Bladder filling variations during concurrent chemotherapy and pelvic radiotherapy in rectal cancer patients: early experience of bladder volume assessment using ultrasound scanner

Impact of belly board immobilization devices and body mass factor on setup displacement using daily cone-beam CT in rectal cancer radiotherapy

OBJECTIVE

The objective of this study is to evaluate the impact of different belly board and daily changes in patient's body-mass factor (BMF) on setup displacement in radiotherapy for rectal cancer.

METHODS

Twenty-five patients were immobilized using the thermoplastic mask with belly board (TM-BB), and 30 used the vacuum bag cushion with belly board (VBC-BB), performing daily cone-beam computed tomography (CBCT) scans 625 times and 750 times, respectively. Daily pretreatment CBCT scans were registered to the planned CT images for BMF change determination and setup displacement measurement. Independent t-tests compared setup displacement between the two groups in left-right (LR), superior-inferior (SI), and anterior-posterior (AP) directions, as well as the BMF changes. The impact of daily BMF changes on setup displacement was evaluated using multivariate logistic regression and 10-fold cross-validation.

RESULTS

The setup displacement for TM-BB in the LR, SI, and AP directions were 0.31 ± 0.25, 0.58 ± 0.40, and 0.19 ± 0.18 cm, respectively, while VBC-BB showed 0.19 ± 0.15, 0.26 ± 0.22, and 0.36 ± 0.29 cm in the corresponding directions, respectively. Margins of planning target volume (PTV) for TM-BB were 8, 10, and 6 mm in LR, SI, and AP directions, while VBC-BB showed margins of 5,7, and 8 mm, respectively. The daily BMF changes for both groups were ranked in descending order as follows: sacral rotation angle (RS), hip lateral diameter (HLD), and hip anterior-posterior diameter (HAPD). HAPD was the main factor affecting setup displacement in both the AP and SI directions in TM-BB, while RS was the primary factor for setup displacement in the AP direction in VBC-BB.

CONCLUSION

Compared with TM-BB, VBC-BB had a larger AP displacement but smaller in LR and SI displacement. Daily changes in BMF have distinct effects on setup displacement in different immobilization devices. Image-guided radiation therapy (IGRT) is highly recommended and BMF changes should be given consideration during radiotherapy.

Impact of bladder size and shape on the accuracy of formula method for bladder volume evaluation

BACKGROUND

To explore the impact of bladder size and shape on the accuracy of the formula method (V = 0.52 × d1 × d2 × d3) for bladder volume evaluation.

METHODS

Data was retrospectively collected from 220 patients without reportable bladder diseases. CT images were imported into 3D Slicer software to measure the bladder volume VA (reference standards). Bladder volume was also measured by the formula method VB = 0.52 × d1 × d2 × d3. Results of these two methods were compared based on bladder size and shape.

RESULTS

The bldder volume was 121.0 ± 83.6 mL with the formula method, compared with 128.5 ± 82.6 mL measured by 3D Slicer (P < 0.0001). Patients were divided into three groups based on bladder size, the mean percent deviations between the two methods were 18.8 ± 20.8%, 3.4 ± 12.9% and 4.6 ± 10.6%, respectively. According to the bladder shape, it can be divided into 5 types. For round and triangle shapes, there was no significant statistical difference in the results of the two methods. For bladder shapes with ellipse, rectangle and irregular shape, the volume evaluated by the formula method was statistically lower. Their deviations were 9.7 ± 17.5%, 12.9 ± 9.6% and 14.4 ± 21.2%, respectively.

CONCLUSION

The accuracy of the formula method for estimating bladder volume is affected by bladder size and shape. Overall, the formula method tends to underestimate the bladder volume. The error of small-sized bladders is much greater than that of large-sized bladders. Furthermore, the formula method has high accuracy in measuring bladder volume with round and triangle shapes.

Comparative Analysis of Bladder Volume Consistency Using Portable Ultrasound Scanners and Biofeedback in Radiotherapy for Pelvic Tumors

PurposeTo evaluate the accuracy of two bladder scanners (BS) in measuring bladder volume (BV) during radiotherapy (RT), and explore the influence of two bladder filling methods and patients' subjective urinary sensation on the consistency of BV.MethodsForty-two patients with pelvic tumors were divided into two groups: Group A (20 patients) and Group B (22 patients). Before the planning CT and each treatment session, all patients drank 500 mL of water after emptying their bladder and rectum. Group A waited for patients to provide feedback on urination, while Group B waited for 1 h. Subsequently, three consecutive measurements using two BSs were performed. The average volumes measured by the BS Padscan HD5 and Padscan HDW1 were recorded as BSHD5-v and BSHDW1-v, respectively. The differences between BSHD5-v, BSHDW1-v, and the BV obtained from planning CT (CT-v) or cone beam CT (CBCT) (CBCT-v) were assessed. The consistency between CBCT-v and CT-v in two patient groups was calculated. Urinary sensation score BV (VSC) was determined by the patient's urge to urinate score and CT-v.ResultsThe average CT-v or CBCT-v was 280 mL (range 78-710 mL, SD = 119 mL). BSHD5-v had an average of 271 mL (range 61-611 mL, SD = 115 mL), with a significant correlation with CT-v or CBCT-v (R = 0.89, p < 0.001). BSHDW1-v averaged 267 mL (range 92-634 mL, SD = 77 mL), positively correlated with CT-v or CBCT-v (R = 0.70, p < 0.001). Group A's CBCT-v proportions within ±20%, ± 30%, and ±50% of CT-v were 51.20%, 66.90%, and 91.90%, respectively, contrasting with Group B's 26.2%, 41.1%, and 67.7%. VSC exhibited a positive association with CBCT-v (R = 0.59, p < 0.001).ConclusionsConsistent and reproducible bladder volume was obtained by using Padscan HD5 and Padscan HDW1. The Padscan HD5 demonstrated greater consistency and accuracy. Furthermore, the urinary feedback method has a more consistent bladder volume than the fixed-time method.

