Systematic review and meta-analysis of small bowel dose–volume and acute toxicity in conventionally-fractionated rectal cancer radiotherapy

Holyoake, D.; Partridge, Mike; Hawkins, M.

doi:10.1016/j.radonc.2019.05.001

Cited by 26 publications

(25 citation statements)

References 29 publications

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“…Toxicity has been mostly reported in prostate patients that are treated with higher doses than rectal cancer. Holyoake et al [ 33 ] conducted a meta-analysis looking at the mean difference in volume for small bowel for different dose levels between grades 0–2 and grade 3 toxicity and a toxicity risk for V10Gy and V40Gy received by normal fractionated radiotherapy. In all included studies the patients were treated with chemotherapy concomitantly.…”

Section: Discussionmentioning

confidence: 99%

Online adaptive radiotherapy compared to plan selection for rectal cancer: quantifying the benefit

et al. 2020

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Background: To compare online adaptive radiation therapy (ART) to a clinically implemented plan selection strategy (PS) with respect to dose to the organs at risk (OAR) for rectal cancer. Methods: The first 20 patients treated with PS between May-September 2016 were included. This resulted in 10 short (SCRT) and 10 long (LCRT) course radiotherapy treatment schedules with a total of 300 Conebeam CT scans (CBCT). New dual arc VMAT plans were generated using auto-planning for both the online ART and PS strategy. For each fraction bowel bag, bladder and mesorectum were delineated on daily Conebeam CTs. The dose distribution planned was used to calculate daily DVHs. Coverage of the CTV was calculated, as defined by the dose received by 99% of the CTV volume (D99%). The volume of normal tissue irradiated with 95% of the prescribed fraction dose was calculated by calculating the volume receiving 95% of the prescribed fraction or more dose minus the volume of the CTV. For each fraction the difference between the plan selection and online adaptive strategy of each DVH parameter was calculated, as well as the average difference per patient. Results: Target coverage remained the same for online ART. The median volume of the normal tissue irradiated with 95% of the prescribed dose dropped from 642 cm3 (PS) to 237 cm3 (online-ART)(p < 0.001). Online ART reduced dose to the OARs for all tested dose levels for SCRT and LCRT (p < 0.001). For V15Gy of the bowel bag the median difference over all fractions of all patients was − 126 cm 3 in LCRT, while the average difference per patient ranged from − 206 cm 3 to − 40 cm 3. For SCRT the median difference was − 62 cm 3 , while the range of the average difference per patient was − 105 cm3 to − 51 cm 3. For V15Gy of the bladder the median difference over all fractions of all patients was 26% in LCRT, while the average difference per patient ranged from − 34 to 12%. For SCRT the median difference of V95% was − 8%, while the range of the average difference per patient was − 29 to 0%. Conclusions: Online ART for rectal cancer reduces dose the OARs significantly compared to a clinically implemented plan selection strategy, without compromising target coverage. Trial registration: Medical Research Involving Human Subjects Act (WMO) does not apply to this study and was retrospectively approved by the Medical Ethics review Committee of the Academic Medical Center (W19_357 # 19.

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Section: Discussionmentioning

confidence: 99%

Online adaptive radiotherapy compared to plan selection for rectal cancer: quantifying the benefit

et al. 2020

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“…Recently, Chen et al showed that the small bowel volume that received 45 Gy was larger when IMRT was delivered on an empty bladder than when IMRT was delivered on a full bladder [ 12 ]. Furthermore, recent meta-analysis reported that grade 3 or more small bowel toxicity was related to multiple parameters in small dose area (range, 5–35 Gy) rather than traditional parameters related to 45 Gy [ 14 ]. Adequate bladder filling can reduce the small bowel volume affected by small dose area.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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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 (Vctsim). Bladder volume was estimated either by bladder scanner (Vscan) or anatomical features from the presacral promontory to the bladder base and dome in the sagittal plane of CT (Vratio). The feasibility of Vratio was validated using daily megavoltage or kV cone-beam CT before treatment. Results Mean Vctsim was 335.6 ± 147.5 cc. Despite a positive correlation between Vctsim and Vscan (R2 = 0.278) and between Vctsim and Vratio (R2 = 0.424), Vratio yielded more consistent results than Vscan, with a mean percentage error of 26.3 (SD 19.6, p < 0.001). The correlation between Vratio and Vctsim was stronger than that between Vscan and Vctsim (Z-score: − 7.782, p < 0.001). An accuracy of Vratio 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.

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“…Radiochemotherapy is a widely accepted treatment mode in patients with locally advanced rectal cancer. It can result in a significant reduction in the local recurrence rate by up to 30% and improve the 5-year disease-free survival rate [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of small bowel motion and feasibility of using the peritoneal space to replace bowel loops for dose constraints during intensity-modulated radiotherapy for rectal cancer

Gong

Yang

et al. 2020

Radiat Oncol

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Background: The goal of this study was to assess small bowel motion and explore the feasibility of using peritoneal space (PS) to replace bowel loops (BL) via the dose constraint method to spare the small bowel during intensity-modulated radiotherapy (IMRT) for rectal cancer. Methods: A total of 24 patients with rectal cancer who underwent adjuvant or neoadjuvant radiotherapy were selected. Weekly repeat CT scans from pre-treatment to the fourth week of treatment were acquired and defined as Plan, 1 W, 2 W, 3 W, and 4 W. The 4 weekly CT scans were co-registered to the Plan CT, BL and PS contours were delineated in all of the scans, an IMRT plan was designed on Plan CT using PS constraint method, and then copied to the 4 weekly CT scans. The dose-volume, normal tissue complication probability (NTCP) of the small bowel and their variations during treatment were evaluated. Results: Overall, 109 sets of CT scans from 24 patients were acquired, and 109 plans were designed and copied. The BL and PS volumes were 250.3 cc and 1339.3 cc. The V 15 of BL and PS based plan of pre-treatment were 182.6 cc and 919.0 cc, the shift% of them were 28.9 and 11.3% during treatment (p = 0.000), which was less in the prone position than in the supine position (25.2% vs 32.1%, p = 0.000; 9.9% vs 14.9%, p = 0.000). The NTCP C and NTCP A based plan of pre-treatment were 2.0 and 59.2%, the shift% during treatment were 46.1 and 14.0% respectively. Majority of BL's D max and V 15 were meet the safety standard during treatment using PS dose limit method except 3 times (3/109) of V 15 and 5 times of D max (5/109).

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Systematic review and meta-analysis of small bowel dose–volume and acute toxicity in conventionally-fractionated rectal cancer radiotherapy

Cited by 26 publications

References 29 publications

Online adaptive radiotherapy compared to plan selection for rectal cancer: quantifying the benefit

Online adaptive radiotherapy compared to plan selection for rectal cancer: quantifying the benefit

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

Evaluation of small bowel motion and feasibility of using the peritoneal space to replace bowel loops for dose constraints during intensity-modulated radiotherapy for rectal cancer

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