The role of stereotactic radiosurgery in the treatment of malignant skull base tumors

Severe pneumocranium after gamma knife stereotactic radiosurgery for brain metastasis: A case report and literature review

RATIONALE

Gamma knife stereotactic radiosurgery (GKRS) is a recognized safe and effective treatment for brain metastasis; however, some complications can present significant clinical challenges. This case report highlights a rare occurrence of cerebrospinal fluid (CSF) leakage and pneumocranium following GKRS, emphasizing the need for awareness and prompt management of these complications.

PATIENT CONCERNS

A 35-year-old male with a history of malignant neoplasm of the lip in 2015 and perineural spread of malignancy into the left cavernous sinus was treated with GKRS in 2017. The patient was admitted emergently 39 days after discharge due to persistent headache and dizziness.

DIAGNOSES

Brain computed tomography (CT) revealed diffuse bilateral pneumocranium alongside an observation of CSF leakage.

INTERVENTIONS

A surgical procedure involving a left frontal-temporal craniotomy was performed to excise a residual skull base tumor and repair the dura, guided by a navigator system. The conclusive pathological assessment revealed the presence of squamous cell carcinoma markers.

OUTCOMES

The patient exhibited excellent tolerance to the entire procedure and experienced a prompt and uneventful recovery process. After surgery, the symptoms alleviated and CSF leak stopped. The follow-up image showed the pneumocranium resolved.

LESSONS

Pneumocranium due to early-stage post-GKRS is uncommon. The rapid tumor shrinkage and timing of brain metastasis spreading through the dura can lead to CSF leak and pneumocranium. We reviewed current treatment options and presented a successful craniotomy-based dura repair case.

Radiation-Induced Retinopathy and Optic Neuropathy after Radiation Therapy for Brain, Head, and Neck Tumors: A Systematic Review

Background: Patients with brain, head, and neck tumors experience a decline in their quality of life due to radiation retinopathy and optic neuropathy. Little is known about the dose–response relationship and patient characteristics. We aimed to systematically review the prevalence of radiation retinopathy and optic neuropathy. Method: The primary outcome was the pooled prevalence of radiation retinopathy and optic neuropathy. The secondary outcome included the effect of the total radiation dose prescribed for the tumor according to the patient’s characteristics. Furthermore, we aimed to evaluate the radiation dose parameters for organs at risk of radiation retinopathy and optic neuropathy. Results: The pooled prevalence was 3.8%. No retinopathy was reported for the tumor’s prescribed dose of <50 Gy. Optic neuropathy was more prevalent for a prescribed dose of >50 Gy than <50 Gy. We observed a higher prevalence rate for retinopathy (6.0%) than optic neuropathy (2.0%). Insufficient data on the dose for organs at risk were reported. Conclusion: The prevalence of radiation retinopathy was higher compared to optic neuropathy. This review emphasizes the need for future studies considering retinopathy and optic neuropathy as primary objective parameters.

Systematic Review Comparing Open versus Endoscopic Surgery in Clival Chordomas and a 10-Year Single-Center Experience

Objectives Chordomas are rare, slow-growing, and osteo-destructive tumors of the primitive notochord. There is still contention in the literature as to the optimal management of chordoma. We conducted a systematic review of the surgical management of chordoma along with our 10-year institutional experience.

Design A systematic search of the literature was performed in October 2020 by using MEDLINE and EMBASE for articles relating to the surgical management of clival chordomas. We also searched for all adult patients surgically treated for primary clival chordomas at our institute between 2009 and 2019.

Participants Only articles describing chordomas arising from the clivus were included in the analysis. For our institution experience, only adult primary clival chordoma cases were included.

Main Outcome Measures Patients were divided into endoscopic or open surgery. Rate of gross total resection (GTR), recurrence, and complications were measured.

Results Our literature search yielded 24 articles to include in the study. Mean GTR rate among endoscopic cases was 51.9% versus 41.7% for open surgery. Among the eight cases in our institutional experience, we found similar GTR rates between endoscopic and open surgery.

Conclusion Although there is clear evidence in the literature that endoscopic approaches provide better rates of GTR with fewer overall complications compared to open surgery. However, there are still situations where endoscopy is not viable, and thus, open surgery should still be considered if required.

Patient Outcomes after Reirradiation of Small Skull Base Tumors using Stereotactic Body Radiotherapy, Intensity Modulated Radiotherapy, or Proton Therapy

Purpose  The aim of this study was to evaluate outcomes of patients who received reirradiation for small skull base tumors utilizing either intensity modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT), and proton radiotherapy (PRT). Methods  Patients who received IMRT, SBRT or PRT reirradiation for recurrent or new small skull base tumors (< 60 cc) between April 2000 and July 2016 were identified. Those with < 3 months follow-up were excluded. Clinical outcomes and treatment toxicity were assessed. The Kaplan-Meier method was used to estimate the local control (LC), regional control (RC), distant control (DC), progression free survival (PFS), and overall survival (OS). Results  Of the 75 patients eligible, 30 (40%) received SBRT, 30 (40%) received IMRT, and 15 (20%) received PRT. The median retreatment volume was 28 cc. The median reirradiation dose was 66 Gy in 33 fractions for IMRT/PRT, and 45 Gy in 5 fractions for SBRT. The median time to reirradiation was 41 months. With a median follow-up of 24 months, the LC, RC, DC, PFS, and OS rates were 84%, 79%, 82%, 60%, and 87% at 1 year, and 75%, 72%, 80%, 49%, and 74% at 2 years. There was no difference in OS between radiation modalities. The 1- and 2-year late Grade 3 toxicity rates were 3% and 11% respectively.. Conclusions  Reirradiation of small skull base tumors utilizing IMRT, PRT, or SBRT provided good local tumor control and low rates of Grade 3 late toxicity. A prospective clinical trial is needed to guide selection of radiation treatment modalities.

Metastatic Complications of Cancer Involving the Central and Peripheral Nervous Systems

Neurologic complications of cancer may involve both the central nervous system and peripheral nervous system manifesting as brain, leptomeningeal, intramedullary, intradural, epidural, plexus, and skull base metastases. Excluding brain involvement, neurologic complications affecting these other sites are relatively infrequent, but collectively they affect more than 25% of patients with metastatic cancer causing significant morbidity and mortality. Early diagnosis and intervention optimize quality of life and improve survival.

Single- and Multi-Fraction Stereotactic Radiosurgery Dose Tolerances of the Optic Pathways

PURPOSE

Dosimetric and clinical predictors of radiation-induced optic nerve/chiasm neuropathy (RION) after single-fraction stereotactic radiosurgery (SRS) or hypofractionated (2-5 fractions) radiosurgery (fSRS) were analyzed from pooled data that were extracted from published reports (PubMed indexed from 1990 to June 2015). This study was undertaken as part of the American Association of Physicists in Medicine Working Group on Stereotactic Body Radiotherapy, investigating normal tissue complication probability (NTCP) after hypofractionated radiation.

METHODS AND MATERIALS

Eligible studies described dose delivered to optic nerve/chiasm and provided crude or actuarial toxicity risks, with visual endpoints (ie, loss of visual acuity, alterations in visual fields, and/or blindness/complete vision loss). Studies of patients with optic nerve sheath tumors, optic nerve gliomas, or ocular/uveal melanoma were excluded to obviate direct tumor effects on visual outcomes, as were studies not specifying causes of vision loss (ie, tumor progression vs RION).

