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Objective: Paraneoplastic neurologic syndrome (pns) is a rare condition indirectly caused by an underlying malignancy. In many cases, the malignancy is occult at the time of the pns diagnosis, and the optimal diagnostic modality to detect the underlying tumour is unclear. In the present study, we aimed to assess the utility of 18F-fluorodeoxyglucose positron-emission tomography (fdg-pet) or pet integrated with computed tomography (pet/ct) in the investigation of these patients. Methods: We retrospectively analyzed data from the PET Access Program (pap) database in the province of Ontario to identify patients who underwent fdg-pet/ct imaging as part of a workup for pns. In all patients, prior conventional imaging was negative or indeterminate. To determine the diagnostic accuracy of fdg-pet/ct, data about demographics, presenting symptoms, and biochemical and radiologic workup, including fdg-pet/ct imaging results, were compared with data collected by the Ontario Cancer Registry (ocr). A systematic review of the literature and meta-analysis using our study inclusion criteria were performed for studies of fdg-pet accuracy. Results: Of 29 patients identified in the pap database, 9 had fdg-pet/ct results suspicious for malignancy. When correlated with data from the ocr, 5 fdg-pet/ct results were informative, resulting in a detection rate of 17%. Local sensitivity and specificity were 0.83 and 0.83 respectively. Two studies meeting our criteria were identified in the literature. The pooled sensitivity and specificity from the literature and local data were 0.88 and 0.90 respectively. Conclusions: When investigating for underlying malignancy in patients with suspected pns and negative conventional imaging, pet has high sensitivity and specificity.

The data about whether patients with a prior urothelial cancer (uca) are at increased risk of colorectal cancer (crc) are conflicting. We used a competing risks analysis to determine the risk of crc after uca. Historical cohorts were assembled by record linkage of Manitoba Cancer Registry and Manitoba Health databases. The incidence of crc for individuals with uca as their first cancer between 1987 and 2009 was compared with the incidence for randomly selected age-and sex-matched individuals without a cancer diagnosis at the index date (uca diagnosis date). Three competing outcomes (crc, another primary cancer, and death) were evaluated by competing risks proportional hazards models with adjustment for relevant confounders. The cohorts of 4591 patients with uca and 22,312 without uca were followed for a total of 179,287 person&ndash, years (py). After uca, the rate of subsequent colon cancer in uca patients was 4.5 per 1000 py compared with 3.6 per 1000 py in the non-cancer cohort. In the multivariable analysis, no overall increase in crc risk was observed for patients first diagnosed with uca (hazard ratio: 0.88, 95% confidence interval: 0.70 to 1.1, p = 0.26). Because of similar crc risk, a similar crc screening strategy should be applied for individuals with and without uca.