish a model to predict whether re-planning is needed in the process of cervical cancer radiotherapy.

METHODS

We collected the clinical indexes of 132 patients diagnosed with cervical cancer receiving concurrent chemotherapy and radiotherapy, including 33 factors about tumor markers [carcinoembryonic antigen (CEA), cancer antigen 125 (CA-125), squamous cell carcinoma antigen (SCC)], tumor volume, rectal volume, bladder volume, volumes receiving 30-50 Gy in organs-at-risk (OARs), and the maximum dose (Dmax) received by 1-2 cc in OARs. We established a multivariate model for re-planning evaluation via principal component analysis, and then verified the model based on the internal data.

RESULTS

We identified the dose index (P1), tumor size index (P2), and volumes receiving 30-50 Gy in OARs and the tumor (P3) as the three most weighted factors of the re-planning model. We set the cut-off for the re-planning modification requirement at 1. The model was consistent with R = 0.12P1 + 0.21P2 + 0.31P3, and it performed accurately that area under the test set characteristics curve (AUC) =0.826].

CONCLUSIONS

Our proposed method can help to reduce image re-examination during treatment, decrease toxicities in OARs, shorten the radiotherapy course, lessen oncologists' efforts, and save medical resources.

Bladder filling volume variation between the first and second day of planning computed tomography for prostate cancer radiation therapy and correlation with renal function

AIM

During radiation therapy (RT) for prostate cancer, bladder filling helps exclude the organ from irradiation and reduces adverse effects. For RT planning, we performed computed tomography (CT) for 2 consecutive days to evaluate inter-day variations in organs such as the bladder. However, the patient factors that are associated with large intra-patient variations in bladder filling volume prior to RT are not known.

METHODS

This was a retrospective study of 97 prostate cancer patients who underwent CT for 2 consecutive days for RT planning between March 2015 and March 2020 and with confirmed water intake volume before the scans. Patients consumed 500 ml of water immediately after urination and underwent CT 30 min after the start of water intake; CT was performed under similar conditions over 2 consecutive days. Patient information was collected from the medical records taken before CT.

RESULTS

The median bladder filling volume was 102.8 cm³ (range: 31.7-774.0), and the median intra-patient bladder filling volume variation was 23.4 cm³ (range: 0.4-277.7). Univariate analysis revealed that the intra-patient variation was significantly larger in patients with an eGFR higher than the median (p = 0.003). No other factor showed correlations with the variation. As the larger bladder filling volume of the 2 consecutive days in patients increased (median 121.5 cm³ , range: 47.8-774.0), the intra-patient variation also increased.

CONCLUSION

Patients with a higher eGFR show greater variation in bladder filling volume, and caution should be exercised when applying RT in these patients.

Intrafractional stability of MR-guided online adaptive SBRT for prostate cancer

Background

MR-guided online adaptive stereotactic body radiation therapy (SBRT) for prostate cancer aims to reduce toxicity by full compensation of interfractional uncertainties. However, the process of online adaptation currently takes approximately 45 min during which intrafractional movements remain unaccounted for. This study aims to analyze the dosimetric benefit of online adaptation and to evaluate its robustness over the duration of one treatment fraction.

Methods

Baseline MR-scans at a MR-linear accelerator were acquired for ten healthy male volunteers for generation of mock-prostate SBRT plans with a dose prescription of 5 × 7.25 Gy. On a separate day, online MR-guided adaptation (ViewRay^® MRIdian) was performed, and thereafter MR images were acquired every 15 min for 1 h to assess the stability of the adapted plan.

Results

A dosimetric benefit of online MR-guided adaptive re-planning was observed in 90% of volunteers. The median D₉₅CTV- and D₉₅PTV-coverage was improved from 34.8 to 35.5 Gy and from 30.7 to 34.6 Gy, respectively. Improved target coverage was not associated with higher dose to the organs at risk, most importantly the rectum (median D_1ccrectum baseline plan vs. adapted plan 33.3 Gy vs. 32.3 Gy). The benefit of online adaptation remained stable over 45 min for all volunteers. However, at 60 min, CTV-coverage was below a threshold of 32.5 Gy in 30% of volunteers (30.6 Gy, 32.0 Gy, 32.3 Gy).

Conclusion

The dosimetric benefit of MR-guided online adaptation for prostate SBRT was robust over 45 min in all volunteers. However, intrafractional uncertainties became dosimetrically relevant at 60 min and we therefore recommend verification imaging before delivery of MR-guided online adapted SBRT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01916-0.

EANM/SNMMI practice guideline for [18F]FDG PET/CT external beam radiotherapy treatment planning in uterine cervical cancer v1.0

PURPOSE

The aim of this EANM / SNMMI Practice Guideline with ESTRO endorsement is to provide general information and specific considerations about [18F]FDG PET/CT in advanced uterine cervical cancer for external beam radiotherapy planning with emphasis on staging and target definition, mostly in FIGO stages IB3-IVA and IVB, treated with curative intention.

