Clinical Significance of Subclassification of Stage FIGO 1B from a Radiation Oncology Perspective

Abstract

Previously, 2014 FIGO staging system divided stage IB into stage IB1 and IB2 for cervical cancer patients. Currently, the revised 2018 FIGO staging system further divides stage IB into stage IB1, IB2, and IB3, aiming to specify patients with small tumors who could receive surgery only, without additional radiotherapy (RT). This study aimed to evaluate the revised FIGO staging in stage IB cervical cancer patients and to suggest the optimal treatment strategies with surgery and/or RT. Medical data of cervical cancer patients who were treated with a curative aim between September 2001 and May 2018 were reviewed. A total of 350 patients were restaged according to the revised 2018 FIGO staging system. Treatment modalities included RT or chemoradiotherapy (CRT) in 71 patients, surgery ± adjuvant chemotherapy in 182 patients, and surgery followed by adjuvant RT/CRT in 97 patients. At a median follow-up of 67.0 months (range, 4.5–215.6 months), FIGO stage IB1 (n = 149), IB2 (n = 161), and IB3 (n = 40) patients showed 5-year progression-free survival (PFS) rates of 86.6%, 80.6%, and 78.3%, respectively, although not statistically significant (p = 0.335). The PFS curve showed a tendency of stage IB2 patients towards poor rates similar with stage IB3 patients as time increased. To further investigate these results, recurrence rates were analyzed depending on the treatment modality received. Among all the stages, stage IB2 patients who received surgery only showed significantly poorer recurrence rates compared to those who received RT or surgery with adjuvant RT (p = 0.017). In addition, the major first patterns of failure were local (36%) or regional recurrences (44%) for those who received surgery only, compared to distant failure as the major first pattern of failure in those who received RT or surgery with adjuvant RT (40% and 37.5%, respectively). Thus, patients who received surgery only were further evaluated. Low risk patients determined by simplified Sedlis criteria who did not receive adjuvant RT were analyzed (n = 100). By multivariate analysis, increasing tumor size was the only significant adverse factor for local recurrence (p = 0.047) and the cutoff value determined by the receiver operating characteristic curve was 2.5 cm. For regional recurrence, the only significant unfavorable factor was adenocarcinoma (p = 0.040). Although surgery without additional RT is generally preferred for revised FIGO stage IB1 and some IB2 patients, this study showed that size and adenocarcinoma pathology were significant factors for local and regional recurrences, respectively. Thus, adjuvant vaginal brachytherapy for those who have tumors larger than 2.5 cm and adjuvant external beam RT for those diagnosed with adenocarcinoma may be considered in stage IB cervix cancer patients undergoing surgery.