Stage Ib
According to the FIGO staging of cervical cancer, stage Ib cervical cancers are clinically evident lesions confined to the cervix or preclinical lesions greater than Ia. Stage Ib1 lesions are no greater than 4.0 cm in size. Stage Ib2 lesions are greater than 4.0 cm in size. Stage IIa is involvement of vagina, but not the lower third, and no obvious parametrial involvement can be present. Stage IIb cancers involve the parametrium. Stage IIIa tumors involve the lower third of the vagina with no extension to the pelvic sidewall.
Reference:
DiSaia PJ, Creasman WT. Clinical Gynecologic Oncology. 8th ed., 2012.