Eugen B. Hug

Management of Atypical and Malignant Meningiomas: Role of High-dose, 3D-conformal Radiation Therapy

AbstractObjective Atypical and malignant meningiomas are at high risk for local failure. The role of radiation therapy (RT) and dose levels required to improve tumor control are poorly defined. This study reviews our experience with RT. Material and methods Thirty-one patients underwent fractionated RT for atypical (AM, 15 patients) or malignant meningioma (MM, 16 patients) of the cranium. Sixteen patients presented with primary and 15 with recurrent disease. Eight patients received RT following total resection, 21 patients after subtotal resection and 2 patient following biopsy only. RT was given using megavoltage photons in 15 patients and combined photons and 160 MeV protons in 16 patients. Total target doses ranged from 50 to 68 (AM, mean 62) and from 40 to 72 (MM, mean 58) Gy or CGE (= cobalt-gray-equivalent). Results With mean observation time of 59 months (range: 7–155 months) actuarial local control rates at 5- and 8-years were similar for both histologies (38% and 19% for AM and 52 and 17% for MM). However, significantly improved local control was observed for proton versus photon RT (80% versus 17% at 5 years, p = 0.003) and target doses ≥60 Gy for both, atypical (p = 0.025) and malignant meningioma (p = 0.0006).At time of analysis, 14/15 patients (93%) with AM and 6/16 (38%) with MM were alive. Three patients (19%) with MM developed distant metastasis. Actuarial 5- and 8-year survival rates for MM were significantly improved by use of proton over photon RT and radiation doses ≥60 CGE. Three patients developed symptomatic radiation damage after 59.3, 68.4 and 72 Gy/CGE. Conclusion Conformal, high dose RT resulted in significant improvement of local control for atypical and malignant meningiomas. Increased local control resulted also in improved rates of survival for patients with malignant meningioma.

Thymoma : histologic subclassification is an independent prognostic factor

Background. Several histologic classifications of thymomas have been proposed, and attempts have been made to correlate the different histologic subtypes to clinical behavior and prognosis. Recently, Marino and Müller‐Hermelink and Kirchner et al. proposed a new morphologic classification of thymomas based on the resemblance of the neoplastic cells to subtypes of the normal thymic epithelial cells. In this classification, six categories of thymic epithelial tumors are recognized, They define four categories of thymoma: medullary, mixed, organoid (predominantly cortical), and cortical, and two subgroups of thymic carcinomas: well differentiated thymic carcinoma and high grade carcinomas.

Brainstem tolerance to conformal radiotherapy of skull base tumors

PURPOSE The aim of this study was to analyze the long-term incidence of brainstem toxicity in patients treated for skull base tumors with high dose conformal radiotherapy. METHODS AND MATERIALS Between 1974 and 1995, 367 patients with chordomas (n = 195) and chondrosarcomas (n = 172) of the base of skull have been treated with combined megavoltage photon and 160 MeV proton radiotherapy. Following 3D treatment planning with delineation of target volumes and critical nontarget structures dose distributions and dose-volume histograms were calculated. Radiotherapy was given an 1.8 Gy or CGE (=Cobalt Gray Equivalent) dose per fraction, with prescribed target doses ranging from 63 CGE to 79.2 CGE (mean = 67.8 CGE). Doses to the brainstem surface were limited to < or = 64 CGE and to the brainstem center to < or = 53 CGE. RESULTS Follow-up time ranged from 6 months to 21.4 years (mean = 42.5 months). Brainstem toxicity was observed in 17 of 367 patients attributable to treatment, resulting in death of three patients. Actuarial rates of 5 and 10-year high-grade toxicity-free survival were 94 and 88%, respectively. Increased risk of brainstem toxicity was significantly associated with maximum dose to brainstem, volume of brainstem receiving > or = 50 CGE, > or = 55 CGE, and > or = 60 CGE, number of surgical procedures, and prevalence of diabetes or high blood pressure. Multivariate analysis identified three independent factors as important prognosticators: number of surgical procedures (p < 0.001), volume of the brainstem receiving 60 CGE (p < 0.001), and prevalence of diabetes (p < 0.01). CONCLUSIONS Tolerance of brainstem to fractionated radiotherapy appears to be a steep function of tissue volume included in high dose regions rather than the maximum dose of brainstem alone. In addition, presence of predisposing factors as well as extent of surgical manipulation can significantly lower brainstem tolerance in the individual patient.

