Prognostic Utility of Histological Growth Patterns of Colorectal Lung Oligometastasis

Histological growth patterns and molecular analysis of resected colorectal lung metastases

Lung is the site of metastasis in about 15-25 % of colorectal cancer (CRC) patients. Lung metastasectomy of CRC represents a standard therapy in patients with resectable metastases. In this study we investigated both histological patterns of metastases and mutations in MAPkinase pathway genes and their relationship to prognosis. The study included 74 patients that underwent metastasectomy of colorectal lung metastasis (CLM). In patients that underwent surgical resection of more than one metastasis in the same operation the largest was chosen. In patients that had undergone multiple lung metastasectomy only the sample from the first metastasectomy was included. Histologically metastases were scored according to amount and distribution of necrosis and fibrosis and three patterns were identified: "pattern A", metastasis with extensive, confluent central necrosis surrounded by a rim of neoplastic glands; "pattern B", metastasis characterized by a proliferation of neoplastic glands in a dense stroma with focal necrosis mainly intraglandular; "pattern C", metastasis with a mixed A and B morphology. In all samples direct sequencing of exon 2 of KRAS and NRAS genes and exon 15 of BRAF genes was carried out.Histological patterns weren't related to metastasis size or other clinical features however pattern C metastases showed a significant worst disease free survival (DFS). KRAS mutations were observed in 39 % of patients. Mutations in KRAS codon 13 resulted significantly associated with synchronous metastasis and poor prognosis. No mutations were identified in exon 2 NRAS gene whilst 1.4 % harboured a mutation in BRAF. To our knowledge this is the first study that investigates in a large series of CLM histological growth patterns, molecular alterations and their relationship to prognosis. Our data suggest a prognostic role in CLM of KRAS specific mutations and histopathological patterns.

Predicting liver metastases growth patterns: Current status and future possibilities

Colorectal cancer is highly incident worldwide and presents a health burden with elevated mortality rate despite prevention, detection, and treatment, mainly due to metastatic liver disease. Histological growth patterns of colorectal cancer liver metastases have emerged as a reproducible prognostic factor, with biological implications and therapeutic windows. Nonetheless, the histological growth patterns of colorectal cancer liver metastases are only known after pathological examination of a liver resection specimen, thus limiting the possibilities of pre-surgical decision. Predicting the histological growth pattern of colorectal cancer liver metastases would provide valuable information for patient-tailored medicine. In this article, we perform a review of the histological growth patterns and their implications, with a focus on the possibilities for their prediction.

A prospective comparison of growth patterns with radiomorphology in 232 lung metastases-basis for patient tailored resection planning?

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.