Individual lymph node position variation for rectal cancer patients treated with long course chemoradiotherapy

Background and purpose

Delivery of high precision radiotherapy lymph node boosts requires detailed information on the interfraction positional variation of individual lymph nodes. In this study we characterized interfraction positional shifts of suspected malignant lymph nodes for rectal cancer patients receiving long course radiotherapy. Furthermore, we investigated parameters which could affect the magnitude of the position variation.

Materials and Methods

Fourteen patients from a prospective clinical imaging study with a total of 61 suspected malignant lymph nodes in the mesorectum, presacral, and lateral regions, were included. The primary gross tumor volume (GTVp) and all suspected malignant lymph nodes were delineated on six magnetic resonance imaging scans per patient. Positional variation was calculated as systematic and random errors, based on shifts of center-of-mass, and estimated relative to either bony structures or the GTVp using a hierarchical linear mixed model.

Results

Depending on location and direction, systematic and random variations (relative to bony structures) were within 0.6-2.8 mm and 0.6-2.9 mm, respectively. Systematic and random variations increased when evaluating position relative to GTVp (median increase of 0.6 mm and 0.5 mm, respectively). Correlations with scan time-point and relative bladder volume were found in some directions.

Conclusions

Using linear mixed modeling, we estimated systematic and random positional variation for suspected malignant lymph nodes in rectal cancer patients treated with long course radiotherapy. Statistically significant correlations of the magnitude of the lymph node shifts were found related to scan time-point and relative bladder volume.

Pretreatment MRI-detected extramural venous invasion as a prognostic and predictive biomarker for neoadjuvant chemoradiotherapy in non-metastatic rectal cancer: a propensity score matched analysis

OBJECTIVES

This study evaluated pretreatment magnetic resonance imaging (MRI)-detected extramural venous invasion (pmrEMVI) as a predictor of survival after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

Medical records of 1184 patients with rectal adenocarcinoma who underwent TME between January 2011 and December 2016 were reviewed. MRI data were collected from a computerized radiologic database. Cox proportional hazards analysis was used to assess local, systemic recurrence, and disease-free survival risk based on pretreatment MRI-assessed tumor characteristics. After propensity score matching (PSM) for pretreatment MRI features, nCRT therapeutic outcomes according to pmrEMVI status were evaluated. Cox proportional hazards analysis was used to identify risk factors for early recurrence in patients receiving nCRT.

RESULTS

Median follow-up was 62.8 months. Among all patients, the presence of pmrEMVI was significantly associated with worse disease-free survival (DFS; HR 1.827, 95% CI 1.285-2.597, p = 0.001) and systemic recurrence (HR 2.080, 95% CI 1.400-3.090, p < 0.001) but not local recurrence. Among patients with pmrEMVI, nCRT provided no benefit for oncological outcomes before or after PSM. Furthermore, pmrEMVI( +) was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

CONCLUSIONS

pmrEMVI is a poor prognostic factor for DFS and SR in patients with non-metastatic rectal cancer and also serves as a predictive biomarker of poor DFS and SR following nCRT in LARC. Therefore, for patients who are positive for pmrEMVI, consideration of alternative treatment strategies may be warranted.

CLINICAL RELEVANCE STATEMENT

This study demonstrated the usefulness of pmrEMVI as a predictive biomarker for nCRT, which may assist in initial treatment decision-making in patients with non-metastatic rectal cancer.

KEY POINTS

• Pretreatment MRI-detected extramural venous invasion (pmrEMVI) was significantly associated with worse disease-free survival and systemic recurrence in patients with non-metastatic rectal cancer. • pmrEMVI is a predictive biomarker of poor DFS following nCRT in patients with LARC. • The presence of pmrEMVI was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

A prospective comparative study on bladder volume measurement with portable ultrasound scanner and CT simulator in pelvic tumor radiotherapy

OBJECTIVE

The consistency of bladder volume is very important in pelvic tumor radiotherapy, and portable bladder scanner is a promising device to measure bladder volume. The purpose of this study was to investigate whether the bladder volume of patients with pelvic tumor treated with radiotherapy can be accurately measured using the Meike Palm Bladder Scanner PBSV3.2 manufactured in China and the accuracy of its measurement under different influencing factors.

