BACKGROUND Cancer patients are considered a priority group for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination given their high risk of contracting severe coronavirus disease 2019 (COVID-19). However, limited data exists regarding the efficacy of immunization in this population. In this study we assess the immunologic response after COVID-19 vaccination of cancer versus non-cancer population. METHODS PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science databases were searched from March 01, 2020, through August 12, 2021. Primary endpoints were anti-SARS-CoV-2 spike protein (S) immunoglobulin G (IgG) seroconversion rates, T-cell response, and documented SARS-CoV-2 infection after COVID-19 immunization. Data was extracted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. Overall effects were pooled using random effects models. RESULTS This systematic review and meta-analysis included 35 original studies. Overall, 51% (95% confidence interval [CI], 41-62) and 73% (95%CI, 64-81) of cancer patients developed anti-S IgG above the threshold level after partial and complete immunization, respectively. Patients with hematologic malignancies had a significantly lower seroconversion rate than those with solid tumors after complete immunization (65% vs 94%; P <0.0001). Compared to non-cancer controls, oncological patients were less likely to attain seroconversion after incomplete (RR 0.45 [95%CI 0.35-0.58]) and complete (RR 0.69 [95%CI 0.56-0.84]) COVID-19 immunization schemes. Cancer patients had a higher likelihood of having a documented SARS-CoV-2 infection after partial (RR 3.21; 95%CI 0.35-29.04) and complete (RR 2.04; 95%CI 0.38-11.10) immunization. CONCLUSIONS Cancer patients have an impaired immune response to COVID-19 vaccination compared to controls. Strategies that endorse the completion of vaccination schemes are warranted. Future studies should aim to evaluate different approaches that enhance oncological patients’ immune response.

The COVID-19 pandemic has had a substantial effect on cancer care. 1 The recent widespread availability of vaccines against SARS-CoV-2 is a promising strategy to prevent COVID-19associated mortality. However, previous reports have shown a high hesitancy rate to receive a COVID-19 vaccine among oncologic patients. 2,3 Because breast cancer is the most commonly diagnosed malignant neoplasm, 4 it is imperative to evaluate the specific concerns regarding COVID-19 vaccination among patients with this disease.Methods | From March 12 to March 26, 2021, any woman with breast cancer residing in Mexico who visited the social media channels of nongovernmental organizations dedicated to improving breast cancer care were invited to complete a webbased survey. To assess COVID-19 vaccine hesitancy rates, participants were dichotomized into a vaccine-acceptant group (ie, willing to be vaccinated immediately) and a vaccinehesitant group (ie, prefer to wait, only if vaccine is mandatory, or refuse). Respondents who previously had been vaccinated against COVID-19 were excluded from the statistical analysis.Data analyses were performed using SPSS, version 27 (IBM Inc). Significance was defined as 2-tailed P < .05. The

Lambert-Eaton syndrome is a rare paraneoplastic disorder of the neuromuscular junction, characterized by impaired release of acetylcholine, which causes proximal muscle weakness, depressed tendon reflexes, and autonomic changes. Most cases of Lambert-Eaton syndrome present in small-cell lung carcinoma, and only a few cases have been reported in other lung subtypes. Herein, we report a case of 69 years old male patient with Lambert-Eaton syndrome as a rare association with a pulmonary large-cell neuroendocrine carcinoma, which presented 5 months before neoplasm diagnosis. A lobectomy was auspiciously performed. A review of the literature is also presented.

