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INTRODUCTION: Despite recent consensus guidelines, there is substantial variability in the management of pheochromocytomas. Our study aimed to characterize the current state of perioperative pheochromocytoma management by Canadian surgeons. METHODS: A 23-item online survey was sent to Canadian surgeons who perform adrenalectomies for pheochromocytoma. We assessed personal and institutional practices, including preoperative and postoperative management. RESULTS: National response rate was 51.8%. Surgeons from nine provinces responded; the majority were general surgeons (70.4%). Reviewing pheochromocytoma patients at a multidisciplinary tumor board was not routine practice (12%) and only 42.3% consistently referred patients for genetic testing. Preoperative α- and ß-blockade at half of the respondent institutions were performed by endocrinology alone (53.8%), with the other half employing a multidisciplinary approach. Half of respondents admitted their pheochromocytoma patients to hospital prior to the day of surgery. Postoperatively, 11.5% of respondents routinely admitted their patients to the intensive care unit (ICU) for monitoring based on personal preference or institutional convention. Multivariate analyses found no significant relationships between demographics or preoperative factors and perioperative management. CONCLUSIONS: Perioperative surgical management of patients undergoing adrenalectomy for pheochromocytoma was highly variable across Canada. Less than half of respondents routinely refer patients for genetic testing, despite recent practice guidelines. Surgeon preference and institutional convention are the main drivers behind preoperative admission and routine postoperative ICU admission, despite a lack of evidence to support this practice.
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It is not fully clarified whether insulin glargine, an analogue with a high affinity for insulin-like growth factor-1 receptor (IGF-1R), increases the risk for cancers that abundantly express IGF-1R such as breast cancer or some types of breast cancer. To gain insight into this issue, female Sprague-Dawley rats fed a high-fat diet were given the carcinogen N-methyl-N-nitrosourea and randomly assigned to vehicle (control), NPH (unmodified human insulin), glargine or detemir (n = 30 per treatment). Insulins were given subcutaneously (15 U/kg/day) 5 days a week. Mammary tumours were counted twice weekly, and after 6 weeks of treatment, extracted for analysis. None of the insulin-treated groups had increased mammary tumour incidence at any time compared with control. At 6 weeks, tumour multiplicity was increased with NPH or glargine (P < 0.05) and tended to be increased with detemir (P = 0.2); however, there was no difference among insulins (number of tumours per rat: control = 0.8 ± 0.1, NPH = 1.8 ± 0.3, glargine = 1.5 ± 0.4, detemir = 1.4 ± 0.4; number of tumours per tumour-bearing rat: control = 1.3 ± 0.1, NPH = 2.2 ± 0.4, glargine = 2.7 ± 0.5, detemir = 2.3 ± 0.5). IGF-1R expression in tumours was lower than that in Michigan Cancer Foundation-7 (MCF-7) cells, a cell line that shows greater proliferation with glargine than unmodified insulin. In rats, glargine was rapidly metabolised to M1 that does not have greater affinity for IGF-1R. In conclusion, in this model of oestrogen-dependent breast cancer in insulin-resistant rats, insulin and insulin analogues increased tumour multiplicity with no difference between insulin types.