Feasibility of delivering grid therapy using a multileaf collimator

The feasibility of using a multileaf collimator (MLC) for grid therapy is demonstrated in this study. Grids with the projected field openings of 10 mm x 10 mm and 5 mm x 5 mm were created using multiple MLC-shaped fields. The deposited doses were measured with films at different depths in a solid water phantom and compared to those of Cerrobend grid collimators of similar hole sizes and hole separations. At the depth of maximum dose (dmax), the valley-to-peak dose ratios of the MLC grids were found to be about 11% and 19% for the respective 10 mm x 10 mm and 5 mm X 5 mm grid openings, and those of the corresponding grid blocks were about 15% and 20%. To quantify the dose contributed by transmission in the blocked areas due to the limited leaf thickness, Monte Carlo simulations (based on convolution/superposition method) were performed to calculate the doses in the solid water phantom using an ideal MLC with no leakage and perfect divergence in both the leaf end and side. About 7% reduction in the valley-to-peak dose ratio was found for both grid sizes at dmax. The results clearly showed that MLCs can be used to provide grid treatments with at least as good dosimetric properties as those of the Cerrobend grid blocks, though the former would in general require a longer delivery time.

Comparative analyses of linac and Gamma Knife radiosurgery for trigeminal neuralgia treatments

Dedicated linac-based radiosurgery has been reported for trigeminal neuralgia treatments. In this study, we investigated the dose fall-off characteristics and setup error tolerance of linac-based radiosurgery as compared with standard Gamma Knife radiosurgery. In order to minimize the errors from different treatment planning calculations, consistent imaging registration, dose calculation and dose volume analysis methods were developed and implemented for both Gamma Knife and linac-based treatments. Intra-arc setup errors were incorporated into the treatment planning process of linac-based deliveries. The effects of intra-arc setup errors with increasing number of arcs were studied and benchmarked against Gamma Knife deliveries with and without plugging patterns. Our studies found equivalent dose fall-off properties between Gamma Knife and linac-based radiosurgery given a sufficient number of arcs (>7) and small intra-arc errors (<0.5 mm) were satisfied for linac-based deliveries. Increasing the number of arcs significantly decreased the variations in the dose fall-off curve at the low isodose region (e.g. from 40% to 10%) and also improved dose uniformity at the high isodose region (e.g. from 70% to 90%). As the number of arcs increased, the effects of intra-arc setup errors on the dose fall-off curves decreased. Increasing the number of arcs also reduced the integral dose to the distal normal brain tissues. In conclusion, linac-based radiosurgery produces equivalent dose fall-off characteristics to Gamma Knife radiosurgery with a high number of arcs. However, one must note the increased treatment time for a large number of arcs and isocentre accuracies.

Concomitant GRID boost for Gamma Knife radiosurgery

We developed an integrated GRID boost technique for Gamma Knife radiosurgery. The technique generates an array of high dose spots within the target volume via a grid of 4-mm shots. These high dose areas were placed over a conventional Gamma Knife plan where a peripheral dose covers the full target volume. The beam weights of the 4-mm shots were optimized iteratively to maximize the integral dose inside the target volume. To investigate the target volume coverage and the dose to the adjacent normal brain tissue for the technique, we compared the GRID boosted treatment plans with conventional Gamma Knife treatment plans using physical and biological indices such as dose-volume histogram (DVH), DVH-derived indices, equivalent uniform dose (EUD), tumor control probabilities (TCP), and normal tissue complication probabilities (NTCP). We found significant increase in the target volume indices such as mean dose (5%-34%; average 14%), TCP (4%-45%; average 21%), and EUD (2%-22%; average 11%) for the GRID boost technique. No significant change in the peripheral dose coverage for the target volume was found per RTOG protocol. In addition, the EUD and the NTCP for the normal brain adjacent to the target (i.e., the near region) were decreased for the GRID boost technique. In conclusion, we demonstrated a new technique for Gamma Knife radiosurgery that can escalate the dose to the target while sparing the adjacent normal brain tissue.

Long-term results of hyperfractionated radiation and high-dose intraarterial cisplatin for unresectable oropharyngeal carcinoma

BACKGROUND

In this report, the authors present the results from a study of patients with unresectable oropharyngeal squamous cell carcinomas who were treated on a protocol of hyperfractionated radiation and high-dose intraarterial cisplatin (HYPERRADPLAT) at the University of Kentucky.

