Background: Breast and pelvic cancers are the most prevalent cancers among women globally. Several studies have reported on the effect of cell adhesion molecules on the growth, multiplication, invasion, and metastasis of tumor cells as well as inflammatory biomarkers, which are responsible for harmful inflammatory processes. Objectives: The purpose of the current study was to assess the serum levels of adhesion molecules intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in patients with cancer before and after radiotherapy, compare these with the levels of healthy subjects, and consider the relationship of these levels with the tumor origin. Methods: The present case-control study investigated 14 patients with breast cancer and 14 patients with pelvic cancer who had been referred to Omid Teaching Hospital’s oncology clinic, Mashhad, Iran between 2015 and 2017. Evaluated by the ELISA method for ICAM-1, VCAM-1, and E-selectin were the serum samples of these 28 cancer patients before and after their course of radiotherapy treatment and the serum samples of the 28 healthy subjects who had no history of cancer, radiotherapy or the risk factor of coronary artery disease. Results: The ICAM-1, VCAM-1, and E-selectin serum levels of all patients with cancer before and after a course of radiotherapy were significantly higher than those of the control group (P value ≤ 0.5). There was no significant difference between the two cancer groups before and after radiotherapy (P value ≥ 0.05). Conclusions: The current study demonstrated that the serum levels of adhesion molecules in patients with cancer before and after radiotherapy increase significantly regardless of the initial location of the tumor.