SUPPORTIVE CARE OF CHILDREN WITH CANCER: DIAGNOSIS AND TREATMENT OF CHEMOTHERAPY-INDUCED PULMONARY TOXICITY

Pulmonary toxicity is a significant complication of bleomycin. Less frequently methotrexate, busulfan, and CCNU have been incriminated in acute lung syndrome, which is believed to be idiosyncratic and not predictable. Radiation therapy to the lung parenchyma reduces pulmonary toxicity thresholds.Pulmonary toxicity from radiation and chemotherapeutic agents may be partially reversible. Ultimately, enough damage to the parenchymal lung tissue could result in death. I. TOXICITY OF BLEOMYCINA. Diagnosis of bleomycin toxicitySlow inspiratory vital capacity and pulmonary capillary blood volume appear to be the proper lung function assessments that specifically reflect alterations induced by bleomycin.Diffusion capacity of carbon monoxide (DLCO) is not a suitable parameter to monitor pulmonary toxicity induced by bleomycin specifically when it is part of a multidrug regimen.a. Investigators have found a poor correlation betweenDLCO and lung toxicity, and DLCO fails to predict the development of serious bleomycin lung toxicity in the majority of patients. When a low DLCO is encountered, look at other parameters as well (see b. below).The clinician should decide to continue bleomycin when it is in the best interest of patient care.i. Bleomycin may be stopped inappropriately after low DLCO measurement. DLCO <65% has a high false positive incidence when used as the standard for withholding chemotherapy.ii. When a low DLCO is encountered, examine and consider other parameters of lung function before discontinuing bleomycin.b. It is important to monitor for respiratory system and chest x-ray abnormalities during bleomycin treatment, as these will be the earliest signs of lung toxicity inmost patients.i. The combination of respiratory symptoms and an abnormal chest x-ray is the earliest manifestation in many patients.ii. Therefore, a careful history of respiratory symptoms and regular chest x-rays is more likely to detect clinically significant bleomycin lung toxicity than the DLCO.iii. Diffuse infiltration with tumor, interstitial pneumonias, generalized pulmonary infections such as Pneumocystis pneumonia, and bleomycin nodularity may have similar signs and symptoms.iv. An aggressive approach is justifiable because the consequence of stopping bleomycin in a patient with a curable cancer may be as devastating as continuing bleomycin in one at risk of bleomycin lung damage.B. Factors contributing to bleomycin toxicityThe serum half-life of bleomycin can be increased in the presence of renal dysfunction such as that induced by cisplatin. Monitor renal function closely when patients are receiving both bleomycin and nephrotoxic chemotherapeutic agents.3. The administration of oxygen in high concentrations, (e.g., during general anesthesia) may cause fulminate respiratory failure in patients previously treated with bleomycin.C. Modifications for pulmonary toxicityBleomycin lung toxicity remains an unpredictable side effect by comparison with the toxicities of many other anticancer drugs. Therefore, it would be advisable to avoid bleomycin in situations in which other drugs can be substituted without compromising results.D. Late effectsBleomycin pulmonary toxicity may be reversible. A decreased force vital capacity and DLCO in the first 15 months after treatment, in terms of long-term follow-up, did not predict outcome.*39\168\2*

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