Differences in radiation dosimetry and anorectal function testing imply that anorectal symptoms may arise from different anatomic substrates

Dataset for predicting single-spot proton ranges in proton therapy of prostate cancer

The number of radiotherapy patients treated with protons has increased from less than 60,000 in 2007 to more than 220,000 in 2019. However, the considerable uncertainty in the positioning of the Bragg peak deeper in the patient raised new challenges in the proton therapy of prostate cancer (PCPT). Here, we describe and share a dataset where 43 single-spot anterior beams with defined proton energies were delivered to a prostate phantom with an inserted endorectal balloon (ERB) filled either with water only or with a silicon-water mixture. The nuclear reactions between the protons and the silicon yield a distinct prompt gamma energy line of 1.78 MeV. Such energy peak could be identified by means of prompt gamma spectroscopy (PGS) for the protons hitting the ERB with a three-sigma threshold. The application of a background-suppression technique showed an increased rejection capability for protons hitting the prostate and the ERB with water only. We describe each dataset, document the full processing chain, and provide the scripts for the statistical analysis.

Towards real-time PGS range monitoring in proton therapy of prostate cancer

Proton therapy of prostate cancer (PCPT) was linked with increased levels of gastrointestinal toxicity in its early use compared to intensity-modulated radiation therapy (IMRT). The higher radiation dose to the rectum by proton beams is mainly due to anatomical variations. Here, we demonstrate an approach to monitor rectal radiation exposure in PCPT based on prompt gamma spectroscopy (PGS). Endorectal balloons (ERBs) are used to stabilize prostate movement during radiotherapy. These ERBs are usually filled with water. However, other water solutions containing elements with higher atomic numbers, such as silicon, may enable the use of PGS to monitor the radiation exposure of the rectum. Protons hitting silicon atoms emit prompt gamma rays with a specific energy of 1.78 MeV, which can be used to monitor whether the ERB is being hit. In a binary approach, we search the silicon energy peaks for every irradiated prostate region. We demonstrate this technique for both single-spot irradiation and real treatment plans. Real-time feedback based on the ERB being hit column-wise is feasible and would allow clinicians to decide whether to adapt or continue treatment. This technique may be extended to other cancer types and organs at risk, such as the oesophagus.

Late Gastrointestinal Tolerance After Prostate Radiotherapy: Is the Anal Canal the Culprit? A Narrative Critical Review

INTRODUCTION

Late gastro-intestinal toxicities (LGIT) secondary to pelvic radiotherapy (RT) are well described in the literature. LGIT are mainly related to rectal or ano-rectal irradiation; however, involvement of the anal canal (AC) in the occurrence of LGIT remains poorly described and understood.

MATERIALS AND METHODS

The aim of this work was to explore the potential role of the AC in the development of LGIT after prostate irradiation and identify predictive factors that could be optimized in order to limit these toxicities. This narrative literature review was realized using the Pubmed database. We identified original articles published between June 1997 and July 2019, relating to LGIT after RT for localized prostate cancer and for which AC was identified independently. Articles defining the AC as part of an anorectal or rectal volume only were excluded.

RESULTS

A history of abdominal surgery or cardio-vascular risk, anticoagulant or tobacco use, and the occurrence of acute GIT during RT increases the risk of LGIT. A dose-effect relationship was identified between dose to the AC and development of LGIT. Identification and contouring of the AC and adjacent anatomical structures (muscles or nerves) are justified to apply specific dose constraints. As a limitation, our review mainly considered on 3DCRT which is no longer the standard of care nowadays; we did not identify any reports in the literature using moderately hypofractionated RT for the prostate and AC specific dosimetry.

CONCLUSION

These results suggest that the AC may have an important role in the development of LGIT after pelvic RT for prostate cancer. The individualization of the AC during planning should be recommended in prospective studies.

Dose-Volume Predictors for Patient-reported Late Diarrhoea, Faecal Incontinence and Urgency after Pelvic Radiotherapy

AIMS

Pelvic radiotherapy adds significantly to the curative treatment of many pelvic malignancies. However, this cure comes at a cost for many patients, where late bowel toxicities, such as faecal incontinence, urgency and diarrhoea, adversely affect quality of life. Despite the implementation of advanced radiotherapy techniques in many centres, there are deficiencies in our knowledge of how to make best use of these techniques to minimise these late toxicities, with dose-volume constraints specifically for late effects needing definition. The aims of this study were to establish dose-volume predictors for patient-reported late bowel toxicities and derive constraints for clinical use to reduce the risk of these toxicities.

MATERIALS AND METHODS

All radiotherapy patients treated in our institution between 2012 and 2014 for gynaecological and urological cancers (bladder, prostate where pelvic nodes are treated) were identified. Patients were sent patient-reported toxicity questionnaires at 12 and 24 months after treatment. Planning computed tomography scans were retrospectively contoured with different definitions of bowel as organs at risk (OARs). Dose-volume data for each OAR were collected and predictors of these toxicities found using multivariate analysis. For those dose-volume predictors found to be significant on multivariate analysis, statistically significant and clinically relevant dose-volume constraints were derived. Furthermore, data collected were used to validate constraints from published studies.

RESULTS

Faecal urgency, incontinence and diarrhoea rates were found in 52, 23.5 and 18.7% of the 203 patients included at 12 months following radiotherapy. Dose-volume parameters for sigmoid colon and large bowel were significant for these toxicities, and constraints for these OARs were derived, which are promising. A previously published constraint for bowel loops was validated with our data.