METHODS

Guidelines from related fields, relevant literature and leading experts have been consulted during the development of this guideline. As this field is rapidly evolving, this guideline cannot be seen as definitive, nor is it a summary of all existing protocols. Local variations should be taken into consideration when applying this guideline.

CONCLUSION

The background, common clinical indications, qualifications and responsibilities of personnel, procedure / specifications of the examination, documentation / reporting and equipment specifications, quality control and radiation safety in imaging is discussed with an emphasis on the multidisciplinary approach.

Bladder volume reproducibility after water consumption in patients with prostate cancer undergoing radiotherapy: A systematic review and meta-analysis

Background

To minimize toxicity due to radiotherapy in patients with prostate cancer, high bladder volume reproducibility is essential. Water consumption is often used to increase bladder volume reproducibility, but the optimal amount of water required to be consumed remains unclear. We aimed to analyzed the relationship between water consumption and bladder volume reproducibility in patients undergoing radiotherapy for prostate cancer.

Methods

We conducted a systematic review and meta-analysis of randomized controlled trials and cohort studies that assessed bladder volume change after water consumption in patients with prostate cancer undergoing radiotherapy. MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched for relevant studies published from database inception up until July 4, 2020. The Newcastle–Ottawa Scale was used to evaluate the risk of bias in the included studies. The outcome was the mean difference (MD) of bladder volume after water consumption, evaluated through meta-analysis using a random-effects model.

Results

Ten cohort studies and one randomized controlled trial with a total of 417 patients were included. For 300–400 ml water consumption, the bladder volume MD between during treatment and at computer tomography-simulation (95% confidence interval [CI]) was −11.97 (−51.68 to 27.74), was −45.99 (−82.85 to −9.13) for 500–540 ml water consumption and −45.92 (−78.86 to −12.98) for water consumption until full-bladder sensation was reached.

Conclusion

Consuming 300–400 ml of water potentially leads to the best bladder volume reproducibility; moreover, the higher the water consumption volume, the lower the bladder volume reproducibility.

Strict bladder filling and rectal emptying during prostate SBRT: Does it make a dosimetric or clinical difference?

Background

To evaluate inter-fractional variations in bladder and rectum during prostate stereotactic body radiation therapy (SBRT) and determine dosimetric and clinical consequences.

Methods

Eighty-five patients with 510 computed tomography (CT) images were analyzed. Median prescription dose was 40 Gy in 5 fractions. Patients were instructed to maintain a full bladder and empty rectum prior to simulation and each treatment. A single reviewer delineated organs at risk (OARs) on the simulation (Sim-CT) and Cone Beam CTs (CBCT) for analyses.

Results

Bladder and rectum volume reductions were observed throughout the course of SBRT, with largest mean reductions of 86.9 mL (19.0%) for bladder and 6.4 mL (8.7%) for rectum noted at fraction #5 compared to Sim-CT (P < 0.01). Higher initial Sim-CT bladder volumes were predictive for greater reduction in absolute bladder volume during treatment (ρ = − 0.69; P < 0.01). Over the course of SBRT, there was a small but significant increase in bladder mean dose (+ 4.5 ± 12.8%; P < 0.01) but no significant change in the D2cc (+ 0.8 ± 4.0%; P = 0.28). The mean bladder trigone displacement was in the anterior direction (+ 4.02 ± 6.59 mm) with a corresponding decrease in mean trigone dose (− 3.6 ± 9.6%; P < 0.01) and D2cc (− 6.2 ± 15.6%; P < 0.01). There was a small but significant increase in mean rectal dose (+ 7.0 ± 12.9%, P < 0.01) but a decrease in rectal D2cc (− 2.2 ± 10.1%; P = 0.04). No significant correlations were found between relative bladder volume changes, bladder trigone displacements, or rectum volume changes with rates of genitourinary or rectal toxicities.

Conclusions

Despite smaller than expected bladder and rectal volumes at the time of treatment compared to the planning scans, dosimetric impact was minimal and not predictive of detrimental clinical outcomes. These results cast doubt on the need for excessively strict bladder filling and rectal emptying protocols in the context of image guided prostate SBRT and prospective studies are needed to determine its necessity.

The implementation of an empty bladder filling protocol for localised prostate volumetric modulated arctherapy (VMAT): early results of a single institution service evaluation

OBJECTIVE

To examine the impact of an empty bladder filling protocol on patients receiving radical RT for localised prostate cancer on post RT toxicity and biochemical progression free survival (bPFS).

METHODS AND MATERIALS

Records of patients receiving radical external beam RT (EBRT) for localised prostate cancer with a full or empty bladder were reviewed. These included the bladder size on planning CT, daily online image guided RT (IGRT) setup data, treatment time and post treatment follow up data.These included bPFS, gastrointestinal(GI) and genitourinary(GU) toxicity scoring post RT using the CTCAE v4.0 scoring system. All patients included in the study were planned and treated under the same departmental clinical protocol with VMAT and daily online IGRT corrections.

