BackgroundThe present study aims to assess the performance of 18F-FDG PET-CT on mediastinal staging of non-small cell lung cancer (NSCLC) in a location with endemic granulomatous infectious disease.MethodsDiagnostic test study including patients aged 18 years or older with operable stage I-III NSCLC and indication for a mediastinal lymph node biopsy. All patients underwent a 18F-FDG PET-scan before invasive mediastinal staging, either through mediastinoscopy or thoracotomy, which was considered the gold-standard. Surgeons and pathologists were blinded for scan results. Primary endpoint was to evaluate sensitivity, specificity and positive and negative predictive values of PET-CT with images acquired in the 1st hour of the exam protocol, using predefined cutoffs of maximal SUV, on per-patient basis.ResultsOverall, 85 patients with operable NSCLC underwent PET-CT scan followed by invasive mediastinal staging. Mean age was 65 years, 49 patients were male and 68 were white. One patient presented with active tuberculosis and none had HIV infection. Using any SUV_max > 0 as qualitative criteria for positivity, sensitivity and specificity were 0.87 and 0.45, respectively. Nevertheless, even when the highest SUV cut-off was used (SUV_max ≥5), specificity remained low (0.79), with an estimated positive predictive value of 54%.ConclusionsOur findings are in line with the most recent publications and guidelines, which recommend that PET-CT must not be solely used as a tool to mediastinal staging, even in a region with high burden of tuberculosis.Trial registrationThe LACOG 0114 study was registered at ClinicalTrials.gov, before study initiation, under identifier NCT02664792.

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Introduction patients with sporadic colorectal cancer or cases associated with syndromes are at risk of having synchronous or metachronous cancer. Although it is an important subject, Brazilian data on the subject are scarce. Objective to evaluate the incidence and epidemiological features in patients with synchronous and metachronous colorectal cancer in a reference service of proctology in the Rio Grande do Sul. Methods cross-sectional observational study, performed between January and July 2012, analyzing all patients admitted in the service that met the inclusion criteria. A retrospective review of records was performed, noting demographic variables, comorbidities and tumor-related variables. Results 150 records were analyzed, of which 53.3% were males and mean age was 63 (± 13.01) years old. The most frequently found tumor location was the sigmoid colon and high rectum (50.67%), followed by the lower rectum (36%). Adenocarcinomas were the most prevalent histological subtype (88%), followed by epidermoid tumors (1.33%). Hereditary syndromes were identified in five patients (3.33%), with four being Familial adenomatous polyposis (FAP) and one hereditary nonpolyposis colorectal cancer (HNPCC). Among the analyzed patients, four (2.67%) had synchronous and one (0.67%) had metachronous cancer. Conclusion the incidence of synchronous and metachronous colorectal cancer was, respectively, 2.67% and 0.67%, results that corroborate those reported in international literature.

INTRODUCTION Current definition of HER2-positive BC follows ASCO/CAP guidelines using immunohistochemistry (IHC) and/or in situ hybridization (ISH)-based techniques. However, HER2 expression can be variable in cells that lack ERBB2 amplification. For example, HER2-negative tumors can express some level of HER2 protein by IHC (i.e. 1+ or 2+ and a negative ISH result) and are identified as HER2-low. Others have no expression and are considered HER2-zero. Innovative therapies have shown promising activity in patients in HER2-low BC. The aim of this study is to evaluate the association of HER2-low and HER2-zero status with response to NACT in HER2-negative BC. METHODS Retrospective cohort of patients with HER2-negative BC treated with NACT in four institutions in Brazil. Protocols of diagnosis, treatment and follow-up were standardized and based on international guidelines. Tumors with HER2 IHC score 0 were classified as HER2-zero whereas tumors with HER2 score 1+ and those with HER2 score 2+ with FISH-negative were classified as HER2-low. Patients were treated with anthracycline- and taxane- based chemotherapy. The following clinicopathological data were evaluated, when available: age, ER, Ki67, tumor size, lymph node (LN) status and response to NACT according to pCR status and residual cancer burden (RCB) index. Primary objective was to evaluate the prevalences and compare pCR rates among HER2-zero and HER2-low cases. Secondary objectives were to perform the same comparison within the HR-positive (HR+) and HR-negative subgroups. Pearsons chi squared tests were performed and a p value of <0.05 was considered statistically significant. RESULTS 331 patients were included in this analysis. 63% were HR+and 37% were TNBC. 50% were HER2-zero and 50% HER-low (36% HER2 IHC 1+ and 14% HER2 IHC 2+/FISH-negative). Median age, initial tumor size, clinical LN status and Ki67 expression were similar among HER2-zero and HER2-low subgroups. In HR+ tumors, 42% (86/207) were HER2-zero and 58% (121/207) were HER2-low. In TNBC, 63% (78/124) were HER2-zero and 37% (46/124) were HER2-low (p<0.001, Pearsons chi squared test). The pCR rate was 26% (85/331) in the entire cohort. As expected, there was a higher rate of pCR in TNBC vs HR+ (50% vs 11%, p<0.001). We found a statistically significant difference in the pCR rates when comparing the HER2-zero versus HER2-low subgroups (31% vs 20%, p=0.03). However, this difference is mostly related to an imbalance between groups (HER2-zero subgroups had a higher proportion of TNBC). Among HR+ tumors, there was no difference in the pCR rates between HER2-zero and HER2-low subgroups (8% vs 13%, p=0.35). In TNBC, we identified an interesting but non-statistically significant difference in pCR in HER2-zero vs. HER2-low tumors (56% vs. 39%, p=0.09). In the TNBC cohort we identified a non-statistically significant difference in RCB 0-I in HER2-zero vs. HER2-low tumors (p=0.06). With a 30 month median follow-up, PFS and OS data are immature. CONCLUSION The distribution of HER2-zero and HER2-low cases is different in HR+ and TNBC. HER2-low is more frequent in HR+ and HER2-zero in TNBC. We identified a higher pCR rate in HER2-zero compared to HER2-low tumors, even though this difference is associated with an imbalance between the two groups. Still, we identified a trend to higher pCR rate in HER2-zero compared to HER2-low tumors even within the TNBC subgroup. Identification of HER2-low and HER2-zero tumors may have clinical implications that should be further explored. Citation Format: Tomas Reinert, Guilherme Parisotto Sartori, Alessandra AB Souza, Rodrigo Pellegrini, Mahira L Rosa, Nathalia Rossatto, Guilherme P Coelho, Isnard E Litvin, Felipe Zerwes, Eduardo Millen, Francisco P Cavalcante, Antonio L Frasson, Marcia S Graudenz, Carlos H Barrios. Prevalence of HER2-low and HER2-zero subgroups and correlation with response to neoadjuvant chemotherapy (NACT) in patients with HER2-negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-22.

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