If the swollen lymph nodes on the left clavicle are present alone, that is, if there are no other swollen lymph nodes, one must be careful of malignant tumors of the stomach because malignant tumors of gastric cancer tend to metastasize to the lymph nodes on the left clavicle. If the lymph nodes are hard to touch and there is no pain or pressure, the possibility of malignant disease is relatively high. If you encounter this situation, you should go to the hospital in time and consider consulting the gastroenterology department. The gastroenterology doctor may recommend gastroscopy, and may even do pathological examination under the gastroscope to see if there is a malignant condition or not. Besides gastric cancer, thyroid cancer, breast cancer, lung cancer, etc. may also present with left supraclavicular lymph node metastasis. If the swollen left supraclavicular lymph node is accompanied by swollen lymph nodes in several other areas, other diseases such as lymphoma, viral infection, etc. should be considered.