BackgroundNanoparticle albumin-bound paclitaxel has been developed to avoid the toxicities associated with Cremophor-solved paclitaxel. Although many studies confirm this hypothesis, there is recent evidence showing no difference between paclitaxel and nab-paclitaxel in their efficacy and safety profile. This study further assesses the toxicity of both paclitaxel and nab-paclitaxel in adult patients with breast and pancreatic cancer in a tertiary hospital in Jeddah, Saudi Arabia. These toxicities include neutropenia, anaemia, and effects on kidney and liver functions.MethodsThe study is a retrospective cohort study done at King Abdulaziz University Hospital, Jeddah, Saudi Arabia, from January 2018 to December 2021, conducted on patients diagnosed with breast or pancreatic cancer treated with paclitaxel or nab-paclitaxel.ResultsThere is a statistically significant difference between the two groups in developing anaemia, renal, and liver toxicity (P<0.05). On the other hand, there are no statistically significant differences in developing neutropenia between the two groups (P=0.084).ConclusionsNab-paclitaxel might not be better than paclitaxel in reducing the risk of neutropenia, anaemia, and liver toxicity, as predicted. Nevertheless, both medications require that the patient's renal functions be monitored during the treatment. Further studies conducted in multiple oncology centres with a larger sample are needed to evaluate the toxicity of paclitaxel and nab-paclitaxel in adult patients with breast and pancreatic cancer.