Distribution of brain metastases: low-risk metastasis areas may be avoided when treating with whole-brain radiotherapy

Abstract

Objective: Previous work has demonstrated that metastases are not uniformly distributed across the brain. This study aims to determine there are low-risk brain metastasis (BM) areas that may be avoided during whole-brain radiotherapy (WBRT) to reduce neurocognitive toxicity. Methods: Clinical and magnetic resonance imaging (MRI) data of 991 metastases in 192 patients with advanced cancer were analyzed retrospectively. Eleven anatomically defined regions of interest (ROIs) were contoured, and the locations of the BMs were recorded. Using the same definition, ROIs were contoured in 20 healthy volunteers.The proportions of patients with BMs in different ROIs, proportion of BMs, and proportion of different ROI volumes relative to the total volume were calculated. Results: The proportion of observed BMs was lower than expected in the brainstem, insula, diencephalon and internal structures, corpus callosum, and pituitary gland. The proportion of BMs was significantly higher than expected in the parietal lobe, occipital lobe, and cerebellum. For those patients with single BM, there was very low rate of low-risk ROIs involvement (0%), with 2-4 BMs, 6-13% of the patients had low-risk ROIs involvement, with ≥5 BMs, significant (> 30%) of the patients had low-risk ROIs involvement. Conclusion: The brainstem, insula, diencephalon and internal structures, corpus callosum, and pituitary gland demonstrate low risk for metastatic involvement. Involvement of low risk areas occurs in patients with more than 1 BM.

Exploration of spatial distribution of brain metastasis from small cell lung cancer and identification of metastatic risk level of brain regions: a multicenter, retrospective study

“…The expected rate of BMS in each brain area was calculated as a proportion of brain area volume to total brain volume. Through comparison, we found that the observation frequency of cerebellum was significantly higher than the expected frequency ( P = 9.80 ×10 −15 ), while the observation frequency of temporal lobe, frontal lobe and occipital lobe was significantly lower than the expected frequency, and the difference of temporal lobe was more significant ( P = 1.65 ×10 −4 ), which was similar to the results of previous studies on heterogenous primary pathological type of brain metastases [ 11 , 13 , 32 ]. In order to make the research more thorough, more detailed atlas was applied to the segmentation.…”

Hypopituitarism secondary to a pituitary metastasis in a young woman with an invasive breast carcinoma

“…However, other tumors have been described such as carcinoma, blastoma, craniopharyngioma, germ cell tumors, mesenchymal tumors, and secondary tumors. The sellar region is known as a low‐risk brain metastasis area 2 . The prevalence of pituitary metastasis represents 1% of all surgical tumors of the pituitary gland 3 .…”

Anatomical and topographical variations in the distribution of brain metastases based on primary cancer origin and molecular subtypes: a systematic review

“… 3 Current National Comprehensive Cancer Network guidelines recommend a combination of surgery, radiosurgery, whole-brain radiotherapy (WBRT), and/or systemic therapy for the treatment of brain metastasis. 4 Treatment choice for brain metastasis is based on pathology, number and size of metastases, and location of the metastatic lesion. Surgery and/or radiosurgery has historically been more appropriate for patients with a surgically accessible or few brain metastasis while WBRT is often used for those with numerous lesions, though continued research into the effectiveness of these treatments is still being performed.…”

“…Surgery and/or radiosurgery has historically been more appropriate for patients with a surgically accessible or few brain metastasis while WBRT is often used for those with numerous lesions, though continued research into the effectiveness of these treatments is still being performed. 4 …”

“…It has long been hypothesized that the anatomical and topographical distribution of brain metastasis varies according to cancer subtype, 4–7 often explained by the “seed and soil” hypothesis where the tumor cells (“seed”) metastasize to a specific area in the brain (“soil”) due to its unique microenvironment that attracts and allows the tumor to grow. 8 More recently it has been shown that the primary cancer origin affects both the “seed” and the “soil,” influencing cellular receptor and protein expressions.…”