Faculty Bibliography

BACKGROUND: To the authors' knowledge, comprehensive human pathologic investigations that explore fundamental radiosurgical effects on metastatic brain tumors are sparse in the literature. The objective of this study was to analyze histopathologic findings in a set of clinically recurrent cerebral metastases after patients underwent stereotactic radiosurgery (SRS). METHODS: In a series of 7500 patients who underwent radiosurgery, 2020 patients (27%) harbored cerebral metastases. Eighteen of 2020 patients (0.9%) underwent subsequent craniotomy for tumor removal anywhere from 1 month to 59 months after they received high-dose irradiation. Histologic and immunohistochemical investigations were performed on the surgically resected tissue specimens. These specimens were within the radiosurgical treatment volume of the metastatic tumor. RESULTS: Light microscopy revealed 3 basic categories of histologic responses: acute-type, subacute-type, and chronic-type tissue reactions. A moderate-to-intense inflammatory cell reaction was seen in the tissue responses of well controlled neoplasms (i.e., in patients who had neoplasms that required craniotomy for recurrent disease > 5 months after SRS), whereas the inflammatory reaction was missing or sparse in poorly controlled neoplasms (patients who required craniotomy for recurrent disease < 5 months after SRS). This reaction was seen within the irradiated tumor volume and not in the peritumoral area nor in areas remote from the radiosurgical treatment volume. Immunohistochemical characterization demonstrated the presence of prominent CD68-positive macrophage and CD3-positive T-lymphocyte populations. A progressively severe vasculopathy also was observed with increasing time after radiosurgery. CONCLUSIONS: Although causality has not been established, a brisk inflammatory response and more severe vasculopathy were observed in lesions in which recurrences were more delayed.

OBJECTIVE: Obtaining and documenting informed consent is of vital importance to physicians. We developed a procedure-based consent form that facilitates patient discussion and validated this process by surveying the patient regarding elements of the consent process, using an independent evaluator. METHODS: One hundred and twenty consecutive outpatients were evaluated before different neurosurgery procedures. The consent form listed specific diagnoses, procedures, alternatives (eight listed), and risks (22 listed), and each point discussed was checked off by the surgeon. Between 10 and 20 minutes later, each element was questioned by one lay-member of the office staff. A group of patients not at risk for cognitive decline were resurveyed months later. RESULTS: One hundred and twenty (100%) of 120 of patients answered correctly regarding their diagnosis and the planned procedure. Four hundred and twenty-eight alternative treatments were discussed, and 420 (98.1%) of the 428 were recalled correctly. Of 1207 risks that were discussed, 1176 (97.4%) were recalled correctly. When a subset of the patients were reevaluated at a mean of 4.5 months later, all 20 patients correctly recalled their procedure and diagnosis. Of 79 alternatives discussed with patients before surgery, 73 (92.4%) were subsequently recalled. Of 217 risks discussed before surgery, 199 (91.7%) were recalled. Although the immediate or delayed recall rates were high (> 90%), there was a reduction in the recall rate over time (alternatives, P = .007; risks, P < 0.0001). CONCLUSION: A consent process designed for an individual surgeon's practice was validated and showed high rates of patient recall in the postprocedural period. We think that this method to obtain and document informed consent should be considered for use by physicians.