Could lung cancer be hiding in kidney cancer patients? Researchers with the Harold C. Simmons Comprehensive Cancer Center's Kidney Cancer Program studied patients with metastatic kidney cancer to the lungs and found that 3.5 percent of the group had a primary lung cancer tumor that had gone undiagnosed.

This distinction can affect treatment choices and rates of survival.

"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 Dr. James Brugarolas, Director of the Kidney Cancer Program and Associate Professor of Internal Medicine at UT Southwestern Medical Center.

Up to 6 percent of patients with metastatic kidney cancer also may have a lung cancer, investigators noted in the study, published in Clinical Genitourinary Cancer.

Nearly 400,000 Americans are now living with a diagnosis of kidney cancer and more than 60,000 people are expected to be diagnosed with kidney cancer this year, according to the National Cancer Institute (NCI).

Five-year survival rate averages range from more than 80 percent for stage 1, when cancer is contained in the kidney, to about 53 percent for stage 3, when it has spread beyond the kidney, to just 8 percent for stage 4, when the cancer spreads to more distant parts of the body or other organs.

Texas has the fifth-highest rate of this cancer in the U.S. and it is the fourth most common cancer treated at the Simmons Comprehensive Cancer Center, where survival rates for patients with stage 4 kidney cancer are double national benchmarks, noted Dr. Brugarolas, a Virginia Murchison Linthicum Scholar in Medical Research at UT Southwestern.

In this retrospective study of 151 patients at the Simmons Comprehensive Cancer Center, investigators identified 85 people who had kidney cancer metastasized to the lungs, and three who had a primary lung cancer.

Investigators found only four previous cases described in the literature, leading them to suspect the incidence of lung cancers in kidney cancer patients may be underreported.

Because UT Southwestern is a tertiary care referral center, investigators noted that rates could be different in the general population.

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

Source: UT Southwestern Medical Center