Patient Preparation and Radiation Protection Guidance for Adult Patients Undergoing Radioiodine Treatment for Thyroid Cancer in the UK

Radioactive iodine is a highly effective treatment for thyroid cancer and has now been used in clinical practice for more than 80 years. In general, the treatment is well tolerated. However, it can be logistically quite complex for patients due to the need to reduce iodine intake and achieve high levels of thyroid-stimulating hormone prior to treatment. Radiation protection precautions must also be taken to protect others from unnecessary radiation exposure following treatment. It has been well documented by thyroid cancer patient support groups that there is significant variation in practice across the UK. It is clear that some patients are being asked to observe unnecessarily burdensome restrictions that make it more difficult for them to tolerate the treatment. At the instigation of these support groups, a multidisciplinary group was assembled to examine the evidence and generate guidance on best practice for the preparation of patients for this treatment and the management of subsequent radiation protection precautions, with a focus on personalising the advice given to individual patients. The guidance includes advice about managing particularly challenging situations, for example treating patients who require haemodialysis. We have also worked together to produce a patient information leaflet covering these issues. We hope that the guidance document and patient information leaflet will assist centres in improving our patients' experience of receiving radioactive iodine. The patient information sheet is available as Supplementary Material to this article.

Radioactive iodine: An unappreciated threat to salivary gland function

Thyroid cancer is an endocrine malignancy whose prevalence is increasing in the United States. Nearly 57,000 new cases of thyroid cancer are estimated to be diagnosed in 2017. The standard of care for differentiated thyroid cancer is thyroidectomy followed by ablation of thyroid remnants with high-dose radioactive iodine (¹³¹ I). Apart from thyroid glands, ¹³¹ I accumulates in cells of salivary glands and compromises its function. Xerostomia is, therefore, a frequent and often persistent complaint of patients. Despite adoption of standard preventive measures, parenchymal damage and chronic salivary dysfunction are observed in a substantial number of patients. Saliva is important for oral homeostasis, and its reduction increases the risk of oral morbidity. As differentiated thyroid cancer patients have an excellent survival rate, preservation of salivary gland function carries added significance. A focus on treatments that preserve or restore long-term salivary flow can significantly improve the quality of life of thyroid cancer survivors.

Interventions for the management of dry mouth: non-pharmacological interventions

BACKGROUND

Xerostomia is the subjective sensation of dry mouth. Common causes of xerostomia include adverse effects of many commonly prescribed medications, disease (e.g. Sjogren's Syndrome) and radiotherapy treatment for head and neck cancers. Non-pharmacological techniques such as acupuncture or mild electrostimulation may be used to improve symptoms.

OBJECTIVES

To assess the effects of non-pharmacological interventions administered to stimulate saliva production for the relief of dry mouth.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 16th April 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 3), MEDLINE via OVID (1948 to 16th April 2013), EMBASE via OVID (1980 to 16th April 2013), AMED via OVID (1985 to 16th April 2013), CINAHL via EBSCO (1981 to 16th April 2013), and CANCERLIT via PubMed (1950 to 16th April 2013). The metaRegister of Controlled Clinical Trials (www.controlled-trials.com) and ClinicalTrials.gov (www.clinicaltrials.gov) were also searched to identify ongoing and completed trials. References lists of included studies and relevant reviews were also searched. There were no restrictions on the language of publication or publication status.

SELECTION CRITERIA

We included parallel group randomised controlled trials of non-pharmacological interventions to treat dry mouth, where participants had dry mouth symptoms at baseline.

DATA COLLECTION AND ANALYSIS

At least two review authors assessed each of the included studies to confirm eligibility, assess risk of bias and extract data using a piloted data extraction form. We calculated mean difference (MD) and 95% confidence intervals (CI) for continuous outcomes or where different scales were used to assess an outcome, we calculated standardised mean differences (SMD) together with 95% CIs. We attempted to extract data on adverse effects of interventions. Where data were missing or unclear we attempted to contact study authors to obtain further information.

MAIN RESULTS

There were nine studies (total 366 participants randomised) included in this review of non-pharmacological interventions for dry mouth which were divided into three comparisons. Eight studies were assessed at high risk of bias in at least one domain and the remaining study was at unclear risk of bias.Five small studies (total 153 participants, with dry mouth following radiotherapy treatment) compared acupuncture with placebo. Four were assessed at high risk and one at unclear risk of bias. Two trials reported outcome data for dry mouth in a form suitable for meta-analysis. The pooled estimate of these two trials (70 participants, low quality evidence) showed no difference between acupuncture and control in dry mouth symptoms (SMD -0.34, 95% CI -0.81 to 0.14, P value 0.17, I(2) = 39%) with the confidence intervals including both a possible reduction or a possible increase in dry mouth symptoms. Acupuncture was associated with more adverse effects (tiny bruises and tiredness which were mild and temporary). There was a very small increase in unstimulated whole saliva (UWS) at the end of 4 to 6 weeks of treatment (three trials, 71 participants, low quality evidence) (MD 0.02 ml/minute, 95% CI 0 to 0.04, P value 0.04, I(2) = 57%), and this benefit persisted at the 12-month follow-up evaluation (two trials, 54 participants, low quality evidence) (UWS, MD 0.06 ml/minute, 95% CI 0.01 to 0.11, P value 0.03, I(2) = 10%). For the outcome of stimulated whole saliva (SWS, three trials, 71 participants, low quality evidence) there was a benefit favouring acupuncture (MD 0.19 ml/minute, 95% CI 0.07 to 0.31, P value 0.002, I(2) = 1%) an effect which also persisted at the 12-month follow-up evaluation (SWS MD 0.28 ml/minute, 95% CI 0.09 to 0.47, P value 0.004, I(2) = 0%) (two trials, 54 participants, low quality evidence).Two small studies, both at high risk of bias, compared the use of an electrostimulation device with a placebo device in participants with Sjögren's Syndrome (total 101 participants). A further study, also at high risk of bias, compared acupuncture-like electrostimulation of different sets of points in participants who had previously been treated with radiotherapy. None of these studies reported the outcome of dry mouth. There was no difference between electrostimulation and placebo in the outcomes of UWS or SWS at the end of the 4-week treatment period in the one study (very low that provided data for these outcomes. No adverse effects were reported.A single study at high risk of bias, compared the stimulatory effect of powered versus manual toothbrushing and found no difference for the outcomes of UWS or SWS.

