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Donald N. Liew, Hideyuki Kano, Douglas Kondziolka, David Mathieu, Ajay Niranjan, John C. Flickinger, John M. Kirkwood, Ahmad Tarhini, Stergios Moschos and L. Dade Lunsford

Object

To evaluate the role of stereotactic radiosurgery (SRS) in the management of brain metastases from melanoma, the authors assessed clinical outcomes and prognostic factors for survival and tumor control.

Methods

The authors reviewed 333 consecutive patients with melanoma who underwent SRS for 1570 brain metastases from cutaneous and mucosal/acral melanoma. The patient population consisted of 109 female and 224 male patients with a median age of 53 years. Two hundred eleven patients (63%) had multiple metastases. One hundred eighteen patients (35%) underwent whole-brain radiation therapy (WBRT). The target volume ranged from 0.1 cm3 to 37.2 cm3. The median marginal dose was 18 Gy.

Results

Actuarial survival rates were 70% at 3 months, 47% at 6 months, 25% at 12 months, and 10% at 24 months after radiosurgery. Factors associated with longer survival included controlled extracranial disease, better Karnofsky Performance Scale score, fewer brain metastases, no prior WBRT, no prior chemotherapy, administration of immunotherapy, and no intratumoral hemorrhage before radiosurgery. The median survival for patients with a solitary brain metastasis, controlled extracranial disease, and administration of immunotherapy after radiosurgery was 22 months. Sustained local tumor control was achieved in 73% of the patients. Sixty-four (25%) of 259 patients who had follow-up imaging after SRS had evidence of delayed intratumoral hemorrhage. Sixteen patients underwent a craniotomy due to intratumoral hemorrhage. Seventeen patients (6%) had asymptomatic and 21 patients (7%) had symptomatic radiation effects. Patients with ≤ 8 brain metastases, no prior WBRT, and the recursive partitioning analysis Class I had extended survivals (median 54.3 months).

Conclusions

Stereotactic radiosurgery is an especially valuable option for patients with controlled systemic disease even if they have multiple metastatic brain tumors.

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Hideyuki Kano, Douglas Kondziolka, Aftab Khan, John C. Flickinger and L. Dade Lunsford

Object

Many patients with acoustic neuromas (ANs) have hearing function at diagnosis and desire to maintain it. To date, radiosurgical techniques have been focused on conformal irradiation of the tumor mass, with less attention to inner ear structures for which there was scant radiobiological information. The authors of this study evaluated tumor control and hearing preservation as they relate to tumor volume, imaging characteristics, and nerve and cochlear radiation dose following stereotactic radiosurgery (SRS) using the Gamma Knife.

Methods

Seventy-seven patients with ANs had serviceable hearing (Gardner-Robertson [GR] Class I or II) and underwent SRS between 2004 and 2007. This interval reflected more recent measurements of inner ear dosimetry during the authors' 21-year experience. The median patient age was 52 years (range 22–82 years). No patient had undergone any prior treatment for the ANs. The median tumor volume was 0.75 cm3 (range 0.07–7.7 cm3), and the median radiation dose to the tumor margin was 12.5 Gy (range 12–13 Gy). At diagnosis, a greater distance from the lateral tumor to the end of the internal auditory canal correlated with better hearing function.

Results

At a median of 20 months after SRS, no patient required any other additional treatment. Serviceable hearing was preserved in 71% of all patients and in 89% (46 patients) of those with GR Class I hearing. Significant prognostic factors for maintaining the same GR class included (all pre-SRS) GR Class I hearing, a speech discrimination score (SDS) ≥ 80%, a pure tone average (PTA) < 20 dB, and a patient age < 60 years. Significant prognostic factors for serviceable hearing preservation were (all pre-SRS) GR Class I hearing, an SDS ≥ 80%, a PTA < 20 dB, a patient age < 60 years, an intracanalicular tumor location, and a tumor volume < 0.75 cm3. Patients who received a radiation dose of < 4.2 Gy to the central cochlea had significantly better hearing preservation of the same GR class. Twelve of 12 patients < 60 years of age who had received a cochlear dose < 4.2 Gy retained serviceable hearing at 2 years post-SRS.

Conclusions

As currently practiced, SRS with the Gamma Knife preserves serviceable hearing in the majority of patients. Tumor volume and anatomy relate to the hearing level before radiosurgery and influence technique. A low radiosurgical dose to the cochlea enhances hearing preservation.

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Juan J. Martin, Ajay Niranjan, Douglas Kondziolka, John C. Flickinger, Karl A. Lozanne and L. Dade Lunsford

Object

Chordomas and chondrosarcomas of the skull base are aggressive and locally destructive tumors with a high tendency for local progression despite treatment. The authors evaluated the effect of stereotactic radiosurgery (SRS) on local tumor control and survival.

Methods

Twenty-eight patients with histologically confirmed chordomas (18) or chondrosarcomas (10) underwent Gamma Knife SRS either as primary or adjuvant treatment. Their ages ranged from 17 to 72 years (median 44 years). The most common presenting symptom was diplopia (26 patients, 93%). In two patients, SRS was the sole treatment. Twenty-six patients underwent between one and five additional surgical procedures. Two underwent an initial trans-sphenoidal biopsy. The average tumor volume was 9.8 cm3. The median dose to the tumor margin was 16 Gy.

Results

No patient was lost to follow-up. Transient symptomatic adverse radiation effects developed in only one patient. The actuarial local tumor control for chondrosarcomas at 5 years was 80 ± 10.1%. For chordomas both the actuarial tumor control and survival was 62.9 ± 10.4%.

Conclusions

Stereotactic radiosurgery is an important option for skull base chordomas and chondrosarcomas either as primary or adjunctive treatment. Multimodal management appears crucial to improve tumor control in most patients.