METHODS

The study was designed as a prospective, single-armed case series that was conducted in the setting of a single, academic, tertiary referral center. The patient cohort consisted of 24 previously untreated patients who were diagnosed with unresectable oropharyngeal carcinoma and were treated on the HYPERRADPLAT regimen, which included hyperfractionated external beam radiotherapy (1.2 grays [Gy] twice daily) was given for 5 weeks (60 Gy) followed by high-dose intraarterial cisplatin (150 mg/m2) and sodium thiosulfate. Shrinking "large-field" portals were started on Week 6 and finished on Week 7 with a cumulative dose of 76.8-81.6 Gy. The main outcome measures of the study were the primary and neck response rates, the 2-year and 5-year overall survival and disease-specific survival rates, and acute and late treatment morbidity.

RESULTS

The median follow-up was 77 months. Complete response rates at the primary and regional lymph nodes were both 88%. The 2-year overall survival and disease-specific survival rates were 57% and 68%, respectively; whereas the 5-year overall survival and disease-specific survival rates were 33% and 42%, respectively. Two patients had Grade 4 mucosal toxicity, and no patient experienced neurologic or significant hematologic toxicities. Within 1 year of treatment, 58% of patients had used a feeding tube.

CONCLUSIONS

The HYPERRADPLAT regimen produced excellent response rates and overall survival rates comparable to those achieved by patients who had unresectable oropharyngeal carcinomas. Tolerance of the therapy was good, and further studies using HYPERRADPLAT with induction therapy may improve outcomes further in this subset of patients with unfavorable disease.

Direct decompressive surgical resection in the treatment of spinal cord compression caused by metastatic cancer: a randomised trial

BACKGROUND

The standard treatment for spinal cord compression caused by metastatic cancer is corticosteroids and radiotherapy. The role of surgery has not been established. We assessed the efficacy of direct decompressive surgery.

METHODS

In this randomised, multi-institutional, non-blinded trial, we randomly assigned patients with spinal cord compression caused by metastatic cancer to either surgery followed by radiotherapy (n=50) or radiotherapy alone (n=51). Radiotherapy for both treatment groups was given in ten 3 Gy fractions. The primary endpoint was the ability to walk. Secondary endpoints were urinary continence, muscle strength and functional status, the need for corticosteroids and opioid analgesics, and survival time. All analyses were by intention to treat.

FINDINGS

After an interim analysis the study was stopped because the criterion of a predetermined early stopping rule was met. Thus, 123 patients were assessed for eligibility before the study closed and 101 were randomised. Significantly more patients in the surgery group (42/50, 84%) than in the radiotherapy group (29/51, 57%) were able to walk after treatment (odds ratio 6.2 [95% CI 2.0-19.8] p=0.001). Patients treated with surgery also retained the ability to walk significantly longer than did those with radiotherapy alone (median 122 days vs 13 days, p=0.003). 32 patients entered the study unable to walk; significantly more patients in the surgery group regained the ability to walk than patients in the radiation group (10/16 [62%] vs 3/16 [19%], p=0.01). The need for corticosteroids and opioid analgesics was significantly reduced in the surgical group.

INTERPRETATION

Direct decompressive surgery plus postoperative radiotherapy is superior to treatment with radiotherapy alone for patients with spinal cord compression caused by metastatic cancer.

A phase I trial of the dual farnesyltransferase and geranylgeranyltransferase inhibitor L-778,123 and radiotherapy for locally advanced pancreatic cancer

PURPOSE

Preclinical and clinical studies have demonstrated that inhibition of prenylation can radiosensitize cell lines with activation of Ras and produce clinical response in patients with cancer. The aim of this study was to determine the maximally tolerated dose of the dual farnesyltransferase and geranylgeranyltransferase I inhibitor L-778,123 in combination with radiotherapy for patients with locally advanced pancreatic cancer.

EXPERIMENTAL DESIGN

L-778,123 was given by continuous intravenous infusion with concomitant radiotherapy to 59.4 Gy in standard fractions. Two L-778,123 dose levels were tested: 280 mg/m2/day over weeks 1, 2, 4, and 5 for dose level 1; and 560 mg/m2/day over weeks 1, 2, 4, 5, and 7 for dose level 2.

RESULTS

There were no dose-limiting toxicities observed in the eight patients treated on dose level 1. Two of the four patients on dose level 2 experienced dose-limiting toxicities consisting of grade 3 diarrhea in one case and grade 3 gastrointestinal hemorrhage associated with grade 3 thrombocytopenia and neutropenia in the other case. Other common toxicities were mild neutropenia, dehydration, hyperglycemia, and nausea/vomiting. One patient on dose level 1 showed a partial response of 6 months in duration. Both reversible inhibition of HDJ2 farnesylation and radiosensitization of a study patient-derived cell line were demonstrated in the presence of L-778,123. K-RAS mutations were found in three of the four patients evaluated.

