Investigating Quantum Feature Maps in Quantum Support Vector Machines for Lung Cancer Classification
Main Article Content
Abstract
Background: Classical algorithms often struggle with the high dimensionality of medical data critical for early lung cancer diagnosis. While Quantum Machine Learning (QML) offers enhanced pattern recognition capabilities, the impact of specific quantum feature encoding strategies on diagnostic accuracy remains underexplored.
Methods: We evaluated Quantum Support Vector Machines (QSVM) using a dataset of 309 lung cancer patients, divided into six balanced subsets to mitigate class imbalance. Models were implemented on a qasm simulator, comparing three encoding strategies: ZFeatureMap, ZZFeatureMap, and PauliFeatureMap. Performance was assessed using standard classification metrics.
Results: The choice of feature map significantly influenced model efficacy. The PauliFeatureMap outperformed other kernels, achieving 100% classification accuracy in three of the six subsets, whereas ZFeatureMap and ZZFeatureMap yielded lower predictive consistency.
Conclusion: Quantum feature map selection is a decisive factor in QSVM performance. Specifically, the PauliFeatureMap demonstrates high separability for medical data, highlighting the potential of optimized quantum kernels to improve diagnostic precision.
Article Details
Copyright (c) 2025 Toufah A, et al.

This work is licensed under a Creative Commons Attribution 4.0 International License.
Cristianini N, Shawe-Taylor J. An introduction to support vector machines and other kernel-based learning methods. Cambridge (UK): Cambridge University Press; 2000. Available from: https://www.cambridge.org/core/books/an-introduction-to-support-vector-machines-and-other-kernelbased-learning-methods/A6A6F4084056A4B23F88648DDBFDD6FC
Schuld M, Sinayskiy I, Petruccione F. An introduction to quantum machine learning. Contemp Phys. 2015;56(2):172–185. Available from: https://doi.org/10.1080/00107514.2014.964942
Havlíček V, Córcoles AD, Temme K, Harrow AW, Kandala A, Chow JM, Gambetta JM. Supervised learning with quantum-enhanced feature spaces. Nature. 2019;567:209–212. Available from: https://doi.org/10.1038/s41586-019-0980-2
Biamonte J, Wittek P, Pancotti N, Rebentrost P, Wiebe N, Lloyd S. Quantum machine learning. Nature. 2017;549:195–202. Available from: https://doi.org/10.1038/nature23474
Asuntha A, Brindha SI, Srinivasan A. Lung cancer detection using SVM algorithm and optimization techniques. J Chem Pharm Sci. 2016;9(4):3198–3203. Available from: https://www.jchps.com/issues/Volume%209_Issue%204/jchps%209(4)%20286%200450716%203198-3203.pdf
Zhao W, Davis CE. A modified artificial immune system-based pattern recognition approach—An application to clinical diagnostics. Artif Intell Med. 2011;52(1):1–9. Available from: https://doi.org/10.1016/j.artmed.2011.03.001
Alam J, Alam S, Hossan A. Multi-stage lung cancer detection and prediction using multi-class SVM classification. In: Proceedings of the IEEE International Conference on Computer, Communication, Chemical, Materials and Electronic Engineering (IC4ME2); 2018. p. 1–4. Available from: https://doi.org/10.1109/IC4ME2.2018.8465593
Parveen SS, Kavitha C. Classification of lung cancer nodules using SVM kernels. Int J Comput Appl. 2014;95(25):25–28. Available from: https://www.ijcaonline.org/archives/volume95/number25/16751-7013/
Kaveh S, Arezi E, Khedri Z, Sohrabei S. Investigating the application of quantum machine learning in breast cancer: a systematic review. Arch Breast Cancer. 2025;12:130–142. Available from: https://doi.org/10.32768/abc.2025122130-142
Schuld M, Bocharov A, Svore KM, Wiebe N. Circuit-centric quantum classifiers. Phys Rev A. 2020;101:032308. Available from: https://doi.org/10.1103/PhysRevA.101.032308