CONCLUSIONS

The sigmoid colon and large bowel are important OARs for the development of faecal urgency, incontinence and diarrhoea. Promising constraints for these OARs were derived, which require further validation before prospective clinical use.

Biologically consistent dose accumulation using daily patient imaging

BACKGROUND

This work addresses a basic inconsistency in the way dose is accumulated in radiotherapy when predicting the biological effect based on the linear quadratic model (LQM). To overcome this inconsistency, we introduce and evaluate the concept of the total biological dose, bEQD_d.

METHODS

Daily computed tomography imaging of nine patients treated for prostate carcinoma with intensity-modulated radiotherapy was used to compute the delivered deformed dose on the basis of deformable image registration (DIR). We compared conventional dose accumulation (DA) with the newly introduced bEQD_d, a new method of accumulating biological dose that considers each fraction dose and tissue radiobiology. We investigated the impact of the applied fractionation scheme (conventional/hypofractionated), uncertainties induced by the DIR and by the assigned α/β-value.

RESULTS

bEQD_d was systematically higher than the conventionally accumulated dose with difference hot spots of 3.3-4.9 Gy detected in six out of nine patients in regions of high dose gradient in the bladder and rectum. For hypofractionation, differences are up to 8.4 Gy. The difference amplitude was found to be in a similar range to worst-case uncertainties induced by DIR and was higher than that induced by α/β.

CONCLUSION

Using bEQD_d for dose accumulation overcomes a potential systematic inaccuracy in biological effect prediction based on accumulated dose. Highest impact is found for serial-type late responding organs at risk in dose gradient regions and for hypofractionation. Although hot spot differences are in the order of several Gray, in dose-volume parameters there is little difference compared with using conventional or biological DA. However, when local dose information is used, e.g. dose surface maps, difference hot spots can potentially change outcomes of dose-response modelling and adaptive treatment strategies.

Derivation of Dose/Volume Constraints for the Anorectum from Clinician- and Patient-Reported Outcomes in the CHHiP Trial of Radiation Therapy Fractionation

PURPOSE

The CHHiP trial randomized 3216 men with localized prostate cancer (1:1:1) to 3 radiation therapy fractionation schedules: 74 Gy in 37 fractions over 7.4 weeks; 60 Gy in 20 fractions over 4 weeks; and 57 Gy in 19 fractions over 3.8 weeks. Literature-based dose constraints were applied with arithmetic adjustment for the hypofractionated arms. This study aimed to derive anorectal dose constraints using prospectively collected clinician-reported outcomes (CROs) and patient-reported outcomes (PROs) and to assess the added predictive value of spatial dose metrics.

METHODS AND MATERIALS

A case-control study design was used; 7 CRO and 5 PRO bowel symptoms were evaluated. Cases experienced a moderate or worse symptom 1 to 5 years after-radiation therapy and did not have the symptom before radiation therapy. Controls did not experience the symptom at baseline or between 1 to 5 years after radiation therapy. The anorectum was recontoured from the anal verge to the rectosigmoid junction; dose/volume parameters were extracted. Univariate logistic regression, atlases of complication indices, and bootstrapped receiver-operating-characteristic analysis (1000 replicates, balanced outcomes) were used to derive dose constraints for the whole cohort (hypofractionated schedules were converted to 2-Gy equivalent schedules using α/β = 3 Gy) and separate hypofractionated/conventional fractionation cohorts. Only areas under the curve with 95% confidence interval lower limits >0.5 were considered statistically significant. Any constraint derived in <95% to 99% of bootstraps was excluded.

RESULTS

Statistically significant dose constraints were derived for CROs but not PROs. Intermediate to high doses were important for rectal bleeding, whereas intermediate doses were important for increased bowel frequency, fecal incontinence, and rectal pain. Spatial dose metrics did not improve prediction of CROs or PROs. A new panel of dose constraints for hypofractionated schedules to 60 Gy or 57 Gy are V20Gy <85%, V30Gy <57%, V40Gy <38%, V50Gy <22%, and V60Gy <0.01%.

CONCLUSIONS

Dose constraints differed among symptoms, indicating potentially different pathogenesis of radiation-induced side effects. Derived dose constraints were stricter than those used in CHHiP and may reduce bowel symptoms after radiation therapy.

A systematic review of dose-volume predictors and constraints for late bowel toxicity following pelvic radiotherapy

BACKGROUND

Advanced pelvic radiotherapy techniques aim to reduce late bowel toxicity which can severely impact the lives of pelvic cancer survivors. Although advanced techniques have been largely adopted worldwide, to achieve their aim, knowledge of which dose-volume parameters of which components of bowel predict late bowel toxicity is crucial to make best use of these techniques. The rectum is an extensively studied organ at risk (OAR), and dose-volume predictors of late toxicity for the rectum are established. However, for other components of bowel, there is a significant paucity of knowledge. The Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) reviews recommend dose-volume constraints for acute bowel toxicity for peritoneal cavity and bowel loops, although no constraints are recommended for late toxicity, despite its relevance to our increasing number of survivors. This systematic review aims to examine the published literature to seek dose-volume predictors and constraints of late bowel toxicity for OARs (apart from the rectum) for use in clinical practice.

METHODS

A systematic literature search was performed using Medline, Embase, Cochrane Library, Web of Science, Cinahl and Pubmed. Studies were screened and included according to specific pre-defined criteria. Included studies were assessed for quality against QUANTEC-defined assessment criteria.