CONCLUSIONS

The combination of L-778,123 and radiotherapy at dose level 1 showed acceptable toxicity in patients with locally advanced pancreatic cancer. Radiosensitization of a patient-derived pancreatic cancer cell line was observed.

Factors predicting local tumor control after gamma knife stereotactic radiosurgery for benign intracranial meningiomas

PURPOSE

To determine the long-term outcomes and prognostic factors in benign intracranial meningiomas treated with gamma knife stereotactic radiosurgery (GK-SRS).

METHODS AND MATERIALS

Between 1992 and 2000, 162 patients with benign meningiomas were treated with GK-SRS at the University of Maryland Medical Center. Complete follow-up was available in 137 patients. All patients underwent magnetic resonance imaging (MRI)-based treatment planning. Serial MRIs and clinical exams were performed to assess tumor response. GK-SRS was the primary treatment in 85 patients (62%), whereas 52 patients (48%) had prior surgical resections. The median prescribed dose was 14 Gy (range, 4-25 Gy) to the 50% isodose line. The median tumor volume, treatment volume, and conformity index were 4.5 cc (range, 0.32-80.0 cc), 6.3 cc (range, 1.0-75.2 cc), and 1.34 (range, 0.65-3.16), respectively. The median follow-up for the entire cohort was 4.5 years (range, 0.33-10.5 years). The following factors were included in the statistical analysis for disease-free survival (DFS) and overall survival (OS): sex, age, dose, gross tumor volume (GTV), conformity index (CI), and dural tail coverage.

RESULTS

Serial MRI analysis was available in 121 patients (88.3%). Decrease in tumor size was observed in 34 patients (28.1%), whereas there was no change in 77 patients (63.6%), for a crude radiographic control rate of 91.7%. Increase in tumor size was seen in 10 patients (8.3%). New neurologic deficits attributed to the treatment developed in 10 patients (8.3%). The mean DFS and OS for the entire cohort are 4.6 years and 5.0 years, respectively. The 5-year actuarial DFS and OS were 86.2% and 91.0%, respectively. Univariate analysis revealed GTV, sex, CI, and dural tail treatment to be significant prognostic factors. Patients with GTV < or =10 cc also had longer survivals, with the 5-years DFS and OS of 91.9% vs. 68.0% (p = 0.038) and 100% vs. 59.7% (p = 0.0001), respectively. The 5-years actuarial DFS and OS for females vs. males were 90.2% vs. 74.2% (p = 0.0094) and 91.6% vs. 89.1% (p = 0.016), respectively. Patients with CI > or =1.4 achieved a longer DFS, with a 5-year DFS of 95.2% vs. 77.3% (p = 0.01). Patients who had the dural tail treated also had higher 5-year DFS (96.0% vs. 77.9%, p = 0.038). Patients with lower conformity (i.e., CI > or =1.4) tended to have the dural tail covered in the prescription isodose line (p = 0.04). The only factor significant in the multivariate analysis was for patients with GTV >10 cc, who had a worse DFS (hazard ratio 4.58, p = 0.05).

CONCLUSIONS

This report adds to the literature that supports the efficacy and safety of GK-SRS in the management of patients with benign intracranial meningiomas. Our report identified male patients, patients with a CI <1.4, and tumor size greater than 10 cc to have a worse prognosis. Patients who were treated with less conformal plans to cover the dural tail had better outcomes. Our data clearly demonstrate the need to adequately cover the dural tail in patients treated with GK-SRS for benign intracranial meningiomas.

Cancer caregiving and subjective stress: a multi-site, multi-dimensional analysis

Although research has emerged documenting the psychosocial impact of family care for cancer patients, few efforts capture the multi-dimensional nature of cancer caregiving stress, particularly among socioeconomically diverse samples. Utilizing data collected from cancer caregivers at a non-urban, Southern US site and an inner-city, Northeastern US site (N=233), the present study identified predictors of multiple dimensions of caregivers' subjective stress (i.e. emotional appraisals of care demands). Various indicators representing the sociodemographic context of care, cancer care demands, and psychosocial resources were found to exacerbate or buffer caregivers from feelings of exhaustion, role entrapment, and loss of intimacy with the cancer patient. The multivariate regression model also emphasized the diffuse yet potent role care recipient mood problems and caregiver mastery/optimism have on multiple dimensions of subjective stress. The findings offer a number of recommendations for future research and practice focused on informal cancer care.

