VASCULAR INVASION AS RISK FACTOR OF STAGE IA NSCLC RECURRENCE

August 24, 2010 — When is a patient with resected stage IA nonsmall-cell lung cancer (NSCLC) cured?

Conventional wisdom says that a patient without recurrence at 5 years is cured.

A new study from Japan indicates that one NSCLC risk factor — vascular invasion — imperils that nearly certain cure.

The study found that patients with vascular invasion have a statistically significant risk for late recurrence more than 5 years after complete resection.

However, patients without vascular invasion — even those with a history of smoking — "may be declared to be cured at 5 years if they are recurrence-free," write the authors, led by Ryo Maeda, MD, from the National Cancer Center Hospital East in Chiba, Japan.

The study is published in the August issue of the Journal of Thoracic Oncology.

An American thoracic surgeon said that the results from the 519-patient single-center study "need to be confirmed in larger series."

Walter Scott, MD, chief of thoracic surgical oncology at the Fox Chase Cancer Center in Philadelphia, Pennsylvania, also acknowledged that the practical meaning of the results was not obvious.

"It's not clear what the clinical implication is for this paper," he told Medscape Medical News.

Surveillance Is "Problematic"

"It's important to know that there is an increased risk of recurrence in some of these patients after 5 years," said Dr. Scott, who said that the presence of vascular invasion might influence decisions about using adjuvant chemotherapy.

However, surveillance is another matter, he explained.

"Most recurrences are in the first 2 years," he said. "If you don't recur at 5 years, we consider you cured generally." A number of studies provide the basis for that belief, Dr. Scott noted.

The reason patients are observed after surgery is for recurrence of the primary tumor or the event of a second lung cancer, he said.

But Dr. Scott pointed out that observation or surveillance for any extended period in lung cancer is "problematic."

"There is not a lot of level I evidence about how to follow-up with lung cancer patients postsurgery," he said.

Furthermore, there is the question of cost and who pays for it. "There is no good evidence that careful surveillance improves outcome," said Dr. Scott. Thus, getting an insurer pay for the surveillance is difficult, he said.

The National Lung Screening Trial will eventually contribute to the scant evidence about the value of surveillance postsurgery, he added.

Another factor that mitigates surveillance is the related radiation, he said.

Everyone is concerned about too much radiation from frequent [computed tomography] scans," Dr. Scott said about the most common lung imaging tool. "My patients ask me about this all the time," he added.

Yet another factor arguing against surveillance long after surgery comes from a recent SEER database study, said Dr. Scott.

The study found that 7 years after surgery in lung cancer patients who are 70 to 79 years of age, the risk of dying of heart disease is greater than dying of lung cancer, he said (Ann Thorac Surg. 2010;90:375-382).

At Fox Chase, the age of the average lung cancer patient is 67 years — very close to the age group in that study, he noted.

One more complicating factor in long-term surveillance is that, by 5 years, "we lose track of some of these patients," said Dr. Scott. The patients have since returned to their primary care physicians, he explained.

In summary, the problems with surveillance for any extended period after surgery are multiple, Dr. Scott said.

Study Results

The Japanese study aimed to quantify the risk for late recurrence in patients with stage IA NSCLC who remained recurrence-free for more than 5 years after resection.

There have been more early NSCLCs detected in Japan in recent decades because of the country's mass screening system, the authors report.

The 519 patients in the study had undergone resection between August 1992 and December 2002; 434 remained recurrence-free for 5 years. All of these patients were followed for a median of 44 months after the first 5 years. Among these 434 patients, 21 (4.8%) developed late recurrence more than 5 years after resection.

Among the 21 patients who had a late recurrence, the median recurrence-free interval was 14 months from the benchmark of 5 years after primary tumor resection.

Multivariate Cox analysis demonstrated that vascular invasion significantly influenced late recurrence (P < .038), write the authors. Other risk factors analyzed included a history of smoking, histologic type, and histologic differentiation. None of these significantly influenced late recurrence.

The 5-year recurrence-free probability from the benchmark of 5 years was 84% for patients with vascular invasion and 95% for patients without vascular invasion (P < .001).

The authors have disclosed no relevant financial relationships.

J Thorac Oncol. 2010;5:1246-1250. Abstract