Paulina Natalia Kopa-Stojak, Rafał Pawliczak
The aim of this review is to determine the effect of alternative tobacco/nicotine products on response to chemotherapy, including mechanistic toxicology evidence, treatment-resistance signals and potential hazard. The literature was searched in PubMed, Embase and Web of Science databases in June 2026. Currently, there has been no epidemiological study investigating effects of alternative products on chemotherapy response. There are some evidence that snus using increases risk of cancer-related death and reduces survival rate. However, for e-cigarettes the weight of such evidence is lower. Furthermore, there is one in vitro study, which found that cisplatin resistance can be associated with EC-induced changes in expression of drug influx/efflux transporters. However, multi-center replication study failed to validate such findings, concluded that e-cigarette aerosols do not significantly increase cisplatin resistance in head and neck squamous cell carcinoma cell lines. Finally, there is some evidence that alternative products affects cancer cells proliferation, growth, epithelial-to-mesenchymal transition, oxidative stress, which may influence survival and metastasis of cancer cells. Due to limited evidence, we are unable to clearly determine effects of using alternative tobacco/nicotine products on patients' response to chemotherapy, cancer progression, metastasis and risk of cancer-related death. The evidence supports cautious interpretation of findings and highlights the need for standardized, reproducible methods and further in vivo preclinical and clinical data before drawing conclusions about the use of alternative products during chemotherapy. Therefore, well-designed prospective cohort studies, real-world evidence studies and cancer patient registries are critical to fully understand potential risks associated with their use during anticancer therapy.