[Normal tissue tolerance to external beam radiation therapy: small bowel]

Safety of Pelvic and Abdominal Radiation Therapy for Patients With Inflammatory Bowel Disease: A Dosimetric Analysis of Acute Bowel Toxicity

PURPOSE

Inflammatory bowel disease (IBD) has been considered a relative contraindication to radiation therapy (RT) because of the potential greater risk of RT-induced toxicities. This study aimed to assess acute toxicity outcomes in patients with IBD treated with abdominal/pelvic RT.

METHODS AND MATERIALS

After institutional review board approval, patients with IBD who received RT to the abdomen/pelvis were identified from an institutional research repository, and their electronic medical records were reviewed. The IBD cohort was matched 1:1 with controls according to all of the following: RT, gender, disease site, age, and year of RT. Acute toxicity was defined as toxicity occurring within 3 months of RT. Primary outcomes were assessed via univariable logistic regression models and the predicted probability of acute toxicity and acute gastrointestinal (GI) toxicity were plotted for the most significant covariates. IBD and control cohorts were compared on demographic and toxicity variables using χ2/Fisher exact tests and Kruskal-Wallis tests where appropriate.

RESULTS

We identified 62 patients with a median age of 64 years (IQR, 54-70 years) who received RT from 2006 to 2022. Patients were treated with intensity modulated RT (38; 61.3%), 3-dimensional conformal RT (12; 19.4%), and stereotactic body RT/brachytherapy (12; 19.4%). After RT, 28 (45.2%) and 23 (37.1%) patients experienced grade ≥2 acute (any) and acute GI toxicity, respectively. Higher overall RT dose and RT dose to small bowel were found to be significantly associated with increased risk of grade ≥2 acute toxicities (OR, 1.041 per unit Gy; 95% CI, 1.005-1.084; P = .034 and OR, 1.046; 95% CI, 1.018-1.082; P = .003, respectively). Between IBD and control cohorts, there were no significant differences in grade ≥2 acute (any) and acute GI toxicities (P = .710 and P = .704, respectively).

CONCLUSIONS

In patients with IBD treated with abdominal/pelvic RT for malignancy, RT was effective and well-tolerated. RT treatment planning should carefully consider the location(s) of IBD inflammation and dose to bowel structures, in particular, dose to the small bowel.

[Impact of IMRT for neoadjuvant rectal cancer?]

The standard management of locally advanced rectal tumors as cT3-T4 and/or N0/N1 is based on preoperative treatment combining radiotherapy of 45 to 50Gy and chemotherapy based on 5-fluorouracil. Intensity-modulated radiotherapy has already shown its interest compared to conformal radiotherapy in other locations, like in pelvic cancer. The role of intensity-modulated radiotherapy in the pre/postoperative treatment of rectal cancers is not a standard of care. Published studies showed its feasibility with the objective of less toxicity with equivalent efficacy.

Impact of external beam pelvic radiotherapy of endometrial carcinoma: A focus on chronic digestive toxicity

PURPOSE

The standard treatment for endometrial cancer is surgery, although depending on the risk factors, adjuvant radiation therapy may also be given. It is proposed for high-risk carcinomas for which an improvement in progression-free survival though not overall survival has been shown. However, despite the development of radiotherapy treatments with intensity modulation and image guidance, adjuvant radiation therapy remains toxic to the digestive system. We aimed to investigate the incidence of digestive toxicity and the presence of any predictive factors.

MATERIALS AND METHODS

Data were retrospectively collected from patients treated with adjuvant radiotherapy for endometrial carcinoma at the Institut de cancérologie de Lorraine and centre hospitalier Émile-Durkheim between January 2010 and October 2016 and analyzed to identify factors associated with chronic digestive toxicity.