RESULTS

101 studies were screened to find 30 relevant studies. Eight studies related to whole bowel, 11 to small bowel, and 21 to large bowel (including 16 of the anal canal). The anal canal is an important OAR for the development of late toxicity, and we recommend an anal canal Dmean <40Gy as a constraint to reduce late incontinence. For other components of bowel (sigmoid, large bowel, intestinal cavity, bowel loops), although individual studies found statistically significant parameters and constraints these findings were not corroborated in other studies.

CONCLUSIONS

The anal canal is an important OAR for the development of late bowel toxicity symptoms. Further validation of the constraints found for other components of bowel is needed. Studies that were more conclusive included those with patient-reported data, where individual symptom scores were assessed rather than an overall score, and those that followed statistical and endpoint criteria as defined by QUANTEC.

Dose-response relationships of the sigmoid for urgency syndrome after gynecological radiotherapy

PURPOSE

To find out what organs and doses are most relevant for 'radiation-induced urgency syndrome' in order to derive the corresponding dose-response relationships as an aid for avoiding the syndrome in the future.

MATERIAL AND METHODS

From a larger group of gynecological cancer survivors followed-up 2-14 years, we identified 98 whom had undergone external beam radiation therapy but not brachytherapy and not having a stoma. Of those survivors, 24 developed urgency syndrome. Based on the loading factor from a factor analysis, and symptom frequency, 15 symptoms were weighted together to a score interpreted as the intensity of radiation-induced urgency symptom. On reactivated dose plans, we contoured the small intestine, sigmoid colon and the rectum (separate from the anal-sphincter region) and we exported the dose-volume histograms for each survivor. Dose-response relationships from respective risk organ and urgency syndrome were estimated by fitting the data to the Probit, RS, LKB and gEUD models.

RESULTS

The rectum and sigmoid colon have steep dose-response relationships for urgency syndrome for Probit, RS and LKB. The dose-response parameters for the rectum were D_50: 51.3, 51.4, and 51.3 Gy, γ₅₀ = 1.19 for all models, s was 7.0e^-09 for RS and n was 9.9 × 10⁷ for LKB. For Sigmoid colon, D₅₀ were 51.6, 51.6, and 51.5 Gy, γ₅₀ were 1.20, 1.25, and 1.27, s was 2.8 for RS and n was 0.079 for LKB.

CONCLUSIONS

Primarily the dose to sigmoid colon as well as the rectum is related to urgency syndrome among gynecological cancer survivors. Separate delineation of the rectum and sigmoid colon in order to incorporate the dose-response results may aid in reduction of the incidence of the urgency syndrome.

Anal and rectal function after intensity-modulated prostate radiotherapy with endorectal balloon

BACKGROUND AND PURPOSE

Late anorectal toxicity influences quality of life after external beam radiotherapy (EBRT) for prostate cancer. A daily inserted endorectal balloon (ERB) during EBRT aims to reduce anorectal toxicity. Our goal is to objectify anorectal function over time after prostate intensity-modulated radiotherapy (IMRT) with ERB.

MATERIAL AND METHODS

Sixty men, irradiated with IMRT and an ERB, underwent barostat measurements and anorectal manometry prior to EBRT and 6 months, one year and 2 years after radiotherapy. Primary outcome measures were rectal distensibility and rectal sensibility in response to stepwise isobaric distensions and anal pressures.

RESULTS

Forty-eight men completed all measurements. EBRT reduced maximal rectal capacity 2 years after EBRT (250 ± 10 mL vs. 211 ± 10 mL; p < 0.001), area under the pressure-volume curve (2878 ± 270 mL mmHg vs. 2521 ± 305 mL mmHg; p = 0.043) and rectal compliance (NS). Sensory pressure thresholds for first sense and first urge (both p < 0.01) increased. Anal maximum pressure diminished after IMRT (p = 0.006).

CONCLUSIONS

Rectal capacity and sensory function are increasingly affected over time after radiotherapy. There is an indication that these reductions are affected less with IMRT + ERB compared to conventional radiation techniques.

Anal sphincter dysfunction in patients treated with primary radiotherapy for anal cancer: a study with the functional lumen imaging probe

BACKGROUND

Sphincter-sparing radiotherapy or chemoradiation are standard treatments for patients with anal cancer. The ultimate treatment goal is full recovery from anal cancer with preserved anorectal function. Unfortunately, long-term survivors often suffer from severe anorectal symptoms. The aim of the present study was to characterize changes in anorectal physiology after radiotherapy for anal cancer.

METHOD

We included 13 patients (10 women, age 63.4 ± 1.9) treated with radiotherapy or chemoradiation for anal cancer and 14 healthy volunteers (9 women, age 61.4 ± 1.5). Symptoms were assessed with scores for fecal incontinence and low anterior resection syndrome. Anorectal physiology was examined with anorectal manometry and the Functional Lumen Imaging Probe.

RESULTS

Patients had a median Wexner fecal incontinence score of 5 (0-13) and a median LARS score of 29 (0-39). Compared to healthy volunteers, patients had lower mean (±SE) anal -resting (38 ± 5 vs. 71 ± 6, p < .001) and -squeeze pressures (76 ± 11 vs. 165 ± 15, p < .001). Patients also had lower anal yield pressure (15.5 ± 1.3 mmHg vs. 28.0 ± 2.0 mmHg, p < .001), higher distensibility, and lower resistance to flow (reduced resistance ratio of the anal canal during distension, q = 5.09, p < .001). No differences were found in median (range) rectal volumes at first sensation (70.5 (15-131) vs. 57 (18-132) ml, p > .4), urge (103 (54-176) vs. 90 (32-212), p > .6) or maximum tolerable volume (173 (86-413) vs. 119.5 (54-269) ml, p > .10).

