Cancer is one of the leading causes of cancer-related deaths worldwide. By detecting cancer early, healthcare providers can intervene promptly with appropriate treatment strategies, potentially preventing the progression of the disease to more advanced stages. Additionally, early detection can lead to more cost-effective treatment approaches, as managing cancer at later stages often requires extensive and expensive interventions. Therefore, this article explores a novel optical fiber-based surface plasmon resonance (SPR) sensor for the detection of cancerous cells, such as Jurkat, HeLa, PC1-2, MDA-MB-231, and MCF7. The proposed sensor comprises HBL core-cladding-silver (Ag)-cerium oxide (CeO2)-tungsten disulfide (WS2)-analyte, whereas Ag provides the sharp resonance dip, CeO2 provides protection from Ag's oxidation and WS2 enhances the sensing capability. The sensor's performance analyzes by applying the wavelength interrogation technique. Firstly, the optimization of Ag, CeO2, and WS2 layers' thicknesses, and indent angles are executed by observing the performance of minimum transmittance power, FWHM, and sensitivity. Secondly, sensing parameters of sensitivity and figure of merit (FoM) are analyzed with the optimized structure. Results show that the maximum achieved parameters are a sensitivity of 29,642.9 nm/RIU\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\text{nm}/\text{RIU}$$\end{document} and a FoM of 120.5 RIU-1.\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{RIU}}<^>{-1}.$$\end{document} The results furnish a substantial improvement in comparison to the reported work in the literature.