Metastasis infiltration: an investigation of the postoperative brain-tumor interface
Bethwel Raore1, Matthew Schniederjan, Roshan Prabhu
1Department of Neurological Surgery, Emory University, Atlanta, GA, USA.
Purpose:
This study aims to evaluate brain infiltration of metastatic tumor cells past the main tumor resection margin to assess the biological basis for the use of stereotactic radiosurgery treatment of the tumor resection cavity and visualized resection edge or clinical target volume.
Methods And Materials:
Resection margin tissue was obtained after gross total resection of a small group of metastatic lesions from a variety of primary sources. The tissue at the border of the tumor and brain tissue was carefully oriented and processed to evaluate the presence of tumor cells within brain tissue and their distance from the resection margin.
Results:
Microscopic assessment of the radially oriented tissue samples showed no tumor cells infiltrating the surrounding brain tissue. Among the positive findings were reactive astrocytosis observed on the brain tissue immediately adjacent to the tumor resection bed margin.
Conclusions:
The lack of evidence of metastatic tumor cell infiltration into surrounding brain suggests the need to target only a narrow depth of the resection cavity margin to minimize normal tissue injury and prevent treatment size-dependent stereotactic radiosurgery complications.
Insights
No brain infiltration by metastatic tumor cells was found past the resection margin. This suggests a narrow margin is sufficient for stereotactic radiosurgery, minimizing normal tissue injury.
Area of Science:
- Neuro-oncology
- Surgical pathology
- Radiation oncology
Background:
- Metastatic brain tumors often require surgical resection.
- Stereotactic radiosurgery (SRS) is used to treat the resection cavity.
- The extent of microscopic tumor spread influences SRS target volume definition.
Purpose of the Study:
- To evaluate brain infiltration of metastatic tumor cells beyond the main tumor resection margin.
- To provide a biological basis for defining the clinical target volume in SRS after resection.
Main Methods:
- Resection margin tissue from gross total resection of metastatic lesions was analyzed.
- Tissue at the tumor-brain border was processed to detect infiltrating tumor cells.
- The distance of any infiltrating cells from the resection margin was measured.
Main Results:
- Microscopic examination revealed no metastatic tumor cells infiltrating the surrounding brain tissue.
- Reactive astrocytosis was observed in brain tissue adjacent to the resection margin.
Conclusions:
- The absence of tumor cell infiltration suggests limited microscopic spread.
- Targeting a narrow margin of the resection cavity for SRS may be sufficient.
- This approach can minimize normal tissue injury and SRS complications.