METHODS

A total of 165 patients with pelvic tumor undergoing radiotherapy were prospectively collected. The bladder volume was measured with PBSV3.2 before simulated localization. CT simulated localization was performed when the bladder volume was 200-400ml. The bladder volume was measured with PBSV3.2 immediately after localization and recorded. The bladder volume was then delineated on CT simulation images and recorded. To compare the consistency of CT simulation bladder volume and bladder volume measured by PBSV3.2. To investigate the accuracy of PBSV3.2 in different sex, age, treatment purpose, and bladder volume.

RESULTS

There was a significant positive correlation with bladder volume on CT and PBSV3.2 (r = 0.874; p < 0.001). The mean difference between CT measured values and PBSV3.2 was (-0.14 ± 50.17) ml. The results of the different variables showed that the overall mean of PBSV3.2 and CT measurements were statistically different in the age ≥ 65 years, bladder volumes > 400ml and ≤ 400ml groups (p = 0.028, 0.002, 0.001). There was no statistical significance between the remaining variables. The volume difference between PBSV3.2 measurement and CT was 12.87ml in male patients, which was larger than that in female patients 3.27ml. Pearson correlation analysis showed that the correlation coefficient was 0.473 for bladder volume greater than 400ml and 0.868 for bladder volume less than 400ml; the correlation coefficient of the other variables ranged from 0.802 to 0.893.

CONCLUSION

This is the first large-sample study to evaluate the accuracy of PBSV3.2 in a pelvic tumor radiotherapy population using the convenient bladder scanner PBSV3.2 made in China. PBSV3.2 provides an acceptable indicator for monitoring bladder volume in patients with pelvic radiotherapy. It is recommended to monitor bladder volume with PBSV3.2 when the planned bladder volume is 200-400ml. For male and patients ≥ 65 years old, at least two repeat measurements are required when using a bladder scanner and the volume should be corrected by using a modified feature to improve bladder volume consistency.

Evaluation of dosimetric predictors of toxicity after IMRT with concurrent chemotherapy for anal cancer

BACKGROUND

This study investigates the impact of dosimetric parameters on acute and late toxicity for patients with anal squamous cell carcinoma (SCC) treated with image-guided intensity modulated radiation therapy (IG-IMRT) and concurrent chemotherapy.

MATERIALS AND METHODS

Patients were enrolled in an observational cohort study between 2008 and 2013 (median follow-up 3.4 years). They were treated with standardized target and organ-at-risk (OAR) contouring, planning, and IG-IMRT. Radiotherapy dose, based on clinicopathologic features, ranged from 45 Gy to 63 Gy to gross targets and 27 Gy to 36 Gy to elective targets. Chemotherapy was concurrent 5-fluorouracil and mitomycin C (weeks 1&5). Toxicity was prospectively graded using NCI CTCAE v.3 and RTOG scales. Logistic regression was used to assess the association between dose/volume parameters (e.g small bowel V5) and corresponding grade 2 + and 3+ (G2+/3 + ) toxicities (e.g. diarrhea).

RESULTS

In total, 87 and 79 patients were included in the acute and late toxicity analyses, respectively. The most common acute G2 + toxicities were skin (dermatitis in 87 % [inguino-genital skin], 91 % [perianal skin]) and hematologic in 58 %. G2 + late anal toxicity (sphincter dysfunction), gastrointestinal toxicity, and skin toxicity were respectively experienced by 49 %, 38 %, and 44 % of patients. Statistically significant associations were observed between: G2 + acute diarrhea and small bowel V35; G2 + acute genitourinary toxicity and bladder D_0.5cc; G2 + inguino-genital skin toxicity and anterior skin V35; G2 + perianal skin toxicity and posterior skin V15; G2 + anemia and lower pelvis bone V45. D0.5 cc was significantly predictive of late toxicity (G2 + anal dysfunction, intestinal toxicity, and inguino-genital/perianal dermatitis). Maximum skin toxicity grade was significantly correlated with the requirement for a treatment break.

CONCLUSION

Statistically significant dose-volume parameters were identified and may be used to offer individualized risk prediction and to inform treatment planning. Additional validation of the results is required.

Can portable ultrasound bladder scanner be applied to young children less than three years old?

INTRODUCTION

The bladder scanner (BS), a portable ultrasound device specialized in bladder volume measurement, has been developed and applied to clinical assessment of postvoid residual urine, which is a requisite in evaluating patients with voiding dysfunction. However, experiences in the application of the BS to the pediatric population remain limited despite commonly encountered reluctance to catheterization. This prospective observational study aimed to evaluate the correlation and accuracy of the newly developed pediatric module of the BS (BioCon-900) in measuring bladder volume in children 0-6 years old.

MATERIALS AND METHODS

This study included 29 patients scheduled to undergo preventive untethering for their spinal dysraphism. When they undergo cystometry for the confirmation of normal neurologic function, bladder volume was measured by BS when recorded volume infusion reached each quartile of the age-adjusted estimated bladder capacity (EBC). The difference (bias) between measured and infused volume was expressed as a percentage of EBC (%EBC). The correlation coefficient and the Bland-Altman plot were obtained to determine the discriminating power and accuracy, respectively. The acceptable limit was set as 30%EBC.

RESULTS

A strong correlation between the measured and infused volume (r = 0.95, P < 0.001) was found for the entire age range. This excellent correlation remained comparable between children less than three years and the older ones. Bladder volume tended to be overestimated, and the mean bias was 33 ± 22.3%EBC, and it became higher with increasing quartiles. The accuracy was acceptable in all ranges of measurement in the older group and first and second quartiles in the younger one.

