Depending on the degree of CEA elevation 1. Mildly elevated, just slightly higher than the normal value of 5, review several times about the same, you can consider an abdominal CT or gastrointestinal scintigraphy to detect any other organ problems, as well as gynecological physical examination. Routine follow-up chest CT, head MRI, bone scan. 2. Moderate elevations, such as around 6-10, repeat 1, or consider MRD testing. 3, severe elevation, such as 15-30, or even higher, it is recommended to do a PET immediately. if PET negative, do a gastroenteroscopy. There are three kinds of CEA elevation: 1. Slightly elevated without significance, and all other imaging tests in the body are fine; these patients should be reviewed regularly, and CT should be reviewed every three months or so. 2. Elevated CEA caused by drug-resistant recurrence of lung cancer, which is the most common reason; some patients can find metastasis by PET, while some cannot see metastasis, and MRD can be considered. 3, CEA elevation caused by other primary tumors in the same period, gastrointestinal tumors, gastric cancer, colorectal cancer, pancreatic cancer, as well as gynecological tumors, ovarian cancer, endometrial cancer and so on can cause CEA elevation, which need to be taken into account to exclude the possibility of these tumors. Other tumor markers, depending on its own correlation with lung cancer. A slight elevation of many tumor markers is not necessarily a problem, especially neurocortisol enzyme NSE (this indicator is only related to small cell lung cancer in long-term heavy smoking).