Effectiveness and Safety of Spot Scanning Proton Radiation Therapy for Chordomas and Chondrosarcomas of the Skull Base: First Long-Term Report

PURPOSE To evaluate effectiveness and safety of spot-scanning-based proton radiotherapy (PT) in skull-base chordomas and chondrosarcomas. METHODS AND MATERIALS Between October 1998 and November 2005, 64 patients with skull-base chordomas (n = 42) and chondrosarcomas (n = 22) were treated at Paul Scherrer Institute with PT using spot-scanning technique. Median total dose for chordomas was 73.5 Gy(RBE) and 68.4 Gy(RBE) for chondrosarcomas at 1.8-2.0 Gy(RBE) dose per fraction. Local control (LC), disease specific survival (DSS), and overall survival (OS) rates were calculated. Toxicity was assessed according to CTCAE, v. 3.0. RESULTS Mean follow-up period was 38 months (range, 14-92 months). Five patients with chordoma and one patient with chondrosarcoma experienced local recurrence. Actuarial 5-year LC rates were 81% for chordomas and 94% for chondrosarcomas. Brainstem compression at the time of PT (p = 0.007) and gross tumor volume >25 mL (p = 0.03) were associated with lower LC rates. Five years rates of DSS and OS were 81% and 62% for chordomas and 100% and 91% for chondrosarcomas, respectively. High-grade late toxicity consisted of one patient with Grade 3 and one patient with Grade 4 unilateral optic neuropathy, and two patients with Grade 3 central nervous system necrosis. No patient experienced brainstem toxicity. Actuarial 5-year freedom from high-grade toxicity was 94%. CONCLUSIONS Our data indicate safety and efficacy of spot-scanning based PT for skull-base chordomas and chondrosarcomas. With target definition, dose prescription and normal organ tolerance levels similar to passive-scattering based PT series, complication-free, tumor control and survival rates are at present comparable.

Locally challenging osteo- and chondrogenic tumors of the axial skeleton: Results of combined proton and photon radiation therapy using three-dimensional treatment planning☆

PURPOSE Tumors of the axial skeleton are at high risk for local failure. Total surgical resection is rarely possible. Critical normal tissues limit the efficacy of conventional photon therapy. This study reviews our experience of using combined high dose proton and photon radiation therapy following three-dimensional (3D) treatment planning. METHODS AND MATERIALS Between December 1980 and September 1992, 47 patients were treated at the Massachusetts General Hospital and Harvard Cyclotron Laboratory for primary or recurrent chordomas and chondrosarcomas (group 1, 20 patients), osteogenic sarcomas (group 2, 15 patients) and giant cell tumors, osteo-or chondroblastomas (group 3, 12 patients). Radiation treatment was given postoperatively in 23 patients, pre- and postoperatively in 17 patients, and 7 patients received radiation therapy as definitive treatment modality following biopsy only. The proton radiation component was delivered using a 160 MeV proton beam and the photon component using megavoltage photons up to 23 MV energy with 1.8-2.0 Cobalt Gray Equivalent (CGE) per fraction, once a day. Total external beam target dose ranged from 55.3 CGE to 82.0 CGE with mean target doses of 73.9 CGE (group 1), 69.8 CGE (group 2), and 61.8 CGE (group 3). RESULTS Group 1 (chordoma and chondrosarcoma): Five of 14 patients (36%) with chordoma recurred locally, and 2 out of 5 patients developed distant metastasis, resulting in 1 death from disease. A trend for improved local control was noted for primary vs. recurrent tumors, target doses > 77 CGE and gross total resection. All patients with chondrosarcoma achieved and maintained local control and disease-free status. Five-year actuarial local control and overall survival rates were 53% and 50% for chordomas and 100% and 100% for chondrosarcomas, respectively. Group 2 (osteogenic sarcoma): Three of 15 patients (20%) never achieved local control and died within 6 months of completion of radiation treatment. Only 1 out of 12 patients who were controlled for more than 6 months failed locally, yielding a 5-year local control rate of 59% for 15 patients. Overall, 4 patients (27%) developed distant metastasis (two in patients with uncontrolled primary); 4 patients succumbed to their disease, 3 patients died of intercurrent disease, resulting in overall survival of 44% at 5 years. Group 3 (giant cell tumors, osteo- and chondroblastoma): One of 8 patients with giant cell tumor failed locally, 1 patient distantly, and all patients are alive. Three of 4 patients with osteo- or chondroblastoma are alive and well. One patient suffered local recurrence and died of disease. Local control rate and overall survival for this group of 12 patients was 76% and 87% and local control for patients with giant cell tumors 83% at 5 years. In the majority of cases radiotherapy was well tolerated. However, one patient with a large base of skull tumor developed retinopathy, one patient required enucleation of a previously blind eye, and another patient with sacral tumor developed chronic diarrhea. CONCLUSION Combined proton and photon radiation therapy optimized by 3D treatment planning, allows the delivery of higher radiation doses to tumors of the axial skeleton, while respecting normal tissue constraints. High radiation doses can result in improved long-term local control.

