放射線肺炎における血清KL-6，SP-Dの有用性の検討

摘要

目的·方法．大阪医科大学放射線科における肺癌を中心とする胸部への放射線治療施行症例に対して血清KL-6，SP-Dを測定し，同時期に施行した胸部単純写真，胸部CTと比較し，放射線肺炎における血清KL-6，SP-Dの有用性について検討した．結果．放射線肺炎の診断における血清KL-6，SP-Dのsensitivityはそれぞれ68.2％，70.0％，specificityは86.6％，80.0％，accuracyは82.0％，77.8％であった．病変の範囲，活動性と血清KL-6値の関係については，照射野外に及ぶものは照射野内に限局するものより高値を呈し，陳旧性のものは活動性のものより低値を呈する傾向があった．経時的に血清KL-6，SP-Dを測定し得た放射線肺炎発生例についての検討では，KL-6は画像上の発見より遅れて上昇する傾向があったが，SP-Dはそれ以前に上昇するものが多かった．また，発生例における照射前と照射直後の値の比較では，SP-Dで着意な上昇が見られた．結論．血清KL-6，SP-Dともに，放射線肺炎の診断における感度，特異度は満足のいくものであった．血清KL-6は病変の範囲，活動性と相関が見られた．血清SP-Dは早期発見の一助となり得ることが示唆された．Objective. To investigate the usefulness of serum KL-6 and SP-D in the diagnosis of radiation pneumonitis. Methods. We measured serum KL-6 and SP-D in patients undergoing radiation therapy of the chest, primarily for lung cancer, in the Department of Radiology, Osaka Medical College and compared the results with the findings on plain chest X-ray films and thoracic computed tomography conducted at the same time. Results. The sensitivity of serum KL-6 and SP-D for diagnosing radiation pneumonitis were 68.2% and 70.0%, respectively, the specificity were 86.6 % and 80.0%, and the accuracy were 82.0% and 77.8%. Examination of the relationship between lesion extent and activity and serum KL-6 showed that serum KL-6 values were higher when the lesion extended beyond the irradiation field than when the lesion was confined to within the irradiation field and that the value tended to be lower for old lesions than for active lesions. In patients with radiation pneumonitis in whom serum KL-6 and SP-D could be measured over time, KL-6 tended to increase after the lesion was discovered by imaging, whereas SP-D increased prior to this in many cases. Examination of the comparison between before radiotherapy and just after radiotherapy in the patients with radiation pneumonitis showed that SP-D had a consistent tendency to increase.