RESULTS

Thirty-four studies (1578 patients) were analyzed. Histologies included pituitary adenoma, cavernous sinus meningioma, craniopharyngioma, and malignant skull base tumors. Prior resection (76% of patients) did not correlate with RION risk (P = .66). Prior irradiation (6% of patients) was associated with a crude 10-fold increased RION risk versus no prior radiation therapy. In patients with no prior radiation therapy receiving SRS/fSRS in 1-5 fractions, optic apparatus maximum point doses resulting in <1% RION risks include 12 Gy in 1 fraction (which is greater than our recommendation of 10 Gy in 1 fraction), 20 Gy in 3 fractions, and 25 Gy in 5 fractions. Omitting multi-fraction data (and thereby eliminating uncertainties associated with dose conversions), a single-fraction dose of 10 Gy was associated with a 1% RION risk. Insufficient details precluded modeling of NTCP risks after prior radiation therapy.

CONCLUSIONS

Optic apparatus NTCP and tolerance doses after single- and multi-fraction stereotactic radiosurgery are presented. Additional standardized dosimetric and toxicity reporting is needed to facilitate future pooled analyses and better define RION NTCP after SRS/fSRS.

Gamma Knife Management of Skull Base Chordomas: Is it a Choice?

Background:

Skull base chordomas are locally invasive tumors which able to extend in different directions with skull base invasion. Although they are histologically benign, they have invasive nature makes total resection virtually impossible to achieve in most cases and this lead to residual tumors after surgery. To decrease postoperative surgical resection morbidity of these tumors, gamma knife radiosurgery (GKRS) was performed as alternative management for these residual chordomas to evaluate its safety and efficacy.

Materials and Methods:

A retrospective study was made on eight residual skull base chordomas treated with GKRS between 2011 and 2015. The mean patient age was 49 years (range 30–73 years). Four patients harboring chordoma were male, and four patients were females with 1:1 ratio. All patients had undergone one prior surgery. Patients were treated with peripheral dose ranged between 12–15 gray (Gy) (mean 13.75 Gy) usually at 35% to 50% isodose curve (mean 38.8%). The maximum dose to the adjacent brain stem area ranged between 10 and 12 Gy. All patients were followed up from 8 to 39 months (mean 18 months).

Results:

The tumor control rate was 50% and 25% after 18 and 36 months, respectively, but we found that their wasdeclined in the tumor control rate with long follow-up time. Four tumors were stable in their size just for 18 months, and then there two of these tumors were progressed in their size, the other four patients showed progression in their tumors in their 1^st year of treatment without sign of central tumor necrosis.

Conclusion:

Skull base chordoma patients complained from symptoms due to tumor mass effect which were not prospected to respond to GKRS alone as the aim of this type of treatment was the local tumor control, the tumor control rate declined with long follow-up time and this correlated with radioresistant nature of skull base chordoma. We advise a gross total resection to decrease the tumor volume, and this making gamma knife a reasonable treatment modality.

Intracranial dural, calvarial, and skull base metastases

Metastatic disease to the intracranial dura, the calvarium, and the skull base is relatively uncommon but presents unique diagnostic and management challenges in the patient with cancer. Modern imaging techniques have facilitated the detection of intracranial tumor deposits, leading to increased incidence. While dural and calvarial metastases often present with nonspecific symptoms, skull base metastases present with distinct clinical syndromes dependent on the local neurovascular structures affected. Intracranial dural metastases can often be confused with meningioma and pose a diagnostic challenge, as well as significant neurologic morbidity, especially in the setting of hemorrhage. Surgical intervention may be helpful in selected patients for symptomatic relief as well as survival benefit. Management paradigms need to take into account the relative risks, benefits, and likely outcomes for each possible modality of treatment. Surgical excision is useful in many patients and in combination with radiation therapy can provide significant palliation. While medical therapy is rarely an initial therapy in these entities, it may be of added benefit dependent on the underlying tumor histology and prior treatment history. Occasionally treatment with curative intent is justified.

Reirradiation of Skull Base Tumors With Advanced Highly Conformal Techniques

PURPOSE OF REVIEW

Skull base reirradiation is challenging due to complex anatomy, enrichment of treatment-resistant clonogens, and increased risk of severe treatment complications. Without local therapy, early mortality is certain and tumor progression can result in debilitating symptoms. Modern radiotherapy advancements, such as image-guided radiation therapy (IGRT), intensity-modulated radiation therapy (IMRT), particle therapy, and stereotactic radiation therapy (SRT), are attractive for skull base reirradiation.

RECENT FINDINGS

Although limited by their retrospective nature and heterogeneous patient populations, several studies have demonstrated that reirradiation with these highly conformal techniques is feasible. Compared to IMRT or particle therapy reirradiation, SRT reirradiation appears promising with lower toxicity and increased convenience. Here, we provide thorough explanations for each technology and summarize the most relevant and recent studies, with particular attention to efficacy and toxicity. Skull base reirradiation using these extremely conformal therapy techniques requires meticulous treatment planning and should be delivered by experienced teams.

Secondary Intracranial Tumors Following Radiotherapy for Pituitary Adenomas: A Systematic Review

Pituitary adenomas are often treated with radiotherapy for the management of tumor progression or recurrence. Despite the improvement in cure rates, patients treated by radiotherapy are at risk of development of secondary malignancies. We conducted a comprehensive literature review of the secondary intracranial tumors that occurred following radiotherapy to pituitary adenomas to obtain clinicopathological characteristics. The analysis included 48 neuroepithelial tumors, 37 meningiomas, and 52 sarcomas which were published between 1959–2017, although data is missing regarding overall survival and type of irradiation in a significant proportion of the reports. The average onset age for the pituitary adenoma was 37.2 ± 14.4 years and the average latency period before the diagnosis of the secondary tumor was 15.2 ± 8.7 years. Radiotherapy was administered in pituitary adenomas at an average dose of 52.0 ± 19.5 Gy. The distribution of pituitary adenomas according to their function was prolactinoma in 10 (7.2%) cases, acromegaly in 37 (27.0%) cases, Cushing disease in 4 (2.9%) cases, PRL+GH in 1 (0.7%) case, non-functioning adenoma in 57 (41.6%) cases. Irradiation technique delivered was lateral opposing field in 23 (16.7%) cases, 3 or 4 field technique in 27 (19.6%) cases, rotation technique in 10 (7.2%) cases, radio surgery in 6 (4.3%) cases. Most of the glioma or sarcoma had been generated after lateral opposing field or 3/4 field technique. Fibrosarcomas were predominant before 1979 (p < 0.0001). The median overall survival time for all neuroepithelial tumors was 11 months (95% confidence intervals (CI), 3–14). Patients with gliomas treated with radiotherapy exhibited a non-significant positive trend with longer overall survival. The median overall survival time for sarcoma cases was 6 months (95% CI, 1.5–9). The median survival time in patients with radiation and/or chemotherapy for sarcomas exhibited a non-significant positive trend with longer overall survival. In patients treated with radiotherapy for pituitary adenomas, the risk of secondary tumor incidence warrants a longer follow up period. Moreover, radiation and/or chemotherapy should be considered in cases of secondary glioma or sarcoma following radiotherapy to the pituitary adenomas.