Analysis of the relationship between tumor dose inhomogeneity and local control in patients with skull base chordoma.

PURPOSE When irradiating a tumor that abuts or displaces any normal structures, the dose constraints to those structures (if lower than the prescribed dose) may cause dose inhomogeneity in the tumor volume at the tumor-critical structure interface. The low-dose region in the tumor volume may be one of the reasons for local failure. The aim of this study is to quantitate the effect of tumor dose inhomogeneity on local control and recurrence-free survival in patients with skull base chordoma. METHODS AND MATERIALS 132 patients with skull base chordoma were treated with combined photon and proton irradiation between 1978 and 1993. This study reviews 115 patients whose dose-volume data and follow-up data are available. The prescribed doses ranged from 66.6 Cobalt-Gray-Equivalent (CGE) to 79.2 CGE (median of 68.9 CGE). The dose to the optic structures (optic nerves and chiasm), the brain stem surface, and the brain stem center was limited to 60, 64, and 53 CGE, respectively. We used the dose-volume histogram data derived with the three-dimensional treatment planning system to evaluate several dose-volume parameters including the Equivalent Uniform Dose (EUD). We also analyzed several other patient and treatment factors in relation to local control and recurrence-free survival. RESULTS Local failure developed in 42 of 115 patients, with the actuarial local control rates at 5 and 10 years being 59% and 44%. Gender was a significant predictor for local control with the prognosis in males being significantly better than that in females (P = 0.004, hazard ratio = 2.3). In a Cox univariate analysis, with stratification by gender, the significant predictors for local control (at the probability level of 0.05) were EUD, the target volume, the minimum dose, and the D5cc dose. The prescribed dose, histology, age, the maximum dose, the mean dose, the median dose, the D90% dose, and the overall treatment time were not significant factors. In a Cox multivariate analysis, the models including gender and EUD, or gender and the target volume, or gender and the minimum target dose were significant. The more biologically meaningful of these models is that of gender and EUD. CONCLUSION This study suggests that the probability of recurrence of skull base chordomas depends on gender, target volume, and the level of target dose inhomogeneity. EUD was shown to be a useful parameter to evaluate dose distribution for the target volume.

Radiation therapy for chordomas of the base of skull and cervical spine: patterns of failure and outcome after relapse

PURPOSE To determine the patterns of failure and outcome following relapse of chordomas of the base of skull and cervical spine. METHODS AND MATERIALS Between November 1975 and October 1993, 204 patients were treated for chordoma of the base of skull or cervical spine, of which 63 have developed relapse. These 63 patients constitute the main focus of this study. Forty-five patients presented with base of skull and 18 with cervical spine tumors. All patients received combined proton and photon beam radiation. The median prescribed dose was 70.1 cobalt-Gray equivalent (CGE) (range 66.6-77.4). There were 25 males and 38 females, with a median age of 41 years (range 7-66). Median follow-up was 54 months (range 8-158). RESULTS Sixty-three of the 204 patients treated (31%) had treatment failure. Among the 63 patients who relapsed, 60 (95%) experienced local recurrence, and in 49 patients (78%), this was the only site of failure. Two of 63 patients (3%) developed regional lymph node relapse and 3 of 63 (5%) developed surgical pathway recurrence (1 left neck, 1 palate and 1 nasal cavity). Thirteen of 204 patients relapsed in distant sites, accounting for 20% (13 of 63) of all patients with recurrence in this series. The most common metastatic sites were lungs and bones presenting in 7 of 13 and 6 of 13 patients, respectively. Only 2 of 13 patients failed with isolated distant metastasis. The actuarial 3- and 5-year survival rates after local relapse (60 patients) were 44 and 5%, respectively. Following distant failure (13 patients), the 3- and 5-year survival rates were 25 and 12%, respectively. After any relapse (63 patients) the corresponding survival rates were 43 and 7%. Following local relapse, 49 of 60 patients underwent salvage therapy consisting of subtotal resection in most patients (46 of 49). The remaining 11 of 60 patients received supportive care only. Salvage therapy resulted in stable or improved status without subsequent disease progression in 26 of 49 (53%), and progressive disease in 16 of 49 patients (33%). The actuarial 2- and 5-year overall survival rates following relapse for the 49 patients who underwent salvage treatment were 63 and 6%, which favorably compared to the 2-year survival rate of 21% for those who received supportive care only (p = 0.001). CONCLUSION Local relapse is the predominant type of treatment failure for chordomas of the base of skull and cervical spine. Salvage treatment may relieve symptoms; however, most patients will ultimately succumb to their disease. Poor long-term survival rates following relapse emphasize the importance of a combined treatment approach with experienced surgeons and radiation oncologists at the time of primary treatment. For most patients, only permanent local tumor control will offer a chance of cure.

