Synchronous pulmonary metastases from renal cell carcinoma--a whole nation study on prevalence and potential resectability.

Background: At the time of diagnosis, almost one third of patients with renal cell carcinoma (RCC) have metastasis. We studied the prevalence, survival, and potential resectability of synchronous pulmonary metastases (SPMs) in a well-defined cohort of RCC patients. Material and Methods: A retrospective whole nation study including RCC patients with SPM diagnosed 1970-2005 in Iceland. Imaging studies and histology were reviewed, the TNM system used for staging the primary tumors, and disease-specific survival estimated. Eligibility for SPM removal was evaluated using different criteria from the literature on surgical management of SPM, including solitary SPM and SPMs confined to one lung. Results: Altogether, 154 patients (16.9%) had SPMs. In 55 of these patients (35.7%) the lungs were the only site, with detailed information available in 46 cases. Of these 46 patients with SPMs, 15 were unilateral, and of those 11 were solitary. All of these 11 patients were in good physical condition and were deemed eligible for surgical resection; however, only one of them was operated with metastasectomy. Disease-specific survival at five years for patients with solitary SPM was 27.2%, as compared to 12.7%, 7.1%, and 12.0% for patients with unilateral SPMs, all patients with SPMs, and patients with extrapulmonal metastases, respectively (p = 0.33). Conclusion: At the time of diagnosis, 16.9% of RCC patients had SPM. In one in three of these SPM patients metastases were confined to the lungs, while one in five had solitary pulmonary metastases. Although the benefit of pulmonary metastasectomy in RCC is still debated and criteria for resection are not well defined, it appears that many RCC patients with SPM are potentially eligible for pulmonary metastasectomy.