Seung S. Hahn

Gamma Knife surgery in the management of radioresistant brain metastases in high-risk patients with melanoma, renal cell carcinoma, and sarcoma

OBJECT The purpose of this study was to examine the results of using Gamma Knife surgery (GKS) for brain metastases from classically radioresistant malignancies. METHODS The authors retrospectively reviewed the records of 76 patients with melanoma (50 patients), renal cell carcinoma (RCC; 23 patients), or sarcoma (3 patients) who underwent GKS between August 1998 and July 2007. Overall patient survival, intracranial progression, and local progression of individual lesions were analyzed. RESULTS The median age of the patients was 57 years (range 18-85 years) and median Karnofsky Performance Scale (KPS) score was 80 (range 20-100). Sixty-two patients (81.6%) had uncontrolled extracranial disease. A total of 303 intracranial lesions (average 3.97 per patient, range 1-27 lesions) were treated using GKS. More than 3 lesions were treated in 30 patients (39.5%). Median GKS tumor margin dose was 18 Gy (range 8-30 Gy). Thirty-seven patients (48.7%) underwent whole brain radiation therapy. The actuarial 12-month rate for freedom from local progression for individual lesions was 77.7% and was significantly higher for RCC compared with melanoma (93.6 vs 63.0%; p = 0.001). The percentage of coverage of the prescribed dose to target volume was the only treatment-related variable associated with local control: 12-month actuarial rate of freedom from local progression was 71.4% for lesions receiving >or= 90% coverage versus 0.0% for lesions receiving < 90% (p = 0.00048). Median overall survival was 5.1 months after GKS and 8.4 months after the discovery of brain metastases. Univariate analysis revealed that KPS score (p = 0.000004), recursive partitioning analysis class (p = 0.00043), and single metastases (p = 0.028), but not more than 3 metastases, to be prognostic factors of overall survival. The KPS score remained significant after multivariate analysis. Overall survival for patients with a KPS score >or= 70 was 7.1 months compared with 1.3 months for a KPS score <or= 60 (p = 0.013). CONCLUSIONS Gamma Knife surgery is an effective treatment option for patients with radioresistant brain metastases. In this setting, KPS score appeared to be a more important factor in predicting survival than having > 3 metastases. Higher rates of local tumor control were achieved for RCC in comparison with melanoma, and this may have an effect on survival in some patients. Although outcomes generally remained poor in this study population, these results suggest that GKS can be considered as a treatment option for many patients with radioresistant brain metastases, even if these patients have multiple lesions.

The linear-quadratic model and fractionated stereotactic radiotherapy

PURPOSE To determine the dose per fraction that could be used when gamma knife or linear accelerator-based stereotactic treatments are delivered in 2 or more fractions. METHODS AND MATERIALS The linear-quadratic (LQ) model was used to calculate the dose per fraction for a multiple-fraction regimen which is biologically equivalent to a given single-fraction treatment. The results are summarized in lookup tables. RESULTS AND CONCLUSION The tables can be used by practicing clinicians as a guide in planning fractionated treatment. For the large doses used in typical stereotactic treatments and for small fraction numbers, the model is not very sensitive to the value of the alpha/beta ratio in the LQ model. A simple rule of thumb is found that for two-fraction and three-fraction treatments the dose per fraction is roughly two-thirds and one-half of the single-fraction treatment dose, respectively.

Gamma knife surgery for trigeminal neuralgia: improved initial response with two isocenters and increasing dose

