Source: www.docguide.com
Author: John Otrompke

Radiation therapy for head and neck cancer may cause an injury to the brachial plexus nerve network in as many as 20% of patients, researchers stated here at the American Society of Therapeutic Radiology and Oncology (ASTRO) 51st Annual Meeting. The incidence of the condition, characterised by numbness in the arms, inability to use the shoulder, and/or atrophy or retraction of chest muscles, may be underreported, suggesting that healthcare providers devise an avoidance strategy when administering high-dose radiation.

“This was the first study that looked at brachial plexus injury and quality-of-life effects in patients for head and neck cancer, because in the past these patients never survived long enough for physicians to notice the symptoms, which include chronic frost-bite sensation in the fingers,” said Allen M. Chen, MD, Department of Radiation Oncology, University of California Davis Health System, Sacramento, California, on November 3.

The study was originally conceived based on clinical observations, he said. “We would see these patients coming in with these odd symptoms all the time, and we couldn’t explain why.”

The study looked at 196 patients, without prior symptoms of brachial plexopathy, who returned for follow-up after high-dose radiation for head and neck cancer and completed a questionnaire designed to look for symptoms of the injury to brachial plexus, a nerve complex in the arm, chest, and shoulder. Symptoms included pain, numbness and tingling, or motor weakness.

Of the patients, 20 (10%) scored positive for injury, with the median onset of the condition occurring 20 months after completion of the radiation. The median time interval between radiation and completion of the questionnaire was 35 months.

“Among long-term survivors, prevalence could be in the ballpark of 15% to 20%,” Dr. Chen said.

Of those patients who developed brachial plexopathy, 80% received more than 1 dose of 70 gray or more to more than 5% of the brachial plexus, and all of them received a dose of 66 gray or higher to at least 5% of the brachial plexus.

Of the patients, 112 (57%) received surgery with postoperative radiation, while 84 (43%) received definitive radiation alone. Additionally, 72 patients (37%) received concurrent chemotherapy.

“It is impossible to blame all these cases on radiation alone, because confounding factors, such as chemotherapy, surgery, osteoarthritis, or occupational hazards, could have contributed to the condition,” said Dr. Chen, adding that groups such as the Radiation Therapy Oncology Group have designed a computer atlas of the brachial plexus to enable avoidance strategies, especially because the nerve complex is difficult to see on a computed tomography scan.

Notes:
1. presented at ASTRO
2. presentation title: Brachial Plexopathy After Radiation Therapy for Head-and-Neck Cancer. Abstract 65