November 18, 2005

Study aims to halt lung cancer development

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Nancy Chescheir, M.D., chair of Obstetrics and Gynecology, in her office.
photo by Dana Johnson

Study aims to halt lung cancer development

Researchers at Vanderbilt-Ingram Cancer Center are enrolling patients in a new study aimed at finding pre-cancerous lesions in the lung and treating them with an investigational drug in an effort to prevent cancer.

The study will focus on current or ex-smokers who have smoked one pack of cigarettes a day for more than 20 years, or two packs a day for 10 years. The participants must be adults who have not already been diagnosed with lung cancer.

Pierre Massion, M.D., assistant professor of Medicine in the Division of Allergy, Pulmonary and Critical Care Medicine, is leading Vanderbilt-Ingram's participation in the multi-center study led by the University of Colorado Health Sciences Center.

“It's the No. 1 cancer killer in both men and women. You really have to approach the disease before it is there,” said Massion.

In the study, patients will be initially screened using a sputum sample. It's as simple as coughing in a cup, mornings, for six consecutive days. The samples will be sent to a pathologist who will look for abnormal, or pre-cancerous, cells that could, over time, develop into cancer. “In 10 percent of people with mild dysplasia or atypical cells, they lead to lung cancer,” said Massion.

Next, participants found to have atypical cells on the sputum testing will have the opportunity to enter this randomized trial. Enrollees will undergo a bronchoscopy, a diagnostic procedure in which a tube with a tiny camera on the end is inserted through the nose or mouth into the lungs allowing for a view of the airways. Massion uses fluorescent bronchoscopy, which allows areas of concern to be detected more clearly. Small biopsies of the areas that appear concerning are taken and examined.

Participants will then be given a placebo (inactive or “sugar” pill) or the study drug, Iloprost, which is a prostacycline analog. It is currently used to treat pulmonary hypertension and peripheral vascular disease, both unrelated to lung cancer.

In animal studies, Massion says, this drug was shown to prevent lung cancer from developing. “In a normal, healthy lung there is a balance of a series of prostanoids known as PGI-2 and PGE-2. In cancer, there is an imbalance of the two. Patients either have too much PGE-2 or too little PGI-2, both of which may participate in causing cancer,” explained Massion.

In the animal studies, tumor growth was prevented by giving mice prostacycline analog, or a synthetic form of PGI-2, which mimics the setting of a healthy lung.

It's a double-blind trial, so Massion, his research nurse, Lynne Fenner, and the participants, don't know who is getting the study drug. Six months after the study begins, patients will undergo another bronchoscopy. Blood tests are performed every month to carefully monitor patients and their tolerance of the drug. The medication will be increased as long as the patient is tolerating it well.

Massion says he understands this prevention concept is hard for some people to embrace. “It is tough to convince people who feel and appear well to be tested and participate in a trial to prevent what could one day be cancer. But most cancers develop slowly; therefore there is a huge window of time we should use to prevent this from happening.”

Massion said most lung cancers are found too late to offer much of a chance for a cure. He said the five-year survival rate is only 15 percent.

“We should not be looking for cancer; we should be looking to prevent cancer.”