CONCLUSION

Patients treated with radiotherapy or chemoradiation for anal cancer have low anal resting and squeeze pressures as well as reduced resistance to distension and flow.

Spatial rectal dose/volume metrics predict patient-reported gastro-intestinal symptoms after radiotherapy for prostate cancer

BACKGROUND

Gastro-intestinal (GI) toxicity after radiotherapy (RT) for prostate cancer reduces patient's quality of life. In this study, we explored associations between spatial rectal dose/volume metrics and patient-reported GI symptoms after RT for localized prostate cancer, and compared these with those of dose-surface/volume histogram (DSH/DVH) metrics.

MATERIAL AND METHODS

Dose distributions and six GI symptoms (defecation urgency/emptying difficulties/fecal leakage, ≥Grade 2, median follow-up: 3.6 y) were extracted for 200 patients treated with image-guided RT in 2005-2007. Three hundred and nine metrics assessed from 2D rectal dose maps or DSHs/DVHs were subject to 50-times iterated five-fold cross-validated univariate and multivariate logistic regression analysis (UVA, MVA). Performance of the most frequently selected MVA models was evaluated by the area under the receiving-operating characteristics curve (AUC).

RESULTS

The AUC increased for dose-map compared to DSH/DVH-based models (mean SD: 0.64 ± 0.03 vs. 0.61 ± 0.01), and significant relations were found for six versus four symptoms. Defecation urgency and faecal leakage were explained by high doses at the central/upper and central areas, respectively; while emptying difficulties were explained by longitudinal extensions of intermediate doses.

CONCLUSIONS

Predictability of patient-reported GI toxicity increased using spatial metrics compared to DSH/DVH metrics. Novel associations were particularly identified for emptying difficulties using both approaches in which intermediate doses were emphasized.

Anal function after endoluminal locoregional resection by transanal endoscopic microsurgery and radiotherapy for rectal cancer

AIM

In patients with rectal cancer, surgery and chemoradiotherapy may affect anal sphincter function. Few studies have evaluated anorectal function after neoadjuvant chemoradiotherapy (n-CRT) and/or transanal endoscopic microsurgery (TEM). The aim of this study was to evaluate the effects of n-CRT and TEM on anorectal function.

METHOD

Thirty-seven patients with rectal cancer underwent anorectal manometry and Wexner scoring for faecal incontinence at baseline, after n-CRT (cT2-T3N0 cancer) and at 4 and 12 months after surgery. Water-perfused manometry measured anal tone at rest and during squeezing, rectal sensitivity and compliance. Twenty-seven and 10 patients, respectively, underwent TEM without (Group A) or with n-CRT (Group B).

RESULTS

In Group A, anal resting pressure decreased from 68 ± 23 to 54 ± 26 mmHg at 4 months (P = 0.04) and improved 12 months after surgery (60 ± 30 mmHg). The Wexner score showed a significant increase in gas incontinence (59%), soiling (44%) and urgency (37%) rates at 4 months, followed by clinical improvement at 1 year (41%, 26% and 18%, respectively). In group B, anal resting pressure decreased from 65 ± 23 to 50 ± 18 mmHg at 4 months but remained stable at 12 months (44 ± 11 mmHg, P = 0.02 vs preoperative values - no significant difference compared with evaluation at 4 months). Gas incontinence, soiling and urgency were observed in 50%, 50%, 25% and in 38%, 12% and 12% of cases, respectively, 4 and 12 months after treatment.

CONCLUSION

TEM does not significantly affect anal function. Instead, n-CRT does affect anal function but without causing major anal incontinence.

The effect of endorectal balloon on anorectal dose during postoperative volumetric arc radiotherapy of prostate cancer

PURPOSE

To evaluate the impact of endorectal balloon (ERB) on anorectal dose during postoperative VMAT of prostate cancer.

METHODS

In ten patients referred for salvage radiotherapy CTs were obtained without ERB and with air-filled ERB of 50ml and 100ml. CTs were repeated weekly (4-6 control CTs) and registered to the respective planning CT. For each planning CT, a VMAT plan was made with defined anorectal dose constraints and propagated on the respective control CTs. The dose volumes V40Gy, V60Gy and V65Gy of the rectal and anal wall (Rwall and Awall, respectively) and the ERB position were obtained from each plan.

RESULTS

In plans with ERB, the mean Rwall dose volumes V40Gy, V60Gy and V65Gy were higher by 8%, 5% and 2% (ERB 50ml) and 2%, 3% and 3% (ERB 100ml) in comparison to plans without ERB. The respective Awall dose volume differences were 2%, 0%, -1% (ERB 50ml), and -3%, -2%, -2% (ERB 100ml). The dose volume variability of the Rwall was comparable with and without ERB, but was slightly reduced by ERB for the Awall. The mean ERB position variability was >2mm in anterior-posterior and inferior-superior directions.

CONCLUSION

The use of ERB during post-operative VMAT has no advantages for anorectal dose.

Non-surgical interventions for late rectal problems (proctopathy) of radiotherapy in people who have received radiotherapy to the pelvis

BACKGROUND

This is an update of a Cochrane review first published in 2002, and previously updated in 2007. Late radiation rectal problems (proctopathy) include bleeding, pain, faecal urgency, and incontinence and may develop after pelvic radiotherapy treatment for cancer.