Proton radiotherapy in management of pediatric base of skull tumors

PURPOSE Primary skull base tumors of the developing child are rare and present a formidable challenge to both surgeons and radiation oncologists. Gross total resection with negative margins is rarely achieved, and the risks of functional, structural, and cosmetic deficits limit the radiation dose using conventional radiation techniques. Twenty-nine children and adolescents treated with conformal proton radiotherapy (proton RT) were analyzed to assess treatment efficacy and safety. MATERIALS AND METHODS Between July 1992 and April 1999, 29 patients with mesenchymal tumors underwent fractionated proton (13 patients) or fractionated combined proton and photon (16 patients) irradiation. The age at treatment ranged from 1 to 19 years (median 12); 14 patients were male and 15 female. Tumors were grouped as malignant or benign. Twenty patients had malignant histologic findings, including chordoma (n = 10), chondrosarcoma (n = 3), rhabdomyosarcoma (n = 4), and other sarcomas (n = 3). Target doses ranged between 50.4 and 78.6 Gy/cobalt Gray equivalent (CGE), delivered at doses of 1.8-2.0 Gy/CGE per fraction. The benign histologic findings included giant cell tumors (n = 6), angiofibromas (n = 2), and chondroblastoma (n = 1). RT doses for this group ranged from 45.0 to 71.8 Gy/CGE. Despite maximal surgical resection, 28 (97%) of 29 patients had gross disease at the time of proton RT. Follow-up after proton RT ranged from 13 to 92 months (mean 40). RESULTS Of the 20 patients with malignant tumors, 5 (25%) had local failure; 1 patient had failure in the surgical access route and 3 patients developed distant metastases. Seven patients had died of progressive disease at the time of analysis. Local tumor control was maintained in 6 (60%) of 10 patients with chordoma, 3 (100%) of 3 with chondrosarcoma, 4 (100%) of 4 with rhabdomyosarcoma, and 2 (66%) of 3 with other sarcomas. The actuarial 5-year local control and overall survival rate was 72% and 56%, respectively, and the overall survival of the males was significantly superior to that of the female patients (p = 0.002). Of the patients with benign tumors, 1 patient (giant cell tumor) had local failure at 10 months. The other 8 patients continued to have local tumor control; all 9 patients were alive at last follow-up (actuarial 5-year local control and overall survival rate of 89% and 100%, respectively). Severe late effects (motor weakness and sensory deficits) were observed in 2 (7%) of 29 patients. CONCLUSION Proton RT for children with aggressively recurring tumors after major skull base surgery can offer a considerable prospect of tumor control and survival. Longer follow-up is necessary to assess the real value of protons, in particular with regard to bone growth and cosmetic outcome.

