Low Incidence of Advanced Neoplasia in Serrated Polyposis Syndrome After (Sub)total Colectomy: Results of a 5-Year International Prospective Cohort Study.

INTRODUCTION: Serrated polyposis syndrome (SPS) is accompanied by a substantially increased colorectal cancer (CRC) risk. To prevent or treat CRC in patients with a very high polyp burden, (sub)total colectomy with ileorectal or ileosigmoidal anastomosis is regularly performed. The CRC risk after (sub)total colectomy might be decreased, but evidence is lacking. We aimed to assess the yield of endoscopic surveillance in patients with SPS who underwent (sub)total colectomy. METHODS: For this post hoc analysis, we used prospectively collected data from a large international prospective cohort study. We included patients diagnosed with SPS (World Health Organization type I and/or III) who underwent (sub)total colectomy. Primary endpoint was the cumulative 5-year incidence of CRC and advanced neoplasia (AN). RESULTS: Forty-eight patients (mean age 61 [±7.8]; 52% men) were included and followed up for a median of 4.7 years (interquartile range 4.7-5.1). None of the patients developed CRC during follow-up. Five patients developed AN, corresponding to a cumulative 5-year AN incidence of 13% (95% confidence interval 1.2-23). In 4 patients, AN was diagnosed at the first surveillance endoscopy after study inclusion, and in 1 patient, AN was detected during subsequent rounds of surveillance. The risk of AN was similar for patients with ileorectal and ileosigmoidal anastomosis (logrank P = 0.83). DISCUSSION: (Sub)total colectomy mitigates much of the excess risk of CRC in patients with SPS. Advanced neoplasms are mainly detected at the first endoscopy after (sub)total colectomy. Based on these results, after the first surveillance, intervals might be extended beyond the currently recommended 1-2 years.

Clinical risk factors of colorectal cancer in patients with serrated polyposis syndrome: a multicentre cohort analysis.

OBJECTIVE: Serrated polyposis syndrome (SPS) is accompanied by an increased risk of colorectal cancer (CRC). Patients fulfilling the clinical criteria, as defined by the WHO, have a wide variation in CRC risk. We aimed to assess risk factors for CRC in a large cohort of patients with SPS and to evaluate the risk of CRC during surveillance. DESIGN: In this retrospective cohort analysis, all patients with SPS from seven centres in the Netherlands and two in the UK were enrolled. WHO criteria were used to diagnose SPS. Patients who only fulfilled WHO criterion-2, with IBD and/or a known hereditary CRC syndrome were excluded. RESULTS: In total, 434 patients with SPS were included for analysis; 127 (29.3%) were diagnosed with CRC. In a per-patient analysis ≥1 serrated polyp (SP) with dysplasia (OR 2.07; 95% CI 1.28 to 3.33), ≥1 advanced adenoma (OR 2.30; 95% CI 1.47 to 3.67) and the fulfilment of both WHO criteria 1 and 3 (OR 1.60; 95% CI 1.04 to 2.51) were associated with CRC, while a history of smoking was inversely associated with CRC (OR 0.36; 95% CI 0.23 to 0.56). Overall, 260 patients underwent surveillance after clearing of all relevant lesions, during which two patients were diagnosed with CRC, corresponding to 1.9 events/1000 person-years surveillance (95% CI 0.3 to 6.4). CONCLUSION: The presence of SPs containing dysplasia, advanced adenomas and/or combined WHO criteria 1 and 3 phenotype is associated with CRC in patients with SPS. Patients with a history of smoking show a lower risk of CRC, possibly due to a different pathogenesis of disease. The risk of developing CRC during surveillance is lower than previously reported in literature, which may reflect a more mature multicentre cohort with less selection bias.

Food insufficiency, housing and health-related quality of life: results from the Positive Spaces, Healthy Places study.

Studies of people living with HIV who are homeless or unstably housed show a high prevalence of food insufficiency (>50%) and associated poor health outcomes; however, most evidence is in the form of cross-sectional studies. To better understand this issue, we conducted a longitudinal study to examine the impact of food insufficiency and housing instability on overall physical and mental health-related quality of life (HRQoL) among people living with HIV in Ontario. Six hundred and two adults living with HIV were enrolled in the Positive Spaces, Healthy Places study and followed from 2006 to 2009. Interviewer-administered questionnaires were used, and generalized linear mixed-effects models constructed to examine longitudinal associations between food insufficiency, housing instability and physical and mental HRQoL. At baseline, 57% of participants were classified as food insufficient. After adjusting for potential confounders, longitudinal analyses revealed a significant, negative association between food insufficiency and physical and mental HRQoL outcomes, respectively [effect size (ES) with 95% confidence interval (CI): (ES = -2.1, CI = -3.9,-0.3); (ES = -3.5, CI = -6.1,-1.5)]. Furthermore, difficulties meeting housing costs were shown to have additional negative impacts on mental HRQoL. Food insufficiency is highly prevalent among people living with HIV in Ontario, particularly for those with unstable housing. This vulnerable group of individuals is in urgent need of changes to current housing programmes, services and policies, as well as careful consideration of their unmet nutritional needs.

