NSE is a tumor marker, if persistently elevated it may be a sign of cancer recurrence, but it needs to be combined with other lab tests. Only when NSE is more than 10 times higher than the normal value can it be cancer, if it is slightly higher, it is not necessarily cancer. A persistent elevation of tumor markers may be a recurrence of cancer. In order to know whether the cancer has recurred, it is necessary to do blood routine, liver and kidney function, CT, MRI and other tests, and if necessary, to do pathological biopsy, and it is not possible to determine whether the tumor has recurred based on the high NSE alone. The high NSE should be actively consulted, and various examinations should be perfected to make a clear diagnosis. Patients should not self-medicate to avoid adverse results.