Be vigilant for lung cancer in metastatic renal cell carcinoma patients

A subsequent diagnosis of primary lung cancer in patients already diagnosed and undergoing treatment for metastatic renal cell carcinoma (RCC) may occur in up to 6% of patients, according to these researchers at the Harold C. Simmons Comprehensive Cancer Center’s Kidney Cancer Program at University of Texas Southwestern Medical Center, Dallas, TX. They published their findings in the journal Clinical Genitourinary Cancer.

In the United States, according to data from the National Cancer Institute (NCI), almost 400,000 individuals have received a diagnosis of kidney cancer, and more than 60,000 additional patients are expected to be diagnosed this year.

“Kidney cancer spreads primarily to the lungs making the detection of a primary lung cancer difficult. Lung cancer is typically more aggressive than kidney cancer. Undetected, lung cancer may spread and eventually kill the patient,” said James Brugarolas, MD, director, Kidney Cancer Program, and associate professor of internal medicine, University of Texas Southwestern Medical Center in Dallas, TX.

UT Southwestern Kidney Cancer Program patient, Mel Moffitt, describes how he was diagnosed with lung cancer while being treated for kidney cancer. Lung cancer is often missed and may be found in as many as 6% of patients with kidney cancer.

Dr. Brugarolas and colleagues identified 151 patients undergoing systemic targeted therapy for metastatic RCC from January 2006 to October 2013, and calculated the proportion and incidence rate for developing non-small cell lung cancer (NSCLC) with preexisting metastatic RCC. Of these patients, 2% were subsequently diagnosed with NSCLC (95% CI: 0.68%-5.68%), 85 of whom had RCC metastasized to the lungs, and 3 who had primary lung cancer. This percentage increased to 3.5% in those with known RCC pulmonary metastasis (95% CI: 1.21%-9.87%). The incidence rate for the development of NSCLC in patients with metastatic RCC was 0.87 per 100 person years (95% CI: 0.22-2.4).

They noted that since UT Southwestern is a tertiary care referral center, these rates may differ in the general population. Upon reviewing the literature, they found only four previous cases. Dr. Brugarolas and colleagues stressed that both the radiographic appearance and clinical behavior of a lesion may be helpful in distinguishing between a new primary and progression of metastatic disease.

“Our report raises an important flag for medical oncologists and radiologists to be on the lookout for a hidden lung cancer,” concluded Dr. Brugarolas.

The study was supported by a SPORE (Specialized Program of Research Excellence) award from the NCI, only the second such award for kidney cancer in the nation. The SPORE investigators are working to better understand how kidney cancer develops and spreads, as well as to develop new therapies targeting adult and pediatric kidney cancer. UT Southwestern also leads a 20-year, multi-institutional SPORE grant in lung cancer that is the largest thoracic oncology effort in the US.