CT-guided cryoablation for unresectable pelvic recurrent colorectal cancer: a retrospective study

Objective: The study aimed to investigate the efficacy of computed tomography (CT)-guided cryoablation debulking of unresectable pelvic recurrent colorectal cancer (CRC). Patients and methods: From January 2013 to April 2016, 30 patients (18 males and 12 females; aged 57.8 +/- 10.5 years) with unresectable pelvic recurrent CRC who had previously received radiotherapy or chemotherapy were included. A total of 35 tumors ranging from 1.2 to 6.3 cm underwent cryoablation. Tumor response was evaluated 1 month after cryoablation according to the Modified Response Evaluation Criteria in Solid Tumors. Logistic regression was used to analyze the risk factors for tumor response. Degree of pain palliation was also determined using the Numerical Rating Scale. Cox proportional hazard models were used to identify predictors of outcomes. Results: Cryoablation was successfully performed in all patients. Complete response (CR) was achieved for 27 tumors in 23 patients and partial response was achieved for eight tumors in seven patients 1 month after cryoablation. The rate of CR was 77.14%, and tumor size was an independent risk factor for CR. Pain relief was satisfactory in 21 symptomatic patients (P<0.001), and the median duration of pain relief was 6.0 months (95% CI: 2.67-9.33). Serum carcinoembryonic antigen (CEA) was significantly decreased after cryoablation in 15 patients with elevated CEA (P=0.005). The median progression-free survival (PFS) was 10.0 months (95% CI: 4.43-15.67). Multivariate analysis revealed that tumor size (HR =3.089, P<0.001), sex (HR =0.089, P=0.002), and elevated CEA (HR =7.015, P=0.002) were independent predictors of PFS. Conclusion: CT-guided cryoablation is a safe and effective therapeutic option for pelvic recurrent CRC. Tumor size is an important predictor of poor outcomes.