OBJECT The authors sought to evaluate the initial response of trigeminal neuralgia (TN) to gamma knife surgery (GKS) based on the number of shots delivered and radiation dose. METHODS Between September 1998 and September 2003, some 63 patients with TN refractory to medical or surgical management underwent GKS at Upstate Medical University. Ten patients had multiple sclerosis and 25 patients had undergone prior invasive treatment. Gamma knife surgery was delivered to the trigeminal nerve root entry zone in one shot in 27 patients or two shots in 36 patients. The radiation dose was escalated to less than or equal to 80 Gy in 20 patients, 85 Gy in 21 patients, and greater than or equal to 90 Gy in 22 patients. Pain before and after GKS was assessed using the Barrow Neurological Institute Pain Scale and the improvement score was analyzed as a function of dose grouping and number of shots. Sixty patients were available for evaluation, with an initial overall and complete response rate of 90% and 27%, respectively. There was a greater improvement score for patients who were treated with two shots compared with one shot, mean 2.83 compared with 1.72 (p < 0.001). There was an increased improvement in score at each dose escalation level: less than or equal to 80 Gy (p = 0.017), 85 Gy (p < 0.001), and greater than or equal to 90 Gy (p < 0.001). Linear regression analysis also indicated that there was a greater response with an increased dose (p = 0.021). Patients treated with two shots were more likely to receive a higher dose (p < 0.001). There were no severe complications. Five patients developed mild facial numbness. CONCLUSIONS Gamma knife surgery is an effective therapy for TN. Initial response rates appear to correlate with the number of shots and dose.

Pediatric cerebellar pleomorphic xanthoastrocytoma with anaplastic features: a case of long-term survival after multimodality therapy

Case reportA 4-year-old girl had a large midline cerebellar solid and cystic mass partially attached to the meninges. The original diagnosis was glioblastoma multiforme and she was treated by a gross-total surgical resection followed by chemotherapy and radiation theraphy to the posterior fossa during the ensuing 14 months. She has received no further theraphy and appears to be doing well 12 years later. This unusual favorable clinical outcome prompted our review of this case.MethodsAdditional special stains and immunocytochemistry were performed on the paraffin embedded tumor sections.ResultsWe have confirmed the original histopathological observations of hypercellularity and focal nuclear pleomorphism, atypical mitoses, vascular hyperplasia, as well as focal necrosis. However, the additional stains revealed that the tumor is a relatively well-circumscribed meningeal-based astrocytic tumor (positive for GFAP) with extensive reticulin deposit and focal neuronal differentiation (positive for synaptophysin). A Ki67 labeling index is generally very low, but is positive in up to 5-10% of tumor cells focally. In the light of the favorable clinical outcome and the overall histological features, this tumor may be best reclassified as a rare example of cerebellar pleomorphic xanthoastrocytoma with foci of anaplasia.

A dwell position verification method for high dose rate brachytherapy.

Misplacement of dwell positions is a potential source of misadministration in high dose rate (HDR) brachytherapy. In this work, we present a dwell position verification method using fluoroscopic images. A mobile C‐arm fluoroscopic machine is used to take a snapshot of the treatment machines check cable as it reaches the most distal dwell position. This fluoroscopic image is displayed side‐by‐side with a treatment planning image on a dual monitor relay station at the HDR treatment console. Any discrepancy between the check cables position on the verification image and the intended dwell position on the planning image can be identified, immediately, thus avoiding the possibility of treating the wrong target volume. PACS numbers: 87.53.Jw, 87.53.Xd, 87.59.Ci

Radiotherapy for the clinically negative neck in supraglottic laryngeal cancer.

PURPOSEThe supraglottic larynx has rich lymphatic drainage, resulting in a high incidence of occult cervical metastases, and the optimal treatment of the clinically uninvolved neck in supraglottic laryngeal cancer remains controversial. Selected retrospective series report a greater than 20% regional failure after treatment by radiotherapy alone, and some investigators recommend routine prophylactic neck dissection. We report on our series of patients who received radiotherapy as sole treatment to the clinically negative neck, either to the bilateral neck for NO disease or to the contralateral neck for ipsilateral lymphatic involvement. PATIENTS AND METHODSBetween 1971 and 1998, 150 patients with supraglottic laryngeal cancer received radiotherapy alone to the clinically negative neck. Fifty-two patients had ipsilateral lymph node metastases (N1 = 16, N2a = 12, N2b = 20, N3 = 4), and 98 patients had no clinical nodal involvement. The primary site (T1/T2 = 74, T3/T4 = 76) was treated with radiotherapy (N = 91) or laryngectomy plus radiotherapy (N = 59). Neck dissection was performed on the involved neck in 36/52 node-positive patients for either multiple involved nodes (N = 20) or size > 3 cm (N = 16). Radiotherapy was delivered in standard fractionation and field arrangement. The median dose to the clinically negative neck was 5000 cGy (range: 4860–6000 cGy). RESULTSWith a median follow-up of 48 months, the clinically negative neck was the first site of failure in 3.3% of patients. The contralateral neck remained disease free in all patients. Five failures occurred in the NO neck, and the median time to recurrence was 12 months (range: 5–30 months). Salvage therapy was neck dissection for the NO neck failures. The 5-year locoregional control, disease-specific survival, and overall survival were 69%, 74%, and 61%, respectively. DISCUSSIONOur data support the use of radiotherapy as a prophylactic treatment for the clinically negative neck. Tumor control in the clinically uninvolved cervical lymphatics is comparable to that in surgical series, suggesting that routine neck dissection may not be necessary. Prospective trials are necessary to further define the role of radiotherapy in this patient population.