DISCUSSION

We have first evaluated the potential use of BS in 0-3 years old children and compared the results with 4-6-year-old children in whom the accuracy of BS has been demonstrated. The strong point of our study was the inclusion of data spanning all quartiles of bladder volume. The use of infused volume as reference enabled us to assess the accuracy in a more precise way than the use of ultrasound. Despite the good discriminating power, the accuracy was not acceptable in higher quartiles in the younger group. If the trend of overestimation especially higher volume, could be understood prior to measurement, it would be helpful to assume the real val.

CONCLUSIONS

The children's module in BS showed excellent discriminating power and generally acceptable accuracy in more than four-year-old children. This may lose accuracy in higher quartiles among less than three years old children.

Assessment of an ultrasound bladder scanner in prostate radiotherapy: A validation study and analysis of bladder filling variability

INTRODUCTION

During prostate radiotherapy treatment, it is important to ensure the position of the bladder and prostate is consistent between treatments. The aim of this study was to provide a quantitative basis for incorporating ultrasound bladder volume estimates into local practice for prostate radiotherapy.

METHODS

Agreement between bladder volume estimates obtained using computed tomography (CT) and ultrasound was assessed. Analysis of bladder volumes between planning and treatment scans was used to quantify expected variations in bladder volume over the course of radiotherapy. Dose-volume statistics were estimated and compared to planned dose constraints to propose a target bladder volume and tolerance.

RESULTS

Bladder volume measurements were obtained from 19 radiotherapy patients using ultrasound and CT. Ultrasound underestimated bladder volume compared to CT with a mean bias of -28 ± 30 ml. Pre-treatment (planning) bladder volumes varied from 71 to 383 ml with a mean of 200 ml. Treatment bladder volumes reduced by more than half in 9% of patients during the course of their treatment, potentially leading to a 30% increase in mean bladder dose. Patients with pre-treatment bladder volumes < 200 ml were most likely to exhibit differences in bladder volume, resulting in 'out of tolerance' increases in dose.

CONCLUSIONS

A pragmatic individualised drinking protocol, aimed at achieving a minimum ultrasound bladder volume of 200 ml at planning CT, may be beneficial to reproducibility in radiotherapy treatment. Ultrasound measurements prior to treatment should ideally confirm that bladder volume is at least half the volume measured at planning.

Simple calculation using anatomical features on pre-treatment verification CT for bladder volume estimation during radiation therapy for rectal cancer

Background

Despite detailed instruction for full bladder, patients are unable to maintain consistent bladder filling during a 5-week pelvic radiation therapy (RT) course. We investigated the best bladder volume estimation procedure for verifying consistent bladder volume.

Methods

We reviewed 462 patients who underwent pelvic RT. Biofeedback using a bladder scanner was conducted before simulation and during treatment. Exact bladder volume was calculated by bladder inner wall contour based on CT images (V_ctsim). Bladder volume was estimated either by bladder scanner (V_scan) or anatomical features from the presacral promontory to the bladder base and dome in the sagittal plane of CT (V_ratio). The feasibility of V_ratio was validated using daily megavoltage or kV cone-beam CT before treatment.

Results

Mean V_ctsim was 335.6 ± 147.5 cc. Despite a positive correlation between V_ctsim and V_scan (R² = 0.278) and between V_ctsim and V_ratio (R² = 0.424), V_ratio yielded more consistent results than V_scan, with a mean percentage error of 26.3 (SD 19.6, p < 0.001). The correlation between V_ratio and V_ctsim was stronger than that between V_scan and V_ctsim (Z-score: − 7.782, p < 0.001). An accuracy of V_ratio was consistent in megavoltage or kV cone-beam CT during treatment. In a representative case, we can dichotomize for clinical scenarios with or without bowel displacement, using a ratio of 0.8 resulting in significant changes in bowel volume exposed to low radiation doses.

Conclusions

Bladder volume estimation using personalized anatomical features based on pre-treatment verification CT images was useful and more accurate than physician-dependent bladder scanners.

Trial registration

Retrospectively registered.

[Individual control of urine volume to improve stability of bladder volume in radiotherapy of urinary tumor]

OBJECTIVE

To explore the training mode of individual urine volume control, to take indi-vidual expected urine volume as the goal of bladder control in patients with urinary system tumors, and to improve the accuracy of bladder control during radiotherapy by active training of bladder receptivity.

METHODS

Twenty-five patients of urinary system tumors were enrolled from May 2019 to September 2019, of whom, 21 patients had prostate cancer, and 4 had bladder cancer. Training of bladder filling started before CT simulation. The patients were required to take the individual bladder filling as the training goal, and the optimal bladder volume range was suggested to be 200－400 mL. After 2－4 weeks of training, the prescribed volume of the bladder was determined according to the patient's bladder receptivity. The volume of the bladder was measured by images of plain CT and images 8-minutes after intravenous contrast injection. The patient's bladder volume was measured using BladderScan before treatment. CBCT (Cone-beam CT) was performed, and bladder volume was measured before treatment. The bladder volume was measured again using BladderScan after treatment.

