RESUMEN
BACKGROUND: The histologic presence of aggressive local growth of pulmonary metastases is associated with an increased risk for local intrapulmonary recurrence after enucleation or wedge resection. Patient tailored resection planning is possible when morphologic pattern of aggressive growth could be identified based on preoperative CT scans. METHODS: Radiomorphology and microscopic growth characteristics from 232 pulmonary metastases from 87 patients were prospectively compared for the presence or absence of aggressive patterns of local intrapulmonary dissemination. RESULTS: Microscopic aggressive local growth was found: pleural involvement (18.5%), lymphatic invasion (6.9%), vascular invasion (7.3%), interstitial growth (38.4%), micro satellite nodules (24.5%), spread through air spaces (STAS) (13.4%), and a smooth, slightly blurred or irregular surface in 34.1%, 43.1% and 22.8%. The radiologic margin demarcation was smooth in 37.1%, blurred in 27.6% or irregular in 35.3% and spiculae were present in 26.3% of the lesions. The microscopic and radiologic description of the metastasis surface correlated well [correlation coefficient (CC) =0.75, P<0.001]. A smooth surface on CT scan corresponded with a smooth microscopic surface in 72/86 (83.7%) of the lesions. The radiomorphologic feature of an irregular or cloudy surface was highly associated with the presence of at least one aggressive pattern of local dissemination (P<0.001). The presence of spiculae on CT scan was well associated with the presence of aggressive local spread (P<0.001) and the microscopic features corresponding with spiculae were interstitial growth, STAS and L1. CONCLUSIONS: Radiomorphologic characteristics of lung metastases correspond well with the microscopic appearance of the resected lesion. Therefore it seems possible to adjust safety margins based on the radiologic appearance of the metastasis.
RESUMEN
OBJECTIVES: Safety margins in pulmonary metastasectomy are not yet well defined. We hypothesize that histological subtype, size of the lesion and local growth characteristics must be taken into consideration during metastasectomy. This study was conducted to examine and classify growth patterns at resection margins and define the relationships between aggressive local growth, metastasis size and local recurrence to direct metastasectomy. METHODS: Histologic sections of pulmonary metastases were prospectively collected and haematoxylin-eosin stains were systematically evaluated and classified by their pattern of lung tissue infiltration. Logistic regression was used to model the association between the subgroups of colorectal, renal cell and epithelial cancers and melanomas and sarcomas. RESULTS: From 183 patients, 412 lung specimens were removed, which contained 459 pulmonary metastases. We found that 58% of all lesions had microscopic signs of aggressive local dissemination. The metastases showed histology-specific patterns of local growth: sarcoma was associated with pleural infiltration; colorectal metastases with interstitial spread and aerogenous spread of floating cancer cell clusters; and melanoma with perivascular growth and with lymph vessel involvement. Aggressive patterns of growth had an increasing probability of around 3% for each additional millimetre of metastasis diameter. Local intrapulmonary recurrence was significantly more common in association with interstitial growth and pleural penetration as well as safety margins <7 mm. CONCLUSIONS: Approximately 40% of all lung metastases have a smooth surface and might be resected with small margins. Growth characteristics within the lung differ with the histologic subtype and safety margins should generally increase with the size of the metastasis.