Proton Beam Therapy Shows Promise in Treating Lung Cancer; Medically Inoperable Patients Have New Treatment Option Backed by Years of Outcome Data.

Business Editors & Health/Medical Writers

SAN BERNARDINO, Calif.--(BW HealthWire)--April 25, 2000

In a recent clinical trial at Loma Linda University Medical Center (LLUMC), years of outcome data show that proton beam radiotherapy compares favorably with traditional radiation for treatment of non-small cell early stage lung cancer.

With protons, local tumor control was 87 percent, significantly higher than the average 50 percent control rate achieved using traditional radiation.

Published in the Fall 1999 issue of Chest and presented at this month's International Proton Therapy Cooperative Group (PTCOG) meeting in Uppsala, Sweden, these strong clinical results represent encouraging news for lung cancer patients, and support the clinical viability of proton therapy as a treatment option.

"Surgery is the standard treatment in many cases," said Dr. David Bush, Department of Radiation Medicine, LLUMC. "However, because non-small cell lung cancer is commonly seen in patients who have extensive smoking histories, we often must consider their smoking-related illnesses in developing treatment plans.

"Diseases such as coronary artery disease, peripheral vascular disease, and chronic obstructive pulmonary disease render 15 to 20 percent of them medically inoperable. These patients are potential candidates for proton treatment."

According to data released by the American Cancer Society, nearly 157,000 people will die from lung cancer in 2000 and an estimated 164,100 new cases will be diagnosed. Traditional X-ray (photon) therapy has been used to treat medically inoperable patients, however, general disease-free survival and local control rates are inferior to those produced with surgery. Proton therapy provides higher radiation, which may enhance survival rates.

The unique properties of protons provide a distinct physical advantage over conventional X-ray beams. Protons are controllable and can be programmed to release their dose in a targeted tumor area, so doses can be increased while reducing the effects to healthy tissue. Pulmonary injury is less significant and the tumor receives higher radiation. Protons can also be shaped to deliver homogeneous radiation to irregular three-dimensional volumes such as those seen in lung tumors.

"Proton radiation reduces both the incidence and severity of pulmonary injury in comparison to treatment plans relying on traditional X-ray therapy," said Bush, citing an American Journal of Roentgenology article supporting the use of protons in treating lung cancer. "We believe this will help us speed patient recovery and eradicate more tumors -- the ultimate endpoint in this treatment."

From June 1994 to March 1998, LLUMC treated 37 patients with non-small cell early stage lung cancer. Average patient age was 72 years, with 27 patients at Stage I disease, two in Stage II and eight in Stage IIIa. Trial participants were not candidates for surgery or refused such treatment. Most had significant underlying chronic obstructive pulmonary disease that precluded a definitive surgical option.

Preliminary analysis showed an overall 63 percent disease- free survival rate two years following treatment, and 86 percent disease-free survival for Stage I patients. Local tumor control at the primary site was 87 percent two years following treatment, compared with control rates ranging from 42 to 55 percent with conventional radiation.

"The main side effect we expected was lung damage - these patients are all at risk because of emphysema and very low pulmonary reserve," said Bush. "What we've seen is virtually no change in their pulmonary function after treatment, which is measured very precisely before and after treatment."

Future phases of this clinical trial will increase the proton dose delivered and extend this treatment option to patients who have locally advanced lung cancers.

About Protons

A December 1998 news release reported protons achieve the same or better results in treating prostate cancer when compared with surgery or radiation. Data presented on 643 prostate cancer patients showed an overall disease-free survival rate of 89 percent five years following the treatment.

Local tumors were controlled in 95 percent of patients. This data was peer-reviewed and published in the Fall issue of the International Journal of Radiation Oncology.

Treatment results of an ongoing macular degeneration trial, presented in a February 1999 news release, showed that 89 percent of patients with wet type age-related macular degeneration (ARMD) demonstrated control of the disease 18 months after being treated with protons.

For additional information on proton beam treatment, contact Optivus at 909/799-8300 or Loma Linda University Medical Center's Proton Treatment Center at 800/PROTONS (776-8667). To access information online, go to www.optivus.com or www.llu.edu/proton.