RESULTS

The mean bladder volume of simulation (V_CT01) was (262±130) mL, ranging from 78 mL to 505 mL. The mean self-evaluation bladder volume before radiotherapy (V_EVA01) was (238±107) mL, ranging from 100 mL to 400 mL. The mean BladderScan measured volume before radiotherapy (V_BVI01) was (253±123) mL, ranging from 60 mL to 476 mL. The mean cone-beam CT measured volume before radiotherapy (V_CBCT) was (270±120) mL, ranging from 104 mL to 513 mL. There was a correlation between V_EVA01 and V_BVI01, V_CT01 and V_BVI01, V_CT01, and V_BVI01, and there was no significant difference in paired t-test. There was a correlation between differences of self-evaluation bladder volume before radiotherapy(V_EVA01) and simulation CT (V_CT01) and differences of self-evaluation bladder volume before radiotherapy (V_EVA01) and cone-beam CT (V_CBCT), and there was no significant difference in paired samples by t-test.

CONCLUSION

During radiotherapy for urinary system tumors, such as prostate cancer and bladder cancer, with the assistance of BladderScan, the patients could try to hold their urine moderately according to their conditions, and individualized bladder prescription may be beneficial to achieve stable bladder volume during radiotherapy.

Unforeseen Computed Tomography Resimulation for Initial Radiation Planning: Associated Factors and Clinical Impact

Purpose

Repeat computed tomography (CT) simulation is problematic because of additional expense of clinic resources, patient inconvenience, additional radiation exposure, and treatment delay. We investigated the factors and clinical impact of unplanned CT resimulations in our network.

Methods and Materials

We used the billing records of 18,170 patients treated at 5 clinics. A total of 213 patients were resimulated before their first treatment. The disease site, location, use of 4-dimensional CT (4DCT), contrast, image fusion, and cause for resimulation were recorded. Odds ratios determined statistical significance.

Results

Our total rate of resimulation was 1.2%. Anal/colorectal (P < .001) and head and neck (P < .001) disease sites had higher rates of resimulation. Brain (P = .001) and lung/thorax (P = .008) had lower rates of resimulation. The most common causes for resimulation were setup change (11.7%), change in patient anatomy (9.8%), and rectal filling (8.5%). The resimulation rate for 4DCTs was 3.03% compared with 1.0% for non-4DCTs (P < .001). Median time between simulations was 7 days.

Conclusions

The most common sites for resimulation were anal/colorectal and head and neck, largely because of change in setup or changes in anatomy. The 4DCT technique correlated with higher resimulation rates. The resimulation rate was 1.2%, and median treatment delay was 7 days. Further studies are warranted to limit the rate of resimulation.

Effects of bladder shape on accuracy of measurement of bladder volume using portable ultrasound scanner and development of correction method

AIMS

To compare the accuracy of using a bladder scanner to measure bladder volume through intermittent catheterization (IC) in patients and to introduce the Bladder Deformation Index (BDI) to develop a correction method.

METHODS

Bladder volume was assessed by a nurse with the scanner. A second nurse catheterized the patient's bladder. A third nurse measured the urine volume in a 500-mL or 1000-mL graduated cylinder.

RESULTS

Sixty one patients were included and 590 pairs of data were obtained. The mean bladder volume measured using a scanner and IC was (332.3 ± 156.1) mL and (339.1 ± 158.8) mL. The mean absolute difference was 30.8 mL. The correlation coefficient was 0.929. Patients were classified into 2 groups depending on whether they had undergone augmentation cystoplasty. The mean absolute difference was 109.2 and 20.4 mL. The correlation coefficient was 0.712 and 0.981. According to the BDI, bladders can be classified into 3 groups. The mean absolute difference was 21.9, 60.4, and 109.4 mL. The correlation coefficient was 0.970, 0.839, and 0.783. The linear regression equations of Grade I and Grade II were Y = 1.11X + 3.1 and Y = 0.76X + 161.5.

CONCLUSIONS

The results showed that bladder shape plays a critical role in accuracy which is inversely associated with BDI. This degree of accuracy is sufficient; especially measurement adjusted using the linear regression equation in patients with high BDI. However, although the preliminary results of the study are promising, a large-scale prospective study should be needed to address the validation of the data in the future.

Assessment of inter- and intra-fractional volume of bladder and body contour by mega-voltage computed tomography in helical tomotherapy for pelvic malignancy

Purpose

We describe the daily bladder volume change observed by mega-voltage computed tomography (MVCT) during pelvic radiotherapy with potential predictors of increased bladder volume variations.

Materials and Methods

For 41 patients who received pelvic area irradiation, the volumes of bladder and pelvic body contour were measured twice a day with pre- and post-irradiation MVCT from the 1st to the 10th fraction. The median prescription dose was 20 Gy (range, 18 to 30 Gy) up to a 10th fraction. The upper and lower margin of MVCT scanning was consistent during the daily treatments. The median age was 69 years (range, 33 to 86 years) and 10 patients (24.4%) were treated postoperatively.

