Local recurrence and residual tumor rates following cryoablation for small early-stage breast cancers: systemic review and meta-analysis.

Abstract

Cryoablation is currently being investigated as a minimally invasive alternative to breast-conserving surgery. This meta-analysis investigates the local recurrence and residual tumor rates after cryoablation for small early-stage breast cancers. A systematic search was conducted on Embase, PubMed, Google Scholar, and the International Clinical Trials Registry Platform from inception to 16 June 2024. Studies of patients with breast cancers ≤ 20mm treated with cryoablation only or cryoablation followed by surgery were included. Pooled local recurrence rates (cryoablation only) and pooled residual tumors rates (cryoablation followed by surgery) were estimated with mixed-effects models. Between-study heterogeneity was assessed using I2 statistics. Where I2 exceeded 50%, outlier and influence analysis, followed by sensitivity analysis excluding outliers, were conducted. Twelve studies met inclusion criteria, of which 7 studies (530 female patients, 531 breast tumors) reported on patients treated with cryoablation only and 5 studies (220 female patients, 222 breast tumors) reported on patients treated with cryoablation followed by surgery. For studies on cryoablation only, pooled local recurrence rate was 1.1% (95% CI 0.42-3.03%) with low between-study heterogeneity (I2 value = 0%; 95% CI 0.0-70.8%; p = 0.95). For studies on cryoablation followed by surgery, pooled residual tumor rate was 12.0% (95% CI 3.85-31.64%); however, substantial between-study heterogeneity (I2 value = 76.1%; 95% CI 41.7-90.2%; p < 0.01) was present. Influence analysis revealed 1 outlier study. When this study was excluded, pooled residual tumor rate was 8.2% (95% CI 3.84-16.68%) with improvement in heterogeneity (I2 value = 0%; 95% CI 0.0-84.7%; p = 0.64). Pooled local recurrence and residual tumor rates after cryoablation are comparable to local recurrence rates after breast-conserving therapy and re-excision rates following breast-conserving surgery, respectively. These results are encouraging but should be interpreted with caution due to lack of comparative studies.