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Summary: Background: Adjuvant imatinib mesylate prolongs recurrence-free survival (RFS) after resection of localised primary gastrointestinal stromal tumours (GIST). We aimed to develop a nomogram to predict RFS after surgery in the absence of adjuvant therapy to help guide patient selection for adjuvant imatinib therapy. Methods: A nomogram to predict RFS based on tumour size (cm), location (stomach, small intestine, colon/rectum, or other), and mitotic index (<5 or ≥5 mitoses per 50 high-power fields) was developed from 127 patients treated at Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA. The nomogram was tested in patients from the Spanish Group for Research on Sarcomas (GEIS; n=212) and the Mayo Clinic, Rochester, MN, USA (Mayo; n=148). The nomogram was assessed by calculating concordance probabilities and testing calibration of predicted RFS with observed RFS. Concordance probabilities were also compared with those of three commonly used staging systems. Findings: The nomogram had a concordance probability of 0·78 (SE 0·02) in the MSKCC dataset, and 0·76 (0·03) and 0·80 (0·02) in the validation cohorts. Nomogram predictions were well calibrated. Inclusion of tyrosine kinase mutation status in the nomogram did not improve its discriminatory ability. Concordance probabilities of the nomogram were better than those of the two NIH staging systems (0·76 [0·03] vs 0·70 [0·04, p=0·04] and 0·66 [0·04, p=0·01] in the GEIS validation cohort; 0·80 [0·02] vs 0·74 [0·02, p=0·04] and 0·78 [0·02, p=0·05] in the Mayo cohort) and similar to those of the AFIP-Miettinen staging system (0·76 [0·03] vs 0·73 [0·004, p=0·28] in the GEIS cohort; 0·80 [0·02] vs 0·76 [0·003, p=0·09] in the Mayo cohort). Nomogram predictions of RFS seemed better calibrated than predictions made with the AFIP-Miettinen system. Interpretation: The nomogram accurately predicts RFS after resection of localised primary GIST and could be used to select patients for adjuvant imatinib therapy. Funding: National Cancer Institute, Bethesda, MD, USA. [Copyright &y& Elsevier]

Background: Gallbladder cancer (GBCA) is a rare malignancy with a variable incidence worldwide. This study analyzed GBCA patients treated at centers in 3 countries. The aim was to assess for location-specific differences in presentation and outcomes, which might suggest differences in pathogenesis or disease biology. Study Design: Data for consecutive patients submitted to operation at Instituto Oncológico Fundación Arturo López Pérez (FALP, Chile), Yokohama City University (YCU, Japan), and Memorial Sloan-Kettering Cancer Center (MSKCC, USA) between 1999 and 2007 were studied retrospectively. Patient demographics, disease- and treatment-related variables and outcomes were analyzed by chi-square, Kruskal-Wallis, and log-rank test. Results: Two hundred sixty-one patients (MSKCC, 130; FALP, 85; YCU, 46) underwent exploration, and 160 (MSKCC, 91; FALP, 33; YCU, 36) underwent R0 resection. Patients treated at FALP were younger (median 57 years, p < 0.001) and more often female (80%, p < 0.005); at YCU there were fewer patients with incidental tumors (19.5% compared with more than 60% at FALP and MSKCC, p < 0.001). En bloc liver and bile duct resections were performed more commonly at MSKCC and YCU (p < 0.001). Patients treated at FALP had more advanced tumor stage compared with those treated at MSKCC and YCU (p < 0.001). Disease-specific survival (DSS) was not different among the groups when patients submitted to an R0 resection were analyzed (p = 0.12). On multivariate analysis, T-stage, nodal involvement, and bile duct involvement were predictors of DSS; center was not significant. Conclusions: Despite some differences in presentation, disease extent, and surgical treatment, DSS after curative intent resection was similar among all 3 groups. The most important predictors of outcomes were related to tumor extent rather than country of origin. [ABSTRACT FROM AUTHOR]