Monte Carlo evaluation of tissue heterogeneities corrections in the treatment of head and neck cancer patients using stereotactic radiotherapy

The purpose of this study was to generate Monte Carlo computed dose distributions with the X-ray voxel Monte Carlo (XVMC) algorithm in the treatment of head and neck cancer patients using stereotactic radiotherapy (SRT) and compare to heterogeneity corrected pencil-beam (PB-hete) algorithm. This study includes 10 head and neck cancer patients who underwent SRT re-irradiation using heterogeneity corrected pencil-beam (PB-hete) algorithm for dose calculation. Prescription dose was 24-40 Gy in 3-5 fractions (treated 3-5 fractions per week) with at least 95% of the PTV volume receiving 100% of the prescription dose. A stereotactic head and neck localization box was attached to the base of the thermoplastic mask fixation for target localization. The gross tumor volume (GTV) and organs-at-risk (OARs) were contoured on the 3D CT images. The planning target volume (PTV) was generated from the GTV with 0 to 5 mm uniform expansion; PTV ranged from 10.2 to 64.3 cc (average = 35.0±17.5 cc). OARs were contoured on the 3D planning CT and consisted of spinal cord, brainstem, optic structures, parotids, and skin. In the BrainLab treatment planning system (TPS), clinically optimal SRT plans were generated using hybrid planning technique (combination of 3D conformal nonco-planar arcs and nonopposing static beams) for the Novalis-Tx linear accelerator consisting of high-definition multileaf collimators (HD-MLCs: 2.5 mm leaf width at isocenter) and 6 MV-SRS (1000 MU/min) beam. For the purposes of this study, treatment plans were recomputed using XVMC algorithm utilizing identical beam geometry, multileaf positions, and monitor units and compared to the corresponding clinical PB-hete plans. The Monte Carlo calculated dose distributions show small decreases (< 1.5%) in calculated dose for D99, Dmean, and Dmax of the PTV coverage between the two algorithms. However, the average target volume encompassed by the prescribed percent dose (Vp) was about 2.5% less with XVMC vs. PB-hete and ranged between -0.1 and 7.8%. The averages for D100 and D10 of the GTV were lower by about 2% and ranged between -0.8 and 3.1%. For the spinal cord, both the maximal dose difference and the dose to 0.35 cc of the structure were higher by an average of 4.2% (ranged 1.2 to -13.6%) and 1.4% (ranged 7.5 to -11.3%), respectively, with XVMC calculation. For the brainstem, the maximal dose dif-ferences and the dose to 0.5 cc of the structure were, on average, higher by 2.4% (ranged 6.4 to -8.0%) and 3.6% (ranged 6.4 to -9.0%), respectively. For the parotids, both the mean dose and the dose to 20 cc of parotids were higher by an average of 3% (ranged -0.2 to -5.9%) and 4% (ranged -0.2 to -8%), respectively, with XVMC calculation. For the optic apparatus, results from both algorithms were similar. However, the mean dose to skin was 3% higher (ranged 0 to -6%), on average, with XVMC compared to PB-hete, although the maximum dose to skin was 2% lower (ranged -5% to 15.5%). The results from our XVMC dose calculations for head and neck SRT patients indicate small to moderate underdosing of the tumor volume when compared to PB-hete calculation. However, Vp was up to 7.8% less for the lower-neck patient with XVMC. Critical structures, such as spinal cord, brainstem, or parotids, could potentially receive higher doses when using XVMC algorithm. Given the proximity to critical structures and the smaller volumes treated with SRT in the region of the head and neck, the differences between XVMC and PB-hete calculation methods may be of clinical interest.

Contemporary management of clival chordomas

PURPOSE OF REVIEW

Clival chordomas are rare malignant tumors associated with a poor prognosis. In this article, we review the current literature to identify a variety of strategies that provide guidelines toward the optimal management for this aggressive tumor.

RECENT FINDINGS

Molecular disease, particularly, the development of characterized chordoma cell lines, has become one of the new cornerstones for the histological diagnosis of chordomas and for the development of effective chemotherapeutic agents against this tumor. Brachyury, a transcription factor in notochord development, seems to provide an excellent diagnostic marker for chordoma and may also prove to be a valuable target for chordoma therapy. Aggressive cytoreductive surgery aiming for gross total resection with maintenance of key neurovascular structures, followed by proton beam or hadron radiation, provides the best local recurrence and overall survival rates.

SUMMARY

Clival chordomas are locally aggressive tumors that are challenging to treat because of their unique biology, proximity to key neurovascular structures and poor prognosis. Currently, chordomas are optimally managed with aggressive surgery, whilst preserving key structures, and postoperative radiation in a multidisciplinary setting with an experienced team. The advancement of molecular techniques offers exciting future diagnostic and therapeutic options in the management of chordomas.

Stereotactic ablative radiosurgery for locally advanced or recurrent skull base malignancies with prior external beam radiation therapy

PURPOSE

Stereotactic ablative radiotherapy (SABR) is an attractive modality to treat malignancies invading the skull base as it can deliver a highly conformal dose with minimal toxicity. However, variation exists in the prescribed dose and fractionation. The purpose of our study is to examine the local control, survival, and toxicities in SABR for the treatment of previously irradiated malignant skull base tumors.

MATERIALS AND METHODS

A total of 31 patients and 40 locally advanced or recurrent head and neck malignancies involving the skull base treated with a common SABR regimen, which delivers a radiation dose of 44 Gy in 5 fractions from January 1st, 2004 to December 31st, 2013, were retrospectively reviewed. The local control rate (LC), progression-free survival rate, overall survival (OS) rate, and toxicities were reported.

RESULTS

The median follow-up time of all patients was 11.4 months (range: 0.6-67.2 months). The median tumor volume was 27 cm(3) (range: 2.4-205 cm(3)). All patients received prior external beam radiation therapy with a median radiation dose of 64 Gy (range: 24-75.6 Gy) delivered in 12-42 fractions. Twenty patients had surgeries prior to SABR. Nineteen patients received chemotherapy. Specifically, eight patients received concurrent cetuximab (Erbitux™) with SABR. The median time-to-progression (TTP) was 3.3 months (range: 0-16.9 months). For the 29 patients (93.5%) who died, the median time from the end of first SABR to death was 10.3 months (range: 0.5-41.4 months). The estimated 1-year OS rate was 35%. The estimated 2-year OS rate was 12%. Treatment was well-tolerated without grade 4 or 5 treatment-related toxicities.

CONCLUSION

Stereotactic ablative radiotherapy has been shown to achieve low toxicities in locally advanced or recurrent, previously irradiated head and neck malignancies invading the skull base.

Calvarial and skull base metastases: expanding the clinical utility of Gamma Knife surgery

OBJECT

Traditionally, the treatment of choice for patients with metastases to the calvaria or skull base has been conventional radiation therapy. Because patients with systemic malignancies are also at risk for intracranial metastases, the utility of Gamma Knife surgery (GKS) for these patients has been explored to reduce excess radiation exposure to the perilesional brain parenchyma. The purpose of this study was to report the efficacy of GKS for the treatment of calvarial metastases and skull base lesions.

METHODS

The authors performed a retrospective chart review of 21 patients with at least 1 calvarial or skull base metastatic lesion treated with GKS during 2001-2013. For 7 calvarial lesions, a novel technique, in which a bolus was placed over the treatment site, was used. For determination of local control or disease progression, radiation therapy data were examined and posttreatment MR images and oncology records were reviewed. Survival times from the date of procedure were estimated by using Kaplan-Meier analyses.

RESULTS

The median patient age at treatment was 57 years (range 29-84 years). A total of 19 (90%) patients received treatment for single lesions, 1 patient received treatment for 3 lesions, and 1 patient received treatment for 4 lesions. The most common primary tumor was breast cancer (24% of patients). Per lesion, the median clinical and radiographic follow-up times were 10.3 months (range 0-71.9 months) and 7.1 months (range 0-61.3 months), respectively. Of the 26 lesions analyzed, 14 (54%) were located in calvarial bones and 12 (46%) were located in the skull base. The median lesion volume was 5.3 cm(3) (range 0.3-55.6 cm(3)), and the median prescription margin dose was 15 Gy (range 13-24 Gy). The median overall survival time for all patients was 35.9 months, and the 1-year local control rate was 88.9% (95% CI 74.4%-100%). Local control rates did not differ between lesions treated with the bolus technique and those treated with traditional methods or between calvarial lesions and skull base lesions (p > 0.05). Of the 3 patients for whom local treatment failed, 1 patient received no further treatment and 2 patients responded to salvage chemotherapy. Subsequent brain parenchymal metastases developed in 2 patients, who then underwent GKS.

