Tumor Size and Endophytic Growth Pattern Affect Recurrence Rates After Laparoscopic Renal Cryoablation

Objective To analyze factors that may contribute to local relapse after laparoscopic cryoablation (LCA) of renal tumors. LCA has gained popularity in the treatment of small renal tumors, but local tumor control remains a concern. Methods We analyzed 163 patients who underwent LCA between 2001 and 2008 either at Allegheny General Hospital or Duke University Medical Center, with at least 6 months of follow-up. Demographics, perioperative variables, tumor characteristics (size, pattern of growth, and biopsy results), and follow-up were recorded. Growth pattern was categorized as exophytic, mesophytic, or endophytic. Regression analyses were performed to evaluate risk factors for local relapse after LCA. Results Median patient age was 66 (range, 33-90) years, with men comprising 60.1% of the cohort. Median tumor size was 2.4 cm (range, 0.5-5.0). Pathology was as follows: renal cell carcinoma in 118 (72.4%), other malignancies in 2 (1.2%), and no malignancy in 43 (26.4%) patients. A single lesion was treated in 95.1% patients and multiple tumors in 4.9%. Endophytic growth pattern was present in 22.8% patients. We observed 7 (4.3%) local recurrences over a median follow-up of 20 months (range, 6-79). Median time to recurrence was 15 months (range, 6-48). On proportional hazards regression, tumor size and endophytic growth pattern were significantly associated with local recurrence ( P = .003 and .028; odds ratios [OR] = 4.1 and 11.4, respectively). Conclusions LCA demonstrated good tumor control over a 5-year follow-up, with an acceptable recurrence rate. Larger tumors and those with endophytic growth pattern may be at increased risk of relapse after LCA.