Megavoltage Radiation Therapy for Axial and Inoperable Giant-Cell Tumor of Bone*

BACKGROUND Treatment of giant-cell tumor of bone generally involves wide en bloc resection of the lesion and the surrounding bone or curettage with or without bone-grafting or the use of cement. Radiation therapy has been used for patients who cannot be operated on for medical reasons or who have a tumor that is technically difficult to resect or that cannot be resected because of its location. We performed the present study to evaluate the efficacy of megavoltage radiation in terms of lack of tumor progression and treatment-related morbidity. METHODS Twenty patients who had giant-cell tumor of bone were managed with a single course of megavoltage radiation (forty to seventy gray administered at 1.8 to 2.0 gray per fraction with an average total duration of treatment of five to seven weeks) between March 1973 and March 1992. We used megavoltage photons, 160-megaelectron-volt proton beams, or a combination of the two. RESULTS After a median duration of follow-up of 9.3 years, the tumor had not progressed in seventeen of the twenty patients. Thus, the actuarial ten-year rate for lack of progression was 85 percent. Local regrowth was evident in one patient who had received radiation alone and in two of the thirteen patients who had been managed with partial resection and radiation. Operative treatment was successful in the three patients in whom the radiation treatment had failed. No radiation-induced tumors were observed in our series. CONCLUSIONS We concluded that giant-cell tumor of bone was effectively treated with megavoltage radiation in our series of twenty patients in whom operative resection would have been difficult or was not feasible. The rate of tumors that did not progress with this regimen of radiation is similar to that reported by investigators from several other centers. Furthermore, these results closely rival those obtained with modern curettage procedures. Malignant sarcomatous transformation was not observed in our series. A longer duration of follow-up of a larger group of patients is necessary to provide a better estimate of the risk of malignant transformation.

Stage III thymoma: pattern of failure after surgery and postoperative radiotherapy and its implication for future study

PURPOSE With the conventional approach of surgery and postoperative radiotherapy for patients with Masaoka Stage III thymoma, progress has been slow for an improvement in the long-term survival rate over the past 20 years. The objective of this study was to evaluate the pattern of failure and survival after surgery and postoperative radiotherapy in Stage III thymoma and search for a new direction for better therapy outcome. METHODS AND MATERIALS Between 1975 and 1993, 111 patients with thymoma were treated at Massachusetts General Hospital. Of these, 32 patients were determined to have Masaoka Stage III thymoma. The initial treatment included surgery for clinically resectable disease in 25 patients and preoperative therapy for unresectable disease in 7 patients. Surgical procedure consisted of thymectomy plus resection of involved tissues. For postoperative radiotherapy (n = 23), radiation dose consisted of 45-50 Gy for close resection margins, 54 Gy for microscopically positive resection margins, and 60 Gy for grossly positive margins administered in 1.8 to 2.0 Gy of daily dose fractions, 5 fractions a week, over a period of 5 to 6.6 weeks. In preoperative radiotherapy, a dose of 40 Gy was administered in 2.0 Gy of daily dose fractions, 5 days a week. For patients with large tumor requiring more than 30% of total lung volume included in the target volume (n = 3), a preoperative radiation dose of 30 Gy was administered and an additional dose of 24-30 Gy was given to the tumor bed region after surgery for positive resection margins. RESULTS Patients with Stage III thymoma accounted for 29% (32/111 patients) of all patients. The median age was 57 years with a range from 27 to 81 years; gender ratio was 10:22 for male to female. The median follow-up time was 6 years. Histologic subtypes included well-differentiated thymic carcinoma in 19 (59%), high-grade carcinoma in 6 (19%), organoid thymoma in 4 (13%), and cortical thymoma in 3 (9%) according to the Marino and Müller-Hermelink classification. The overall survival rates were 71% and 54% at 5 and 10 years, respectively. Ten of the 25 patients who were subjected to surgery as initial treatment were found to have incomplete resection by histopathologic evaluation. The 5- and 10-year survival rates were 86% and 69% for patients (n = 15) with clear resection margins as compared with 28% and 14% for those (n = 10) with incomplete resection margins even after postoperative therapy, p = 0.002. Survival rates at 5 and 10 years were 100% and 67% for those with unresectable disease treated with preoperative radiation (n = 6) and subsequent surgery (n = 3). Recurrence was noted in 12 of 32 patients and 11 of these died of recurrent thymoma. Recurrences at pleura and tumor bed accounted for 77% of all relapses, and all pleural recurrences were observed among the patients who were treated with surgery initially. CONCLUSION Incomplete resection leads to poor results even with postoperative radiotherapy or chemoradiotherapy in Stage III thymoma. Pleural recurrence is also observed more often among patients treated with surgery first. These findings suggest that preoperative radiotherapy or chemoradiotherapy may result in an increase in survival by improving the rate of complete resection and reducing local and pleural recurrences.