Squamous cell carcinoma antigen in follow-up of cervical cancer treated with radiotherapy: evaluation of cost-effectiveness

Abstract

Purpose: The squamous cell carcinoma (SCC) antigen is still considered the most accurate serologic tumor marker in cervical carcinoma. We assessed the contribution of the SCC assay to the detection of recurrences in patients treated with radiotherapy.

Methods and materials: The pattern of recurrence and follow-up data were prospectively recorded for 135 patients. Of the 135 patients, 103 (76.3%) had primary cervical carcinoma and 32 (23.7%) had already experienced disease recurrence that had been successfully treated with surgery (n = 2), surgery plus radiotherapy (n = 2), radiotherapy (n = 5), or concomitant chemoradiotherapy (n = 23). The follow-up evaluations (chest X-ray, abdominopelvic magnetic resonance imaging, gynecologic examination with colposcopy, Papanicolaou smear, and SCC assay) were performed at 6-month intervals; the evaluation was done earlier if recurrent disease was suspected. The median follow-up time was 29 months (range, 6-131). The SCC serum levels were assayed, and a cost analysis was done.

Results: A total of 481 SCC determinations were performed. Of the 135 patients, 43 (31.8%) experienced disease recurrence. The SCC levels were higher in those with recurrent disease than in the disease-free patients. Elevation of SCC was documented in 34 (79.1% sensitivity) of 43 recurrences before symptoms appeared. Of the 38 patients with serum SCC elevation, 34 developed a recurrence (positive predictive value, 89.5%). Of the 97 patients with negative SCC serum levels, 88 had negative findings at the clinicoradiologic evaluation (negative predictive value, 90.7%). A simplified approach (SCC plus gynecologic examination) was evaluated. Compared with the complete follow-up program, the rate of missed recurrence was 2.2%. The total projected cost per patient for 5 years of follow-up for the simplified procedure was approximately 12.2-fold lower than the standard approach.

Conclusions: Our results have shown that a simplified diagnostic approach, including the SCC assay and gynecologic examination, can detect a high rate of recurrence from cervical cancer, with a very favorable cost-effective profile.