Recursive Partitioning Analysis Classifications I and II

PURPOSE

Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) prognostic classes I and II for patients with brain metastases is derived from a database made up primarily of patients with unresected and multiple metastases. An analysis of a previously published randomized trial was performed to determine the applicability of these RPA prognostic classes in the setting of resection of single metastases to the brain.

PATIENTS AND METHODS

Ninety-five patients with single metastases to the brain that were treated with complete surgical resection entered this study. Patients were randomly assigned to treatment with postoperative whole brain radiotherapy (WBRT) (n = 49 patients) or no further brain treatment (n = 46 patients). All patients entered on this study had a Karnofsky performance status of > or =70. Therefore, although the RTOG RPA has 3 classes, only patients with RPA classes I (n = 26) or II (n = 69) were eligible for this study analysis.

RESULTS

For RPA class I, the median survival was 10.9 months versus 9.8 months for class II patients (P = 0.45). Multivariate analysis showed that only postoperative WBRT, independent of RPA class I or II, lessened the risk of brain tumor recurrence (P < 0.0001).

CONCLUSION

This analysis of a randomized trial evaluating postoperative WBRT in the treatment of single metastases to the brain showed no difference in survival between RPA class I or II patients. In addition, the use of postoperative WBRT after complete surgical resection of single brain metastases results in substantially better control of disease in the brain independent of RPA classes I or II.

Gamma knife surgery for trigeminal neuralgia: Outcome, imaging, and brainstem correlates

PURPOSE

To review our results with gamma knife surgery (GKS) in the treatment of trigeminal neuralgia (TN), and to determine whether pain relief, medication usage, and the development of facial numbness are affected by trigeminal nerve compression, MRI imaging quality, or brainstem radiation dose.

METHODS AND MATERIALS

One hundred twelve patients with TN refractory to medical or surgical management were treated at the University of Maryland Gamma Knife Center between June 1996 and July 2001. Patients were treated using a 4-mm shot to the trigeminal nerve, at a point 2-4 mm anterior to the root entry zone of the nerve into the pons. The median dose prescribed was 75 Gy (range, 60-80 Gy). T1- and T2-weighted, axial, 1.5-mm-thick MRI images were obtained using three-dimensional gradient echo acquisition after contrast injection for treatment planning. MRI images were evaluated for imaging quality (i.e., the adequacy of visualization of the affected prepontine trigeminal nerve), the presence of trigeminal nerve compression, and the brainstem dose. Follow-up data were obtained via telephone interviews, and patients were asked to rate their pre-GKS and post-GKS pain using the Barrow Neurological Institute (BNI) Pain Intensity Scale. Patients were also asked about side effects from GKS and were asked to rate any facial numbness on the BNI Facial Numbness Scale. Medication use, time to pain response, and duration of relief were also evaluated.

RESULTS

Ninety-six patients who had follow-up data were included in the analysis. Eighty-six patients (89.6%) responded to GKS with an improvement in BNI pain class. Ten patients (10.4%) were found to have an MRI of poor quality, 30 (31.3%) fair quality, and 56 (58.3%) good quality. Forty-two (43.8%) received 10% of the maximal dose to the brainstem edge, whereas 54 (56.2%) received 20%. Eleven (11.5%) patients were found to have obvious nerve compression by MRI. Imaging quality (p = 0.1863), presence of compression (p = 0.1147), and brainstem dose (p = 0.3168) did not correlate with treatment response. There was also no correlation between these variables (MRI quality, compression, and brainstem dose) and medication use (p = 0.5372, p = 0.0913, p = 0.6832, respectively). Facial numbness was the only side effect experienced. Thirteen patients reported varying degrees of facial numbness, but there was no correlation between imaging quality (p = 0.0600), brainstem dose (p = 0.6773), and presence of compression (p = 0.5785) with the development of facial numbness.

CONCLUSIONS

Gamma knife surgery is effective in the treatment of TN and has a favorable side effect profile. Treatment response and the development of facial numbness do not correlate with MRI imaging quality, presence of nerve compression, or radiation dose to the brainstem.

The evolving role of postoperative adjuvant radiation therapy for pancreatic cancer

The benefit of postoperative adjuvant chemoradiation in the treatment of resected pancreatic cancers was first established by a randomized trial conducted by the Gastrointestinal Tumor Study Group in 1974. During the past 3 decades, treatment has evolved toward more dose-intensive regimens of chemoradiation. Historical split-course conventional radiation therapy has been replaced by continuous-course radiotherapy to higher doses, and gemcitabine is being actively investigated as a potentially more effective agent than 5-fluorouracil. This article critically examines the results of important randomized multi-institutional trials and reviews the evolution toward dose-intensive adjuvant treatment regimens. Implications of the recently completed intergroup study are discussed, modern radiation therapy delivery techniques are reviewed, and suggestions for future trials are made.