CONCLUSIONS

GKS is an effective treatment modality for patients with metastases to the calvarial bones or skull base. For patients with superficial calvarial lesions, a novel approach with bolus application resulted in excellent rates of local control. GKS provides an effective therapeutic alternative to conventional radiation therapy and should be considered for patients at risk for calvarial metastases and brain parenchymal metastases.

Delayed cerebral radiation necrosis after neutron beam radiation of a parotid adenocarcinoma: a case report and review of the literature

Cerebral radiation necrosis (CRN) is a well described possible complication of radiation for treatment of intracranial pathology. However, CRN as sequelae of radiation to extracranial sites is rare. Neutron beam radiation is a highly potent form of radiotherapy that may be used to treat malignant tumors of the salivary glands. This report describes a patient who underwent neutron beam radiation for a parotid adenocarcinoma and who developed biopsy-confirmed temporal lobe radiation necrosis thirty months later. This represents the longest time interval described to date, from initial neutron radiation for extracranial pathology to development of CRN. Two other detailed case studies exist in the literature and are described in this report. These reports as well as our patient's case are reviewed, and additional recommendations are made to minimize the development of CRN after extracranial neutron beam radiation. Physicians should include the possible diagnosis of CRN in any patient with new neurologic signs or symptoms and a history of head and neck radiation that included planned fields extending to the base of the skull. Counseling of patients prior to neutron beam radiation should include potential neurologic complications associated with CRN and risks of treatment for CRN including neurosurgical intervention.

Treatment and Outcome of Patients with Skull Base Chordoma: A Meta-analysis

Objective Chordoma is a locally aggressive tumor. The aim of this study was to assess the efficacy of different surgical approaches and adjuvant radiation modalities used to treat these patients. Design Meta-analysis. Main Outcome Measures Overall survival (OS), disease-specific survival (DSS), and progression-free survival (PFS). Results The 5-year OS and PFS rates of the whole cohort (n = 467) were 86% and 65.7%, respectively. The 5-year DSS for patients who underwent open surgery and endoscopic surgery was 45% and 49%, respectively (p = 0.8); PFS was 94% and 79%, respectively (p = 0.11). The 5-year OS of patients treated with surgery followed by adjuvant radiotherapy was 90% compared with 70% of those treated by surgery alone (p = 0.24). Patients undergoing partial resection without adjuvant radiotherapy had a 5-year OS of 41% and a DSS of 45%, significantly lower than in the total-resection group (p = 0.0002 and p = 0.01, respectively). The complication rates were similar in the open and endoscopic groups. Conclusions Patients undergoing total resection have the best outcome; adjuvant radiation therapy improves the survival of patients undergoing partial resection. In view of the advantages of minimally invasive techniques, endoscopic surgery appears an appropriate surgical approach for this disease.

Fractionated stereotactic radiosurgery treatment results for skull base chordomas

Chordomas are uncommon neoplasms and there is still controversy regarding establishment of diagnosis and management. The aim of this study was to evaluate efficacy and toxicity of fractionated stereotactic radiosurgery (FSRS) in skull base chordomas. There were 4 female (36%) and 7 male (64%) patients. FSRS was delivered with CyberKnife (Accuray Inc., Sunnyvale, CA). The median tumor volume was 14.7 cc (range, 3.9-40.5 cc). The median marginal tumor dose was 30 Gy (range, 20-36 Gy) in a median 5 fractions (range, 3-5 fractions). The median follow-up time was 42 months (range, 17-63 months). At the time of analysis, 10 (91%) patients were alive and 1 (9%) had died due to tumor progression. Of 10 patients, 8 (73%) had stable disease and the remaining 2 (18%) had progressive disease. The actuarial overall survival (OS) after FSRS was 91% at two-years. Two patients developed radiation-induced brain necrosis as a complication in the 8th and 28th months of follow-up, respectively. Our results with robotic FSRS in skull base chordomas are promising for selected patients. However, due to the slow growth pattern of skull base chordomas, a longer follow-up is required to determine exact treatment results and late morbidity.

Surgical management of cranial base metastases

BACKGROUND

Cranial base metastases (CBM) are rare and have received limited attention in the medical literature. Questions remain regarding the role of surgery, if any, in the management of these tumors.

OBJECTIVE

To report surgical outcomes in a consecutive series of patients with CBM and to better define the role of surgery in their management.

METHODS

Twenty-seven patients with CBM underwent surgery between 1996 and 2009 at MD Anderson Cancer Center. A retrospective review of their prospectively collected data was performed after obtaining institutional review board approval. The median patient age was 52 years. The most common pathology was renal cell carcinoma (6 patients). Surgical indications were worsening neurological deficit, disfiguring mass, and the need for a diagnosis.

RESULTS

Gross total resection was achieved in 59% of the cases. The median survival was 11.4 months. The median progression-free survival was 5.8 months. A Karnofsky Performance Scale score less than 90, dural invasion, and brain invasion were associated with a shorter survival. Seven patients were neurologically intact preoperatively; all of them remained intact after surgery. Among all patients with preoperative neurological deficit, 11 remained stable, 7 improved, and 2 had worsening of their deficit postoperatively.

CONCLUSION

The goal of surgery for CBM is to provide symptom relief and to preserve functional status in well-selected cases. Patient selection is critical because the surgery is usually palliative, and only a minority of patients are surgical candidates. Radiation therapy remains the management option of choice for the majority of patients.

Skull base chordomas: clinical features, prognostic factors, and therapeutics

Chordomas of the skull base are one of the rarest intracranial malignancies that arise from ectopic remnants of embryonal notochod. The proximity of many chordomas to neurovascular structures makes gross total resection difficult, and the tendency for recurrence leads to the routine use of adjuvant postoperative radiation. Several surgical approaches are used ranging from extensive craniotomies to minimally invasive endonasal endoscopic approaches. In this review, the histopathology and epidemiology, imaging characteristics, surgical approaches, adjuvant therapies, prognostic factors, and molecular biology of chordomas are described.

Feasibility of proton beam therapy for chordoma and chondrosarcoma of the skull base

We explored the general feasibility of proton beam therapy for chordoma and chondrosarcoma of the skull base. Clinical records and treatment-planning data of patients with the pathological diagnosis of chordoma or chondrosarcoma were examined. Proton beam therapy was administered for gross tumor mass as well as microscopic residual disease after surgery. The prescribed dose was determined to maximize the coverage of the target and to not exceed predefined constraints for the organs at risk. Eight cases of chordoma and eight cases of chondrosarcoma were enrolled. The median tumor volume was 40 cm(3) (range, 7 to 546 cm(3)). The prescribed dose ranged from 50 to 70 Gy (relative biological effectiveness [RBE]), with a median of 63 Gy RBE. The median follow-up duration was 42 months (range 9 to 80 months). The overall survival rate was 100%, and the local control rate at 3 years of chordoma and chondrosarcoma were 100% and 86%. None of the patients developed radiation-induced optic neuropathy, brain stem injury, or other severe toxicity. Proton beam therapy is generally feasible for both chordoma and chondrosarcoma of the skull base, with excellent local control and survival rates.