OBJECTIVES

To assess the effectiveness and safety of non-surgical interventions for managing late radiation proctopathy.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 11, 2015); MEDLINE (Ovid); EMBASE (Ovid); CANCERCD; Science Citation Index; and CINAHL from inception to November 2015.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing non-surgical interventions for the management of late radiation proctopathy in people with cancer who have undergone pelvic radiotherapy for cancer. Primary outcomes considered were: episodes of bowel activity, bleeding, pain, tenesmus, urgency, and sphincter dysfunction.

DATA COLLECTION AND ANALYSIS

Study selection, 'Risk of bias' assessment, and data extraction were performed in duplicate, and any disagreements were resolved by involving a third review author.

MAIN RESULTS

We identified 1221 unique references and 16 studies including 993 participants that met our inclusion criteria. One study found through the last update was moved to the 'Studies awaiting classification' section. We did not pool outcomes for a meta-analysis due to variation in study characteristics and endpoints across included studies.Since radiation proctopathy is a condition with various symptoms or combinations of symptoms, the studies were heterogeneous in their intended effect. Some studies investigated treatments targeted at bleeding only (group 1), some investigated treatments targeted at a combination of anorectal symptoms, but not a single treatment (group 2). The third group focused on the treatment of the collection of symptoms referred to as pelvic radiation disease. In order to enable some comparison of this heterogeneous collection of studies, we describe the effects in these three groups separately.Nine studies assessed treatments for rectal bleeding and were unclear or at high risk of bias. The only treatments that made a significant difference on primary outcomes were argon plasma coagulation (APC) followed by oral sucralfate versus APC with placebo (endoscopic score 6 to 9 in favour of APC with placebo, risk ratio (RR) 2.26, 95% confidence interval (CI) 1.12 to 4.55; 1 study, 122 participants, low- to moderate-quality evidence); formalin dab treatment (4%) versus sucralfate steroid retention enema (symptom score after treatment graded by the Radiation Proctopathy System Assessments Scale (RPSAS) and sigmoidoscopic score in favour of formalin (P = 0.001, effect not quantified, 1 study, 102 participants, very low- to low-quality evidence), and colonic irrigation plus ciprofloxacin and metronidazole versus formalin application (4%) (bleeding (P = 0.007, effect not quantified), urgency (P = 0.0004, effect not quantified), and diarrhoea (P = 0.007, effect not quantified) in favour of colonic irrigation (1 study, 50 participants, low-quality evidence).Three studies, of unclear and high risk of bias, assessed treatments targeted at something very localised but not a single pathology. We identified no significant differences on our primary outcomes. We graded all studies as very low-quality evidence due to unclear risk of bias and very serious imprecision.Four studies, of unclear and high risk of bias, assessed treatments targeted at more than one symptom yet confined to the anorectal region. Studies that demonstrated an effect on symptoms included: gastroenterologist-led algorithm-based treatment versus usual care (detailed self help booklet) (significant difference in favour of gastroenterologist-led algorithm-based treatment on change in Inflammatory Bowel Disease Questionnaire-Bowel (IBDQ-B) score at six months, mean difference (MD) 5.47, 95% CI 1.14 to 9.81) and nurse-led algorithm-based treatment versus usual care (significant difference in favour of the nurse-led algorithm-based treatment on change in IBDQ-B score at six months, MD 4.12, 95% CI 0.04 to 8.19) (1 study, 218 participants, low-quality evidence); hyperbaric oxygen therapy (at 2.0 atmospheres absolute) versus placebo (improvement of Subjective, Objective, Management, Analytic - Late Effects of Normal Tissue (SOMA-LENT) score in favour of hyperbaric oxygen therapy (HBOT), P = 0.0019) (1 study, 150 participants, moderate-quality evidence, retinol palmitate versus placebo (improvement in RPSAS in favour of retinol palmitate, P = 0.01) (1 study, 19 participants, low-quality evidence) and integrated Chinese traditional plus Western medicine versus Western medicine (grade 0 to 1 radio-proctopathy after treatment in favour of integrated Chinese traditional medicine, RR 2.55, 95% CI 1.30 to 5.02) (1 study, 58 participants, low-quality evidence).The level of evidence for the majority of outcomes was downgraded using GRADE to low or very low, mainly due to imprecision and study limitations. 

AUTHORS' CONCLUSIONS

Although some interventions for late radiation proctopathy look promising (including rectal sucralfate, metronidazole added to an anti-inflammatory regimen, and hyperbaric oxygen therapy), single small studies provide limited evidence. Furthermore, outcomes important to people with cancer, including quality of life (QoL) and long-term effects, were not well recorded. The episodic and variable nature of late radiation proctopathy requires large multi-centre placebo-controlled trials (RCTs) to establish whether treatments are effective. Future studies should address the possibility of associated injury to other gastro-intestinal, urinary, or sexual organs, known as pelvic radiation disease. The interventions, as well as the outcome parameters, should be broader and include those important to people with cancer, such as QoL evaluations.

Long-term anorectal, urinary and sexual dysfunction causing distress after radiotherapy for anal cancer: a Danish multicentre cross-sectional questionnaire study

AIM

The objective of primary radiotherapy for anal cancer is to remove cancer while maintaining anorectal function. However, little is known about anorectal function among long-term survivors without colostomy. Using a cross-sectional questionnaire study, we examined symptoms and distress related to the dysfunction of pelvic organs after radiotherapy for anal cancer.

METHOD

A questionnaire regarding anorectal, urinary and sexual symptoms was sent to anal cancer patients without recurrence or colostomy, diagnosed during 1996-2003, and treated with curative intent (chemo)radiotherapy at three Danish centres. For each symptom we assessed frequency and severity and the level of symptom-induced distress (no, little, moderate or great distress).

