Regina Barragan-Carrillo, MD, medical oncologist, postdoctoral fellow, Department of Medical Oncology and Therapeutics Research, City of Hope Comprehensive Cancer Center, discusses findings from a large population-based study which found there to be significantly higher rates of nephrectomy among patients with renal cell carcinoma (RCC) who had received prior thymectomy vs the incidence of nephrectomy overall.
0:10 | For the end points, we tested for the rate of nephrectomies, or renal cell diagnosis specifically. How we did this and how we chose that is because of the methodology we had available. We used the [California Office of Statewide Health Planning and Development (OSHPD)] database, which is the standard for the office of statewide planning and development which is a database based in California [and] accounts for all the procedures that are done in the inpatient and outpatient settings, and also for all ER visits. What we have seen with the information available are the procedures through the CPT and ICD-9/10 codes.
0:49 | What we decided is to use the coding for thymectomy and the coding for nephrectomy to identify both groups. For example, the rate we have in the state of California accounting for all adult patients, meaning 40 years or older, the rate we have for nephrectomy for renal cell carcinoma is around 0.2%. The rate we noticed in those patients who had previously undergone a thymectomy was 0.56%, which is more than double what we would have expected for the state of California.
1:26 | One might raise the question, and I think it is a valid question, is whether there was a risk of bias in the selection of the population because these are patients who are already under certain scrutiny because of their past surgical history. We included in our analysis, another 3 surgical procedures, which were a cholecystectomy, a hip arthroscopy, and a knee arthroscopy. In all 3 sub-populations who had undergone those procedures and afterwards required nephrectomy for RCC, the rates for RCC after diagnosis were also pretty similar to what we saw in the overall population, which were around 0.20%. Which also, historically, are the numbers that make sense in that regard. The difference between the patient with a prior time made to me was quite clear to us.
2:20 | This is only hypothesis generating. We still need to make a lot of efforts to understand whether there is an association of causation between those 2, but at least it raises the question to know whether patients that are in this nonclassical immunosuppressive state who have a higher risk to develop other secondary malignancies. We ask the clinical team as the healthcare providers could appropriately counsel these patients during their follow-up.