PurposeThe glomerular filtration rate (GFR) is essential for carboplatin chemotherapy dosing; however, the best method to estimate GFR in patients with cancer is unknown. We identify the most accurate and least biased method.MethodsWe obtained data on age, sex, height, weight, serum creatinine concentrations, and results for GFR from chromium-51 (51Cr) EDTA excretion measurements (51Cr-EDTA GFR) from white patients ≥ 18 years of age with histologically confirmed cancer diagnoses at the Cambridge University Hospital NHS Trust, United Kingdom. We developed a new multivariable linear model for GFR using statistical regression analysis. 51Cr-EDTA GFR was compared with the estimated GFR (eGFR) from seven published models and our new model, using the statistics root-mean-squared-error (RMSE) and median residual and on an internal and external validation data set. We performed a comparison of carboplatin dosing accuracy on the basis of an absolute percentage error > 20%.ResultsBetween August 2006 and January 2013, data from 2,471 patients were obtained. The new model improved the eGFR accuracy (RMSE, 15.00 mL/min; 95% CI, 14.12 to 16.00 mL/min) compared with all published models. Body surface area (BSA)–adjusted chronic kidney disease epidemiology (CKD-EPI) was the most accurate published model for eGFR (RMSE, 16.30 mL/min; 95% CI, 15.34 to 17.38 mL/min) for the internal validation set. Importantly, the new model reduced the fraction of patients with a carboplatin dose absolute percentage error > 20% to 14.17% in contrast to 18.62% for the BSA-adjusted CKD-EPI and 25.51% for the Cockcroft-Gault formula. The results were externally validated.ConclusionIn a large data set from patients with cancer, BSA-adjusted CKD-EPI is the most accurate published model to predict GFR. The new model improves this estimation and may present a new standard of care.

OBJECTIVE To report the clinical experience and management of patients with small cell carcinoma (SCC) of the bladder, treated in the Anglia Cancer network from 1992 to 2007, and to review published studies, as SCC is a rare condition, accounting for <1% of all bladder tumours, and there is no established treatment strategy for managing these patients. PATIENTS AND METHODS We analysed retrospectively data from all patients diagnosed with SCC of the urinary bladder between 1992 and 2007, with an emphasis on stage, treatment and overall survival. RESULTS Twenty patients were identified with primary bladder SCC (male: female ratio 3:1; mean age 68 years; mean follow‐up 15.8 months). Nine patients (45%) had extensive‐stage disease at diagnosis. Four patients received best supportive care, three had a radical cystectomy, one radical radiotherapy and six sequential chemo‐radiotherapy. In all, 13 patients were treated with chemotherapy, with six receiving cyclophosphamide, doxorubicin and vincristine, three receiving carboplatin and etoposide, and the remainder receiving alternative platinum‐based regimens. For 12 patients with assessable disease, six had a complete response, three a partial response and three had progressive disease after chemotherapy. No patient received prophylactic cranial irradiation (PCI). At the time of analysis, 14 (70%) patients had died, with one (5%) developing brain metastasis. The median survival was 33 months for patients receiving chemotherapy, vs 3 months with no chemotherapy. CONCLUSIONS SCC of the bladder tends to occur in an older population, more commonly in men. It is an aggressive tumour with a propensity for early metastasis. The response rate to chemotherapy is high but the overall prognosis is poor. Brain secondaries are less common than for SCC of the lung and currently the role of PCI is unclear. As there is no standard of care for these patients, they are treated according to local protocols. Further efforts should be made to develop more effective treatments and the role of PCI should be assessed in the setting of a clinical trial, in conjunction with other extrapulmonary SCCs.