Lung cancer ranks among the three most prevalent cancers worldwide. Polarization imaging technology can effectively distinguish between cancerous and normal tissues. The most commonly applied method for cancer detection is the dual-rotating wave plate polarization imaging system (DWRPIS), which is cumbersome and prone to significant error due to 60 mechanical rotations. To address this, our experiment leveraged the stability of the Liquid Crystal Variable Retarder (LCVR) and, based on existing theoretical foundations for simplifying the use of LCVRs, designed a symmetric single-LCVR polarization imaging system (SSLPIS) for the first time to detect lung cancer images. The SSLPIS is easy to operate, completing the entire acquisition process in just 150 s, with effective Mueller matrix imaging and an overall accuracy rate of over 90%, offering a faster and more precise detection method. This new approach provides an innovative pathway for the rapid detection of lung cancer.