The swelling of feet caused by lung cancer depends on what kind of cause. The swelling of feet caused by lung cancer may be related to tumor depletion and decrease of albumin, so it can be treated by supplementing albumin plus appropriate diuretic treatment. The foot swelling due to malnutrition is mainly symmetrical sunken edema of both lower limbs. It can also be caused by inguinal or pelvic lymph node metastasis of lung cancer, which compresses the venous return of lower limbs, thus leading to foot swelling, which is often unilateral limb swelling. Other causes are unilateral limb vein thrombosis, especially after lung cancer restricts its activities, which can cause deep vein thrombosis in the lower limbs, resulting in unilateral swelling of the feet, which requires radiotherapy for pelvic or inguinal lymph nodes to reduce edema. If the foot swelling is caused by deep vein thrombosis in the lower limbs, anticoagulation therapy should be added, and the affected limb can be elevated at the same time.