The efficacy and safety of microwave ablation in patients with retroperitoneal metastases.

BACKGROUND: Retroperitoneal metastases are common, and most present with symptoms; however, treatments for this condition are limited. This retrospective study verified the efficacy and safety of microwave ablation (MWA) in retroperitoneal metastases patients.

METHODS: Patients with pathologically confirmed malignant carcinoma and imaging showing retroperitoneal metastases were enrolled and underwent MWA. The end-points included objective response rate, time to local progression (TTLP), overall survival, visual analogue scale (VAS) score, dose of morphine pre- and post-ablation and complications.

RESULTS: Twenty-three patients were enrolled. The mean tumour diameter was 3.6 cm. Altogether, 29 tumour sites in 23 patients were ablated during 23 procedures; technical success was achieved in all 23 patients. The objective response and disease control rates were 95.7% and 100.0%, respectively. The mean TTLP and median OS were 22.8 months (95% CI: 16.1-29.6 months) and 10.6 months (95% CI: 7.4-13.8 months), respectively. In 13 patients with symptoms, the VAS values before ablation and 48 h, 1 month, 2 months, 3 months and 6 months after ablation were 5.38, 2.77 (p = 0.015), 2.15 (p = 0.001), 2.17 (p = 0.001), 1.40 (p = 0.000) and 1.71 (p = 0.006), respectively. The corresponding morphine doses were 76.9 mg, 70.7 mg (p = 0.584), 50.7 mg (p = 0.031), 55.0 mg (p = 0.097), 46.0 mg (p = 0.057) and 40.0 mg (p = 0.363), respectively. No ablation-associated mortality was observed. Major complications, minor complications and adverse events were observed in eight (34.8%), five (21.7%) and four (17.4%) patients, respectively.

CONCLUSION: MWA for the treatment of retroperitoneal metastases was effective and the complications were common.