RESULTS

90 patients were treated with 60 Gy in 20 fractions with a median follow up of 48 months. At 4 years bPFS in the empty bladder group was 100 and 98% in the full bladder group (p = 0.27). There were no statistically significant differences in cumulative ≥Grade 2GU (p = 0.10) and GI (p = 0.27) toxicity rates between the two bladder filling protocols. No statistically significant differences in the IGRT setup between the two groups of patients. Although the median treatment times per fraction were not statistically different between the two groups (p = 0.47), patients in the full bladder filling group were required to spend a longer time in the RT department per treatment session for bladder filling.

CONCLUSION

An empty bladder filling protocol has non-inferior bPFS, GI and GU toxicities at 4 years in patients with localised prostate cancer using advanced RT techniques in comparison to a full bladder filling protocol. A longer follow up with a larger sample size is required to validate this approach.

ADVANCES IN KNOWLEDGE

This study suggests that an empty bladder filling protocol can be used in external beam EBRT for localised prostate cancer with non-inferior treatment outcomes.

Overview of patient preparation strategies to manage internal organ motion during radiotherapy in the pelvis

Introduction:

Pelvic internal organs change in volume and position during radiotherapy. This may compromise the efficacy of treatment or worsen its toxicity. There may be limitations to fully correcting these changes using online image guidance; therefore, effective and consistent patient preparation and positioning remain important. This review aims to provide an overview of the extent of pelvic organ motion and strategies to manage this motion.

Methods and Materials:

Given the breadth of this topic, a systematic review was not undertaken. Instead, existing systematic reviews and individual high-quality studies addressing strategies to manage pelvic organ motion have been discussed. Suggested levels of evidence and grades of recommendation for each strategy have been applied.

Results:

Various strategies to manage rectal changes have been investigated including diet and laxatives, enemas and rectal emptying tubes and rectal displacement with endorectal balloons (ERBs) and rectal spacers. Bladder-filling protocols and bladder ultrasound have been used to try to standardise bladder volume. Positioning the patient supine, using a full bladder and positioning prone with or without a belly board, has been examined in an attempt to reduce the volume of irradiated small bowel. Some randomised trials have been performed, with evidence to support the use of ERBs, rectal spacers, bladder-filling protocols and the supine over prone position in prostate radiotherapy. However, there was a lack of consistent high-quality evidence that would be applicable to different disease sites within the pelvis. Many studies included small numbers of patients were non-randomised, used less conformal radiotherapy techniques or did not report clinical outcomes such as toxicity.

Conclusions:

There is uncertainty as to the clinical benefit of many of the commonly adopted interventions to minimise pelvic organ motion. Given this and the limitations in online image guidance compensation, further investigation of adaptive radiotherapy strategies is required.

The value of a bladder-filling protocol for patients with prostate cancer who receive post-operative radiation: results from a prospective clinical trial

BACKGROUND AND PURPOSE

This study compares two different strategies for maintaining a constant bladder volume during a course of postoperative radiotherapy in prostate cancer. In addition, we studied how changes in bladder filling affect the clinical target volume (CTV) and the coverage hereof.

MATERIAL AND METHODS

Twenty-nine patients with PSA-relapse after radical prostatectomy were divided into two groups: voiding and drinking 300 ml 1 hour before treatment (Group 1); and maintained a comfortably filled bladder (Group 2). The bladder volumes were calculated based on the planning CT (pCT) and a weekly Cone Beam CT (CBCT) during the treatment period. Furthermore, the variability of bladder extension was analyzed and correlated to the volume of the bladder covered with the 95% of the dose (V_95%,bladder).

RESULTS

The estimated median bladder volumes were 120 ml (95% CI: (93, 154)) and 123 ml (95% CI: (98, 155)) in groups 1 and 2, respectively. The intra-individual variation in bladder volume, assessed as the standard deviation, was 64 ml (95% CI: (46, 105)) in Group 1 and 61 (95% CI: (45, 94)) ml in Group 2. Increasing the bladder volume extended the bladder cranially while the caudal extension was almost constant. The correlation between bladder volume and V_95%,bladder was 3.5 ml per 100 ml in group 1 and 1.2 ml per 100 ml in group 2 with no significant difference.

CONCLUSIONS

The intention to maintain a constant volume for the bladder is not fulfilled with either of the protocols in this study, and changes in bladder volumes does not seem to affect the position, or the coverage of the CTV.

High-dose intensity-modulated radiation therapy as primary treatment of prostate cancer: genitourinary/gastrointestinal toxicity and outcomes, a single-institution experience

PURPOSE

Prostatectomy, radiotherapy and watchful waiting are the main therapeutic options available for local stage of prostate cancer (PCa). We report our experience on 394 patients affected by prostate cancer primarily treated with high-dose, image-guided, IMRT, focusing on gastrointestinal, genitourinary toxicities and biochemical control.

METHODS

From July 2003 to August 2014, 394 patients were treated with radical high-dose radiotherapy (HDRT) for prostate cancer; the mean total radiation dose was 79 Gy in standard fractions. Hormonal therapy (HT) was administered to 7.6% of low-risk patients, to 20.3% of intermediate-risk patients and to 72% of high-risk patients. Patients were evaluated for biochemical failure, local recurrence (LR) and metastases.

