Objectives: This study aims to explore the incidence of, and risk factors for medical adhesive-related skin injury (MARSI) at peripherally inserted central venous catheter (PICC) sites in patients with cancer., Design: A prospective observational cohort study was conducted at a tertiary hospital in Shenzhen, China., Setting: This was a single-centre study conducted in a tertiary hospital in Shenzhen, China., Participants: A total of 340 patients with cancer and PICC placement from January 2022 to June 2023 were selected using a convenience sampling method., Methods: Factors potentially associated with PICC-related MARSI (PICC-MARSI) were recorded, including patient demographics, and catheter placement and maintenance. Patients were divided into MARSI and non-MARSI groups. Univariate analysis was performed to screen for associated variables, and logistic regression analysis was used to identify independent risk factors for PICC-MARSI., Results: Of all 340 patients enrolled, 33 (9.7%) developed PICC-MARSI, including skin tear (8, 24.2%), tension injury (5, 15.2%), irritant contact dermatitis (10, 30.3%), allergic dermatitis (7, 21.2%) and maceration (3, 9.1%). Multivariable analysis showed that age (OR=1.058, p=0.001, 95% CI 1.023-1.094), wet skin (OR=4.873, p=0.003, 95% CI 1.728-13.742), dry skin (OR=6.247, p<0.0001, 95% CI 2.239-17.431), oedema (OR=3.302, p=0.008, 95% CI 1.365-7.985), allergy history (OR=6.044, p=0.001, 95% CI 2.040-17.906), dressing type (OR=3.827, p=0.003, 95% CI 1.595-9.185), body mass index (BMI) <18.5 (OR=4.271, p=0.015, 95% CI 1.327-13.742) and BMI 25-30 (OR=2.946, p=0.027, 95% CI 1.131-7.678) were independent risk factors for PICC-MARSI., Conclusions: Proper catheter maintenance and appropriate dressing selection are crucial for the prevention of this condition., Competing Interests: Competing interests: There is no conflict of interest between all authors. All authors have made substantial contributions for this article. Meanwhile, we have reviewed the final version of the manuscript and approve it for publication. The authors have approved the final article and acknowledge that all those entitled to authorship., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)