Results

Overall bladder volume on planning computed tomography was 139.7 ± 92.8 mL. Generally, post-irradiation bladder volume (POSTBV) was larger than pre-irradiation bladder volume (PREBV) (p < 0.001). The mean PREBV and POSTBV was reduced after 10 fraction treatments by 21.3% (p = 0.028) and 25.4% (p = 0.007), respectively. The MVCT-scanned body contour volumes had a tendency to decrease as the treatment sessions progressed (p = 0.043 at the 8th fraction and p = 0.044 at the 10th fraction). There was a statistically significant correlation between bladder filling time and PREBV (p = 0.001).

Conclusion

Daily MVCT-based bladder volume assessment was feasible both intra- and inter-fractionally.

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.

Transabdominal Ultrasonography-Defined Optimal and Definitive Bladder-Filling Protocol With Time Trends During Pelvic Radiation for Cervical Cancer

Purpose:

Advanced radiotherapy techniques have emphasized on the importance of accurate target volume localization and delineation. The aim of this study was to determine time taken to achieve moderate bladder volume under physiological conditions, using transabdominal ultrasound.

Materials and Methods:

Patients with cervical cancer undergoing radical radiation with or without concomitant chemotherapy underwent serial ultrasound to estimate bladder filling. With a strict bladder protocol of consuming 1000 mL of water orally over 30 minutes after emptying the bladder, ultrasound was done after 45 minutes from bladder emptying time and repeated at 15-minute interval till 300 (25) mL filling was achieved and repeated every week.

Results:

Forty-six patients with weekly ultrasound for bladder-filling documentation were evaluated. The mean (standard deviation) bladder volume measured at 45 minutes was 220 (93), 210 (95), 195 (91), 195 (96), and 190 (85) mL (average: 200; median: 195 mL) for the first to fifth week, respectively, and the mean (standard deviation) volume at 75 minutes was 300 (95), 310 (80), 290 (80), 295 (80), and 285 (70) mL (average: 295; median: 300 mL). The mean (standard deviation) time for bladder filling to 300 mL in the first, second, third, fourth, and fifth week was 57 ( 13.5), 67 (16.6), 66 (16.7), 66 (15.5), and 69 (17.1) minutes, respectively.

Conclusion:

Bladder filling to a definitive moderate volume at a reasonably fixed time period in each week of radiation is well tolerated, feasible, and measurable by weekly transabdominal ultrasound measurements.

Reduced pelvic field sparing anastomosis for postoperative radiotherapy in selected patients with mid-upper rectal cancer

The aim of this study was to report the clinical results of reduced pelvic field radiotherapy (RT), excluding the anastomotic site, after total mesorectal excision in selected patients with rectal cancer. Between 2011 and 2014, 99 patients underwent upfront surgery for clinically less-advanced tumors but were finally diagnosed as pT3/N+. Among them, 50 patients with mid-upper rectal cancer who received postoperative RT with a reduced pelvic field were included in this retrospective review. This group was composed of patients with high seated tumors, complete resection with a clear circumferential resection margin, and no complication during surgery. We investigated treatment outcomes, toxicity and the effect of RT-field reduction on organs-at risk in 5 randomly selected patients. During the median follow-up period of 42 months (range: 15-59 months), tumors recurred in 9 patients (18%). The 3-year overall and disease-free survival were 98% and 81%, respectively. Distant metastasis was the dominant failure pattern (n = 8, 16%), while no recurrences occurred at or near anastomotic sites. No anastomotic complications were found on pelvic examination, images and/or colonoscopy. Reported acute and late RT-related toxicities were mostly mild to moderate, with only small numbers of Grade 3 toxicities. None of the patients developed Grade 4-5 acute or late toxicity. With a caudally reduced field, 64% reduction in absolute anastomotic exposure at the maximum dose was achieved compared with the traditional whole-pelvic field (P = 0.008). The reduced pelvic field RT was able to minimize late anastomotic complication without increasing its recurrence in selected patients with mid-upper rectal cancer in the postoperative setting.

Implementation of ultrasound bladder volume scanning for patients receiving intensity-modulated radiotherapy to the cervix or endometrium: clinical experiences from a United Kingdom radiotherapy department

Background and purpose

Achieving daily consistent bladder volume is acknowledged as challenging for patients undergoing radiotherapy to the cervix or endometrium. We investigated if use of an ultrasound bladder volume scanner (BioCon-700) improves bladder reproducibility when used during an active volume correction protocol.

Materials and methods

During our method-comparison study, prospectively recruited patients (n=20) followed a fluid-loading protocol to achieve acceptable bladder volume. Bladder ultrasound was performed daily to verify planned volume, with patients actively correcting volumes outside a planned range up to a maximum of three times. Using the Bland–Altman method, we compared mean ultrasound readings (USMean) with mean cone-beam computed tomography (CBCT) volumes (CBCTMean). We also conducted staff focus groups exploring issues encountered during implementation of bladder scanning.

Results

Comparing USMean with CBCTMean produced a mean of the differences −10±49·92 mL (1 SD), demonstrating that bladder volume scanning is equivalent to our standard measure for the stated confidence levels. The cohort mean bladder volume decrease from week 1 to 5 was only 8·4%. Mean USMean was 323 mL, mean CBCTMean was 313 mL. Staff experience with the scanner overall was positive.

Conclusions

The BioCon-700 is suitable for the purpose of daily pre-treatment volume verification, facilitating daily assessment and modification of bladder volume, resulting in reproducible treatment volumes.

