<p>One of the primary causes of cancer-related mortality on a global scale is colorectal cancer. Early colorectal cancer detection can stop the disease from progressing and save lives. Detection of colorectal cancer at an early stage yields significant financial savings, lowers mortality rates, and allows for a broader range of less invasive, more effective treatment options, thereby improving patient outcomes. The copper (Cu), carbon nanotube (CNT), and Hafnium Diselenide (HfSe₂) with CaF₂ prism-based structure have been proposed for colorectal and other cancer detection. The proposed sensor can detect the refractive index (RI) of the sensing medium (SM) between 1.33 and 1.35. The optimal thickness of Cu, CNT, and HfSe₂ has been taken at 41nm, 1nm, and 2nm, respectively. At optimal structure have been determined the sensitivity, detection accuracy (DA), and figure of merit (FoM). The maximum sensitivity 356.66deg/RIU is attained at RI of SM 1.33–1.35. For the detection of colorectal cancer, the sensitivity, DA, and FoM of 387.60deg/RIU, 0.253/deg, and 98.6/RIU, respectively, are obtained. By comparison with the reported work in the literature, the results provide a significant improvement. At optimal structure have been determined the sensitivity, DA, and FoM.</p> Graphical abstract <p></p>