Microbiota composition effect on immunotherapy outcomes in colorectal cancer patients: A systematic review.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have emerged as an effective treatment for colorectal cancer (CRC). Studies indicate that the composition of gut microbiota could potentially serve as a biomarker for predicting the clinical effectiveness of immune checkpoint inhibitors. METHODS: Following PRISMA guidelines, the review was conducted after registering the protocol with PROSPERO. A comprehensive literature search was carried out across five databases: PubMed, Scopus, Web of Science, Embase, and Cochrane Library. Assessment tools from the National Institutes of Health (NIH) were used to gauge the quality of the studies. RESULTS: A total of 5,132 papers were identified, and three studies and one conference abstract published between 2017-2022 met the inclusion criteria and were summarized in a descriptive synthesis table. These four studies were in accord with the following findings, four main phyla, Firmicutes, Bacteroidata, Actinobacteria, and Verrucomicrobiota were associated with CRC patients' clinical response toward ICIs treatment. Ruminococcaceae was predominantly related to CRC patients responding to therapy, while the Micrococcaceae family was more common among the non-responders. Bacterial taxa such as Faecalibacterium and Prevotellaceae were associated with better responses to ICIs and could be predictive biomarkers. The signature of fecal microbiota with Akkermansia muciniphila and Eubacterium rectale enrichment, and Rothia mucilaginosa depletion could independently predict better response to ICIs in patients with CRC. CONCLUSION: The findings have brought attention to the notable differences in terms of richness and composition of microbiota between patients who responded positively to the treatment and those who did not. Bacterial species and families, such as Faecalibacterium, Bifidobacterium, Lachnospiraceae, Akkermansia sp., Ruminococcaceae, and Prevotellaceae, have consistently surfaced as potential indicators of immunotherapeutic responses. Furthermore, this review also emphasizes the need for additional comprehensive, multi-center studies with larger sample sizes to validate reported microbiota and expand our understanding of the role of gut microbiota in CRC ICIs therapy. PROSPERO ID: CRD42021277691.

Unilateral Axillary Lymphadenopathy in Cancer Patients Post-COVID-19 Vaccination: Review and Case Series.

Novel coronavirus-19 (COVID-19) variants continue to spread worldwide with the development of highly transmissible strains. Several guidelines addressing management of cancer patients during the COVID-19 pandemic have been published, primarily based upon expert opinion. The COVID-19 pandemic has affected all aspects of breast cancer care including screening, diagnosis, treatment, and long-term follow-up. Recent reports indicate that mRNA COVID-19 vaccines can provoke lymphadenopathy in both cancer patients and healthy individuals. Unilateral axillary lymphadenopathy (UAL) post-COVID-19 vaccination is a challenging presentation for cancer patients because of the potential for misinterpretation as malignancy. The World Health Organization's target to vaccinate 70% of the world's population by mid-2023 is likely to increase the incidence of post-COVID-19 vaccination UAL. In this article, we review the published evidence regarding UAL post-COVID-19 vaccination and present diverse cases of breast cancer patients where false-positive UAL post-COVID-19 vaccination proved to be a therapeutic challenge. The United Arab Emirates (UAE) vaccination program is well ahead of other countries in the world, having accomplished the target of 100% vaccination of the population with at least one dose. Therefore, an increasing number of recently vaccinated patients are likely to present with UAL, detected by surveillance imaging, post-vaccination. We have therefore made recommendations regarding the management of cancer patients with UAL post-COVID-19 vaccination in order to avoid misdiagnosis and unnecessary imaging or invasive biopsy procedures.