AUTHORS' CONCLUSIONS

There is low quality evidence that acupuncture is no different from placebo acupuncture with regard to dry mouth symptoms, which is the most important outcome. This may be because there were insufficient participants included in the two trials to show a possible effect or it may be that there was some benefit due to 'placebo' acupuncture which could have biased the effect to the null. There is insufficient evidence to determine the effects of electrostimulation devices on dry mouth symptoms. It is well known that dry mouth symptoms may be problematic even when saliva production is increased, yet only two of the trials that evaluated acupuncture reported dry mouth symptoms, a worrying reporting bias. There is some low quality evidence that acupuncture results in a small increase in saliva production in patients with dry mouth following radiotherapy.There is insufficient evidence to determine the effects of electrostimulation devices on dry mouth symptoms or saliva production in patients with Sjögren's Syndrome. Reported adverse effects of acupuncture are mild and of short duration, and there were no reported adverse effects from electrostimulation.

Interventions for the management of dry mouth: topical therapies

BACKGROUND

Xerostomia (the feeling of dry mouth) is a common symptom especially in older adults. Causes of dry mouth include medications, autoimmune disease (Sjögren's Syndrome), radiotherapy or chemotherapy for cancer, hormone disorders and infections.

OBJECTIVES

To determine which topical treatments for dry mouth are effective in reducing this symptom.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group Trials Register (28 October 2011), The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4 2011), MEDLINE via OVID (1950 to 28 October 2011), EMBASE via OVID (1980 to 28 October 2011), CINAHL via EBSCO (1980 to 28 October 2011), AMED via OVID (1985 to 28 October 2011), CANCERLIT via PubMed (1950 to 28 October 2011).

SELECTION CRITERIA

We included randomised controlled trials of topical interventions such as lozenges, sprays, mouthrinses, gels, oils, chewing gum or toothpastes for the treatment of dry mouth symptom. We classified interventions into two broad categories, saliva stimulants and saliva substitutes, and these were compared with either placebo or another intervention. We included both parallel group and crossover trials.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently carried out data extraction and assessed risk of bias. Trial authors were contacted for additional information as required.

MAIN RESULTS

Thirty-six randomised controlled trials involving 1597 participants met the inclusion criteria. Two trials compared saliva stimulants to placebo, nine trials compared saliva substitutes to placebo, five trials compared saliva stimulants directly with saliva substitutes, 18 trials directly compared two or more saliva substitutes, and two trials directly compared two or more saliva stimulants. Only one trial was at low risk of bias and 17 were at high risk of bias. Due to the range of interventions, comparisons and outcome measures in the trials, meta-analysis was possible for only a few comparisons. Oxygenated glycerol triester (OGT) saliva substitute spray shows evidence of effectiveness compared to an electrolyte spray (standardised mean difference (SMD) 0.77, 95% confidence interval (CI) 0.38 to 1.15) which corresponds to approximately a mean difference of 2 points on a 10-point visual analogue scale (VAS) for mouth dryness. Both integrated mouthcare systems (toothpaste + gel + mouthwash) and oral reservoir devices show promising results but there is insufficient evidence at present to recommend their use. Although chewing gum is associated with increased saliva production in the majority of those with residual capacity, there is no evidence that gum is more or less effective than saliva substitutes.

AUTHORS' CONCLUSIONS

There is no strong evidence from this review that any topical therapy is effective for relieving the symptom of dry mouth. OGT spray is more effective than an aqueous electrolyte spray (SMD 0.77, 95% CI 0.38 to 1.15) which is approximately equivalent to a mean difference of 2 points on a 10-point VAS scale for mouth dryness. Chewing gums appear to increase saliva production in those with residual secretory capacity and may be preferred by patients, but there is no evidence that gum is better or worse than saliva substitutes. Integrated mouthcare systems and oral reservoir devices may be helpful but further research is required to confirm this. Well designed, adequately powered randomised controlled trials of topical interventions for dry mouth, which are designed and reported according to CONSORT guidelines, are required to provide evidence to guide clinical care. For many people the symptom of dry mouth is a chronic problem and trials should evaluate whether treatments are palatable, effective in reducing xerostomia, as well as the long-term effects of treatments on quality of life of those with chronic dry mouth symptoms.