RESULTS

Ninety-seven patients (26.65%) developed acute GU toxicity at the medium dose of 25.4 Gy, grade 1 (G1) or grade 2 (G2) in 94 cases. Only 16 patients (4.06%) reported chronic GU toxicity (G1 or G2), and one case developed G3 cystitis. No G3 GI acute and late toxicity were detected. Fifty-six (14.2%) patients experienced LR, 26 (6.6%) developed metastases and 70 patients (17.8%) were deceased. Gleason sum score > 7 was predictive for worse overall survival (GS = 7 was borderline) and for metastasis. No factors resulted predictive for local relapse. HT pre-RT had been demonstrated as a negative predictor for OS and DFS-DM.

CONCLUSIONS

Data confirm the safety of HDRT for PCa. Treatment was efficient with low toxicity profile. Moreover, continued technologic advancements, as image-guided radiotherapy, could lead to further reduction in toxicity, thus increasing the therapeutic index.

Impact of bladder volume on acute genitourinary toxicity in intensity modulated radiotherapy for localized and locally advanced prostate cancer

BACKGROUND AND PURPOSE

To evaluate the effect of changes in bladder volume during high-dose intensity-modulated-radiotherapy (IMRT) of prostate cancer on acute genitourinary (GU) toxicity and prospectively evaluate a simple biofeedback technique for reproducible bladder filling with the aim of reducing acute GU toxicity.

METHODS

One hundred ninety-three patients were trained via a biofeedback mechanism to maintain a partially filled bladder with a reproducible volume of 200-300 cc at planning CT and subsequently at each fraction of radiotherapy. We prospectively analyzed whether and to what extent the patients' ability to maintain a certain bladder filling influenced the degree of acute GU toxicity and whether cut-off values could be differentiated.

RESULTS

We demonstrated that the ability to reach a reproducible bladder volume above a threshold volume of 180 cc and maintain that volume via biofeedback throughout treatment predicts for a decrease in acute GU toxicity during curative high-dose IMRT of the prostate. Patients who were not able to reach a partial bladder filling to that cut-off value and were not able to maintain a partially filled bladder throughout treatment had a significantly higher risk of developing ≥grade 2 GU acute toxicity.

CONCLUSION

Our results support the hypothesis that a biofeedback training for the patient is an easy-to-apply, useful, and cost-effective tool for reducing acute GU toxicity in high-dose IMRT of the prostate. Patients who are not able to reach and maintain a certain bladder volume during planning and treatment-two independent risk factors-might need special consideration.

A comparison of bladder volumes based on treatment planning CT and BladderScan® BVI 6100 ultrasound device in a prostate radiation therapy population

OBJECTIVE:

The aim of this study is to investigate if a handheld ultrasound device (BladderScan® BVI 6100) can accurately measure bladder volumes in prostate radiotherapy (RT) patients.

METHODS:

A comparison was made of contoured bladder volumes based on treatment planning CT (TPCT) and BladderScan® BVI 6100 ultrasound device in a large prostate RT population. Three bladder volume (BV) measurements were taken using the bladder volume instrument (BVI) device on prostate RT patients immediately prior to TPCT (n = 190). The CT delineation bladder volumes were also recorded. The mean of the three BVI readings (BVImean) and the maximum (BVImax) of the readings were considered for a comparative analysis.

RESULTS:

There was a strong positive correlation between the BVI and CT delineated bladder volumes (BVImean r = 0.825; BVImax r = 0.830). The mean difference [± standard deviation (SD)] was an underestimation of BV for both BVImean and BVImax (44.8 ± 88.2 ml and 32.9 ± 87.5 ml, respectively).

CONCLUSION:

This is the largest study to date (n = 190), assessing the accuracy of the BladderScan® BVI 6100 in the prostate RT population. The BVI 6100 provides an acceptable indication of BV for use in prostate RT patients for the purposes of monitoring BV.

ADVANCES IN KNOWLEDGE:

The BladderScan® BVI 6100 provides a convenient and non-irradiating method of indicating BV for use in prostate RT patients.

Reduction of intra-fraction prostate motion - Determining optimal bladder volume and filling for prostate radiotherapy using daily 4D TPUS and CBCT

•

An optimal bladder volume and filling protocol is proposed.

•

The current hydration protocol was well-accepted and tolerated.

Background and purpose

Inconsistent bladder and rectal volumes have been associated with motion uncertainties during prostate radiotherapy. This study investigates the impact of these volumes to determine the optimal bladder volume.

Materials and methods

60 patients from two Asian hospitals were recruited prospectively. 1887 daily cone-beam computed tomography (CBCT) images were analysed. Intra-fraction motion of the prostate was monitored real-time using a four-dimension transperineal ultrasound (4D TPUS) Clarity® system. The impact of planned bladder volume, adequacy of daily bladder filling, and rectum volume on mean intra-fraction motion of the prostate was analysed. Patients’ ability to comply with the full bladder hydration protocol and level of frustration was assessed using a questionaire. Acute side effects were assessed using the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 and quality of life (QoL) assessed using the International Prostate Symptom Score (IPSS).

