A novel radiotherapy approach has shown promise as a treatment option, and may possibly increase the cure rate, for people with early stage lung cancer who are unable to tolerate surgery, according to findings from a five-year study led by SUNY Upstate Medical University.
SUNY Upstate was among 10 institutions nationwide participating in this first prospective radiotherapy study specific to high-risk patients with early stage lung cancer. The findings were presented at the American Society of Clinical Oncology meeting June 4 in Chicago.
“Although the majority of patients with stage 1 non-small cell lung cancer (NSCLC) may be cured following surgery to remove a whole section of the lung, a substantial portion of these patients have poor lung function or other medical problems, making them unsuitable for major surgery,” said the study's principal investigator, Jeffrey A. Bogart, M.D., professor and chair of the Department of Radiation Oncology at SUNY Upstate Medical University. “We need to find a safe and effective way to treat this patient population.”
Bogart noted that an earlier study tested an approach of limited surgery on these patients, removing the tumor with only a small portion of the diseased lung. However, while findings from this study indicated that limited surgery may be effective in certain patients, the role of limited surgical resection in the high-risk population remained unclear. This led investigators to test a new theory that would involve treating the tumor solely with dose-intensive accelerated three-dimensional conformal radiotherapy.
“Our primary objectives were to determine the maximally accelerated course of conformal radiotherapy for high-risk stage 1 NSCLC and to describe the short- and long-term toxic effects of conformal radiotherapy in this population,” said Bogart. “We also wanted to assess the efficacy of such a technique.”
Conformal radiotherapy uses advanced technology to precisely target the tumor and the surrounding normal structures in 3 dimensions using CT or MRI scans, and then sculpt the radiation dose to the shape of the tumor. “We are better able to conform the radiation dose to the exact location of the tumor, avoiding critical structures and providing more intense therapy directly to the tumor,” said Bogart.
This, according to Bogart, reduces radiation exposure to the surrounding normal tissue, thus reducing the risk of radiation toxicity to the patient.
To conduct the study, 40 male and female stage 1 NSCLC patients, ranging in age from 48 years to 87, were recruited between 2001 and 2005. “The radiotherapy schedule was reduced from 28 treatments in 5.5 weeks to 17 treatments in 3.5 weeks while maintaining a nominal dose of radiation of 7000 cGy. Bogart noted that just about one-half of all patients survived at least three years, a very promising result in this population. In addition, only three of the patients had a recurrence of the tumor in the same location in the lung. Importantly, only one of the patients had experienced a severe adverse effect of the radiation therapy, such as difficulty breathing.
“Our outcomes demonstrated that accelerated 3-D conformal radiotherapy is feasible in high-risk early stage NSCLC and therapy can safely be completed in less than half the time of traditional regimens,” said Bogart. “Our outcomes were comparable to alternate therapies, such as limited resections, with less apparent severe radiation toxicity.”
Bogart noted that more studies are being planned to test new, non-surgical ways to treat this patient population. Particularly exciting are recent advances at University Hospital that help account for the fact that many lung tumors move when a patient breathes. Technology such as four-dimensional CT scans (4DCT), respiratory gating and Image Guided Radiotherapy (IGRT) work together to first identify how a lung tumor moves (by monitoring the patients unique breathing pattern) and then permits delivery of radiation only when the tumor is in the proper position.
The study, titled “Accelerated Conformal Radiotherapy for Stage 1 Non-small Cell Lung Cancer (NSCLC) in Patients with Pulmonary Dysfunction," or “CALGB 39904 was funded through the Cancer and Leukemia Group B (CALGB), a national clinical research group sponsored by the National Cancer Institute of the National Institutes of Health.