Regulation of TRAIL receptor expression by ß-catenin in colorectal tumours.

Tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL) is being investigated as a targeted cancer therapeutic and the expression of its pro-apoptotic receptors, DR4 and DR5, increases during colorectal carcinogenesis. This study investigated the role of ß-catenin in the regulation of these receptors. In human colorectal adenoma and carcinoma cell lines, downregulation of ß-catenin resulted in lower total DR4 and DR5 protein levels. Similarly, cell membrane expression of DR4 and DR5 was reduced after downregulation of ß-catenin in colon carcinoma cells, whereas induction of ß-catenin in HeLa cells led to increased cell membrane expression of DR4 and DR5. Downregulation of ß-catenin decreased the recombinant human TRAIL sensitivity of human colon carcinoma cells. Activation of the transcription factor T-cell factor-4 (TCF-4) is an important function of ß-catenin. Dominant-negative TCF-4 overexpression, however, did not significantly affect TRAIL receptor expression or recombinant human TRAIL sensitivity. Human colorectal adenomas (N = 158) with aberrant (cytoplasmic and nuclear) ß-catenin expression had a higher percentage of immunohistochemical DR4 and DR5 staining per tumour (mean: 73 and 88%, respectively) than those with membranous ß-catenin staining only (mean: 50 and 70%, respectively, P < 0.01 for both). Furthermore, aberrant ß-catenin staining co-localized with DR4 and DR5 expression in 92% of adenomas. In 53 human colorectal carcinomas, aberrant ß-catenin expression was present in most cases and DR4/5 expression was largely homogenous. Similarly, in adenomas from APC(min) mice, cytoplasmic ß-catenin staining co-localized with staining for the murine TRAIL death receptor. In conclusion, the gradual increase in TRAIL receptor expression during colorectal carcinogenesis is at least partially mediated through increased ß-catenin expression, independently of TCF-4-signalling.

Quality colonoscopy and risk of interval cancer in Lynch syndrome.

PURPOSE: Despite colonoscopic surveillance, Lynch syndrome patients develop colorectal cancer (CRC). Identification of modifiable factors has the potential to improve outcome of surveillance. The aims of this study were to determine (1) characteristics of patients with CRC, (2) endoscopic and histological features of these cancers, and (3) quality of the previous colonoscopy. METHODS: Approximately 2,200 medical reports from proven and obligate mutation carriers identified at the Dutch Lynch Syndrome Registry and two large hospitals were retrospectively analyzed for the presence of an interval cancer defined as CRC diagnosed within 24 months of previous colonoscopy. RESULTS: Thirty-one interval cancers were detected in 29 patients (median age of 52 [range 35-73]), after a median time of 17 months. All were MLH1 or MSH2 mutation carriers, and 39 % had a previous CRC. In patients without previous surgery for CRC, 84 % was proximally located. Of all interval cancers, 77 % were at local stage (T1-3N0Mx). In three patients (9 %) with an incomplete previous colonoscopy, CRC was located in the unexamined colon. In six of the nine patients with an adenoma during previous colonoscopy, the cancer was detected in the same colonic segment as the previously removed adenoma. CONCLUSIONS: Interval cancers were detected in MLH1 and MSH2 mutation carriers, especially in those with a history of previous CRC and between 40 and 60 years. Interval cancer could be related to incompleteness of previous endoscopy and possibly residual adenomatous tissue. Further reduction of the interval cancer risk may be achieved by optimizing endoscopy quality and individualization of surveillance guidelines.

Nurse endoscopists perform colonoscopies according to the international standard and with high patient satisfaction.