Results

The mean (SD) bladder and rectum volumes achieved during daily treatment were 139.7 cm³ (82.4 cm³) and 53.3 cm³ (18 cm³) respectively. Mean (SD) percentage change from planned CT volumes in bladder volume was reduced by 8.2% (48.7%) and rectum volume was increased by 12.4% (42.2%). Linear Mixed effect model analysis revealed a reduction in intra-fraction motion in both the Sup/Inf (p = 0.008) and Ant/Post (p = 0.0001) directions when the daily bladder was filled between 82 and 113% (3rd Quartiles) of the planned CT volumes. A reduction in intra-fraction motion of the prostate in the Ant/Post direction (z-plane) (p = 0.03) was observed when the planned bladder volume was greater than 200 ml. Patients complied well with the hydration protocol with minimal frustration (mean (SD) scores of 2.1 (1.4) and 1.8 (1.2) respectively). There was a moderate positive correlation (0.496) between mean bladder volume and IPSS reported post-treatment urinary straining (p = 0.001).

Conclusions

A planned bladder volume >200 cm³ and daily filling between 82 and 113%, reduced intra-fraction motion of the prostate. The hydration protocol was well tolerated.

Compliance with bladder protocol during concurrent chemoradiation for cancer of the cervix and its impact on enteritis: A prospective observational study

Aim

This prospective study aims to assess the compliance with bladder protocol and the correlation with enteritis during pelvic radiation.

Background

Bladder protocol is routinely used for patients undergoing pelvic radiation to reduce radiation enteritis. It is very difficult to maintain constant volume especially in the last two weeks due to radiation enteritis and cystitis.

Materials and methods

Histologically proven 35 cervical cancer patients treated with concurrent chemoradiation in a tertiary care center were the subjects of this prospective study. Following CT simulation and after every fraction, patients were asked to void urine in a calibrated urine container and the volume was documented. Patients were assessed for the highest grade of radiation enteritis weekly as per common toxicity criteria. The mean voided urine volume was correlated with the radiation enteritis.

Results

The mean urine volume at planning CT scan was 295.85 ± 300 ml (SD) with a range of 75-650. At the end of treatment, it was reduced to 233.14 ± 250 ml (range 50-400 ml), a reduction by 21% (p < 0.001). The maximum grade of enteritis was grade I (11%), II (11.4%), III (3-29%) in week 1,2 and 3-5, respectively with a p value of <0.001. A mean urine volume of 230 ml was associated with grade III enteritis in the third week.

Conclusions

Urine output volume measured using a calibrated container is a simple, efficient and practical method to monitor bladder distension thereby reducing enteritis in cervical cancer patients treated with concurrent chemoradiation.

Interventions to reduce acute and late adverse gastrointestinal effects of pelvic radiotherapy for primary pelvic cancers

BACKGROUND

An increasing number of people survive cancer but a significant proportion have gastrointestinal side effects as a result of radiotherapy (RT), which impairs their quality of life (QoL).

OBJECTIVES

To determine which prophylactic interventions reduce the incidence, severity or both of adverse gastrointestinal effects among adults receiving radiotherapy to treat primary pelvic cancers.

SEARCH METHODS

We conducted searches of CENTRAL, MEDLINE, and Embase in September 2016 and updated them on 2 November 2017. We also searched clinical trial registries.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of interventions to prevent adverse gastrointestinal effects of pelvic radiotherapy among adults receiving radiotherapy to treat primary pelvic cancers, including radiotherapy techniques, other aspects of radiotherapy delivery, pharmacological interventions and non-pharmacological interventions. Studies needed a sample size of 20 or more participants and needed to evaluate gastrointestinal toxicity outcomes. We excluded studies that evaluated dosimetric parameters only. We also excluded trials of interventions to treat acute gastrointestinal symptoms, trials of altered fractionation and dose escalation schedules, and trials of pre- versus postoperative radiotherapy regimens, to restrict the vast scope of the review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. We used the random-effects statistical model for all meta-analyses, and the GRADE system to rate the certainty of the evidence.

