When a 72-year-old Japanese man developed life-threatening airway damage six months after completing proton beam therapy for lung cancer, his medical team faced a challenge that highlights both the power and limitations of modern radiation oncology. The patient’s bronchial cartilage had begun to disintegrate—a rare but devastating complication called chondronecrosis—creating a gaping hole in his airway that conventional treatments could not address. The intervention that ultimately saved his airway came not from surgery or pharmaceuticals, but from hyperbaric oxygen therapy (HBOT), a decades-old treatment now finding new applications in radiation injury management.
The Case: When Proton Therapy Causes Collateral Damage
The patient, treated at Tokyo Medical University Hospital, had undergone proton beam therapy for stage I lung cancer—a treatment widely regarded as one of the most precise forms of radiation delivery available. Unlike conventional photon radiation, proton therapy can be precisely controlled to release most of its energy within the tumor, sparing surrounding healthy tissue. Yet even this precision was not enough to prevent catastrophic injury to the patient’s left main bronchus.
Six months after completing treatment, the man presented with fever, cough, and difficulty breathing. Imaging revealed a concerning finding: a fistula—an abnormal connection—between the bronchus and the mediastinum, the central compartment of the thoracic cavity. Bronchoscopy, a procedure using a camera to visualize the airways, confirmed the diagnosis: chondronecrosis, or death of the cartilage that provides structural support to the bronchial tubes. The cartilage had essentially dissolved, leaving a 15-millimeter defect in the airway wall.
“The necrotic changes in the bronchial cartilage were progressive despite antibiotic therapy and nutritional support,” the treating physicians reported in the August 2026 issue of Respirology Case Reports. The team faced a dilemma: surgical repair of such defects in irradiated tissue carries high failure rates, and the patient’s condition made him a poor candidate for aggressive intervention.
The HBOT Intervention
With few options remaining, the medical team turned to hyperbaric oxygen therapy—a treatment the U.S. Food and Drug Administration has cleared specifically for “late radiation tissue injury.” The mechanism is well-established: HBOT delivers 100% oxygen at pressures two to three times higher than atmospheric pressure, dissolving oxygen directly into plasma and driving it deep into hypoxic tissues. For radiation-damaged tissue, this oxygen surge stimulates angiogenesis (new blood vessel formation), collagen synthesis, and the recruitment of stem cells capable of rebuilding damaged structures.
The patient received 30 HBOT sessions over six weeks, breathing pure oxygen at 2.0 atmospheres absolute (ATA) for 90 minutes per session. The results, documented through serial bronchoscopies, were striking. After just 10 sessions, the inflammatory changes in the airway had begun to subside. By session 20, granulation tissue—new connective tissue and microscopic blood vessels—was filling the defect. At the completion of therapy, the fistula had completely closed, and the bronchial wall had regained structural integrity.
“HBOT was effective in healing the bronchial chondronecrosis after proton beam therapy,” the authors concluded, noting that the patient remained symptom-free at six-month follow-up.
Radiation Injury: An Expanding Frontier for HBOT
The case adds to a growing body of literature supporting HBOT’s role in managing radiation-induced tissue damage. While radiation therapy has saved countless lives in oncology, it can leave lasting scars. The high-energy beams that destroy cancer cells also damage blood vessels, reducing blood flow to irradiated tissues and creating chronic hypoxia. Months or years later, this can manifest as non-healing wounds, bone necrosis, or—in this case—airway collapse.
The FDA recognizes late radiation tissue injury as one of 13 cleared indications for HBOT, alongside decompression sickness, carbon monoxide poisoning, and certain non-healing diabetic wounds. A 2023 Cochrane review analyzed data from over 1,100 patients across 19 randomized trials and found that HBOT improved healing in radiation-induced injuries of the jaw, rectum, and bladder. The review noted that while evidence quality varied, the biological rationale is robust: oxygen is a prerequisite for collagen synthesis, and hypoxic tissue cannot heal regardless of other interventions.
“HBOT is the only therapy that addresses the fundamental pathophysiology of radiation injury—tissue hypoxia,” said Dr. Gayle Gordillo, a wound healing specialist at The Ohio State University Wexner Medical Center who was not involved in the case. “For patients with established radiation damage, it’s often the difference between healing and chronic disability.”
The FDA’s Caution on Unproven Uses
While cases like this demonstrate HBOT’s potential for specific, FDA-cleared indications, the agency continues to warn against its use for conditions lacking rigorous evidence. The FDA has not cleared HBOT for cancer treatment itself, autism, Alzheimer’s disease, Lyme disease, or cerebral palsy—despite marketing claims made by some wellness clinics. In August 2025, the FDA issued a safety letter to healthcare providers emphasizing fire risks associated with hyperbaric chambers and reminding facilities to follow manufacturer protocols.
“If your healthcare provider recommends HBOT, the FDA advises you to receive treatment at a hospital or facility that has been inspected and accredited by the Undersea and Hyperbaric Medical Society,” the agency stated in a July consumer update, citing UHMS accreditation as a marker of quality and safety.
The distinction matters for patient outcomes. Radiation-induced bronchial chondronecrosis, as demonstrated in this case, represents a well-documented indication with clear biological rationale and supporting evidence. The same cannot be said for many of the wellness applications marketed directly to consumers.
Looking Forward
As proton beam and other advanced radiation therapies become more widely available, cases of radiation-induced tissue injury—while remaining statistically rare—may become more visible simply due to increased treatment volume. For the subset of patients who develop these complications, HBOT offers a non-surgical pathway to healing that works with the body’s own repair mechanisms.
The Tokyo case also raises questions about patient selection and monitoring. Could earlier intervention with HBOT prevent progression to fistula formation? Would certain patients benefit from prophylactic HBOT after high-dose radiation to the chest? These questions remain open, awaiting prospective clinical trials that could define optimal protocols.
For now, the case stands as a testament to the potential of targeted oxygen therapy to salvage seemingly hopeless situations—and a reminder that even the most advanced radiation technologies carry risks that sometimes require equally sophisticated interventions to resolve.