Impact of low iodine diets on ablation success in differentiated thyroid cancer: A mixed-methods systematic review and meta-analysis.

BACKGROUND: Debate remains regarding whether to recommend a low iodine diet (LID) before radioactive-iodine treatment and its duration and stringency. This mixed-methods review aimed to determine if iodine status affects treatment success, the most effective diet to reduce iodine status, and how LID impacts wellbeing. METHODS: Five electronic databases were searched until February 2021. An effectiveness synthesis (quantitative studies) and views synthesis (qualitative, survey, and experience-based evidence) were conducted individually and then integrated. Quality assessment was undertaken. RESULTS: Fifty-six quantitative and three qualitative studies were identified. There was greater ablation success for those with an iodine status of <50 mcg/L (or mcg/gCr) compared with ≥250 (odds ratio [OR] = 2.63, 95% confidence interval [CI], 1.18-5.86, n = 283, GRADE certainty of evidence very low). One study compared <50 mcg/L (or mcg/gCr) to 100-199 and showed similar rates of ablation success (OR = 1.59, 95% CI, 0.48-6.15, n = 113; moderate risk of bias). People following a stricter LID before ablation had similar rates of success to a less-strict diet (OR = 0.67, 95% CI, 0.26-1.73, n = 256, GRADE certainty of evidence very low). A stricter LID reduced iodine status more than a less strict (SMD = -0.40, 95% CI, -0.56 to -0.24, n = 816), and reduction was seen after 1 and 2 weeks. The main challenges were a negative impact on psychological health, over restriction, confusion, and difficulty for sub-groups. CONCLUSIONS: Although a LID of 1-2 weeks reduces iodine status, it remains unclear whether iodine status affects treatment success as only a few low-quality studies have examined this. LIDs are challenging for patients. Higher-quality studies are needed to confirm whether a LID is necessary.

Low iodine diet advice and differentiated thyroid cancer treatment: A historic exploration in three UK centres.

BACKGROUND AND AIMS: Patients with differentiated thyroid cancer are often advised to follow a low iodine diet (LID) one to two weeks before radioiodine remnant ablation (RRA). We describe treatment practices and ablation success rates in centres (C1, C2, C3) in the UK with different approaches to LID advice. METHODS: Historic cohort of patients with differentiated thyroid cancer treated with RRA in 2015/16 in C1 (n = 50, 1-week LID), C2 (n = 59, 2-week LID) and C3 (n = 108, no LID advice). Response to RRA was stratified as excellent, indeterminate, or incomplete by the adapted American Thyroid Association Dynamic Risk Stratification Score. RESULTS: There was little difference in age, sex and staging between centres, but the percentage receiving 1.1 GBq vs higher administered activities differed (C1:22%, C2:44%, C3:15%, p < 0.001). Excellent response was recorded for: C1:48%, C2:36%, C3:49% (p = 0.61). Differences in RRA preparation and outcome assessment at C3 precluded comparison across all centres. Adjusted odds ratio for excellent response at C2 vs C1 was 0.57 (95%CI: 0.25,1.32), p = 0.19. CONCLUSIONS: There was no evidence that advising a LID for 2-weeks before RRA improves outcomes compared to 1-week. For definitive recommendations on LIDs prior to RRA, a prospective multi-centre study with a more homogenous approach to patient management or, randomised controlled trial, is needed.

Pre-admission interventions (prehabilitation) to improve outcome after major elective surgery: a systematic review and meta-analysis.

OBJECTIVE: To determine the benefits and harms of pre-admission interventions (prehabilitation) on postoperative outcomes in patients undergoing major elective surgery. DESIGN: Systematic review and meta-analysis of randomised controlled trials (RCTs) (published or unpublished). We searched Medline, Embase, CENTRAL, DARE, HTA and NHS EED, The Cochrane Library, CINAHL, PsychINFO and ISI Web of Science (June 2020). SETTING: Secondary care. PARTICIPANTS: Patients (≥18 years) undergoing major elective surgery (curative or palliative). INTERVENTIONS: Any intervention administered in the preoperative period with the aim of improving postoperative outcomes. OUTCOMES AND MEASURES: Primary outcomes were 30-day mortality, hospital length of stay (LoS) and postoperative complications. Secondary outcomes included LoS in intensive care unit or high dependency unit, perioperative morbidity, hospital readmission, postoperative pain, heath-related quality of life, outcomes specific to the intervention, intervention-specific adverse events and resource use. REVIEW METHODS: Two authors independently extracted data from eligible RCTs and assessed risk of bias and the certainty of evidence using Grading of Recommendations, Assessment, Development and Evaluation. Random-effects meta-analyses were used to pool data across trials. RESULTS: 178 RCTs including eight types of intervention were included. Inspiratory muscle training (IMT), immunonutrition and multimodal interventions reduced hospital LoS (mean difference vs usual care: -1.81 days, 95% CI -2.31 to -1.31; -2.11 days, 95% CI -3.07 to -1.15; -1.67 days, 95% CI -2.31 to -1.03, respectively). Immunonutrition reduced infective complications (risk ratio (RR) 0.64 95% CI 0.40 to 1.01) and IMT, and exercise reduced postoperative pulmonary complications (RR 0.55, 95% CI 0.38 to 0.80, and RR 0.54, 95% CI 0.39 to 0.75, respectively). Smoking cessation interventions reduced wound infections (RR 0.28, 95% CI 0.12 to 0.64). CONCLUSIONS: Some prehabilitation interventions may reduce postoperative LoS and complications but the quality of the evidence was low. PROSPERO REGISTRATION NUMBER: CRD42015019191.

Experiences of low iodine diets in the treatment of differentiated thyroid cancer with radioactive iodine ablation therapy.

