Objective: The most common diagnoses of intracranial neoplasms are metastases, with the highest incidences observed in cases originating from the breast and lung. In cases where the primary oncological disease is unknown, it is crucial to distinguish between different types of brain metastases in order to implement the most appropriate treatment strategies. The objective of this study is to present and compare the magnetic resonance spectroscopy (MRS) findings of breast cancer brain metastases (BCBMs) and lung adenocarcinoma brain metastases (LACBMs). Method: In this retrospective study, adult patients with histopathologically confirmed breast carcinoma or lung adenocarcinoma and known brain metastases who underwent MRS between December 2022 and February 2024 were consecutively included. Patients without histopathological confirmation, with nondiagnostic MRS due to artifacts, or who had received cranial radiotherapy before MRS were excluded. Choline (Cho), creatine (Cr), N-acetylaspartate (NAA), lipid–lactate (LL), and myo-inositol (MI) levels, as well as Cho/Cr, Cho/NAA, and NAA/Cr ratios, were obtained from the solid components of the largest metastatic lesion. Continuous variables were assessed for normality using the Shapiro–Wilk test and compared using Welch’s t-test or the Mann–Whitney U test, as appropriate. Gender distribution was compared using Fisher’s exact test. Results: Thirty-three patients (17 women, 16 men; mean age 57.8 ± 13.3 years) met the inclusion criteria, including 15 patients with BCBMs and 18 with LACBMs. Both groups demonstrated elevated Cho levels and increased Cho/Cr and Cho/NAA ratios. The Cho/Cr ratio was higher in the BCBM group than in the LACBM group; however, this difference did not reach statistical significance (p = 0.059). No significant differences were observed for Cho/NAA or NAA/Cr ratios. A significant difference in gender distribution was observed between groups, with all BCBM patients being female and a predominance of male patients in the LACBM group (p = 0.00002). Conclusion: The present study demonstrated that proton MRS imaging findings show increased Cho levels and Cho/Cr and Cho/NAA ratios, indicating elevated rates of cell membrane turnover. While the findings did not attain statistical significance, the observation that LACBMs exhibited lower Cho/Cr ratios compared to BCBMs prompts the recommendation for the execution of prospective, large-scale studies on this subject.
Topcuoğlu et al. (Wed,) studied this question.