RESULTS

Of 94 eligible patients, 84 (89%) returned the completed questionnaire at a median of 33 months after radiotherapy. Incontinence for solid stools, liquid stools and gas occurred at least monthly in 31%, 54% and 79% of patients, respectively. Overall 40% of patients reported great distress from incontinence for solid or liquid stools at least monthly. Faecal urgency occurring at least monthly was experienced by 87% of patients and caused great distress in 43%. Stress, urge or another type of urinary incontinence occurred at least monthly in 45% and caused great distress in 21%. Urinary urgency occurred at least monthly in 48% but only caused great distress in 14%. Sexual desire was severely decreased in 58% and only 24% were satisfied with their sexual function.

CONCLUSION

Distressing long-term anorectal and sexual dysfunction was common after radiotherapy for anal cancer, and morbidity due to urinary dysfunction was moderate.

Relationships between dose to the gastro-intestinal tract and patient-reported symptom domains after radiotherapy for localized prostate cancer

BACKGROUND

Gastrointestinal (GI) morbidity after radiotherapy (RT) for prostate cancer is typically addressed by studying specific single symptoms. The aim of this study was to explore the interplay between domains of patient- reported outcomes (PROs) on GI morbidity, and to what extent these are explained by RT dose to the GI tract.

MATERIAL AND METHODS

The study included men from two Scandinavian studies (N = 211/277) who had undergone primary external beam radiotherapy (EBRT) for localized prostate cancer to 70-78 Gy (2 Gy/fraction). Factor analysis was applied to previously identified PRO-based symptom domains from two study-specific questionnaires. Number of questions: 43; median time to follow-up: 3.6-6.4 years) and dose-response outcome variables were defined from these domains. Dose/volume parameters of the anal sphincter (AS) or the rectum were tested as predictors for each outcome variable using logistic regression with 10-fold cross-validation. Performance was assessed using area under the receiver operating characteristic curve (Az) and model frequency.

RESULTS

Outcome variables from Defecation urgency (number of symptoms: 2-3), Fecal leakage (4-6), Mucous (4), and Pain (3-6) were defined. In both cohorts, intermediate rectal doses predicted Defecation urgency (mean Az: 0.53-0.54; Frequency: 70-75%), and near minimum and low AS doses predicted Fecal leakage (mean Az: 0.63-0.67; Frequency: 83-99%). In one cohort, high AS doses predicted Mucous (mean Az: 0.54; Frequency: 96%), whereas in the other, low AS doses and intermediate rectal doses predicted Pain (mean Az: 0.69; Frequency: 28-82%).

CONCLUSION

We have demonstrated that Defecation urgency, Fecal leakage, Mucous, and Pain following primary EBRT for localized prostate cancer primarily are predicted by intermediate rectal doses, low AS doses, high AS doses, or a combination of low AS and intermediate rectal doses, respectively. This suggests that there is a domain-specific dose-response for the GI tract. To reduce risk of GI morbidity, dose distributions of both the AS region and the rectum should, therefore, be considered when prescribing prostate cancer RT.

Can Anorectal Manometry Findings Predict Subsequent Late Gastrointestinal Radiation Toxicity in Prostate Cancer Patients?

PURPOSE

The purpose of this study is to investigate the influence of radiotherapy (RT) on anorectal function and radiation-induced toxicity in patients with prostate cancer.

MATERIALS AND METHODS

Fifty-four patients who were treated with RT for prostate cancer (T1c-4N0-1M0) were evaluated. To assess the changes in anorectal function, two consecutive anorectal manometry readings were performed in patients, before and after 4-6 months of RT. Late gastrointestinal (GI) toxicity was defined as symptoms occurring more than 6 months after RT. The median radiation dose was 70.0 Gy (range, 66.0 to 74.0 Gy). Whole pelvis field RT was performed in 16 patients (29.6%). Grade of late radiation toxicity was defined in accordance to the severity of symptoms (Gulliford's scoring system).

RESULTS

The median follow-up period was 60 months. Resting anal pressure (p=0.001), squeeze pressure (p < 0.001), and urge to defecate volume (p=0.025) were significantly reduced after RT. Fourteen patients (25.9%) experienced late GI toxicities. Among them, nine (16.7%) showed severe (grade ≥ 2) late toxicities. Elevated resting and squeeze external anal sphincter pressure prior to RT and large urge to defecate volumes after RT were associated with the occurrence of late GI toxicities.

CONCLUSION

RT caused symptomatic anorectal dysfunction and resulted in a weakened anal sphincter. Increased urge to defecate volumes after RT were related to late GI toxicities. Elevated resting and squeeze anal sphincter pressure prior to RT rodcan be used to identify patients with an increased risk of late GI toxicities.