RESULTS

One hundred and thirty-nine patients received a total dose of 50Gy fractionated into 25 sessions, five per week for five weeks. The median follow-up after irradiation completion was 38 months. The incidence of gastrointestinal and rectal toxicity in all patients treated with pelvic irradiation for endometrial carcinoma was 11.1% (95% confidence interval [95%CI]: 5.4-19%) for grade 3-4 and 25.6% (95%CI: 17.0-34.9%) for grade 2-4. No factor was found to be significantly predictive of chronic digestive toxicity. At five years, the overall survival was 74.3%, (95%CI: 65.3-81.4%), progression-free survival was 69.6% (95%CI: 60.1-77.3%) and incidence of pelvic recurrence was 7.9% (95%CI: 3.8-13.9%).

CONCLUSION

Our results confirmed that pelvic radiotherapy can induce a relatively high rate of digestive toxicity but failed to identify relevant factors able to predict it.

Citrulline, A Potential Biomarker of Radiation-Induced Small Intestine Damage

Radiation damage assessment of the small intestine is important in nuclear accidents or routine radiotherapy of abdominal tumors. This article reviews the clinical symptoms and molecular mechanisms of radiation-induced small intestinal damage and summarizes recent research on biomarkers of such damage. Citrulline is the most promising biomarker for the evaluation of radiation-induced small intestinal damage caused by radiotherapy and nuclear accidents. This article also summarizes the factors influencing plasma citrulline measurement investigated in the latest research, as well as new findings on the concentration of citrulline in saliva and urine after different types of radiation.

An Amino Acid-Based Oral Rehydration Solution Regulates Radiation-Induced Intestinal Barrier Disruption in Mice

BACKGROUND

Radiotherapy inadvertently affects gastrointestinal (GI) epithelial cells, causing intestinal barrier disruption and increased permeability.

OBJECTIVE

We examined the effect of amino acid-based oral rehydration solution (AA-ORS) on radiation-induced changes of intestinal barrier function and epithelial tight junctions (TJs) in a randomized experimental study using a total-body irradiation (TBI) mouse model.

METHODS

Eight-week-old male Swiss mice received a single-dose TBI (0, 1, 3, or 5 Gy), and subsequent gastric gavage with AA-ORS (threonine, valine, serine, tyrosine, and aspartic acid) or saline for 2 or 6 d. Intestinal barrier function of mouse ileum was characterized by electrophysiological analysis of conductance, anion selectivity, and paracellular permeability [fluorescein isothiocyanate (FITC)-dextran]. Ultrastructural changes of TJs were evaluated by transmission electron microscopy. Membrane protein and mRNA expression of claudin-1, -2, -3, -5, and -7, occludin, and E-cadherin were analyzed with western blot, qPCR, and immunohistochemistry. Nonparametric tests were used to compare treatment-dose differences for each time point.

RESULTS

Saline-treated mice had a higher conductance at doses as low as 3 Gy, and as early as 2 d post-TBI compared with 0 Gy (P < 0.001). Paracellular permeability and dilution potential were increased 6 d after 5 Gy TBI (P < 0.001). Conductance decreased with AA-ORS after 2 d in 3-Gy and 5-Gy mice (P < 0.05 and P < 0.001), and on day 6 after 5 Gy TBI (P < 0.001). Anion selectivity and FITC permeability decreased from 0.73 ± 0.02 to 0.61 ± 0.03 pCl/pNa (P < 0.01) and from 2.7 ± 0.1 × 105 to 2.1 ± 0.1 × 105 RFU (P < 0.001) in 5-Gy mice treated with AA-ORS for 6 d compared with saline. Irradiation-induced ultrastructural changes of TJs characterized by decreased electron density and gap formation improved with AA-ORS. Reduced claudin-1, -3, and -7 membrane expression after TBI recovered with AA-ORS within 6 d, whereas claudin-2 decreased indicating restitution of TJ proteins.

CONCLUSIONS

Radiation-induced functional and structural disruption of the intestinal barrier in mice is reversed by AA-ORS rendering AA-ORS a potential treatment option in prospective clinical trials in patients with gastrointestinal barrier dysfunction.

