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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Role of nutritional intervention in patients treated with radiotherapy for pelvic malignancy

C McGough, C Baldwin, G Frost, and HJ Andreyev.

Review published: 2004.

Link to full article: [PMC free article: PMC2409534]

CRD summary

This review examined the efficacy of nutritional interventions for gastrointestinal side-effects in patients undergoing pelvic radiotherapy. Weaknesses in the methodology of both the included studies and the review (e.g. search strategy and validity assessment) resulted in there being no evidence to recommend dietary interventions. Further randomised controlled trials of low-fat diets, probiotic supplementation and elemental diets are suggested.

Authors' objectives

To examine the efficacy of therapeutic nutritional interventions for gastrointestinal side-effects in patients undergoing pelvic radiotherapy. The authors also reported the incidence and significance of malnutrition in these patients, but these data are beyond the remit of this abstract.

Searching

MEDLINE and EMBASE (from 1966 to May 2003) and the Cochrane Library were searched; some search terms were reported. Bibliographic searches of the identified papers were also undertaken. Abstracts of radiology and nutrition conferences and UK doctoral theses were searched. Internet searches using commercial search engines (e.g. Google, Ask Jeeves) were performed. The authors did not report whether any language restrictions were applied.

Study selection

Study designs of evaluations included in the review

The authors did not specify which types of study designs were eligible for inclusion. The included studies were randomised controlled trials (RCTs), prospective cohorts, a retrospective study, a pilot feasibility study, qualitative studies and case reports.

Specific interventions included in the review

Studies assessing nutritional interventions for the gastrointestinal side-effects of pelvic radiotherapy were eligible for inclusion. The included studies used a variety of nutritional interventions, given during or after radiotherapy: low-fat diets with or without additional medium-chain triglyceride supplementation or bile sequesterant; lactose restriction or modification; low-residue diet; probiotic supplementation and modified food intake; elemental diet with or without modified food intake; enteral and parenteral protein-calorie nutrition support; enzyme preparation supplement; gluten-free, cow's milk protein-free diet with additional lactose and reduced fat and residue; reduction in high-fibre foods; vitamins A, C, E and magnesium. Comparison diets included unrestricted fat intake or low-fat diets, normal diets, modified food intake and total parenteral nutrition.

Participants included in the review

Studies assessing participants with gynaecological, rectal or urological malignancy who were treated with pelvic radiotherapy were eligible for inclusion. The included studies involved both adults and children; no further details were provided.

Outcomes assessed in the review

Studies that reported acute or chronic bowel toxicity, as defined by the Radiation Therapy Oncology Group scoring tool, were eligible for inclusion. Eligible surrogate markers for this primary outcome included stool frequency and consistency, the use of antidiarrhoea medication, and patient-reported gastrointestinal symptoms. Eligible secondary outcomes included nutritional status (as assessed by change in weight), other anthropometric indicators and change in dietary intake. The review also reported other outcomes assessed by the included studies.

How were decisions on the relevance of primary studies made?

The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.

Assessment of study quality

The methodological quality of the RCTs was assessed in terms of the method of randomisation, the use of allocation concealment, blinding and intention-to-treat analyses. Other non-randomised studies were assessed according to the methodology and sampling procedure used, but not using any validated assessment procedure. The authors did not state how the validity assessment was performed.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

The data appear to have been reported as described in the original study reports, using percentage values for outcome incidences where available.

Methods of synthesis

How were the studies combined?

The studies were combined in a narrative, grouped according to the type of nutritional intervention.

How were differences between studies investigated?

The narrative synthesis identified similarities and differences between the studies.

Results of the review

Thirty-five studies (2,344 patients) were included in the review: 16 RCTs, 11 prospective cohorts, 3 retrospective studies, 2 qualitative studies, 1 feasibility pilot study and 2 case reports.

Dietary modifications during pelvic radiotherapy (18 studies).

One RCT (143 patients) of a low-fat dietary regimen found that the intervention was associated with a reduction in the incidence of diarrhoea in comparison with the control group: 1.1 versus 1.7 loose stools per week for the intervention versus the control group (p<0.01). Another RCT (21 patients) found a low-fat diet was associated with a significant reduction in the frequency of bowel motions: 1.6 and 2.0 bowel motions per day for the intervention and control groups, respectively (p<0.05). However, both studies suffered from methodological weaknesses. One RCT (190 patients) of probiotics found a significant reduction in grade 4 bowel symptoms (21.4% versus 0%), but significantly more grade 2 symptoms (65.3% versus 23.8%), for the intervention group compared with the control group. Another RCT (24 patients) of probiotics, found a significant reduction in the incidence of diarrhoea in the intervention group compared with the control group (18 to 27% versus 80 to 90%, respectively).