BACKGROUND AND STUDY AIMS: Colonoscopy is increasingly performed by nurse endoscopists. We aimed to assess the endoscopic quality and patient experience of these procedures. PATIENTS AND METHODS: This prospective multicenter study analyzed 100 consecutive colonoscopies each for 10 trained nurse endoscopists with respect to endoscopic quality and patient experience. Colonoscopies were performed under the supervision of a gastroenterologist, using the techniques and protocols of the participating hospitals. Patient experience was assessed using a questionnaire. RESULTS: Most nurse endoscopists were female (90 %; median age 43 [range 35 - 49]). Before the start of the study, they had performed a median of 528 colonoscopies (range 208 - 2103). For the 1000 patients, mean age was 56 ± 15 years; 55 % were women; and 96 % were in class I or II according to the American Society of Anesthesiologists' physical status classification system. Colonoscopies were performed for screening or surveillance in 42 %; for symptomatic indications in 58 % of patients. The unassisted cecal intubation rate was 94 %; the mean withdrawal time was 10 ±â€Š5 minutes. The adenoma detection rate was 26.7 %. In 229 of the colonoscopies (23 %), the nurse endoscopists required assistance from the supervising gastroenterologist. The complication rate was 0.2 %: one perforation and one cardiopulmonary complication. The questionnaire was completed by 734 /1000 patients (73 %) and of these 694 /734 (95 %) were satisfied with the endoscopic procedure. Among the respondents 530 /734 (72 %) had no specific preference for a physician or nurse endoscopist, whereas 113 /734 (15 %) preferred a physician endoscopist, and 91 /734 (12 %) preferred a nurse endoscopist. CONCLUSION: The nurse endoscopists performed colonoscopies according to the internationally recognized quality standards and with high patient satisfaction.

Increased colorectal cancer risk in first-degree relatives of patients with hyperplastic polyposis syndrome.

INTRODUCTION: Hyperplastic polyposis syndrome (HPS) is characterised by the presence of multiple colorectal hyperplastic polyps and is associated with an increased colorectal cancer (CRC) risk. For first-degree relatives of HPS patients (FDRs) this has not been adequately quantified. Reliable evidence concerning the magnitude of a possible excess risk is necessary to determine whether preventive measures, like screening colonoscopies, in FDRs are justified. AIMS AND METHODS: We analysed the incidence rate of CRC in FDRs and compared this with the general population through person-year analysis after adjustment for demographic characteristics. Population-based incidence data from the Eindhoven Cancer Registry during the period 1970-2006 were used to compare observed numbers of CRC cases in FDRs with expected numbers based on the incidence in the general population. RESULTS: A total of 347 FDRs (41% male) from 57 pedigrees were included, contributing 11 053 person-years of follow-up. During the study period, a total of 27 CRC cases occurred among FDRs compared to five expected CRC cases (p<0.001). The RR of CRC in FDRs compared to the general population was 5.4 (95% CI 3.7 to 7.8). Four FDRs satisfied the criteria for HPS. Based on the estimated HPS prevalence of 1:3000 in the general population the projected RR of HPS in FDRs was 39 (95% CI 13 to 121). CONCLUSIONS: FDRs of HPS patients have an increased risk for both CRC and HPS compared to the general population. Hence, as long as no genetic substrate has been identified, screening colonoscopies for FDRs seem justified but this needs to be prospectively evaluated.

Double balloon enteroscopy for endoscopic retrograde cholangiopancreaticography after Roux-en-Y reconstruction: case series and review of the literature.

BACKGROUND: Endoscopic access to the biliary system can be difficult in patients with surgically altered anatomy, such as a Roux-en-Y reconstruction. Double balloon enteroscopy (DBE) is a relatively new procedure that enables access to the small bowel. DBE has recently been advocated as a method for endoscopic retrograde cholangiopancreaticography (ERCP) in patients with surgical reconstructions, with the potential to perform diagnostic and therapeutic interventions. METHODS: In three patients with a hepaticojejunostomy and Roux-en-Y reconstruction, the experiences using DBE to perform ERCP are described. The literature on DB-ERCP in patients with a Roux-en-Y reconstruction was reviewed. RESULTS: In all patients, the Roux limb was entered and a diagnostic cholangiography was carried out. In one patient, endoscopic therapy could be performed, consisting of balloon dilation of a stenotic biliodigestive anastomosis, repeated balloon dilation of biliary strictures and removal of bile casts. CONCLUSION: This series confirms recent data emerging from the literature that double balloon enteroscopy is a safe and feasible technique to obtain biliary access in patients with surgically altered anatomical configurations, such as those with a Roux-en-Y reconstruction. The diagnostic and therapeutic potential of DB-ERCP is great, and the utility of the procedure could be further improved if customised accessories become more widely available.

