Role of carbon monoxide diffusing capacity in the early detection of major bleomycin-induced pulmonary toxicity

Fifteen patients with malignant teratoma and twelve with squamous cancer of the head and neck received treatment with bleomycin. Routine measurements of carbon monoxide diffusing capacity (DLco) were performed. Both groups showed a gradual fall of similar magnitude in their DLco measurements during treatment. No patient in the group with squamous cancer developed clinical or radiological evidence of major pulmonary toxicity. Two of the teratoma patients suffered fatal pulmonary toxicity and their DLco measurements before any signs of major pulmonary toxicity were no different from the measurements of those patients who remained free of major clinical toxicity. The two patients who died both showed a sustained reduction in renal function during chemotherapy which may have been a major risk factor in the development of severe clinical toxicity. The magnitude of the decline in DLco in this series was not a useful predictor of those patients who developed severe and radiological toxicity.