MAIN RESULTS

We included 92 RCTs involving more than 10,000 men and women undergoing pelvic radiotherapy. Trials involved 44 different interventions, including radiotherapy techniques (11 trials, 4 interventions/comparisons), other aspects of radiotherapy delivery (14 trials, 10 interventions), pharmacological interventions (38 trials, 16 interventions), and non-pharmacological interventions (29 trials, 13 interventions). Most studies (79/92) had design limitations. Thirteen studies had a low risk of bias, 50 studies had an unclear risk of bias and 29 studies had a high risk of bias. Main findings include the following:Radiotherapy techniques: Intensity-modulated radiotherapy (IMRT) versus 3D conformal RT (3DCRT) may reduce acute (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.26 to 0.88; participants = 444; studies = 4; I2 = 77%; low-certainty evidence) and late gastrointestinal (GI) toxicity grade 2+ (RR 0.37, 95% CI 0.21 to 0.65; participants = 332; studies = 2; I2 = 0%; low-certainty evidence). Conformal RT (3DCRT or IMRT) versus conventional RT reduces acute GI toxicity grade 2+ (RR 0.57, 95% CI 0.40 to 0.82; participants = 307; studies = 2; I2 = 0%; high-certainty evidence) and probably leads to less late GI toxicity grade 2+ (RR 0.49, 95% CI 0.22 to 1.09; participants = 517; studies = 3; I2 = 44%; moderate-certainty evidence). When brachytherapy (BT) is used instead of external beam radiotherapy (EBRT) in early endometrial cancer, evidence indicates that it reduces acute GI toxicity (grade 2+) (RR 0.02, 95% CI 0.00 to 0.18; participants = 423; studies = 1; high-certainty evidence).Other aspects of radiotherapy delivery: There is probably little or no difference in acute GI toxicity grade 2+ with reduced radiation dose volume (RR 1.21, 95% CI 0.81 to 1.81; participants = 211; studies = 1; moderate-certainty evidence) and maybe no difference in late GI toxicity grade 2+ (RR 1.02, 95% CI 0.15 to 6.97; participants = 107; studies = 1; low-certainty evidence). Evening delivery of RT may reduce acute GI toxicity (diarrhoea) grade 2+ during RT compared with morning delivery of RT (RR 0.51, 95% CI 0.34 to 0.76; participants = 294; studies = 2; I2 = 0%; low-certainty evidence). There may be no difference in acute (RR 2.22, 95% CI 0.62 to 7.93, participants = 110; studies = 1) and late GI toxicity grade 2+ (RR 0.44, 95% CI 0.12 to 1.65; participants = 81; studies = 1) between a bladder volume preparation of 1080 mls and that of 540 mls (low-certainty evidence). Low-certainty evidence on balloon and hydrogel spacers suggests that these interventions for prostate cancer RT may make little or no difference to GI outcomes.Pharmacological interventions: Evidence for any beneficial effects of aminosalicylates, sucralfate, amifostine, corticosteroid enemas, bile acid sequestrants, famotidine and selenium is of a low or very low certainty. However, evidence on certain aminosalicylates (mesalazine, olsalazine), misoprostol suppositories, oral magnesium oxide and octreotide injections suggests that these agents may worsen GI symptoms, such as diarrhoea or rectal bleeding.Non-pharmacological interventions: Low-certainty evidence suggests that protein supplements (RR 0.23, 95% CI 0.07 to 0.74; participants = 74; studies = 1), dietary counselling (RR 0.04, 95% CI 0.00 to 0.60; participants = 74; studies = 1) and probiotics (RR 0.43, 95% CI 0.22 to 0.82; participants = 923; studies = 5; I2 = 91%) may reduce acute RT-related diarrhoea (grade 2+). Dietary counselling may also reduce diarrhoeal symptoms in the long term (at five years, RR 0.05, 95% CI 0.00 to 0.78; participants = 61; studies = 1). Low-certainty evidence from one study (108 participants) suggests that a high-fibre diet may have a beneficial effect on GI symptoms (mean difference (MD) 6.10, 95% CI 1.71 to 10.49) and quality of life (MD 20.50, 95% CI 9.97 to 31.03) at one year. High-certainty evidence indicates that glutamine supplements do not prevent RT-induced diarrhoea. Evidence on various other non-pharmacological interventions, such as green tea tablets, is lacking.Quality of life was rarely and inconsistently reported across included studies, and the available data were seldom adequate for meta-analysis.

AUTHORS' CONCLUSIONS

Conformal radiotherapy techniques are an improvement on older radiotherapy techniques. IMRT may be better than 3DCRT in terms of GI toxicity, but the evidence to support this is uncertain. There is no high-quality evidence to support the use of any other prophylactic intervention evaluated. However, evidence on some potential interventions shows that they probably have no role to play in reducing RT-related GI toxicity. More RCTs are needed for interventions with limited evidence suggesting potential benefits.

The impact of bladder preparation protocols on post treatment toxicity in radiotherapy for localised prostate cancer patients

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Our study suggests that excellent outcome in terms of post radiotherapy toxicity.

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The empty bladder preparation protocol has non-inferior post radiotherapy toxicity.

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This empty bladder approach can provide better patient comfort and reproducibility.

Objective

This study compares the post radiotherapy related toxicity between the use of an empty and a full bladder preparation protocol in patients receiving radical radiotherapy for localised prostate cancer.

Methods and materials

A retrospective review of patient treatment records in which they were treated with a standard radiotherapy schedule (60Gy/20 fractions) to prostates and base of seminal vesicles only and followed two different bladder preparation (empty and full) protocols was carried out. This included each patient's daily image guided radiotherapy (IGRT) setup, treatment time, bladder size on planning computed tomography, organs at risk dose volume histograms (OAR DVHs) and 12 months post treatment gastrointestinal (GI) and genitourinary (GU) toxicity data.

Results

20 patients were included. There were significant differences in IGRT setup between the two groups. Although treatment times of the two groups were not significantly different, 5/200 (2.5%) sessions were longer than 20 min in the full bladder group while this was not found in the other group.