Stereotactic body radiation therapy for locally recurrent, previously irradiated nonsquamous cell cancers of the head and neck

BACKGROUND

Stereotactic body radiotherapy (SBRT) has emerged as a promising salvage strategy for patients with recurrent, previously irradiated head and neck cancer; however, data are limited predominantly to squamous cell carcinomas. Herein, we report the efficacy of SBRT in recurrent, nonsquamous cell cancers of the head and neck (NSCHNs).

METHODS

In all, 34 patients with pathologically proven NSCHN were re-irradiated with SBRT to a median dose of 40 Gy in 5 fractions (interquartile range, 30-44 Gy). Toxicity and quality of life were followed prospectively.

RESULTS

Median follow-up was 10 months (absolute range, 0-55 months). The 6-month/1-year local control rate was 77/59%, with a 6-month/1-year overall survival of 76/59%. Local control was significantly improved for tumors <25 mL (p = .030). Acute/late grade 3 toxicity was 15/6%, with no grade 4-5 toxicity.

CONCLUSIONS

SBRT for previously irradiated, locally recurrent NSCHN provides promising local control, especially for tumors <25 mL, with minimal toxicity. The optimal dose for larger tumors remains to be defined.

Sellar and parasellar metastatic tumors

The sellar and parasellar (SPS) region is a complex area rich in vital neurovascular structures and as such may be the location of first manifestation of a systemic malignancy. Metastases to this region are rare; breast cancer is the most common source among those that metastasize to the SPS region. Ophthalmoplegia, headache, retroorbital or facial pain, diabetes insipidus, and visual field defects are the most commonly reported symptoms. Lack of specific clinical and radiological features renders SPS metastases difficult to differentiate from the other frequently encountered lesions in this area, especially when there is no known history of a primary disease. Currently accepted management is multimodality therapy that includes biopsy and/or palliative surgical resection, radiation, and chemotherapy. Although no significant survival benefits have been shown by the surgical series, surgical resection may improve quality of life. Here we review the relevant literature and present six illustrative cases from our own institution.

Cranial chondrosarcoma and recurrence

The literature regarding recurrences in patients with cranial chondrosarcoma is limited to small series performed at single institutions, raising the question if these data precisely reflect the true recurrence of this tumor for guiding the clinician in the management of these patients. An extensive systematic review of the English literature was performed. The patients were stratified according to treatment modality, treatment history, histological subtype, and histological grade, and the recurrence rates were analyzed. A total of 560 patients treated for cranial chondrosarcoma were included. Five-year recurrence rate among all patients was 22% with median follow-up of 60 months and median disease-free interval of 16 months. Tumor recurrence was more common in patients who only received surgery or had mesenchymal subtype tumors. Our systematic review closely reflects the actuarial recurrence rate and provides predictive factors in the recurrence of cranial chondrosarcoma.

The treatment outcome depending on the extent of resection in skull base and spinal chordomas

PURPOSE

The authors tried to assess the treatment outcomes depending on the extent of resection in axial chordomas and compare the outcome of two adjunctive therapies (external beam radiation therapy vs. stereotactic radiosurgery) following incomplete tumour resection in terms of local tumour control.

PATIENTS AND METHODS

We retrospectively reviewed 30 consecutive patients with chordoma involving skull base, sacrum and mobile spine between 1993 and 2008. Their initial treatments had different extent of resection. Wide resection was performed for 12 (40%), subtotal resection and adjunctive radiotherapy/radiosurgery for 12 (40%), while six patients (20%) were solely treated with radiotherapy/radiosurgery. For these three groups, overall and progression-free survival rate were compared.

RESULTS

The overall survival rate was 96% at 5 years and 67% at 10 years. Tumour progression-free survival (PFS) rates were 73% and 43% at 5 and 10 years, respectively. Local tumour progression was seen in 67% in all patients, 58% in wide resection group, 67% in subtotal resection plus radiotherapy/radiosurgery group, and 75% in radiotherapy/radiosurgery group; however, this was not statistically significant (P = 0.69). Neither the extent of resection nor tumour location significantly influenced overall and progression-free survival (P > 0.05). With regard to the type of radiotherapy, tumour progression occurred in all lesions treated with external photon beam radiation therapy (EBRT) but only 38% of lesions treated with stereotactic radiosurgery (SRS) (P = 0.003).

CONCLUSIONS

Adjunctive radiotherapy/radiosurgery following subtotal resection showed comparable local control and survival to wide resection. SRS offered superior local tumour control compared to EBRT.

Sarcoma of the sella after radiotherapy for pituitary adenoma

Secondary malignancies are infrequent sequelae of pituitary radiotherapy. The goal of the present case study is to analyze clinical features of a selected group of cases to define the special characteristics of these tumors. We report the illustrative case of a 38-year-old man with acromegaly who had transsphenoidal surgery and radiotherapy 7 years before presenting with a sellar high-grade sarcoma. Transsphenoidal and transcranial resection, as well as repeated gamma knife radiosurgery, could not prevent tumor progression and development of meningiosis sarcomatosa. We performed a thorough search of the literature and reviewed numerous publications and reports on primary and secondary sarcomas of the sella. Our search revealed 51 cases of mesenchymal malignancies after sellar radiotherapy. For further analysis, we identified and selected a group of patients based on the criteria for studying radiation-induced tumors as described by Cahan.Compared to the surgically treated group, secondary sarcomas of the sella are more frequent in patients who have had radiotherapy. These tumors occur at normal dose schedules with long latencies. Their growth is very aggressive and they may develop meningiosis sarcomatosa. Until now, no treatment modalities have been able to stop the progression of these neoplasms. Radiation-induced sarcoma is a rare sequela of pituitary radiotherapy. It is important for the treating physician to keep in mind the possibility of post-radiation sarcoma development. Additionally, one must include these tumors into the differential diagnosis in pituitary patients presenting with tumor recurrence more than 5 years after radiotherapy in combination with a secondary lack of hormonal activity.

A systematic review of proton therapy in the treatment of chondrosarcoma of the skull base

Chondrosarcoma (CSA) of the skull base (SB) is an uncommon, slowly growing, neoplasm comprising approximately 0.1% of all intracranial tumors and 6% of SB lesions. Even though its growth is slow, CSA is a potentially lethal tumor. The therapeutic approach to CSA of the SB is still controversial and clinical experience is limited because of the relative rarity of this tumor. The use of proton therapy (PT) after maximal surgery is widely accepted, but there are no controlled studies demonstrating the need of PT and its superiority in comparison to radiotherapy with photons. We conducted a systematic review of the scientific literature published during the period between January 1980 and June 2008 on data regarding irradiation of CSA of the SB with PT and a series of inclusion criteria. During August 2008, two independent reviewers (M.A. and D.A.), by applying the key words "skull base", "chondrosarcoma", and "proton therapy" selected those studies from the PubMed database in which a minimum of ten patients received palliative, radical, or postoperative irradiation with protons and which furnished a minimum of 24 months of follow-up. Forty nine reports were retrieved. There were no prospective trials (randomized or nonrandomized) but just nine uncontrolled single-arm studies for PT mainly related to advanced and frequently incompletely resected tumors. According to the inclusion criteria, only four articles, reporting the most recent updated results of the publishing institution, were included in the analysis providing clinical outcomes for 254 patients in total. Therapeutic approach to CSA of the SB has traditionally relied on surgical control. Radiation therapy has demonstrated to be a valuable modality for local control in the postoperative setting or in advanced/inoperable cases treated with definitive intent. The use of PT following maximal surgical resection shows a very high probability of medium- and long-term cure with a relatively low risk of significant complications.

