Survival of NSCLC Patients May Relate to Tumor Growth Habits

[Amy P]

Vol. No: 30:10 Posted: 10/19/2005

Survival of NSCLC Patients May Relate to Tumor Growth Habits

US Pharm. 2005;10:12.

Patients with second primary tumors, commonly found in patients with non-small cell lung cancer, tend to have an overall better survival rate than patients without second primary tumors, a team of researchers report.1

"Based on the experience with head and neck cancer revealing many second primary tumors, we wanted to know what the clinical practice is with respect to second primary tumors in NSCLC: What is the prevalence of second primary tumors, and what does it mean for survival?" stated Dr. Stokkel, of the Department of Radiology at Leiden University Medical Center in the Netherlands. The researchers had several other important questions as well: Should it be possible to detect more second primary tumors when staging NSCLC? What should the interval be between initial diagnosis and follow-up PET studies to increase the diagnostic yield of second primary tumors? And would it be helpful to perform PET studies, for example, twice a year after initial diagnosis of NSCLC?

They retrospectively studied 860 patients for whom NSCLC had been diagnosed in the 1990s. Patients were assigned to one of the following groups: Group 1 consisted of patients with NSCLC as the first tumor; these patients had another primary tumor found during follow-up. Group 2 included patients with another primary tumor in their history that was not NSCLC. Group 3 consisted of patients with NSCLC as the only tumor. Group 4 comprised patients with more than two primary tumors in their history and/or during follow-up.

Drs. Duchateau and Stokkel found that in 25% of study participants with NSCLC, additional primary tumors were diagnosed either in their history or during the follow-up period. In 34 patients, more than one other primary tumor was found; 30 had three primary tumors, and four had four primary tumors. Second primary tumors were most frequently located in the lungs, the head and neck region, and the urinary tract. In more than 80% of patients, the second primary tumors were detected within one year after NSCLC was diagnosed.

Factors Affecting Survival Rates

According to the researchers, survival rates tended to be better among patients with additional primary tumors than among patients who did not have additional primary tumors. The five-year survival rate was significantly better for patients with more than two primary tumors than for those without two primary tumors or with only one other tumor in their history. The five-year survival rate was better among patients diagnosed with a second tumor during follow-up than among patients without any other second tumor. The researchers said the difference in survival rates between patients with and without additional primary tumors suggests differences in growth habits of NSCLC between these patients.

The investigators remarked that initially they expected the stage of the primary tumor--derived from TNM criteria--to be an important factor for the prevalence of second primary tumors. However, they found that TNM stage and therapy were comparable among the different groups and, moreover, could not be used as an explanation for the difference in survival rates. Although the effects of chemotherapy might have had some influence on the results, Dr. Stokkel emphasized that the number of patients in each subgroup in the current study was rather small. He noted that more patients would need to be studied prospectively in a multicenter setting to further investigate this theory.

Because the findings suggest "a difference in growth habits of NSCLC between patients with and without second primary tumors, studies should focus on this aspect to get a better understanding of this possible prognostic feature," the researchers recommended. Additional studies should be conducted "to assess the role of more sophisticated imaging techniques, such as fluorodeoxyglucose positron emission tomography, in the early detection of second primary tumors in relation to the costs and consequences for treatment and survival," they said. Dr. Stokkel noted that the results "may have consequences with respect to treatment protocols, but we have to ... study the proliferation rate in NSCLC as first, second, or single primary tumor in relation to the outcome."

REFERENCE

1. Duchateau CSJ, Stokkel MPM. Second primary tumors involving non-small cell lung cancer. Chest. 2005;127:1152-1158.