Multiple metastases but not all accessible

Introduction

Metastatic brain tumors are the most common type of brain tumors in adults, in which approximately 30% of cancer patients will develop metastatic brain tumors. ^, This number is expected to rise as systemic disease control continues to improve. ^, However, despite improvement in cancer diagnosis and treatment, the median survival remains 4 months, with 2-year survival rates less than 6%. The current treatment paradigm for patients with metastatic brain tumors is heavily dependent on individual patient characteristics, including age, functional status, disease control, and tumor molecular characteristics, among others. ^, ^, Surgery has been shown to play an important role in certain circumstances, namely for lesions causing significant neurologic symptoms, as tumor resection remains the only effective method in providing immediate relief of mass effect. This usually applies to large tumors (>3 cm), as well as tumors causing mass effect, neurologic deficits, and seizures. A relative contraindication to surgery is the presence of multiple lesions, as surgery may not improve the natural history of the individual’s disease, and there may be significant morbidity associated with accessing and resecting some of the lesions with little added benefit. In cases with multiple brain tumors in which there is a large dominant lesion, surgical resection of the more symptomatic lesion may be warranted. In this chapter, we present a case of multiple brain lesions in which some may not be surgically accessible without inherent risks.

Example case

Chief complaint: headache, imbalance, and speaking difficulties

History of present illness

A 35-year-old, right-handed woman with a history of metastatic breast cancer status post bilateral mastectomy and local radiation therapy and chemotherapy who presented with progressive headaches, imbalance, and speaking difficulties. These headaches are diffuse, bifrontal, and exacerbated with straining. She also complained of imbalance and decreased coordination with both hands but denies any focal weakness. She also complained of difficulty getting her words out. These symptoms have been going on for the past week. She saw her oncologist, and imaging was done ( Fig. 35.1 ).

Medications : Lisinopril.
Allergies : No known drug allergies.
Past medical and surgical history : Metastatic breast adenocarcinoma status bilateral mastectomy.
Family history : Strong family of history of breast cancer.
Social history: Teacher, no smoking or alcohol history.
Physical examination : Awake, alert, oriented to person, place, and time; Language: dysarthric and slowness with speech; Cranial nerves II to XII intact; No drift, moves all extremities with full strength; Cerebellar: right > left finger-to-nose dysmetria.
Computed tomography chest/abdomen/pelvis : Two small lung nodules and one liver lesion suspicious for metastatic disease.

	Miguel A. Arraez, MD, PhD, Carlos Haya University, Hospital Malaga, Spain	Mark Bernstein, MD, University of Toronto, Toronto, Canada	Michael Lim, MD, Stanford University School of Medicine, Stanford, CA, United States	Gabriel Zada, MD, University of Southern California, Los Angeles, CA, United States
Preoperative
Additional tests requested	Oncology evaluation	Neuropsychological assessment fMRI		Full-body PET Physical therapy Radiation Oncology/oncology evaluation
Surgical approach selected	Right suboccipital +/– left frontal craniotomy	Right posterior fossa and left frontal craniotomies if symptoms do not respond with steroids, SRS for left paracentral lesion	Right suboccipital craniotomy and left frontal craniotomy for tumor with IOM	SRS for all three lesions
Anatomic corridor	Right cerebellar hemisphere	Right cerebellar hemisphere and left frontal	Right cerebellar hemisphere and left frontal	SRS
Goal of surgery	Gross total resection of posterior fossa lesion	Gross total resection of both lesions	Maintaining quality of life	Tumor control
Perioperative
Positioning	Right park bench	Right park bench followed by left supine	Prone followed by left supine	Leksell frame
Surgical equipment	Surgical navigation Surgical microscope with 5-ALA Ultrasonic aspirator	Surgical navigation Surgical microscope IOM (BAERs)	IOM (SSEP)	Gamma knife
Medications	Steroids	Steroids	Steroids Mannitol Hyperventilation	Steroids
Anatomic considerations	Transverse sinus, tentorium, cerebellar surface	Cerebellar lesion: transverse sinus Frontal lesion: speech cortex	Cerebellar lesion: swelling Frontal lesion: speech cortex	Cerebellar lesion: swelling Frontal lesion: speech and motor cortex
Complications feared with approach chosen	Injury to transverse sinus and cerebellum	Neurologic worsening, language dysfunction	Language dysfunction	Language dysfunction, motor deficit
Intraoperative
Anesthesia	General	General	General	Conscious sedation
Skin incision	Right paramedian	Cerebellar lesion: curvilinear Frontal lesion: linear	Cerebellar lesion: linear paramedian Frontal lesion: linear	None
Bone opening	Right suboccipital	Cerebellar lesion: right posterior fossa up to transverse sinus above foramen magnum Frontal lesion: left frontal	Cerebellar lesion: overlying lesion Frontal lesion: left MFG	None
Brain exposure	Cerebellum overlying lesion	Cerebellar lesion: right cerebellar hemisphere up to transverse sinus Frontal lesion: left MFG	Cerebellar lesion: overlying lesion Frontal lesion: left MFG	None
Method of resection	Right suboccipital craniotomy based on navigation, dural opening and reflected toward transverse sinus, microsurgical intralesional removal with ultrasonic aspirator, watertight dural closure	Cerebellar lesion first, suboccipital craniectomy with bur holes and rongeurs up to transverse sinus but maintaining foramen magnum based on navigation, dural opening based on transverse sinus, resection with microscopic visualization, dural closure with dural substitute if necessary, cranioplasty with mesh. Head refixed for left frontal lesion, craniotomy based on navigation, dural opening, microsurgical removal of tumor	Cerebellar lesion first, suboccipital craniotomy guided by navigation, cruciate dural opening, corticectomy over most superficial aspect of tumor, internal debulking of tumor, mobilize capsule, gross total resection. Head refixed, left MFG craniotomy based on navigation, cruciate dural opening, en bloc resection	None
Complication avoidance	Awareness of transverse sinus, intralesional resection	Cerebellar lesion: large opening Frontal lesion: access lesion where lesion comes to surface	Cerebellar lesion: opening confined to tumor Frontal lesion: en bloc resection	Avoidance of surgery
Postoperative
Admission	ICU	Floor	ICU	Home
Postoperative complications feared	Cerebellar edema	Cerebellar edema, language dysfunction	CSF leak, language dysfunction	Peritumoral edema, radiation effect, language dysfunction, right-sided weakness, hydrocephalus
Follow-up testing	CT within 24 hours after surgery MRI within 72 hours after surgery	CT within 24 hours after surgery MRI prior to radiation	MRI within 48 hours after surgery	MRI 2 months after SRS
Follow-up visits	7 days after surgery	14 days after surgery	14 days after surgery	14 days after surgery
Adjuvant therapies recommended	SRS for left frontal and perirolandic lesions	SRS for all resected and nonresected lesions	SRS boost for all resected and nonresected lesions or WBRT	Chemotherapy per oncology