BERKELEY, CA (UroToday.com) - Metastatic renal cell carcinoma (RCC) is present in 20% - 30% of patients with newly diagnosed disease and 20% of patients treated for localized disease. The most common site for metastases is the lung. Despite the high rate of metastatic disease to the lung, the clinical significance of indeterminate pulmonary nodules (IPNs) was reported by a single study that found an association between the presence of IPNs and a worse disease-free survival.
The current study evaluated whether the presence of IPNs, their size, or number were associated with the patient's outcome. The study cohort included 748 patients with pulmonary nodules less than 2cm in size, identified on pre-operative chest CT scans, and who did not have metastatic disease or concurrent pulmonary disease. Using Cox proportional hazard models we evaluated whether the presence of IPNs, their number, or size were associated with lung metastases, any distant metastases, or death from kidney cancer. We also evaluated whether adding the IPN information to a prognostic model adjusted for tumor stage, size, and histology significantly improved the ability of the model to predict oncologic outcome.
In the study cohort, 51% of patients had IPNs on preoperative axial chest imaging. Patients with IPNs were significantly older than patients without IPNs, however no other differences were noted between the two groups. At 5 years, lung metastases developed in 27% of patients with IPNs > 1cm, but in only 10% and 9% of patients with IPNs < 1cm and without IPNs, respectively. In 76% of cases with metastatic lung disease during follow-up and pre-operative IPNs, the metastatic lesion developed from the IPNs identified on pre-operative imaging. On multivariate analysis of all patients, adjusted for tumor histology, AJCC stage, and tumor size, the presence of IPNs > 1cm was significantly associated with lung metastasis and any distant metastasis, and the presence of multiple IPNs was significantly associated with any distant metastases, however these findings were not associated with a decreased cancer-specific survival. Furthermore, when the group of patients with IPNs was evaluated separately, only nodule size > 1cm remained a significant predictor of adverse outcome. Finally, adding nodule number to a basic predictive model did not increase the c-index of the model, while adding IPN size only slightly increased the model’s c-index for all patients and for patients with IPNs.
Taken together, these findings suggest the presence of IPNs > 1cm of size may predict metastatic disease; however, more importantly, the presence of subcentimeter IPNs was not associated with disease progression and should not affect the decision to treat patients, nor affect routine follow-up protocols. Further studies are required to validate these findings and evaluate whether different follow-up protocols, based on IPN size, may optimize the detection of metastatic disease while minimizing radiation exposure and unnecessary imaging tests, and whether simple chest X-ray may be sufficient for the evaluation and follow-up of patients with RCC since clinically significant nodules were > 1cm in size and possibly detectable on chest X-ray.
Roy Mano and Paul Russo as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Urology Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY USA
Subcentimeter pulmonary nodules are not associated with disease progression in patients with renal cell carcinoma - Abstract