Capsule endoscopy: a review from the clinician's perspectives.

The possibility of visualization of the small bowel has dramatically improved with the introduction of capsule endoscopy (CE) and it has rapidly become standard practice in investigating diseases of the small bowel. Nowadays, there are many reasons to perform CE: most often suspected obscure gastrointestinal bleeding, inflammatory bowel disease, celiac disease and small bowel neoplasia. CE has higher diagnostic yields than other (more invasive) diagnostic modalities for most of these indications. Furthermore, there are virtually no real contra-indications anymore for the procedure. CE appears also to be safe in selected paediatric cases in which it has similar diagnostic yields compared with adults. This review is a practical update for the clinician on CE, including the complementary role of double balloon enteroscopy and the new developments of Pillcam ESO and the Pillcam COLON.

Independent induction of caspase-8 and cFLIP expression during colorectal carcinogenesis in sporadic and HNPCC adenomas and carcinomas.

BACKGROUND: TNF-Related Apoptosis Inducing Ligand (TRAIL) is a promising agent for the induction of apoptosis in neoplastic tissues. Important determinants of TRAIL sensitivity are two intracellular proteins of the TRAIL pathway, caspase-8 and its anti-apoptotic competitor cellular Flice-Like Inhibitory Protein (cFLIP). METHODS: The aim of this study was to investigate basic expression of caspase-8 and cFLIP in normal colorectal epithelium (n=20), colorectal adenomas (n=66) and colorectal carcinomas (n=44) using immunohistochemistry performed on both sporadic and Hereditary Non-Polyposis Colorectal Cancer (HNPCC or Lynch syndrome)-associated adenomas and carcinomas. RESULTS: Expression of both caspase-8 and cFLIP was similar in cases with sporadic and hereditary origin. Expression of caspase-8 in colorectal adenomas and carcinomas was increased when compared to normal colon tissue (P=0.02). Nuclear, paranuclear as well as cytoplasmic localizations of caspase-8 were detected. Immunohistochemistry revealed an upregulation of cFLIP in colorectal carcinomas in comparison to normal epithelium and colorectal adenomas (P<0.001). A large variation in the caspase-8/cFLIP ratio was observed between the individual adenomas and carcinomas. CONCLUSION: Caspase-8 and cFLIP are upregulated during colorectal carcinogenesis. Upregulation of caspase-8 and/or downregulation of cFLIP may be interesting approaches to maximize TRAIL sensitivity in colorectal neoplasms.

Increased risk of fundic gland polyps during long-term proton pump inhibitor therapy.

BACKGROUND: It is controversial whether proton pump inhibitor use leads to fundic gland polyp development. AIM: To determine whether fundic gland polyp development is due to proton pump inhibitor use and to investigate mechanisms involved. METHODS: Proton pump inhibitor use and the presence of fundic gland polyps were assessed in consecutive patients undergoing oesophagogastroduodenoscopy. Biopsies from fundic gland polyps and gastric mucosa were taken. Dysplasia was graded as negative, low or high grade. Prevalence of parietal cell hyperplasia and parietal cell protrusions and the proportional cystic area were assessed. RESULTS: 599 patients participated, 322 used proton pump inhibitors, 107 had fundic gland polyps. Long-term proton pump inhibitor use was associated with an increased risk of fundic gland polyps (1-4.9 years use: OR 2.2, 95% CI: 1.3-3.8; > or =5 years: OR 3.8, 95% CI: 2.2-6.7) while short-term therapy (<1 year) was not (OR 1.0, 95% CI: 0.5-1.8). Low-grade dysplasia was found in one fundic gland polyp. Fundic gland polyps associated with long-term proton pump inhibitor use had a larger proportional cystic area and higher frequency of parietal cell hyperplasia and parietal cell protrusion. CONCLUSIONS: Long-term proton pump inhibitor use is associated with an up to fourfold increase in the risk of fundic gland polyps. Risk of dysplasia is negligible. Aetiologically, these polyps seem to arise because of parietal cell hyperplasia and parietal cell protrusions resulting from acid suppression.

Non-steroidal anti-inflammatory drugs and molecular carcinogenesis of colorectal carcinomas.

