摘要
To the Editor: Multiple primary carcinoma (MPC) or secondary primary carcinoma refers to two or more malignant tumors occurring in the same organ or different organs of a patient. MPC is classified into synchronous MPC (time between diagnoses ≤6 months) and metachronous MPC (time between diagnoses >6 months).[1] Clinically, MPC was easily misdiagnosed as the recurrence and metastasis of malignant tumor. In head and neck MPC patients, the correct diagnosis and active treatments are important.