Associations between bladder preparation protocols and GI (p = 1.0) and GU (p = 0.6) toxicities were not statistically significant. The bladder size on planning CT was not significantly correlated to the GI (R = 0.06, p = 0.8) or GU (R = 0.27, p = 0.3) toxicity scores. No significant differences were found in OAR DVHs between patients with and without GI and GU toxicities. No grade 3/4 toxicities were reported.

Conclusion

The empty bladder preparation approach has non-inferior acute and intermediate post RT GI and GU toxicities in patients treated for localised prostate cancer with advanced radiotherapy techniques compared to the full bladder preparation.

A Dosimetric Evaluation of Threshold Bladder Volumes for Prostate Cancer Radiotherapy

BACKGROUND

An interfraction variation in bladder filling results in uncertainties of dose received and also has workflow implications for busy departments. This study aims to examine the dosimetric impact of a reduced bladder volume while determining a suitable threshold for treatment.

MATERIALS AND METHODS

A total of 15 definitive prostate patients were included for this retrospective dosimetry study. Each patient was planned to receive 80 Gy in 40 fractions using intensity-modulated radiation therapy. For each patient, a series of shrunken bladder volumes were created in 50-mL increments. The volume of bladder receiving 65 Gy (V65), 70 Gy, 75 Gy, and 80 Gy for each "shrunken" bladder volume were analyzed with paired samples t-tests. The effect of the shrunken volume relative to the established dose-volume constraint (DVC) was then assessed using single sample t-tests.

RESULTS

The mean planning bladder volume was 345.01 ± 138.51 mL. Under maximum bladder shrinkage, mean difference between the percentage dose received and each DVC was seen to be statistically significant (P < .05). However, for the majority of patients, DVCs were only violated once the bladder volume shrunk to less than 150 mL. On average, the DVCs were violated once the bladder volume fell below 150 mL for the V75 and V80 constraints, with no violations noted for V65 and V70.

CONCLUSION

Even under exacerbated bladder shrinkage, bladder DVC violations were found to be rare. A bladder threshold of 150 mL would prove sufficient to meet bladder DVCs in over 90% of patients; however, case-by-case assessment is required to ensure patient suitability.

[Partial delegation to radiation therapists of the control by cone beam CT of prostate positioning]

PURPOSE

Intensity modulated radiotherapy for prostate cancer involves daily monitoring of the positioning of the prostate, possible with cone beam CT (CBCT). It allows increased accuracy compared to readjustments but induces an increase in the time dedicated to these medical checks. The aim of the study was to evaluate the possibility of delegation of this task to the radiation therapists by comparing their readjustments to the doctors.

PATIENTS AND METHODS

Five consecutive patients treated with radiation for prostate cancer (76Gy) were analysed. All had a daily CBCT for position control. The movements of the prostate relative to the bony part, the positional variations of the prostate measured by the radiation therapists and the doctors and medical time required to analyse imagery (filling of the rectum and bladder and perform a recalibration) were measured.

RESULTS

One hundred seventy-six CBCT were analysed or 980 steps in the three axes. The movements of the prostate relative to bony part were respectively at least 5mm in 19%, 7% and 3% in the anterior-posterior, upper-lower and right-left axes. Changes readjustments between radiation therapists and doctors were in 95% of cases at the most 4mm in the anterior-posterior and upper-lower axis, and 3mm in the left-right axis. The time for medical use of the CBCT averaged 8min 40 [4 to 22min].

CONCLUSION

The daily readjustment on the prostate using CBCT may be delegated to radiation therapists with acceptable concordance of less than 4mm for 95% of measurements. An initial and ongoing training will ensure treatment safety.

Optimal bladder volume at treatment planning for prostate cancer patients receiving volumetric modulated arc therapy

PURPOSE

To investigate optimal bladder volumes at treatment planning (TP) in prostate cancer patients who undergo volumetric modulated arc therapy (VMAT).

METHODS AND MATERIALS

To determine the minimum value, 122 patients were classified into 6 groups according to the bladder volume at TP: <100 mL (group 1), 100-149 mL (group 2), 150-199 mL (group 3), 200-249 mL (group 4), 250-299 mL (group 5), and ≥300 mL (group 6). Bladder volumes receiving more than 70 Gy (V_70Gy) and V_50Gy were calculated in each subgroup and compared with the bladder dose-volume constraints specified in our institution. To determine the maximum value, 64 patients who underwent uniform nursing interventions were classified into the same 6 groups. Bladder volumes on cone beam computed tomography (CBCT) images were measured once weekly during treatment, for a total of 8 measurements. Relative bladder volumes (bladder volume on CBCT image [mL]/bladder volume at TP [mL] × 100%) were evaluated in each of the 6 subgroups.

RESULTS

The upper bounds of the 95% confidence intervals of the mean V_70Gy and V_50Gy values in group 1 exceeded the dose constraints at our institution. The mean relative bladder volumes were 104%, 91%, 77%, 81%, 63%, and 59% in groups 1, 2, 3, 4, 5, and 6, respectively. The institutional criterion of 70% for the mean relative bladder volume was achieved in groups 1-4, but it could not be achieved in groups 5-6. Therefore, the patients in groups 2-4 met both institutional dose constraints for the bladder at TP and the institutional criterion for the mean relative bladder volume during treatment.