CONTEXT: Colorectal cancer is the second most common cause of cancer-related mortality in the west. The high incidence and mortality make effective prevention an important public-health and economic issue. Non-steroidal anti-inflammatory drugs (NSAIDs) can inhibit colorectal carcinogenesis and are among the few agents known to be chemopreventive. Randomised trials have shown that sulindac and celecoxib suppress the development of adenomatous polyps and cause regression of existing polyps in patients with familial adenomatous polyposis (FAP), who have a high risk for developing colorectal cancer. The mechanisms by which NSAIDs inhibit neoplastic growth are not fully known. STARTING POINT: Two recently reported randomised placebo-controlled trials show a chemopreventive effect of aspirin in populations other than those with FAP (Robert Sandler and colleagues, N Engl J Med 2003; 348: 883-90; John Baron and colleagues, N Engl J Med 2003; 348: 891-99). In the Sandler study 635 patients with colorectal cancer were randomised to receive 325 mg aspirin or placebo daily. After a follow-up of around 31 months, the mean number of adenomas was lower in the aspirin group than in the placebo group, corresponding to a relative risk of any recurrent adenoma in the aspirin group of 0.65. In the Baron study 1121 patients with colorectal adenomas were assigned to receive 81 or 325 mg aspirin or placebo daily. Follow-up colonoscopy, 32 months after the index endoscopy, showed an incidence of one or more adenomas of 38% in the 81 mg aspirin group, 45% in the 325 mg aspirin group, and 47% in the placebo group. Together, these studies indicate a moderate chemopreventive effect of aspirin in populations with an intermediate risk of developing colorectal cancer. WHERE NEXT? The anticancer properties of NSAIDs have been demonstrated in vitro and in animal studies, epidemiological reports, and intervention studies. Several mechanisms through which NSAIDs alter colonic carcinogenesis have been elucidated, including the induction of apoptosis in neoplastic cells, via mechanisms dependent and independent of cyclo-oxygenase. Some studies have suggested an important role for the cell-cycle regulating protein p21 in mediating the chemopreventive effect of sulindac. A decrease in p21 expression may be one of the main oncogenic events in the development of colorectal cancer. Thus p21 could be the molecular link in the chemopreventive effects of NSAIDs.

Review article: the potential of combinational regimen with non-steroidal anti-inflammatory drugs in the chemoprevention of colorectal cancer.

Non-steroidal anti-inflammatory drugs are chemopreventive agents in colorectal cancer. Non-steroidal anti-inflammatory drugs do not, however, offer complete protection against adenoma and carcinoma development. There is increasing interest in combining non-steroidal anti-inflammatory drugs with agents that target specific cell signalling pathways in malignant and premalignant cells. This review aims to describe the current knowledge regarding the efficacy of peroxisome proliferator-activated receptor-gamma ligands, cholesterol synthesis inhibitors (statins), epidermal growth factor signalling inhibitors and tumour necrosis factor-related apoptosis-inducing ligand against colorectal neoplasms and the rationale for combining these drugs with non-steroidal anti-inflammatory drugs to improve efficacy in the chemoprevention of colorectal cancer, a PUBMED computer search of the English language literature was conducted to identify relevant papers published before July 2004. Peroxisome proliferator-activated receptor-gamma ligands and statins, both in clinical use, reduce the growth rate of human colon cancer cells in vitro and in rodents models. In vitro, preclinical in vivo and clinical studies have shown efficacy of epidermal growth factor signalling inhibition in colorectal cancer. In vitro, tumour necrosis factor-related apoptosis-inducing ligand induces apoptosis in human colon cancer cells, but not in normal cells. These drugs have all been shown to interact with non-steroidal anti-inflammatory drugs in colorectal cancer cells and/or in rodent models. Combinational regimen are a promising strategy for the chemoprevention of colorectal cancer and should be further explored.

[Statins for the prevention of colorectal carcinoma: not yet recommended]. / Statinen ter preventie van colorectaal carcinoom vooralsnog niet aanbevolen.

Statins are widely prescribed as lipid-lowering agents in the primary and secondary prevention of cardiovascular disease. They are increasingly associated with potential chemopreventive effects with respect to cancer. A recent case-control study reported a 47% relative reduction in the risk of colorectal cancer associated with statin use after adjustment for other known risk factors. There is evidence of an inhibitory effect of statins on colorectal carcinogenesis from in vitro studies, animal experiments, and observational and epidemiological reports in humans. Although statins seem promising as chemopreventive agents, it is still too early to recommend their use against colorectal cancer outside the context of clinical trials.

[Eosinophilic oesophagitis in young men with food swallowing complaints]. / Eosinofiele oesofagitis bij jonge mannen met voedselpassageklachten.

