Magnetic resonance (MR) patterns of brain metastasis in lung cancer patients

Introduction: Asymptomatic brain metastasis in lung cancer patients, if detected early have been reported to show survival benefit with treatment. These asymptomatic metastasis have been found to be smaller and less in number than those with symptoms. We however observed that many lung cancer patients bear a significant metastatic load in the brain irrespective of the stage or neurologic symptoms at the time of initial presentation. Material and Methods: A retrospective study was conducted on 175 patients of proven non-small cell lung cancer to assess the patterns of brain metastasis in the two groups of patients, with and without neurologic symptoms. All patients had undergone screening magnetic resonance imaging for brain metastasis as an initial staging protocol. The patients with brain metastasis were divided into two groups: asymptomatic (group I) and symptomatic (group II). The lesions were studied with regards to the number, size, site, nature (solid with and without necrosis), and presence of perilesional edema and intralesional hemorrhage in both the groups in various stages of disease. Results: Brain metastasis was seen in 62 (31.3%) patients of whom 46.7% were neurologically asymptomatic. Patients (90.3%) with brain metastasis were in stage IV at the time of presentation. No statistically significant correlation was found between the two groups regarding the number of lesions (p = 0.554), size of lesion (p = 0.282), site of lesion (p = 0.344), nature of lesion (p = 0.280), presence of perilesional edema (p = 0.404), and presence or absence of intralesional hemorrhage (p = 0.09). In our study, brain metastases were present only in stages III and IV disease with no statistically significant difference in the lesion patterns. Conclusion: The study reveals almost equal number of patients with brain metastasis in the symptomatic and asymptomatic groups with no significant difference in lesion patterns. We therefore conclude that although imaging surveillance of the brain for metastasis will detect asymptomatic metastasis early for early institution of appropriate therapy the prognosis in these patients would not solely depend on the presence or absence of symptoms and the pattern of lesion may have an influence on the patients' response to therapy and survival benefit specially for those asymptomatic patients with equally large metastatic load.