Endoscopic endonasal transclival resection of chordomas: operative technique, clinical outcome, and review of the literature

OBJECT

Transcranial approaches to clival chordomas provide a circuitous route to the site of origin of the tumor often involving extensive bone drilling and brain retraction, which places critical neurovascular structures between the surgeon and pathology. For certain chordomas, the endonasal endoscopic transclival approach is a novel minimal access, but it is an equally aggressive alternative providing the most direct route to the tumor epicenter.

METHODS

The authors present a consecutive series of patients undergoing endonasal endoscopic resection of clival chordomas. Extent of resection was determined by postoperative volumetric MR imaging and divided into > 95% and < 95%.

RESULTS

Seven patients underwent 10 operations. Preoperative cranial neuropathies were present in 4. The mean patient age was 52.0 years. The mean tumor volume was 34.9 cm3. Intraoperative lumbar drainage was used in 1 patient, and the tumors extended intradurally in 3. One patient underwent 2 intentionally palliative procedures for subtotal debulking. Greater than 95% resection was achieved in 7 of 8 operations in which radical resection was the goal (87%). All tumors with volumes < 50 cm3 had > 95% resection (p = 0.05). The overall mean follow-up was 18.0 months. Cranial neuropathies resolved in all 3 patients with cranial nerve VI palsies. One patient with recurrent nasopharyngeal chordoma died of disease progression; another experienced 2 recurrences before receiving radiation therapy. All surviving patients remain progression free. There were no intraoperative complications; however, 1 patient developed a pulmonary embolus postoperatively. There were no postoperative CSF leaks.

CONCLUSIONS

The endonasal endoscopic transclival approach represents a less invasive and more direct approach than a transcranial approach to treat certain moderate-sized midline skull base chordomas. Longer follow-up is necessary to determine comparability to transcranial approaches for long-term control. Large tumors with significant extension lateral to the carotid artery may not be suitable for this approach.

Stereotactic radiotherapy using Novalis for skull base metastases developing with cranial nerve symptoms

Skull base metastases are challenging situations because they often involve critical structures such as cranial nerves. We evaluated the role of stereotactic radiotherapy (SRT) which can give high doses to the tumors sparing normal structures. We treated 11 cases of skull base metastases from other visceral carcinomas. They had neurological symptoms due to cranial nerve involvement including optic nerve (3 patients), oculomotor (3), trigeminal (6), abducens (1), facial (4), acoustic (1), and lower cranial nerves (1). The interval between the onset of cranial nerve symptoms and Novalis SRT was 1 week to 7 months. Eleven tumors of 8-112 ml in volume were treated by Novalis SRT with 30-50 Gy in 10-14 fractions. The tumors were covered by 90-95% isodose. Imaging and clinical follow-up has been obtained in all 11 patients for 5-36 months after SRT. Seven patients among 11 died from primary carcinoma or other visceral metastases 9-36 months after Novalis SRT. All 11 metastatic tumors were locally controlled until the end of the follow-up time or patient death, though retreatment for re-growth was done in 1 patient. In 10 of 11 patients, cranial nerve deficits were improved completely or partially. In some patients, the cranial nerve symptoms were relieved even during the period of fractionated SRT. Novalis SRT is thought to be safe and effective treatment for skull base metastases with involvement of cranial nerves and it may improve cranial nerve symptoms quickly.

Long-term control of clival chordoma with initial aggressive surgical resection and gamma knife radiosurgery for recurrence

PURPOSE

Chordomas are locally destructive tumors with high rates of recurrence, and therapeutic strategies remain controversial. This study analyzed long-term outcomes for clival chordomas after initial aggressive surgical resection and gamma knife radiosurgery for recurrence and investigated clinical factors predicting recurrence.

METHODS

Clinical records were reviewed for 19 consecutive patients (11 men, 8 women; mean age, 43.1 years) with clival chordoma who underwent initial surgical resection using skull base approaches (mean follow-up after surgical resection, 87.2 months). All tumors were aggressively removed, along with the surrounding bone. Four patients were treated with radiotherapy after surgical resection.Recurrent lesions were treated with gamma knife radio surgery or reoperation. Factors predicting tumor recurrence were analyzed, including age, tumor extension, extent of resection and MIB-1 labeling index. Patient status was evaluated using the Karnofsky performance scale (KPS).

RESULTS

Tumor resection was total, subtotal and partial in 14, 4 and 1 patients, respectively. Tumors recurred in 11 patients. Overall, 2- and 5-year progression-free survival rates were 77.9% and 47.9%, respectively. The MIB-1 labeling index was independently associated with recurrence.The optimum cutoff point for the MIB-1 labeling index was 3.44%. All recurrent tumors were totally resected or controlled by gamma knife (mean follow-up after recurrence, 71.2 months). All patients survived and were active (mean KPS at final follow-up, 89.5%).

CONCLUSION

Long-term control of clival chordomas was achieved. Recurrent tumors were controlled with gamma knife radiosurgery, since lesions were localized and small after initial aggressive resection. The MIB-1 labeling index can provide important information for predicting tumor recurrence.

A systematic review of intracranial chondrosarcoma and survival

Most data regarding survival in patients with chondrosarcoma are limited to case studies and small series performed at single institutions. A systematic review was performed to study the relationship between potential prognostic factors and survival. The survival rates were analyzed according to modality of treatment, treatment history, histological subtype, and histological grade. A total of 560 patients with intracranial chondrosarcoma were analyzed. Median follow-up time was 60 months. The 5-year mortality among all patients was 11.5% with median survival of 24 months. Mortality at 5 years was significantly greater for patients with tumors of higher grade, or of the mesenchymal subtype, or who had received surgical resection alone. The results of our systematic review provide useful data in predicting survival among intracranial chondrosarcoma patients.

Comparison of single versus fractionated dose of stereotactic radiotherapy for salvaging local failures of nasopharyngeal carcinoma: a matched-cohort analysis

BACKGROUND

Local failure is an important cause of morbidity and mortality in nasopharyngeal carcinoma (NPC). Although surgery or brachytherapy may be feasible in selected cases, most patients with local failure require external beam re-irradiation. Stereotactic radiation using single or multiple fractions have been employed in re-irradiation of NPC, but the optimal fractionation scheme and dose are not clear.

METHODS

Records of 125 NPC patients who received salvage stereotactic radiation were reviewed. A matched-pair design was used to select patients with similar prognostic factors who received stereotactic re-irradiation using single fraction (SRS) or multiple fractions (SRM). Eighty-six patients were selected with equal number in SRS and SRM groups. All patients were individually matched for failure type (persistent or recurrent), rT stage (rT1-2 or rT3-4), and tumor volume (< or = 5 cc, >5-10 cc, or >10 cc). Median dose was 12.5 Gy in single fraction by SRS, and 34 Gy in 2-6 fractions by SRM.

RESULTS

Local control rate was better in SRM group although overall survival rates were similar. One- and 3-year local failure-free rates were 70% and 51% in SRS group compared with 91% and 83% in SRM group (p = 0.003). One- and 3-year overall survival rates were 98% and 66% in SRS group compared with 78% and 61% in SRM group (p = 0.31). The differences in local control were mainly observed in recurrent or rT2-4 disease. Incidence of severe late complications was 33% in SRS group vs. 21% in SRM group, including brain necrosis (16% vs. 12%) and hemorrhage (5% vs. 2%).

CONCLUSION

Our study showed that SRM was superior to SRS in salvaging local failures of NPC, especially in the treatment of recurrent and rT2-4 disease. In patient with local failure of NPC suitable for stereotactic re-irradiation, use of fractionated treatment is preferred.

