对中晚期直肠癌进行腔内微波热化疗，观察治疗前后的癌组织超微结构。治疗前癌细胞有丰富的微绒毛，细胞间连接以桥粒为主，膜间腔中有微绒毛；线粒体丰富，胞核大而异形，核浆比例大，核内常染色质比例高。热化疗后见细胞膜破裂，微绒毛减少，线粒体明显肿胀、变性；溶酶体含量明显增多，内质网肿胀，脱粒，腔隙扩大；核及核仁固缩，核内出现空泡。提示癌细胞的膜系统是热化疗的主要靶器官之一。 Intraluminal microwave thermochemotherapy was performed on middle and late stage rectal cancer to observe the ultrastructure of the cancer tissue before and after treatment. Before treatment, the cancer cells were rich in microvilli, intercellular connections were mainly composed of desmosomes, microvilli existed in the space between the membranes, mitochondria were abundant, the nucleus was large and shaped, the proportion of nuclear plasma was large, and the proportion of nuclear chromatin was high. After thermochemotherapy, cell membrane rupture, microvilli decreased, and mitochondria were obviously swollen and degenerated; lysosome content increased significantly, endoplasmic reticulum was swollen, threshing, and lacunar space was enlarged; nucleus and nucleolus were pyknosis and vacuoles appeared in the nucleus. It suggests that the membrane system of cancer cells is one of the main target organs of thermochemotherapy.