Stereotactic radiosurgery in two cases of presumed fourth cranial nerve schwannoma.

A 47-year-old woman and a 45-year-old man with gradually progressive fourth cranial nerve palsy underwent stereotactic radiosurgery for presumed fourth cranial nerve schwannomas with the gamma knife at a marginal tumor dose of 14 and 13 Gy, respectively. In one patient, the ocular misalignment disappeared; in the other patient, it stabilized. MRI showed shrinkage of the tumors. These patients represent the second and third reported cases of presumed fourth cranial nerve schwannoma treated with radiosurgery and the first cases with substantial follow-up information.

Impact of the number of metastatic brain lesions on survival after Gamma Knife radiosurgery

Effectiveness of Gamma Knife radiosurgery (GKRS: Elekta AB, Stockholm, Sweden) for patients with metastatic brain disease and the prognostic factors influencing their survival were analyzed in a 5 year retrospective data analysis (July 2001 to June 2006). Kaplan-Meier survival curves were constructed using univariate and multivariate analyses with the respective salient prognostic factors. This study analyzed data on 330 patients with brain metastases who underwent GKRS. Lung carcinoma (55%) was the most common primary cancer followed by breast (17.8%), melanoma (9.4%), colorectal (4.8%) and renal (3.9%). The median survival for all patients was 8 months. Survival ranged from 13 months for breast metastases, 10 months for renal, and 8 months for lung to 5 months for colorectal and melanoma. Mean age of patients was 58.5 years (range 18-81). Melanoma patients were younger with a mean age of 49 and also had the highest number of lesions (3.8) when compared to patients with renal (2.5), lung (2.8), colorectal (3) and breast (3.6). When stratified according to the number of lesions patient survival was 8 months (one to three lesions), 7.5 months (four or five lesions) and 7 months (six lesions or more). Mean Karnofsky Performance Status score (KPS) was 77 and survival dropped significantly from 8 months to 4.5 months if KPS was less than 70. Survival improved with a KPS of 70 or more, regardless of the number of lesions treated. Selection of patients based on the number of lesions may not be justified. A prospective trial is required to further define the prognostic factors affecting survival.

Long-term survival in a patient with metastatic oropharynx squamous cell carcinoma to liver

The traditionally held view is that the patients with metastatic disease cannot be cured and should be treated palliatively as it was believed that the patients will eventually succumb to the disease progression due to lack of effective treatments for systemic disease. In this article, we report our experience in a patient who was diagnosed with metastatic oropharynx squamous cell carcinoma to the liver, who has now survived five years since the original diagnosis, and is three years disease free. This case report illustrates the curative potential in selected patients with limited burden of metastatic disease with aggressive local therapy to all known sites of disease. It underscores the importance of imaging modalities in monitoring progression of disease, and most importantly illustrates the importance of multidisciplinary care for oncology patients.

Optic Pathway Glioma

There is perhaps no other tumor of the eye or orbit whose treatment evokes as much controversy as that of the optic glioma. The reader is left thinking of a group of blind men describing an elephant while each touching a different part of the animal. Different specialists’ preferred options range from no treatment, through partial excision, complete excision and radiation therapy to surgery plus radiotherapy, and now also include chemotherapy. The treatment selected is a direct reflection of the anatomical site of involvement, the symptoms and signs, the age of the patient, and the consequences of surgical extirpation of the lesion and of irradiation.