Treatment of malignant tumors of the skull base with multi-session radiosurgery

OBJECTIVE

Malignant tumors that involve the skull base pose significant challenges to the clinician because of the proximity of critical neurovascular structures and limited effectiveness of surgical resection without major morbidity. The purpose of this study was to evaluate the efficacy and safety of multi-session radiosurgery in patients with malignancies of the skull base.

METHODS

Clinical and radiographic data for 37 patients treated with image-guided, multi-session radiosurgery between January 2002 and December 2007 were reviewed retrospectively. Lesions were classified according to involvement with the bones of the base of the skull and proximity to the cranial nerves.

RESULTS

Our cohort consisted of 37 patients. Six patients with follow-up periods less than four weeks were eliminated from statistical consideration, thus leaving the data from 31 patients to be analyzed. The median follow-up was 37 weeks. Ten patients (32%) were alive at the end of the follow-up period. At last follow-up, or the time of death from systemic disease, tumor regression or stable local disease was observed in 23 lesions, representing an overall tumor control rate of 74%. For the remainder of lesions, the median time to progression was 24 weeks. The median progression-free survival was 230 weeks. The median overall survival was 39 weeks. In the absence of tumor progression, there were no cranial nerve, brainstem or vascular complications referable specifically to CyberKnife radiosurgery.

CONCLUSION

Our experience suggests that multi-session radiosurgery for the treatment of malignant skull base tumors is comparable to other radiosurgical techniques in progression-free survival, local tumor control, and adverse effects.

Stereotactic body radiation therapy for primary, recurrent, and metastatic tumors in the head-and-neck region

PURPOSE

To determine the feasibility, safety, and efficacy of stereotactic body radiation therapy (SBRT), also known as radiosurgery, in patients with head-and-neck cancers.

METHODS AND MATERIALS

Patients with pathologically proven malignant lesions in the head-and-neck region were treated using single-dose SBRT (S-SBRT) or fractionated SBRT (F-SBRT). Radiation doses were either single-fraction 13-18 Gy for S-SBRT or 36-48 Gy in five to eight fractions for F-SBRT. Response evaluation was based on clinical examinations and computed tomography/magnetic resonance imaging scans. Pre- and post-SBRT tumor dimensions were measured in three axes, and tumor volumes were calculated. Response evaluation also was performed using World Health Organization criteria.

RESULTS

Fifty-five lesions were treated in 44 patients (25 men, 19 women). There were three groups of patients: those with primary (n = 10), recurrent (n = 21), and metastatic tumors (n = 13). The predominant histologic type was squamous cell carcinoma (n = 33). The majority of lesions were treated using F-SBRT (n = 37). Based on radiographic and clinical assessment, a 77% (complete + partial response) response rate was noted. Percentage of reduction in tumor volume was 52% +/- 38% based on follow-up scans in 24 patients. Tumor control rates at 1 year were 83.3% and 60.6% in the primary and recurrent groups, respectively. Median overall survival was 28.7, 6.7, and 5.6 months for the primary, recurrent, and metastatic groups, respectively. Radiation Therapy Oncology Group Grade 1-2 mucositis was noted in all patients treated for oropharyngeal or laryngeal lesions.

CONCLUSIONS

The SBRT in single or fractionated doses offers a viable treatment option for selected patients with primary, recurrent, and metastatic head-and-neck cancers with functional preservation.

Proton therapy in chordoma of the base of the skull: a systematic review

Chordoma is a rare, slow-growing, locally aggressive, primary bone tumor that arises from the skull base region in approximately 25-35% of cases. The therapeutic approach to chordoma has traditionally been surgery, followed by radiation therapy. The advent of charged particle radiotherapy has let us consider protons as the postoperative treatment of choice, but no controlled studies have yet confirmed the superiority of protons over photons. During January 2008, two independent researchers conducted a systematic review of the current data on the treatment of base of the skull chordoma C with proton therapy (PT) and, for comparison, with other irradiation techniques (conventional radiation therapy, ion therapy, fractionated stereotactic radiation therapy, and radiosurgery). Two hundred and ten reports in total were retrieved (81 concerning PT). According to the inclusion criteria, 47 articles were considered in the analysis. There were no prospective trials (randomized or nonrandomized) but just seven uncontrolled single-arm studies for PT, providing clinical outcomes for 416 patients in total; these reports were mainly related to advanced inoperable or incompletely resected tumors. The therapeutic approach to chordoma of the base of the skull has traditionally relied on surgical control. Radiation therapy has demonstrated to be a valuable modality for local control in the postoperative setting, particularly with the advent of charged particle radiotherapy. The use of protons has shown better results in comparison to the use of conventional photon irradiation, resulting in the best long-term (10 years) outcome for this tumor with relatively few significant complications considering the high doses delivered with this therapeutic modality.

Cerebrospinal fluid leakage after gamma knife radiosurgery for skull base metastasis from renal cell carcinoma: a case report

We report a rare case of cerebrospinal fluid (CSF) leakage after radiosurgery for skull base metastasis from renal cell carcinoma. A mass invading the left petrous bone and sphenoid sinus was treated with gamma knife radiosurgery, and CSF rhinorrhea developed 4 months after the procedure. The CSF leak was successfully controlled by endoscopic sinus surgery. CSF leakage may develop as a rare complication after radiosurgery for skull base lesions, and the endoscopic repair technique is a useful therapeutic method.

Neuronavigation using an image-guided endoscopic transnasal-sphenoethmoidal approach to clival chordomas

OBJECTIVE

Surgical approaches described for resection of clival tumors have been complicated, extensive, traumatic, and invasive. They are also associated with significant mortality and morbidity rates. We describe a minimally invasive, endoscopic transsphenoidal surgical treatment for clival tumors.

METHODS

Three men, aged 43, 46, and 66 years, each presented with a history of headaches, diplopia, and multiple cranial nerve deficits. All preoperative magnetic resonance imaging scans showed large clival tumors. A neuronavigational image-guided endoscopic transnasal-sphenoethmoidal approach was performed to resect the clival tumors.

RESULTS

All three patients had near-total removal of clival tumors using this method, and the histology revealed chordomas. They underwent postoperative adjuvant radiotherapy. No complications were encountered. All patients were able to resume their usual activities on the same day after surgery. Furthermore, this technique greatly reduced patient discomfort, hastened recovery, and shortened the hospital stay.

CONCLUSION

The neuronavigation image-guided transsphenoidal approach is a viable, minimally invasive alternative for surgical treatment of clival tumors.

Endonasal microscopic removal of clival chordomas

INTRODUCTION

Clival chordomas have traditionally been removed using a variety of anterior and lateral skull base approaches. Herein, we evaluate the outcomes of patients who underwent an extended endonasal transsphenoidal removal of a clival chordoma.

METHOD

All consecutive patients with a clival chordoma treated using an endonasal microscope approach were identified. In 8 cases, frameless surgical navigation was used, and in 4 cases, endoscopic assistance was used. Patients treated with prior radiotherapy were excluded.

RESULT

Over 5 years, 18 procedures were performed on 14 patients (7 females; mean age, 47 years). Patients were followed from 3 to 58 months (median, 20 months). Mean tumor diameter was 32 +/- 17 mm; 7 (50%) patients had intradural extension. Postoperative MRIs after the initial operation showed gross total, near-total (>90%), and subtotal resection in 43%, 43%, and 14% of patients, respectively. Use of the endoscope was associated with gross total or near-total tumor removal in 4 of 4 cases. Tumor regrowth occurred in 2 (14%) cases 10 and 12 months after the initial surgery and before radiotherapy. Two patients had multiple operations, in one as a planned staged operation, and in the other, 3 additional debulkings were performed despite an initial gross total removal. Nine patients, all with CS invasion, had subsequent stereotactic radiation. Of 10 patients with cranial neuropathy, 80% improved or resolved including 75% and 67% of sixth and fifth CN palsies, respectively. Complications included one each of adrenal insufficiency and chemical meningitis. There were no CSF leaks or new neurological deficits.

