The records of 171 patients with lymph node-negative stage IB and IIA cervical cancer primarily treated with radical hysterectomy and pelvic lymphadenectomy from 1974 to 1992 were retrospectively reviewed to identify poor prognostic factors and evaluate the role of adjuvant pelvic radiotherapy. One hundred sixteen patients (68%) were treated with radical hysterectomy alone (RH) and 55 patients (32%) received adjuvant radiotherapy (RH + RT). Factors predictive of recurrence for the entire group of patients included lymph-vascular space invasion (LVSI) (P = 0.003) and grade 3 histology (P = 0.04). Patients receiving RH + RT were older and more likely to have outer third cervical wall invasion, LVSI, positive margins, > or =2 cm pathologic tumor size, and >4 cm clinical tumor size (all P < 0.05). Overall, 28 patients (16%) developed recurrent disease with no difference between RH and RH + RT groups. After controlling for confounding variables, patients with LVSI who received RH + RT were less likely to develop disease recurrence than patients receiving RH alone (P = 0.04). LVSI is an important prognostic variable in lymph node-negative stage IB and IIA cervical cancer. Although adjuvant pelvic radiotherapy may decrease the risk of recurrence in patients with LVSI, the majority of patients with negative lymph nodes may be treated with radical surgery alone.