The INTER-ROMA Project - a Survey among Italian Radiation Oncologists on Their Approach to the Treatment of Bone Metastases

Aims and background

Radiotherapy has an established palliative role for bone metastases but despite the large number of patients treated there is still controversy surrounding the optimal radiotherapy schedule to prescribe. The aim of this survey was to determine the decision patterns of Italian radiation oncologists in four different clinical cases of patients with bone metastases.

Methods and study design

During the latest national meeting of the Italian Association of Radiation Oncology (AIRO), four clinical cases were presented to attending radiation oncologists. The cases were different with respect to the histology of the primary tumor, performance status, pain before and after analgesics, tumor site, and radiological characteristics of the metastatic lesions. For each clinical case the respondents were asked to give an indication for treatment; prescribe doses, volumes and treatment field arrangements; decide whether to prescribe prophylactic supportive therapy or not; and provide information about factors that particularly influenced prescription. Finally, a descriptive statistical analysis was performed.

Results

Three hundred questionnaires were distributed to radiation oncologists attending the congress. One hundred twenty-five questionnaires were returned but only 122 (40.6%) were adequately completed and considered for the analysis. Considerable differences were observed among radiation oncologists in prescribing and delivering radiotherapy for bone metastases. There was also a notable divergence from international guidelines, which will be discussed in this report.

Conclusions

Despite the results of clinical trials, Italian radiation oncologists differ considerably in their decisions on treatment doses and volumes. National guidelines are needed in order that patients can be treated uniformly and better data will become available for evidence-based palliative radiotherapy.

[Use of chemotherapy and radiotherapy in the treatment of urothelial carcinoma of the upper urinary tract]

Urothelial carcinomas of the upper urinary tract are rare entities. Surgery remains the mainstay of the management. The use of others therapeutic modalities is not clearly defined yet. However, the frequency of local recurrence and locoregional encourage us to evaluate the indication of adjuvant therapies. We conducted a synthesis of key data in the literature on the use of chemotherapy and radiotherapy in the treatment of urothelial carcinoma of the renal pelvis and ureter. A literature search on PubMed was performed using the following keywords (MeSH) "urothelial carcinoma", "upper urinary tract", "radiation", "chemotherapy", and adjuvant.

Gastrointestinal radiation injury: Symptoms, risk factors and mechanisms

Ionising radiation therapy is a common treatment modality for different types of cancer and its use is expected to increase with advances in screening and early detection of cancer. Radiation injury to the gastrointestinal tract is important factor working against better utility of this important therapeutic modality. Cancer survivors can suffer a wide variety of acute and chronic symptoms following radiotherapy, which significantly reduces their quality of life as well as adding an extra burden to the cost of health care. The accurate diagnosis and treatment of intestinal radiation injury often represents a clinical challenge to practicing physicians in both gastroenterology and oncology. Despite the growing recognition of the problem and some advances in understanding the cellular and molecular mechanisms of radiation injury, relatively little is known about the pathophysiology of gastrointestinal radiation injury or any possible susceptibility factors that could aggravate its severity. The aims of this review are to examine the various clinical manifestations of post-radiation gastrointestinal symptoms, to discuss possible patient and treatment factors implicated in normal gastrointestinal tissue radiosensitivity and to outline different mechanisms of intestinal tissue injury.

High-dose pre-operative helical tomotherapy (54 Gy) for retroperitoneal liposarcoma

Purpose

To evaluate the feasibility of pre-operative radiotherapy (54 Gy) with Helical Tomotherapy (HT) followed by surgery.

Methods and materials

Ten patients with non-metastatic resectable retroperitoneal liposarcomas were treated by pre-operative tomotherapy (54 Gy) and surgery. Clinical and biological toxicities were evaluated on the CTCAEV3.0 scale. For nine patients, delivered tomotherapy plans were compared with retrospectively-planned dynamic intensity-modulated radiotherapy (IMRT) dosimetric studies.

