The tumor cells remain confined within the capsule, which is intact.
Standard Treatment A non-invasive malignant thymoma is treated by the surgical removal of the tumor. Very specific and special precautions are needed for patients with myasthenia gravis because of the possibility of respiratory problems. Anesthesiologists experienced in this problem can dramatically reduce the rate of operative mortality.
If there is absolutely no evidence of spread through or beyond the capsule, no further therapy is needed. But if follow-up cannot be counted on, radiation therapy , possibly with adjuvant chemotherapy , may be given after surgery to try to improve the chances for long-term control.
There is a difference of opinion about the role of adjuvant radiotherapy for patients with encapsulated non-invasive thymomas. Since the recurrence rate is extremely low (about 2 percent), some physicians prefer to avoid the risks of radiation therapy. Others believe that radiotherapy is an essential part of treatment and can help prevent local recurrence, especially for larger tumors.
If, as sometimes happens, the mass is discovered at surgery to have invaded adjacent organs and is therefore Stage II, radiation therapy is used in addition to or instead of surgery.