CONCLUSIONS

The optimal bladder volumes at TP were between 100 and 250 mL in this setting. Nursing intervention needs to be implemented before treatment planning to ensure that patients achieve the optimal bladder volume range.

A focus group consultation round exploring patient experiences of comfort during radiotherapy for head and neck cancer

Purpose

The aim of this study was to consult patients about their experiences of comfort while wearing a thermoplastic mask during head and neck radiotherapy before designing a study to develop a comfort scale for radiotherapy.

Methods

A qualitative method using a focus group of patients receiving radiotherapy for head and neck cancer was deployed. Five patients were invited and agreed to participate. Semi-structured questions guided the focus group interview. Thematic analysis was used to identify themes.

Findings

Three patients participated in the focus group. Three main themes were identified: Physical comfort, Mental perception, Passivity. Physical comfort derived from feelings of pressure, unpleasantness, and generally being uncomfortable. Mental perception derived from how the physical comfort was perceived and derived from feelings of shock, anxiety, indifference and sensory systems. Passivity arose from feelings such as the ‘doctor knows best’, ‘putting up with it’, and ‘being taken for a ride’.

Conclusion

The insight of patient’s comfort and experiences are valuable for clinicians to provide patient-centred care. Findings of this study implicate further investigation of how the themes of patient comfort can be measured in radiotherapy to improve the patient experience.

Use of a prospective cohort study in the development of a bladder scanning protocol to assist in bladder filling consistency for prostate cancer patients receiving radiation therapy

INTRODUCTION

Evidence of variations in bladder filling effecting prostate stability and therefore treatment and side-effects is well established with intensity modulated radiation therapy (IMRT). This study aimed to increase bladder volume reproducibility for prostate radiation therapy by implementing a bladder scanning (BS) protocol that could assist patients' bladder filling at computed tomography (CT) simulation and treatment.

METHODS

Based on a retrospective review of 524 prostate cancer patients, a bladder volume of 250-350 mL was adopted as 'ideal' for achieving planning dose constraints. A prospective cohort study was conducted to assess the clinical utility of measuring patients' bladder volumes at CT simulation using an ultrasound bladder scanner (Verathon 9400 BladderScan(®)). A revised bladder preparation protocol was utilised by a bladder scan group (BS) and a non-BS group followed the standard departmental bladder preparation protocol. Time and volume data for the BS group (n = 17) were compared with the non-BS group (n = 17).

RESULTS

The BS cohort had a CT bladder volume range of 221-588 mL; mean 379 mL, SD 125 mL. The non-BS group had a larger range: 184-757 mL; mean 373 mL, SD 160 mL (P = 0.9171). There was a positive correlation between CT volume and BS volume in the BS group (r = 0.797; P = 0.0002) although BS volumes were smaller: range 160-420 mL; mean 251 mL; SD 91 mL; P < 0.0001). The maximum bladder volume receiving 50 Gy (V50) from the BS group was 46.4%, mean 24.5%. The maximum bladder V50 from the non-BS group was 50.9%, mean 27.3% (P = 0.5178). Treatment data from weekly cone beam CT scans were also compared over 6 weeks. They were assessed as being a pass if bladder and bowel requirements were acceptable. The BS group proceeded to treatment on the basis of a pass 92.7% of the time, whereas the pass rate for non-BS group was 75%; difference 17.7% (P < 0.0001).

CONCLUSION

The BS is a useful tool for achieving consistent, appropriately sized bladder volumes in prostate cancer patients.

Reducing radiation-associated toxicity using online image guidance (IGRT) in prostate cancer patients undergoing dose-escalated radiation therapy

AIM

To determine the influence of IGRT in terms of toxicities compared to non-IGRT patients undergoing definitive RT.

BACKGROUND

Image-guided radiotherapy (IGRT) enables immediate correction of target movement by online imaging. For prostate cancer patients undergoing radiation therapy (RT), a geographical miss of the prostate may result in increased dose-volume effects in the rectum and bladder.

METHODS

A total of 198 prostate cancer patients treated between 2003 and 2013 were recruited randomly for this evaluation. The rates of genitourinary (GU) and gastrointestinal (GI) toxicity for 96 non-IGRT patients (total dose: 72/73.8 Gy) were compared to those for 102 IGRT patients (total dose: 77.4 Gy) according to the Common Toxicity Criteria Version 3.0 (CTCAEv3.0). Follow-up information included treatment-related symptoms and PSA relapse.

RESULTS

After a median follow-up of 55.4 months, a statistically significant difference was noted for acute GI toxicities ≥1 in favour of IGRT. Significantly more patients treated by IGRT were free of acute GI symptoms (43% vs. 19%, p = 0.0012). In the non-IGRT group, more patients experienced acute GU side effects (89% vs. 80%, p = 0.07). Late toxicity scores were comparable for both cohorts.

CONCLUSIONS

Based on the data, we demonstrated that despite dose escalation, IGRT enabled us to reduce the GI side effects of radiation. IGRT can therefore be considered to be the standard of care for dose-escalated RT of localized prostate cancer.