Transitioning from conventional radiotherapy to intensity-modulated radiotherapy for localized prostate cancer: changing focus from rectal bleeding to detailed quality of life analysis

With the advent of modern radiation techniques, we have been able to deliver a higher prescribed radiotherapy dose for localized prostate cancer without severe adverse reactions. We reviewed and analyzed the change of toxicity profiles of external beam radiation therapy (EBRT) from the literature. Late rectal bleeding is the main adverse effect, and an incidence of >20% of Grade ≥2 adverse events was reported for 2D conventional radiotherapy of up to 70 Gy. 3D conformal radiation therapy (3D-CRT) was found to reduce the incidence to ∼10%. Furthermore, intensity-modulated radiation therapy (IMRT) reduced it further to a few percentage points. However, simultaneously, urological toxicities were enhanced by dose escalation using highly precise external radiotherapy. We should pay more attention to detailed quality of life (QOL) analysis, not only with respect to rectal bleeding but also other specific symptoms (such as urinary incontinence and impotence), for two reasons: (i) because of the increasing number of patients aged >80 years, and (ii) because of improved survival with elevated doses of radiotherapy and/or hormonal therapy; age is an important prognostic factor not only for prostate-specific antigen (PSA) control but also for adverse reactions. Those factors shift the main focus of treatment purpose from survival and avoidance of PSA failure to maintaining good QOL, particularly in older patients. In conclusion, the focus of toxicity analysis after radiotherapy for prostate cancer patients is changing from rectal bleeding to total elaborate quality of life assessment.

Pathophysiology of late anorectal dysfunction following external beam radiotherapy for prostate cancer

BACKGROUND

Patients treated with external beam radiotherapy (EBRT) may suffer from long-term anorectal adverse effects. The purpose of the present study was to assess long-term functional and structural anorectal changes in patients previously treated with EBRT for prostate cancer and to suggest the mechanism behind the development of the adverse effects.

MATERIAL AND METHODS

Our previously proposed RT-induced anorectal dysfunction (RT-ARD) score, developed with the intention to survey anorectal dysfunction was used to identify patients with and without anorectal symptoms. Among 309 patients surveyed with the questionnaire, we chose 23 patients with the highest RT-ARD score and 19 patients with the lowest RT-ARD score. They were investigated by multimodal rectal sensory stimulation, standard anal physiological tests. Changes of the rectal mucosa were assessed by flexible sigmoidoscopy and graded by the Vienna Rectoscopy Score (VRS).

RESULTS

The mean follow-up time was 3.8 (range, 2.8; 8.6) years in patients with high RT-ARD and 3.8 (range, 2.6; 5.9) in patients with low RT-ARD. Endoscopic evaluation revealed higher VRS scores in patients with high RT-ARD compared to patients with low RT-ARD (p = 0.002). Patients with high RT-ARD had increased rectal sensory response to distension manifested both as volume (p = 0.006) and cross-sectional area (p = 0.04), and they had reduced maximum anal resting pressure assessed by anal manometri (p = 0.02).

CONCLUSIONS

Long-term anorectal symptoms correlate to changes in anorectal biomechanical properties and rectal mucosal injury. Our data suggests that RT-induced long-term anorectal dysfunction is multifactorial caused by injury of the rectal mucosa and the internal anal sphincter combined with increased rectal sensitivity and reduced rectal functional capacity.

Systematic review: anal and rectal changes after radiotherapy for prostate cancer

PURPOSE

Pelvic radiotherapy may lead to changes of anorectal function resulting in incontinence-related complaints. The aim of this study was to systematically review objective findings of late anorectal physiology and mucosal appearance after irradiation for prostate cancer.

METHODS

MEDLINE, EMBASE, and the Cochrane library were searched. Original articles in which anal function, rectal function, or rectal mucosa were examined ≥3 months after EBRT for prostate cancer were included.

RESULTS

Twenty-one studies were included with low to moderate quality. Anal resting pressures significantly decreased in 6 of the 9 studies including 277 patients. Changes of squeeze pressure and rectoanal inhibitory reflex were less uniform. Rectal distensibility was significantly impaired after EBRT in 7 of 9 studies (277 patients). In 4 of 9 studies on anal and in 5 of 9 on rectal function, disturbances were associated with urgency, frequent bowel movements or fecal incontinence. Mucosal changes as assessed by the Vienna Rectoscopy Score revealed telangiectasias in 73 %, congestion in 33 %, and ulceration in 4 % of patients in 8 studies including 346 patients, but no strictures or necrosis. Three studies reported mucosal improvement during follow-up. Telangiectasias, particularly multiple, were associated with rectal bleeding. Not all bowel complaints (30 %) were related to radiotherapy.

CONCLUSIONS

Low to moderate quality evidence indicates that EBRT reduces anal resting pressure, decreases rectal distensibility, and frequently induces telangiectasias of rectal mucosa. Objective changes may be associated with fecal incontinence, urgency, frequent bowel movements, and rectal bleeding, but these symptoms are not always related to radiation damage.

Long term rectal function after high-dose prostatecancer radiotherapy: results from a prospective cohort study

PURPOSE

To prospectively evaluate long-term late rectal bleeding (lrb) and faecal incontinence (linc) after high-dose radiotherapy (RT) for prostate cancer in the AIROPROS 0102 population, and to assess clinical/dosimetric risk factors.

MATERIALS AND METHODS

Questionnaires of 515 patients with G0 baseline incontinence and bleeding scores (follow-up ≥6 years) were analysed. Correlations between lrb/linc and many clinical and dosimetric parameters were investigated by univariate and multivariate logistic analyses. The correlation between lrb/linc and symptoms during the first 3 years after RT was also investigated.

RESULTS

Of 515 patients lrb G1, G2 and G3 was found in 32 (6.1%), 2 (0.4%) and 3 (0.6%) patients while linc G1, G2 and G3 was detected in 50 (9.7%), 3 (0.6%) and 3 (0.6%), respectively. The prevalence of G2-G3 lrb events was significantly reduced compared to the first 3-years (1% vs 2.7%, p=0.016) ≥G1 lrb was significantly associated with V75 Gy (OR=1.07). In multivariate analysis, ≥G1 linc was associated with V40 Gy (OR=1.015), use of antihypertensive medication (OR=0.38), abdominal surgery before RT (OR=4.7), haemorrhoids (OR=2.6), and G2-G3 acute faecal incontinence (OR=4.4), a nomogram to predict the risk of long-term ≥G1 linc was proposed. Importantly, the prevalence of ≥G1 linc was significantly correlated with the mean incontinence score during the first 3 years after RT (OR=16.3).