Three men, aged 20, 24 and 42 years, reported difficulties in passing food through the oesophagus. The diagnosis of eosinophilic oesophagitis was made after endoscopic investigation, laboratory tests and histological tests. In all three patients the symptoms disappeared: respectively spontaneously, during systemic treatment with corticosteroids due to a kidney complaint, and after topical corticosteroid treatment lasting 6 weeks. Eosinophilic oesophagitis occurs in particular in young men. There are complaints about the passage of food through the oesophagus, with frequent food impaction, also without any obvious stenosis. Endoscopic features are subtle and comprise a vulnerable oesophageal mucosa with a ringed appearance or small white spots on the oesophageal mucosa. Histopathology reveals an eosinophilic infection infiltrate in the oesophageal epithelium. Food allergies may play a causal role. With respect to the treatment, favourable results have been described for oral fluticasone, while endoscopic treatment may consist of dilation.

Changes in apoptosis during the development of colorectal cancer: a systematic review of the literature.

The development of colorectal cancer is characterised by an accumulation of molecular genetic alterations causing disorders in cell growth, differentiation and apoptosis. Although changes in apoptosis with colorectal cancer development have been studied extensively, a clear consensus of opinion has not yet emerged. In this review, the literature about changes in the frequency and distribution of apoptosis in tissue sections of normal and neoplastic colorectal tissues was reviewed systematically. Using a PUBMED search, 53 relevant articles were identified. Data from these studies are discussed with respect to the following aspects: methods used to detect apoptotic cell death; frequency and locoregional distribution of apoptosis in normal mucosa, adenomas and carcinomas; the correlation between levels of apoptosis and proliferation and the prognostic significance of the degree of apoptosis in colorectal cancer. Possible underlying mechanisms of dysregulation of apoptosis are discussed briefly. Finally, possible therapeutic implications of knowledge of the molecular regulation of apoptosis are discussed and potential options for further research are suggested.

Ticlopidine-induced thrombocytopenia.

A case is presented of a 58-year-old woman developing profound thrombocytopenia within one week after starting treatment with ticlopidine. Ticlopidine was prescribed following coronary artery stenting. The patient recovered rapidly after discontinuation of the drug, suggesting a possible relationship between ticlopidine and thrombocytopenia. Haematological disorders associated with ticlopidine, such as neutropenia, thrombocytopenia and bone marrow aplasia, are rare and usually seen within the first three months of therapy. As the use of ticlopidine increases, clinicians should be aware of haematological complications associated with its use and inform their patients appropriately.

Clinical and biochemical changes following 131I therapy for hyperthyroidism in patients not pretreated with antithyroid drugs.

BACKGROUND: Radioiodine therapy (131I) for the treatment of hyperthyroidism has been shown to be effective and safe. Despite the extensive experience with radioiodine therapy, the necessity for pretreatment with antithyroid drugs is controversial. Pretreatment is partly based on the concept that antithyroid drugs deplete the thyroidal hormonal stores, thereby reducing the risk of a radioiodine-induced aggravation of hyperthyroidism or thyroid storm. Few data are available on the frequency of clinically significant exacerbations of hyperthyroidism following 131I therapy without prior treatment with antithyroid drugs. The aim of the present study was to determine prospectively the early clinical and biochemical changes after 131I therapy in patients who were not pretreated with antithyroid drugs. METHODS: Patients with Graves' disease (n = 21), toxic multinodular goiter (n = 11) or toxic adenoma (n = 2) were studied before and after 131I therapy. Clinical and biochemical parameters of thyroid function were investigated before and 1, 2, 8, 11, 18 and 25 days after 131I treatment. Patients were given no antithyroid drugs prior to 131I therapy, all patients received beta-blocking agents for symptomatic relief. RESULTS: In 19 of 34 patients, a transient increase in thyroid hormone levels was observed, predominantly in the first week following 131I therapy. None of these patients experienced worsening of thyrotoxic symptoms. This transient increase in thyroid hormone levels was demonstrated in all patients with toxic multinodular goiter, whereas it was found in only six of 21 patients with Graves' disease. This difference could not readily be explained by differences in pretreatment thyroid hormone levels, administered dose or effectively absorbed dose of 131I. CONCLUSIONS: 131I treatment of hyperthyroidism without pretreatment with antithyroid drugs may cause a transient increase in thyroid hormone levels. Clinically significant exacerbations of hyperthyroidism were, however, not observed in our study population. Increased hormone levels following 131I therapy were more often seen in patients with toxic multinodular goiter than in patients with Graves' disease.