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PURPOSE In response to the worldwide shortage of oncologists, ASCO established Oncology Student Interest Groups (OSIGs) to increase oncology exposure at medical schools. However, there is limited guidance on the activities they should undergo. The main purposes of this study were (1) to assess the preferences and perceptions of OSIG members about their group events and (2) to describe the difficulties faced by leaders to carry out OSIGs' tasks. METHODS In this multicenter, cross-sectional study, group members and leaders from five active Latin American OSIGs were invited to answer anonymous web-based surveys exploring members' attitudes toward group activities and leaders' challenges when carrying them out. Data collection was conducted from March to June 2021. RESULTS Responses from 142 medical students and four OSIGs leaders were analyzed. In total, 83% of student members considered that lectures with an oncology-related expert was very useful for increasing their overall interest in oncology. For increasing interest in cancer research, 87% deemed that participating in oncology research projects was very useful. Shadowing oncology professionals was very useful for at least 70% of members to increase their oncology knowledge and their interest in following an oncology-related career. Moreover, leaders' main challenges were having a high academic load, little response from members, lack of interesting ideas and protected time for OSIGs' events, and limited support from their school. CONCLUSION OSIGs' leaders, medical schools, and international oncology organizations should work together to design activities that increase medical students' exposure to oncology-related professionals and encourage their participation in international oncological events. These schools and organizations should actively support OSIG leaders when facing difficulties to prevent members' disengagement and groups' discontinuation.

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e12624 Background: Obesity (BMI ≥30 kg/m2) and breast cancer (BC) are two major public health concerns worldwide. Obesity has been linked with aggressive clinicopathological features and inferior survival rates in patients with BC, regardless of molecular subtype. In addition, obesity has been associated with decreased pathological complete response (pCR) rates in some BC cohorts. However, the impact of obesity on pCR rates in different BC molecular subtypes is still a subject of debate. This study aims to explore the impact of obesity on pCR rates in women with different BC subtypes in a public health-care center. Methods: Medical records of women diagnosed with primary BC between 2009 and 2020 in a center in Monterrey, Mexico were reviewed. Patients with stage II or III at diagnosis treated with neoadjuvant chemotherapy (NAC) were considered eligible. Associations between variables were examined using Fisher's exact test of independence, employing logistic regression to calculate odds ratios (OR) when appropriate. Results: A total of 559 patients with a median age at diagnosis of 48 years (range 25-85) were included. Patients were diagnosed with stages II (37%) and III (63%). The most common molecular subtype was HR+/HER2- (49%), followed by TNBC (25%), HR-/HER2+ (15%), and HR+/HER2+ (11%). Regarding BMI, a significant proportion of patients was either overweight (34%) or obese (47%). In this cohort, a total of 134 (24%) patients achieved pCR following NAC with anthracycline- and/or taxane-containing regimens. pCR rates by subtype were as follows: HR-/HER2+ (41%), TNBC (34%), HR+/HER2+ (31%), and HR+/HER2- (13%). A significant association between pCR rates and molecular subtype was found (p<0.001). Overall, obesity was not significantly associated with pCR rates. However, on a stratified analysis, obese patients with HR+/HER2+ tumors had significantly decreased pCR rates compared to their non-obese counterparts (OR=0.21; 95%CI 0.05-0.93; p=0.040). pCR rates according to molecular subtype and obesity status are shown in the table below. Conclusions: Obesity has an adverse influence on pCR rates in patients with HR+/HER2+ tumors. Given the endemic nature of obesity in several low- and middle-income countries, effective programs that focus on prevention, weight reduction strategies, and health promotion are warranted. Furthermore, women should be encouraged to improve their diet and engage in regular physical activity. Efforts to elucidate potential factors that underlie lower pCR rates in obese patients with certain BC subtypes are required. [Table: see text]

were receiving first line ET at a single institution. Two cohorts were defined: ET alone (2012-2104, prior to approval of CDK 4/6i) and ET+ CDK 4/6i (2015-2017. Data was extracted from the electronic medical record (EPIC) and entered into a REDCap database: demographics, CVD, comorbidities, cardiac medication/procedures, and HCU. Summary statistics include medians and interquartile ranges for continuous variables and frequencies and percentages for categorial variables. Results:The study population included 108 patients: 62 on ET alone and 46 on ET+CDK4/ 6i. Median age was 61.5 and 63.5 years, respectively. Baseline characteristics were similar between groups (data not shown). CVD and HCU are presented in the table. Conclusions:In this retrospective single institution cohort study, baseline CVD and HCU during treatment was similar in pts prescribed ET alone and ET + CDK4/6i. Presence of CVD did not seem to dissuade practitioners from prescribing ET + CDK4/ 6i. Further research is needed to understand the impact of CDK4/6i on CV health and HCU in a larger cohort of pts.