CONCLUSION

In this small series with relatively short follow-up, endonasal microscopic removal of clival chordomas proved safe and elfective with gross total or near-total removal in 86% of patients and improvement of cranial neuropathy in 80% of patients. Endoscopy for aiding tumor removal and assessing completeness of resection, as well as surgical navigation, are recommended for all cases.

Combination of microsurgery and Gamma Knife surgery for the treatment of intracranial chondrosarcomas

Object

Intracranial chondrosarcomas have a high risk of recurrence after surgery. This retrospective study of patients with intracranial chondrosarcoma was conducted to determine the long-term results of microsurgery followed by Gamma Knife surgery (GKS) for residual tumor or recurrence.

Methods

The authors treated nine patients whose median age was 36 years. Seven patients had low-grade chondrosarcomas (LGCSs), whereas mesenchymal chondrosarcomas (MCSs) were diagnosed in two. Radiosurgery was performed in eight patients, whereas one patient declined further surgical intervention and tumor-volume reduction necessary for the GKS.

The patients were followed up for 15 to 173 months (median 108 months) after diagnosis and 3 to 166 months (median 88 months) after GKS. Seven patients had residual tumor tissue after microsurgery, and two operations appeared radical. In the two latter cases, tumors recurred after 25 and 45 months. Thus, definite tumor control was not achieved after surgery alone in any patient, whereas the addition of radiosurgery allowed tumor control in all six patients with LGCSs. Two of these patients experienced an initial tumor regrowth after GKS; in both cases the recurrences were outside the prescribed radiation field. The patients underwent repeated GKS, and subsequent tumor control was observed. An MCS was diagnosed in the remaining two patients. Complications after microsurgery included diplopia, facial numbness, and paresis. After GKS, one patient had radiation necrosis, which required microsurgery, and two patients had new cranial nerve palsies.

Conclusions

Tumor control after microsurgery alone was not achieved in any patient, whereas adjuvant radiosurgery provided local tumor control in six of eight GKS-treated patients. Tumor control was not achieved in the two patients with MCS. Similar to other treatments for intracranial chondrosarcoma, morbidity after micro- and radiosurgical combination therapy was high and included severe cranial nerve palsies.

Recent Advances in Radiation Therapy for Head and Neck Cancer

The treatment of locally advanced or recurrent head and neck cancers has improved from single modality interventions of surgery and radiation therapy alone to include combined modality therapy with surgery, chemotherapy and radiation. Combined therapy has led to improved local control and disease-free survival. New developments in radiation oncology such as altered fractionation, three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, stereotactic radiosurgery, fractionated stereotactic radiotherapy, charged-particle radiotherapy, neutron-beam radiotherapy, and brachytherapy have helped to improve this outlook even further. These recent advances allow for a higher dose to be delivered to the tumor while minimizing the dose delivered to the surrounding normal tissue. This article provides an update of the new developments in radiotherapy in the management of head and neck cancers.

Predictive factors of tumor control and survival after radiosurgery for local failures of nasopharyngeal carcinoma

BACKGROUND

Stereotactic radiosurgery has been employed as a salvage treatment of local failures of nasopharyngeal carcinoma (NPC). To identify patients that would benefit from radiosurgery, we reviewed our data with emphasis on factors that predicted treatment outcome.

PATIENTS AND METHODS

A total of 48 patients with local failures of NPC were treated by stereotactic radiosurgery between March 1996 and February 2005. Radiosurgery was administered using a modified linear accelerator with single or multiple isocenters to deliver a median dose of 12.5 Gy to the target periphery. Median follow-up was 54 months.

RESULTS

Five-year local failure-free probability after radiosurgery was 47.2% and 5-year overall survival rate was 46.9%. Neuroendocrine complications occurred in 27% of patients but there were no treatment-related deaths. Time interval from primary radiotherapy, retreatment T stage, prior local failures and tumor volume were significant predictive factors of local control and/or survival whereas age was of marginal significance in predicting survival. A radiosurgery prognostic scoring system was designed based on these predictive factors. Five-year local failure-free probabilities in patients with good, intermediate and poor prognostic scores were 100%, 42.5%, and 9.6%. The corresponding five-year overall survival rates were 100%, 51.1%, and 0%.

CONCLUSION

Important factors that predicted tumor control and survival after radiosurgery were identified. Patients with good prognostic score should be treated by radiosurgery in view of the excellent results. Patients with intermediate prognostic score may also be treated by radiosurgery but those with poor prognostic score should receive other salvage treatments.

Stereotactic radiosurgery as a salvage treatment for recurrent epipharyngeal carcinoma

Fourteen patients with recurrent epipharyngeal carcinoma (EPC) were treated by gamma knife stereotactic radiosurgery. The tumor volume ranged from 0.3 to 80 ml (median 18.9 ml). Treatment was done with a tumor margin dose of 10-27 Gy (median 15 Gy). The median follow-up period was 15 months (range 2-47 months). Ten patients were alive and 4 were dead at the end of the follow-up period. In 6 patients (43%), the tumor disappeared or decreased in size until the end of the follow-up period. In 2 (14%), the tumor remained unchanged in size. In 6 (43%), the tumor showed regression initially but was enlarged later. A second radiosurgery was performed in 4 of those 6 cases and the tumor decreased in size again in 3 of them. Thus, the overall control rate of local tumor was 79% (11/14). In selected patients with recurrent EPC, stereotactic radiosurgery can be considered as a salvage treatment producing local control.

Stereotactic radiosurgery as a salvage treatment for recurrent skull base adenoid cystic carcinoma

Twelve patients (15 lesions) with recurrent skull base adenoid cystic carcinoma (ACC) were treated by Gamma Knife stereotactic radiosurgery (SRS). The tumor volume ranged from 2 to 103 ml (median 15 ml). Treatment was prescribed at the 40-60% isodose line and ranged from 10 to 18 Gy (median: 13.0 Gy). The median follow-up period was 18 months (range 3-55). Six patients were alive and 6 dead at the end of the follow-up period. Only 1 patient died from local tumor recurrence. Ten among 15 tumors treated by SRS decreased in size until the end of the follow-up period or the patients' death. Three remained unchanged in size. Two tumors initially regressed but then increased in size. In selected patients with recurrent skull base ACC, SRS can be considered as a salvage treatment with good local control.

Skull-base metastases

Metastasis to the skull-base particularly affects patients with carcinoma of the breast and prostate. Clinically, the key feature is progressive ipsilateral involvement of cranial nerves. Five syndromes have been described according to the metastatic site including the orbital, parasellar, middle-fossa, jugular foramen and occipital condyle syndromes. Magnetic resonance imaging (MRI) is nowadays the most useful examination to establish the diagnosis but plain films, CT scans with bone windows and isotope bone scans remain helpful to demonstrate bone erosion. Normal imaging studies do not exclude the diagnosis. The treatment depends on the nature of the underlying tumor. Radiotherapy is generally the standard treatment, while some patients with chemosensitive or hormonosensitive lesions benefit from chemotherapy or hormonotherapy and selected patients from surgical removal. Gamma Knife radiosurgery is sometimes a useful alternative, particularly for previously irradiated skull-base regions, and for small tumors (diameter < 30 mm). The overall prognosis is poor, with an overall median survival of about 2.5 years, probably because skull-base metastases appear late in the course of the disease.