Intrapulmonary metastasis of lung cancer: soft x-ray investigation of inflated and fixed lung.
BACKGROUND
Intrapulmonary metastasis (IPM) of lung cancer is thought to be an important factor influencing patient prognosis. It is not easy to detect a small IPM by preoperative examination and sometimes even by postoperative pathologic investigation. We applied soft x-ray investigation to inflated and fixed lungs for the detection of IPM.


METHODS
From 1990 to 1992, 75 patients with lung cancer who had no metastatic lesions on preoperative whole CT, MRI, and technetium-99m bone scintigram examinations underwent lung resection. The resected lungs were fixed in an inflated condition, sliced at the corresponding CT levels into 10-mm-thick sections, and submitted for soft x-ray examination. When an accessory nodular shadow(s) was detected on the soft x-ray images, the size of the nodule and its distance from the primary tumor were measured.


RESULTS
In 23 of the 75 patients, accessory nodular shadows were detected on the soft x-ray images. Six nodules in 6 patients proved to be IPM, 2 of which were also detected by postoperative macroscopic examination. Another 2 microscopic IPM were found only by postoperative pathologic examination. The total detection rate of IPM was 10.7% (8 of 75 patients) in this series. The detection rate of IPM at our institute was 5.4% before this study (1979 to 1989). The mean diameter of the IPM detected by the soft x-ray method was 2.8 +/- 1.5 mm, and this was significantly smaller than that of the macroscopically detected nodules (7.2 +/- 3.2 mm).


CONCLUSIONS
Our data show that soft x-ray investigation is an effective procedure to detect relatively small intrapulmonary metastatic nodules and will contribute to precise postoperative staging of patients with lung cancer.
Kobayashi
O
O
Department of Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
Haniuda
M
M
Honda
T
T
Kubo
K
K
Sakai
F
F
Sone
S
S
D000230:Adenocarcinoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018196:Carcinoma, Adenosquamous / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D018287:Carcinoma, Large Cell / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D018288:Carcinoma, Small Cell / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D005260:Female; D005404:Fixatives; D006801:Humans; D007327:Insufflation; D008175:Lung Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011013:Pneumonectomy / Q000379:methods; D011379:Prognosis; D019275:Radiopharmaceuticals; D013667:Technetium; D016707:Tissue Fixation; D014057:Tomography, X-Ray Computed
D005404:Fixatives; D019275:Radiopharmaceuticals; D013667:Technetium