Stage IB includes: T1b, N0, M0. T1b: For leiomyosarcoma and endometrial stromal sarcoma: tumor more than 5 cm in greatest dimension. For adenosarcoma: tumor invades to less than half of the myometrium. N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 7th ed.) [from NCI]