Proton Therapy Now Targets Lung Cancer

May 18, 1999

More than 170,000 thousand Americans are expected to be diagnosed with lung cancer in 1999. Despite technical advances in surgery, standard radiation therapy and chemotherapy, long-term survival rates remain discouragingly low.

The best results are obtained in patients whose tumors are small enough to be surgically removed. However, because of heart, lung and other medical problems, only about 20 percent of those patients can be treated with surgery.

That's why physicians at the Proton Treatment Center at Loma Linda University Medical Center in southern California are keeping a close eye on a clinical study designed to treat such patients using proton therapy. The clinical study, begun in 1994, gives patients with early-stage , medically inoperative lung cancer an alternative to conventional radiation therapy.

"Many of these patients are very sick," says Dr. David A. Bush, assistant professor of radiation medicine at Loma Linda University School of Medicine, who is also a radiation oncologist. "It is critical to minimize lung tissue damage, and protons allow us to do that," notes Dr. Bush.

Proton therapy offers a distinct advantage over conventional radiation (photons) therapy in that it can deliver higher doses to a localized target area (cancerous tumors), and spare damage to surrounding tissue. Which means patients experience considerably less side effects.

To date, some 50 lung cancer patients have now been treated at LLUMC's Proton Center. To be eligible for the clinical research study, patients must have localized, early-stage lung cancer that can not be treated with surgery because of other related health problems. Also, the tumor must be limited to the lung, with no mediastinal lymph node involvement.

Currently, only a limited number of patients can be treated. However, current research is expected to enhance the expansion of lung cancer treatment protocols with protons, as well as adding breast cancer in the near future to the list of tumor sites.

According to Dr. Bush, preliminary results are encouraging. A recent research paper submitted for publication by Dr. Bush and his colleagues reports that proton beam therapy is associated with less pulmonary injury than combined photon/proton therapy.

The paper reports that long-term survival data cannot be documented until sufficient time has elapsed, but early results are promising: the three-year cancer-specific survival rate for stage 1 patients is 79 percent.

Dr. Bush estimates that approximately 5,000 Americans per year are diagnosed with early-stage, medically inoperable lung cancer. If early indications are accurate, proton therapy may become an important tool, and likely a preferred option, in the treatment of these patients. Since it opened its proton center in 1990, more than 5,000 cancer patients have been treated with proton therapy. More than half for prostate cancer.

More information about proton therapy is available by calling 1-800-PROTONS (1-800-776-8667), or visit .

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