One RCT (680 patients) of an elemental diet intervention reported a lower level of grade 1 (16% versus 25%) and grade 2 (12% versus 27%) bowel toxicity in the intervention group compared with the control group. A phase two pilot study (17 patients) of an elemental diet also showed a reduction in the number and severity of diarrhoea days (5.9 versus 12.2 days, respectively; p<0.05). The remaining studies of elemental diets (2 RCTs and a prospective cohort study) failed to report a measure of bowel toxicity.

One RCT (56 patients) of an enzyme supplement found a reduction in moderate bowel symptoms in comparison with controls (57% versus 36%; p=0.01).

One retrospective study (156 patients) of a reduced residue regimen did not identify statistically significant differences in bowel symptoms.

Bowel toxicity was not reported in 3 studies (2 RCTs and 1 prospective cohort study) of protein or calorie supplementation, 1 RCT of micronutrient supplementation, 2 RCTs of parenteral nutrition and 1 RCT of a low lactose diet.

Dietary modifications after pelvic radiotherapy.

Two RCTs (246 patients) of probiotics did not report any improvements in chronic bowel symptoms.

One case report of an elemental diet noted resolution of symptoms for the patient. One crossover study (8 patients) of an elemental diet failed to report an objective measure of bowel toxicity.

A prospective cohort study (7 patients) of a low-fat dietary regimen reported moderate improvements in all patients. Another prospective cohort study failed to report an objective measure of bowel toxicity.

A gluten-free, cow's milk protein-free, low-residue, low-fat diet was reported to improve malabsorption and nutritional status in 5 case reports of children.

One case report found vitamin A to be beneficial for pain and signs of anal ulceration. One prospective cohort study (9 patients) of combined vitamins C and E resulted in the subsidence of symptoms after 6 to 12 weeks. Another prospective cohort study (20 patients) of combined vitamins C and E found that diarrhoea, urgency and bleeding resolved after 4 weeks. One prospective cohort study (20 patients) found magnesium supplementation resolved diarrhoea in patients with proctosigmoiditis.

Four cohort studies of parenteral nutrition and 2 qualitative studies of various self-imposed dietary changes did not report objective measures of bowel toxicity.

Authors' conclusions

Weaknesses in the methodology of the included studies resulted in there being no evidence base for the use of nutritional interventions in the prevention or management of bowel symptoms attributable to radiotherapy.

CRD commentary

This review answered an identified research question that was defined in terms of the intervention, participants and outcomes; criteria for the study design were not defined. The reviewers searched several literature sources for both published and unpublished data, but did not report whether any language restrictions were applied; this suggests that attempts were made to eliminate publication bias but the risk of language bias is unclear. A complete list of keywords was not provided, therefore the search strategy cannot be reproduced. The authors also failed to report whether appropriate steps were taken to reduce the risk of bias and errors during the study selection, validity assessment and data extraction processes. The formal validity assessment was restricted to RCTs; methodological aspects of other study designs were informally assessed, but not using validated criteria. However, details of the quality of the individual studies were not reported, making it difficult for the reader to assess the likely significance of the findings, although a number of the studies used poorer designs.

The narrative synthesis appeared appropriate given the wide range of studies included in the review. Data tables accompanied the review text but provided insufficient details of the primary studies, particularly the characteristics of the participants (e.g. age and gender of the patients, details of radiotherapy treatment). Consequently, although some similarities and differences between the studies were discussed, information about important confounders may be missing. However, despite concerns about the methodology of the review and the quality of the included studies, the authors' conclusions are suitable cautious and appear reasonable.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that the use of low-fat diets, probiotic supplementation and elemental diets to relieve gastrointestinal symptoms in patients treated with pelvic radiotherapy requires further investigation in RCTs. Future studies should incorporate validated and clinically relevant end points.

Bibliographic details

McGough C, Baldwin C, Frost G, Andreyev H J. Role of nutritional intervention in patients treated with radiotherapy for pelvic malignancy. British Journal of Cancer 2004; 90(12): 2278-2287. [PMC free article: PMC2409534] [PubMed: 15162154]

Indexing Status

Subject indexing assigned by NLM

MeSH

Diarrhea /etiology /prevention & control; Diet; Female; Humans; Incidence; Male; Malnutrition /epidemiology /etiology /therapy; Nutritional Status; Parenteral Nutrition; Pelvic Neoplasms /radiotherapy; Radiation Injuries /prevention & control /therapy; Randomized Controlled Trials as Topic; Research Design; Treatment Outcome

AccessionNumber

12004001316

Database entry date

31/05/2007

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 15162154