Question: If a patient has been diagnosed with cancer, does a "history of cancer" diagnosis start at that moment, after the cessation of active treatment for the cancer, or after some predetermined time limit? Pennsylvania Subscriber Answer: As soon as the physician ends treatment specifically directed at the tumor and there is no evidence of any cancer remaining at that site, you may properly apply a "history of cancer" diagnosis. For example, a patient with breast cancer undergoes, in turn, a biopsy, mastectomy, and chemotherapy and radiation therapy. The entire process takes about nine months. During all this time you would report a diagnosis of 174.X (Malignant neoplasm of female breast -). Because the breast cancer is the reason for continued treatment, this diagnosis remains appropriate even though the surgeon believes all cancer was removed at the time of surgery. After the patient has completed radiation therapy, you can apply V10.3 (Personal history of malignant neoplasm; breast). Although the patient may continue to receive maintenance drugs or monitoring visits after this acute phase of treatment, the history code is appropriate. Of course, if there is a recurrence of cancer at the same site (meaning either the same breast or the other breast), you would drop the "history" diagnosis in favor of 174.X once again.