BACKGROUND AND AIMS: International guidelines on the treatment of differentiated thyroid cancers (DTC) promote the use of low iodine diets (LID) prior to radioactive iodine remnant ablation (RIA), as high iodine status may interfere with radioiodine uptake. Most UK treatment centres adhere to these guidelines and advise people to consume a LID. There is limited research as to how people cope with the LID or its impact on daily life and wellbeing, and no studies have been conducted in the UK. This study explored peoples' views and experiences in relation to consuming a LID during treatment for DTC with RIA. METHODS: Twenty-eight semi-structured interviews were conducted with people from across three treatment centres where differing advice had been delivered regarding a LID. Interviews were recorded, transcribed verbatim and key themes were developed through inductive thematic analyses. RESULTS: Individuals advised to consume a LID believed that adhering to the diet would help their treatment. Most restricted their diets beyond what was recommended and there was confusion surrounding what they could eat as part of the diet. Food selection and preparation were important which included substitution of foods and ingredient checking. Being on the diet was considered to have both a physical and psychological impact. CONCLUSIONS: The findings of this study provide a qualitative insight into the lived experiences of people with DTC in relation to consuming a LID. The results have relevance for professionals providing dietary guidance at oncology centres treating patients with RIA therapy in the UK.

A Survey of UK Centres on Low Iodine Diet Recommendations prior to Radioiodine Ablation Therapy for Differentiated Thyroid Cancer.

BACKGROUND: Guidelines suggest that a low iodine diet (LID) is advised prior to radioiodine ablation (RIA) for thyroid cancer. We aim to describe current practice regarding LID advice in the UK, determine uptake of the 2016 UK LID Working Group diet sheet and discover whether there are differences in practice. METHODS: We used an online survey distributed between November 2018 and April 2019 to centres in the UK that administer 131I. We asked questions on whether a LID is advised, for how long, how advice is presented, whether and how compliance is measured and whether treatment is delayed if LID advice is not followed. RESULTS: Fifty-six clinicians from 47 centres that carry out RIA for thyroid cancer responded. Forty-four centres (94%) advise a LID prior to RIA, the majority for 14 days (82%). Two-thirds of the centres use the UK LID Working Group diet sheet. Patients are told to resume normal eating when 131I is administered at 17 centres (39%), with 18 (41%) advising waiting for 24-48 h after administration. Most centres (95%) use only a simple question or do not assess compliance. Only 2 (5%) indicate that RIA would be delayed if someone said they had not followed LID advice. CONCLUSIONS: UK practice regarding LID prior to RIA for thyroid cancer is consistent with current guidelines, but non-adherence does not usually delay RIA. The UK Low Iodine Diet Working Group diet sheet is widely recognised and used. Practice could be improved by centres working to harmonise advice on when to restart a normal diet.

Sweet satiation: Acute effects of consumption of sweet drinks on appetite for and intake of sweet and non-sweet foods.

Sensory-specific satiety (SSS) describes a reduction in the pleasantness of the taste of (momentary liking) and desire to consume a food that occurs with eating, compared with the relative preservation of liking and desire for uneaten foods. We conducted three studies in healthy female and male participants to test whether SSS generalises from sweet drinks to sweet foods. Studies 1 (n = 40) and 2 (n = 64) used a two-condition cross-over design. Participants consumed non-carbonated, fruit squash drinks sweetened with low-calorie sweeteners (LCS) versus water and evaluated various food and drink samples (stimuli). Generalisation of SSS was evident across all sweet stimuli, without having an effect on non-sweet (savoury) stimuli. These SSS effects were present when measured shortly after consumption of the sweet drink, but not 2 h later. There was no evidence of a 'rebound' increase above baseline in liking or desire to consume sweet foods 2 h after the sweet drink versus water. In study 3, 51 participants consumed labelled and branded 500 ml cola and water drinks (4 conditions, cross-over design) immediately before and during ad libitum consumption of sweet and non-sweet snack foods. Compared with still water, 'diet' (LCS-sweetened) cola reduced sweet food intake, but not total ad libitum intake. Carbonated water decreased hunger and increased fullness compared with still water, without differentially affecting thirst. Energy compensation from the ad libitum snacks for consumption of sugar-containing cola averaged only 20%. Together, these results demonstrate that consumption of LCS drinks acutely decreases desire for sweet foods, which supports their use in place of sugar-sweetened drinks. Further studies on the effects of carbonation of appetite are warranted.

Dietary restriction during the treatment of cancer: results of a systematic scoping review.

BACKGROUND: Diets that restrict energy or macronutrient intake (e.g. fasting/ketogenic diets (KDs)) may selectively protect non-tumour cells during cancer treatment. Previous reviews have focused on a subset of dietary restrictions (DR) or have not performed systematic searches. We conducted a systematic scoping review of DR at the time of cancer treatment. METHODS: MEDLINE, Embase, CINAHL, AMED and Web of Science databases were searched for studies of adults undergoing DR alongside treatment for cancer. Search results were screened against inclusion/exclusion criteria. Data from included studies were extracted by two independent reviewers. Results were summarised narratively. RESULTS: Twenty-three independent studies (34 articles), with small sample sizes, met the inclusion criteria. Four categories were identified: KDs (10 studies), fasting (4 studies), protein restriction (5 studies) and combined interventions (4 studies). Diets were tolerated well, however adherence was variable, particularly for KDs. Biomarker analysis in KDs and fasting resulted in the expected increase in ketones or reduction in insulin-like growth factors, respectively, however they did not reduce glucose. CONCLUSIONS: Future research with adequately powered studies is required to test the effects of each DR intervention on treatment toxicities and outcomes. Further research into improving adherence to DR may improve the feasibility of larger trials.