Results

No immediate or late Grade>2 toxicities were observed after radiotherapy. Post-operatively, one patient died and three patients experienced Grade 3 toxicity (two digestive and one metabolic). These toxicities disappeared and only two patients presented persistent Grade 1 paresthesia. R0 resection was obtained for four patients, R1 for four, and R2 resection for two. With a median follow-up of 26 months, no local or metastatic relapse was observed. Dosimetric comparisons between HT and retrospectively-planned IMRT demonstrate adequate target volume coverage for both techniques. Gastrointestinal sparing is higher with HT with a D200cc reduced by 5 Gy. Integral dose (ID) was increased in HT.

Conclusions

High dose pre-operative radiotherapy (54 Gy) for retroperitoneal liposarcoma is feasible and mostly well tolerated. Cumulative toxicity and tolerance depend mainly on patient’s general status. Image-guided radiation therapy (IGRT) is essential, irrespective of the IMRT technique used. Furthermore, HT offers the possibility of sparing selected areas in such complex volumes.

[Intensity-modulated radiation therapy for anal carcinoma]

Anal canal carcinoma are highly curable by irradiation, combined with chemotherapy in locally advanced disease, with preservation of sphincter function. The clinical target volume for the nodes is extended, often including the inguinal nodes, which is not usual for other pelvic tumours. Acute and late effects are correlated with the volume and dose delivered to organs at risk, i. e. small bowel, bladder and increased by concomitant chemotherapy. Intensity modulated irradiation (IMRT) makes it possible to optimize the dose distribution in this "complex U shaped" volume, while maintaining the dose distribution for the target volumes. The conversion from conformal irradiation to IMRT necessitates good knowledge of the definition and skills to delineate target volumes and organs at risk, including new volumes needed to optimize the dose distribution. Dosimetric and clinical benefits of IMRT are described, based on early descriptions and evidence-based publication. The growing development of IMRT in anal canal radiotherapy must be encouraged, and long-term benefits should be soon published. Radiation oncologists should precisely learn IMRT recommendations before starting the technique, and evaluate its early and late results for adverse effects, but also for long-term tumour control.

[Intensity modulated radiotherapy as adjuvant post-operative treatment for retroperitoneal sarcoma: acute toxicity]

PURPOSE

To assess the acute toxicity of intensity modulated radiotherapy as post-operative adjuvant treatment for retroperitoneal sarcoma.

PATIENTS AND METHODS

Patients who received adjuvant intensity modulated radiotherapy from January 2009 to September 2010 were retrospectively reviewed.

RESULTS

Fourteen patients entered the study (seven primary tumours and seven relapses). All tumours were liposarcoma and had macroscopically complete resection, epiploplasty was systematically realized. Median tumour size was 21 cm (range: 15-45), median planning target volume was 580 cm(3) (range: 329-1172) and median prescribed dose was 50.4 Gy (range: 45-54). Median follow-up was 11.5 months (range: 2-21.4). Acute toxicity was mild: acute digestive toxicity grade 1-2 occurred in 12/14 patients (86%). However, there was no weight loss of more than 5% during radiotherapy and no treatment interruption was required. Two months after completion of radiotherapy, digestive toxicity grade 1 remained present in 1/14 patients (7%). One case of grade 3 toxicity occurred during follow-up (transient abdominal pain). Three relapses occurred: two were outside treaded volume and one was both in and outside treated volume.

CONCLUSIONS

Intensity modulated radiotherapy in the postoperative setting of retroperitoneal sarcoma provides low acute toxicity. Longer follow-up is needed to assess late toxicity, especially for bowel, kidney and radio-induced malignancies.

[Adjuvant radiotherapy in patients with endometrial cancers]

The treatment of patients with endometrial cancer has been extensively modified in recent years. Several randomized studies have redefined the indications for adjuvant therapy in tumours staged 1. In the absence of poor prognostic factors, the management tends to be less aggressive than before, often limited to vaginal brachytherapy. Conversely, for more advanced lesions, for which prognosis is poor, combinations of chemoradiation are currently being evaluated. This literature review aims to provide an update on recent developments in the management of adjuvant radiotherapy for endometrial carcinoma.