Bag and loop small bowel contouring strategies differentially estimate small bowel dose for post-hysterectomy women receiving pencil beam scanning proton therapy

Background Small bowel (SB) dose-volume relationships established during initial computed tomography (CT) simulations may change throughout therapy due to organ displacement and motion. We investigated the impact of organ motion on SB dose-volume histograms (DVHs) in women with gynecologic malignancies treated with pencil beam scanning (PBS) proton therapy and compared PBS SB DVHs to intensity-modulated radiation therapy (IMRT). Material and methods Post-hysterectomy patients (n = 11) treated for gynecologic cancers were enrolled on an image-guided proton therapy protocol involving CT simulation with full (CTF) and empty (CTE) bladders and weekly/biweekly on-treatment scans. IMRT plans were generated for comparative analysis. SB was contoured as bowel loops or bowel bag. Wilcoxon signed-rank tests were used for matched-pair comparisons of SB, bladder, and rectum dose-volumes between CT scans and between PBS and IMRT plans. Results In PBS loops analysis, on-treatment DVH was significantly higher than CTF for doses <45 Gy (p < 0.05), and not significantly different than CTE. Specifically, V15 for loops was higher on-treatment (median 240 cm(3)) compared to CTF (median 169 cm(3), p = 0.03). In PBS bag analysis, on-treatment DVH was not significantly different from CTF across all dose ranges. Bowel bag V45 was not significantly different between on-treatment (median 540 cm(3)) and CTF (median 499 cm(3), p = 0.53). Decreasing bladder volume was associated with increasing V15 for loops and V45 for bowel bag (p < 0.005, both). Comparing PBS and IMRT, PBS resulted in significantly lower DVHs at low dose regions (<38 Gy) and higher DVHs at high dose regions (42.5-45.5 Gy) in both loops and bag analysis. IMRT plans demonstrated higher on-treatment SB loop DVHs and only minimal differences in bowel bag DVHs compared to CTF. Conclusions SB DVHs were well estimated by CTF bowel bag and underestimated by CTF loops in the setting of inconsistent bladder filling. Verifying bladder filling prior to treatment or using CTE for planning may more conservatively estimate SB dose-volume relationships.

Circumferential resection margin positivity after preoperative chemoradiotherapy based on magnetic resonance imaging for locally advanced rectal cancer: implication of boost radiotherapy to the involved mesorectal fascia

OBJECTIVE

To identify patients who are at a higher risk of pathologic circumferential resection margin involvement using preoperative magnetic resonance imaging.

METHODS

Between October 2008 and November 2012, 165 patients with locally advanced rectal cancer (cT4 or cT3 with <2 mm distance from tumour to mesorectal fascia) who received preoperative chemoradiotherapy were analysed. The morphologic patterns on post-chemoradiotherapy magnetic resonance imaging were categorized into five patterns from Pattern A (most-likely negative pathologic circumferential resection margin) to Pattern E (most-likely positive pathologic circumferential resection margin). In addition, the location of mesorectal fascia involvement was classified as lateral, posterior and anterior. The diagnostic accuracy of the morphologic criteria was calculated using receiver operating characteristic curve analysis.

RESULTS

Pathologic circumferential resection margin involvement was identified in 17 patients (10.3%). The diagnostic accuracy of predicting pathologic circumferential resection margin involvement was 0.73 using the five-scale magnetic resonance imaging pattern. The sensitivity, specificity, positive predictive value and negative predictive value for predicting pathologic circumferential resection margin involvement were 76.5, 65.5, 20.3 and 96.0%, respectively, when cut-off was set between Patterns C and D. On multivariate logistic regression, the magnetic resonance imaging patterns D and E (P= 0.005) and posterior or lateral mesorectal fascia involvement (P= 0.017) were independently associated with increased probability of pathologic circumferential resection margin involvement. The rate of pathologic circumferential resection margin involvement was 30.0% when the patient had Pattern D or E with posterior or lateral mesorectal fascia involvement.

CONCLUSIONS

Patients who are at a higher risk of pathologic circumferential resection margin involvement can be identified using preoperative magnetic resonance imaging although the predictability is moderate.

Morphologic change of rectosigmoid colon using belly board and distended bladder protocol

Purpose

This study investigates morphologic change of the rectosigmoid colon using a belly board in prone position and distended bladder in patients with rectal cancer. We evaluate the possibility of excluding the proximal margin of anastomosis from the radiation field by straightening the rectosigmoid colon.

Materials and Methods

Nineteen patients who received preoperative radiotherapy between 2006 and 2009 underwent simulation in a prone position (group A). These patients were compared to 19 patients treated using a belly board in prone position and a distended bladder protocol (group B). Rectosigmoid colon in the pelvic cavity was delineated on planning computed tomography (CT) images. A total dose of 45 Gy was planned for the whole pelvic field with superior margin of the sacral promontory. The volume and redundancy of rectosigmoid colon was assessed.

