A LC-MSMS method for the simultaneous determination of tamoxifen, N-desmethyltamoxifen, 4-hydroxytamoxifen and endoxifen in dried blood spots samples was developed and validated. The method employs an ultrasound-assisted liquid extraction and a reversed phase separation in an Acquity(®) C18 column (150×2.1 mm, 1.7 µm). Mobile phase was a mixture of formic acid 0.1% (v/v) pH 2.7 and acetonitrile (gradient from 60:40 to 50:50, v/v). Total analytical run time was 8 min. Precision assays showed CV % lower than 10.75% and accuracy in the range 94.5 to 110.3%. Mean analytes recoveries from DBS ranged from 40% to 92%. The method was successfully applied to 91 paired clinical DBS and plasma samples. Dried blood spots concentrations were highly correlated to plasma, with rs>0.83 (P<0.01). Median estimated plasma concentrations after hematocrit and partition factor adjustment were: TAM 123.3 ng mL(-1); NDT 267.9 ng mL(-1), EDF 10.0 ng mL(-1) and HTF 1.3 ng mL(-1,) representing in average 98 to 104% of the actually measured concentrations. The DBS method was able to identify 96% of patients with plasma EDF concentrations below the clinical threshold related to better prognosis (5.9 ng mL(-1)). The procedure has adequate analytical performance and can be an efficient tool to optimize adjuvant breast cancer treatment, especially in resource limited settings.

CYP3A4 contributes to the bioactivation of TAM through formation of HTF and becomes increasingly important in case of reduced or absent CYP2D6 activity. EDF and HTF exposure were associated to seasonal variations, with considerable higher plasma concentrations during summer.

The presence of CYP3A4*22 might compensate the reduction of EDF concentrations related to CYP2D6 inactivity, especially due to increased HTF concentrations.

In Latin America and the Caribbean (LAC), progress has been made in some national and regional cancer control initiatives, which have proved useful in reducing diagnostic and treatment initiation delays. However, there are still significant gaps, including a lack of oncology clinical trials. In this article, we will introduce the current status of the region’s clinical research in cancer, with a special focus on academic cancer research groups and investigator-initiated research (IIR) initiatives. Investigators in LAC have strived to improve cancer research despite drawbacks and difficulties in funding, regulatory timelines, and a skilled workforce. Progress has been observed in the representation of this region in clinical trial development and conduct, as well as in scientific productivity. However, most oncology trials in the region have been sponsored by pharmaceutical companies, highlighting the need for increased funding from governments and private foundations. Improvements in obtaining and/or strengthening the LAC cancer research group’s financing will provide opportunities to address cancer therapies and management shortcomings specific to the region. Furthermore, by including this large, ethnic, and genetically diverse population in the world’s research agenda, one may bridge the gap in knowledge regarding the applicability of results of clinical trials now mainly conducted in populations from the Northern Hemisphere.

Background. We aimed to identify clinicopathological and molecular features associated with progression-free survival (PFS) and overall survival (OS) after pulmonary metastasectomy for metastatic colorectal cancer in a retrospective cohort in Brazil. Materials and Methods. We did a retrospective review of thoracic surgeries performed in a single large academic hospital in Brazil from January 1985 to September 2019. Demographics, previously described prognostic factors, and clinicopathological and molecular characteristics were abstracted. Univariate Cox regression was performed for each variable, and, when significant, data were dichotomized to provide clinically meaningful thresholds. Results. Records from 698 patients were reviewed. Fiftyeight patients underwent pulmonary metastasectomy with curative intent. Of those, 53.4% had a single metastatic lesion. The median size of the largest lesion was 1.5 cm.Results of RAS, RAF, and mismatch repair testing and of cytokeratin 20 (CK20) and CDX2 testing were available for 13.8% and 58.6% of the sample, respectively. Median PFS was 14 months, median OS was 58 months, and 5-year survival was 49.8%. Unfavorable prognostic factors for OS included disease-free interval (DFI) <24 months, synchronous presentation, size of the largest lesion ≥2 cm, and loss of CK20 expression. Presenting with more than one lesion was prognostic for PFS but not for OS. Conclusion.In this Brazilian cohort, our findings corroborate existing data supporting DFI, synchronous presentation, and number and size of lesions as prognostic factors. Furthermore, we found that loss of CK20 expression may be associated with more aggressive disease and shorter OS. Additional molecular prognostic factors after pulmonary metastasectomy for colorectal cancer should be further explored. The Oncologist 2021;26:1-8Implications for Practice: This study consolidates disease-free interval, synchronous presentation, and number and size of lesions as clinically relevant data that may help guide therapy for patients with colorectal cancer and lung metastases who are candidates for curative-intent metastasectomy. Additionally, in this sample, lack of cytokeratin 20 expression in metastases was associated with shorter progression-free survival and overall survival, suggesting that biomarkers also may have a role in guiding therapy in this setting and that additional biomarkers should be further explored.