CONCLUSIONS

Long-term (median: 7 years) rectal symptoms are prevalently mild and strongly correlated with moderate/severe events occurring in the first 3 years after RT. Linc was associated with several risk factors.

Impact of late anorectal dysfunction on quality of life after pelvic radiotherapy

PURPOSE

Anorectal dysfunction is common after pelvic radiotherapy. This study aims to explore the relationship of subjective and objective anorectal function with quality of life (QoL) and their relative impact in patients irradiated for prostate cancer.

METHODS

Patients underwent anal manometry, rectal barostat measurement, and completed validated questionnaires, at least 1 year after prostate radiotherapy (range 1-7 years). QoL was measured by the Fecal Incontinence Quality of Life scale (FIQL) and the Expanded Prostate Cancer Index Composite Bowel domain (EPICB)-bother subscale. Severity of symptoms was rated by the EPICB function subscale.

RESULTS

Anorectal function was evaluated in 85 men. Sixty-three percent suffered from one or more anorectal symptoms. Correlations of individual symptoms ranged from r = 0.23 to r = 0.53 with FIQL domains and from r = 0.36 to r = 0.73 with EPICB bother scores. They were strongest for fecal incontinence and urgency. Correlations of anal sphincter pressures, rectal capacity, and sensory thresholds ranged from r = 0.00 to r = 0.42 with FIQL domains and from r = 0.15 to r = 0.31 with EPICB bother scores. Anal resting pressure correlated most strongly. Standardized regression coefficients for QoL outcomes were largest for incontinence, urgency, and anal resting pressure. Regression models with subjective parameters explained a larger amount (range 26-92 %) of variation in QoL outcome than objective parameters (range 10-22 %).

CONCLUSIONS

Fecal incontinence and rectal urgency are the symptoms with the largest influence on QoL. Impaired anal resting pressure is the objective function parameter with the largest influence. Therefore, sparing the structures responsible for an adequate fecal continence is important in radiotherapy planning.

The dose-response of the anal sphincter region--an analysis of data from the MRC RT01 trial

PURPOSE

Most studies investigating the dose-response of the rectum focus on rectal bleeding. However, it has been reported that other symptoms such as urgency or sphincter control have a large impact on quality-of-life and that different symptoms are related to the dose to different parts of the anorectal wall. In this study correlations between the 3D dose distribution to the anal-sphincter region and radiation-induced side-effects were quantified.

MATERIALS AND METHODS

Dose-surface maps of the anal canal were generated. Next, longitudinal and lateral extent and eccentricity were calculated at different dose levels; DSHs and DVHs were also determined. Correlations between these dosimetric measures and seven clinically relevant endpoints were determined by assessing dosimetric constraints. Furthermore, an LKB model was generated. The study was performed using the data of 388 prostate patients from the RT01 trial (ISRCTN 47772397).

RESULTS

Subjective sphincter control was significantly correlated with the dose to the anal surface. The strongest correlations were found for lateral extent at 53 Gy (p=0.01). Outcome was also significantly correlated with the DSH and the mean dose to the anal surface.

CONCLUSIONS

The dose to the anal sphincter region should be taken into account when generating treatment-plans. This could be done using shape-based tools, DSH/DVH-based tools or an NTCP model.

Increased rectal wall stiffness after prostate radiotherapy: relation with fecal urgency

BACKGROUND

  Late anorectal toxicity is a frequent adverse event of external beam radiotherapy (EBRT) for prostate cancer. The pathophysiology of anorectal toxicity remains unknown, but we speculate that rectal distensibility is impaired due to fibrosis. Our goal was to determine whether EBRT induces changes of rectal distensibility as measured by an electronic barostat and to explore whether anorectal complaints are related to specific changes of anorectal function.

METHODS

  Thirty-two men, irradiated for localized prostate carcinoma, underwent barostat measurements, anorectal manometry, and completed a questionnaire prior to and 1 year after radiotherapy. The primary outcome measure was rectal distensibility in response to stepwise isobaric distensions. In addition, we assessed sensory thresholds, anal pressures, and anorectal complaints.

KEY RESULTS

  External beam radiotherapy reduced maximal rectal capacity (227 ± 14 mL vs 277 ± 15 mL; P < 0.001), area under the pressure-volume curve (3212 ± 352 mL mmHg vs 3969 ± 413 mL mmHg; P < 0.005), and rectal compliance (15.7 ± 1.2 mL mmHg(-1) vs 17.6 ± 0.9 mL mmHg(-1) ; P = 0.12). Sensory pressure thresholds did not significantly change. Sixteen of the 32 patients (50%) had one or more anorectal complaints. Patients with urgency (n = 10) had a more reduced anal squeeze and maximum pressure (decrease 29 ± 11 mmHg vs 1 ± 7 mmHg; P < 0.05 and 31 ± 12 mmHg vs 2 ± 8 mmHg; P < 0.05 respectively) compared with patients without complaints, indicating a deteriorated external anal sphincter function.

CONCLUSIONS & INFERENCES

  Irradiation for prostate cancer leads to reduced rectal distensibility. In patients with urgency symptoms, anal sphincter function was also impaired.