Mitarai K, Negoro M, Kitagawa M, Fujii K. Quantum circuit learning. Phys Rev A. 2018;98:032309. Available from: https://doi.org/10.1103/PhysRevA.98.032309
Şendil A. Lung cancer dataset [Internet]. Kaggle; 2025 [cited 2025 Dec 25]. Available from: https://www.kaggle.com/datasets/ahmetsendil/lung-cancer-dataset
Oyelade J, Isewon I, Oladipupo O, Emebo O, Omogbadegun Z, Aromolaran O, Uwoghiren E, Olaniyan D, Olawole O. Data clustering: algorithms and their applications. In: Proceedings of the IEEE International Conference on Computer Science and Its Applications (ICCSA); 2019. p. 71–81. Available from: https://doi.org/10.1109/ICCSA.2019.000-1
Chawla NV, Bowyer KW, Hall LO, Kegelmeyer WP. SMOTE: synthetic minority over-sampling technique. J Artif Intell Res. 2002;16:321–357. https://doi.org/10.1613/jair.953
Boser BE, Guyon IM, Vapnik VN. A training algorithm for optimal margin classifiers. In: Proceedings of the Fifth Annual Workshop on Computational Learning Theory (COLT ’92); 1992. https://doi.org/10.1145/130385.130401
Combarro E, González-Castillo S. A practical guide to quantum machine learning and quantum optimization: hands-on approach to modern quantum algorithms. 2023. Available from: https://quantumatlas.ir/wp-content/uploads/2025/01/A-Practival-Guide-to-Quantum-Machine-Learning-and-Quantum-Optimization.pdf
Pontil M, Verri A. Support vector machines for 3D object recognition. IEEE Trans Pattern Anal Mach Intell. 1998;20(6):637–646. Available from: https://doi.org/10.1109/34.683777
Schölkopf B, Smola AJ. Learning with kernels. Cambridge (MA): MIT Press; 2001. https://doi.org/10.7551/mitpress/4175.001.0001
Cortes C, Vapnik V. Support-vector networks. Mach Learn. 1995;20:273–297. Available from: https://doi.org/10.1007/BF00994018
Schuld M, Killoran N. Quantum machine learning in feature Hilbert spaces. Phys Rev Lett. 2019;122:040504. Available from: https://doi.org/10.1103/PhysRevLett.122.040504
Suzuki T, Hasebe T, Miyazaki T. Quantum support vector machines for classification and regression on a trapped-ion quantum computer. Quantum Mach Intell. 2024;6. Available from: https://doi.org/10.1007/s42484-024-00165-0
Özpolat Z, Yıldırım Ö, Karabatak M. The effect of linear discriminant analysis and quantum feature maps on QSVM performance for obesity diagnosis. Balkan J Electr Comput Eng. 2024. Available from: https://doi.org/10.17694/bajece.1475896
Bartkiewicz K, Gneiting C, Černoch A, Jiráková K, Lemr K, Nori F. Experimental kernel-based quantum machine learning in finite feature space. Sci Rep. 2020;10:12356. Available from: https://doi.org/10.1038/s41598-020-68911-5
Toufah MA, Kadim MA, El Hafidi MY. Overcoming SVM limitations in lung cancer classification with a quantum feature map. BMC Artif Intell. 2025;1. Available from: https://doi.org/10.1186/s44398-025-00016-3
Kim H, Seo J. High-performance FAQ retrieval using an automatic clustering method of query logs. Inf Process Manag. 2006;42(3):650–661. Available from: https://doi.org/10.1016/j.ipm.2005.04.002
Powers DMW. Evaluation: from precision, recall and F-measure to ROC, informedness, markedness and correlation. arXiv. 2020:2010.16061. Available from: https://arxiv.org/abs/2010.16061
Huang L. Normalization techniques in deep learning. San Rafael (CA): Morgan & Claypool Publishers; 2022. https://doi.org/10.1007/978-3-031-14595-7
Salmi M, Atif D, Oliva D, Abraham A, Ventura S. Handling imbalanced medical datasets: review of a decade of research. Artif Intell Rev. 2024;57. Available from: https://doi.org/10.1007/s10462-024-10884-2
Jolliffe IT. Principal component analysis. New York: Springer-Verlag; 2002. Available from: https://doi.org/10.1007/b98835