Results

Patients in group B had straighter rectosigmoid colons than those in group A (no redundancy; group A vs. group B, 10% vs. 42%; p = 0.03). The volume of rectosigmoid colon in the radiation field was significantly larger in group A (56.7 vs. 49.1 mL; p = 0.009). In dose volume histogram analysis, the mean irradiated volume was lower in patients in group B (V45 27.2 vs. 18.2 mL; p = 0.004). In Pearson correlation coefficient analysis, the in-field volume of rectosigmoid colon was significantly correlated with the bladder volume (R = 0.86, p = 0.003).

Conclusion

Use of a belly board and distended bladder protocol could contribute to exclusion of the proximal margin of anastomosis from the radiation field.

Evaluating Variations of Bladder Volume Using an Ultrasound Scanner in Rectal Cancer Patients during Chemoradiation: Is Protocol-Based Full Bladder Maintenance Using a Bladder Scanner Useful to Maintain the Bladder Volume?

PURPOSE

The maintenance of full bladder is important to reduce radiation-induced toxicities and maintain the therapeutic consistency in locally advanced rectal cancer patients who underwent radiotherapy (RT). So, the aim of this study was to evaluate the effectiveness of protocol-based full bladder maintenance by assessing bladder volume variation using an ultrasound bladder scanner to maintain bladder volume.

MATERIALS AND METHODS

From March 2011 to May 2011, twenty consecutive rectal cancer patients receiving external beam RT participated in this prospective study. Protocol-based full bladder maintenance consisted of education, training and continuous biofeedback by measuring bladder volume. Bladder volume was measured by bladder scan immediately before simulation CT scan and before each treatment three times weekly during the RT period. The relative bladder volume change was calculated. Intra-patient bladder volume variations were quantified using interquartile range (IQR) of relative bladder volume change in each patient. We compared intra-patient bladder volume variations obtained (n=20) with data from our previous study patients (n=20) performing self-controlled maintenance without protocol.

RESULTS

Bladder volumes measured by bladder scan highly correlated with those on simulation CT scan (R=0.87, p<0.001). Patients from this study showed lower median IQR of relative bladder volume change compared to patients of self-controlled maintenance from our previous study, although it was not statistically significant (median 32.56% vs. 42.19%, p=0.058). Upon logistic regression, the IQR of relative bladder volume change was significantly related to protocol-based maintenance [relative risk 1.045, 95% confidence intervals (CI) 1.004-1.087, p=0.033]. Protocol-based maintenance included significantly more patients with an IQR of relative bladder volume change less than 37% than self-controlled maintenance (p=0.025).

CONCLUSION

Our findings show that bladder volume could be maintained more consistently during RT by protocol-based management using a bladder scan.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Review of ultrasound image guidance in external beam radiotherapy: I. Treatment planning and inter-fraction motion management

In modern radiotherapy, verification of the treatment to ensure the target receives the prescribed dose and normal tissues are optimally spared has become essential. Several forms of image guidance are available for this purpose. The most commonly used forms of image guidance are based on kilovolt or megavolt x-ray imaging. Image guidance can also be performed with non-harmful ultrasound (US) waves. This increasingly used technique has the potential to offer both anatomical and functional information.This review presents an overview of the historical and current use of two-dimensional and three-dimensional US imaging for treatment verification in radiotherapy. The US technology and the implementation in the radiotherapy workflow are described. The use of US guidance in the treatment planning process is discussed. The role of US technology in inter-fraction motion monitoring and management is explained, and clinical studies of applications in areas such as the pelvis, abdomen and breast are reviewed. A companion review paper (O'Shea et al 2015 Phys. Med. Biol. submitted) will extensively discuss the use of US imaging for intra-fraction motion quantification and novel applications of US technology to RT.

Two-week course of preoperative chemoradiotherapy followed by delayed surgery for rectal cancer: a phase II multi-institutional clinical trial (KROG 11-02)

PURPOSE

The aim of this study was to evaluate the efficacy and safety of a two-week schedule of radiotherapy with oral capecitabine in locally advanced rectal cancer.

METHODS AND MATERIALS

Eighty patients with rectal cancer located in the mid to low rectum, staged cT3-4N0-2M0, were prospectively enrolled. They underwent preoperative chemoradiotherapy and delayed surgery 6-8 weeks after the completion of radiation therapy. A radiation dose of 33 Gy in 10 fractions was delivered to the pelvis for 2 weeks. One cycle of oral capecitabine was administered at a dose of 1650 mg/m(2)/day during radiotherapy. Tumor response and toxicity were the study endpoints. This study was registered at ClinicalTrials.gov (number, NCT01431599).

RESULTS

All included patients underwent total mesorectal excisions including 12 cases of robot assisted surgery and 50 cases of laparoscopic surgery. Of the 80 patients, 27 (33.8%) achieved downstaging (ypT0-2N0) of a rectal tumor and 11 (13.8%) had a pathologically complete response (ypCR). Downstaging rates were 45% for T classification and 65% for N classification. Sphincter saving was achieved in 73 (91.3%) of the 80 patients. Of the 80 patients, 3 (3.8%) experienced grade 3 hematologic toxicity, and 2 (2.5%) had grade 3 postoperative complications such as ileus and wound dehiscence. There was no grade 4 toxicity.

CONCLUSION

A two-week schedule of radiotherapy with oral capecitabine in locally advanced rectal cancer patients showed low toxicity profiles and promising results in terms of tumor response.