Stereotatic radiosurgery of 468 brain metastases < or =2 cm: implications for SRS dose and whole brain radiation therapy

PURPOSE

The national standard stereostatic radiosurgery (SRS) dose for brain metastases < or =2 cm is 24 Gy as established by the Radiation Therapy Oncology Group study 90-05, in which planned whole brain radiotherapy (WBRT) was not used. On the basis of our institutional experience, the goal of this study was to determine the optimal SRS dose and influence of WBRT on local tumor control among 468 < or =2-cm metastases.

METHODS AND MATERIALS

Between October 1992 and May 2001, 468 newly diagnosed or recurrent < or =2-cm brain metastases, among 160 patients, were treated with SRS (dose range, 7-30 Gy; median, 20). A total of 240 metastases received planned WBRT (range, 6.75-50.4 Gy; median, 40.5) vs. 228 metastases that did not. The variables tested by multivariate analysis for their potential effect on tumor control included histologic type, site of metastasis, primary diagnosis, tumor volume, SRS dose, newly diagnosed vs. recurrent metastasis, and planned WBRT vs. no planned WBRT.

RESULTS

Follow-up ranged from 1 to 82 months (median 7). On multivariate analysis, the addition of WBRT was the most significant predictor of local tumor control. Overall, patients who received WBRT had superior local tumor control rates (97% vs. 87% in those who did not receive WBRT; p = 0.0001). Patients receiving WBRT and SRS > or =20 Gy achieved local control rates of 99% compared with 91% control rates when treated with WBRT and SRS <20 Gy (p = 0.0029). Increasing the SRS dose to >20 Gy resulted in no improvement in local tumor control and a higher rate of Grade 3 and 4 neurotoxicity, approaching statistical significance (5.9% vs. 1.9%, p = 0.078).

CONCLUSION

First, optimal control of brain metastasis < or =2 cm was seen with 20-Gy SRS combined with planned WBRT. Second, SRS doses >20 Gy resulted in no obvious improvement in local control and appeared to be associated with a greater rate of complications.

Feasibility of neurocognitive outcome evaluations in patients with brain metastases in a multi-institutional cooperative group setting: results of Radiation Therapy Oncology Group trial BR-0018

PURPOSE

A multi-institutional trial was conducted by the Radiation Therapy Oncology Group (RTOG) to test the feasibility of performing a test battery consisting of five neurocognitive measures and a quality-of-life instrument in patients with brain metastases.

METHODS AND MATERIALS

The major eligibility requirements included histologic proof of a primary malignancy, measurable single or multiple brain metastases, Zubrod performance status of 0-1, neurologic function status of 0-2, and "certification" for administration of neurocognitive assessments. This certification process required either attendance at an RTOG neurocognitive assessment training workshop or review of an instructional video, followed by submission of an audiotape of mock/simulated test sessions for central review. The test battery included the following measures: the Mini-Mental Status Examination, Hopkins Verbal Learning Test, Verbal Fluency/Controlled Word Association Test, Ruff 2 and 7 test, Trailmaking Test, and Profile of Mood States-Short Form. The primary objective of this trial was to establish whether patients were able to complete this test battery. Compliance was defined as successful completion of a test measure. The test battery was to be administered just before, at completion of, and 1 month after whole brain radiotherapy to 37.5 Gy at 2.5 Gy/fraction once daily. Fifty-nine patients were enrolled in the trial.

RESULTS

The patient characteristics included 32% > or =65 years; 44% with Zubrod performance status of 0; and 81% with multiple brain metastases. The overall compliance rate for administration and completion of the five neurocognitive measures and a quality-of-life instrument before treatment, at treatment completion, and 1 month after treatment was > or =95%, > or =84%, and > or =70%. The most common causes of noncompliance were patient-related factors (e.g., performance status or inability to understand test instructions) and not institutional error.

CONCLUSION

Neurocognitive evaluation of patients with brain metastases in a multi-institutional and cooperative group setting is feasible using the test battery and certification process used in this study. This battery and certification process will be incorporated into future RTOG brain tumor trials.

Low-dose fractionated radiation as a chemopotentiator of neoadjuvant paclitaxel and carboplatin for locally advanced squamous cell carcinoma of the head and neck: results of a new treatment paradigm

PURPOSE

Current therapies for locally advanced squamous cell carcinoma of the head and neck (SCCHN) result in 50% long-term remission. Low-dose radiotherapy (<100 cGy) induces enhanced cell killing in vitro via the hyper-radiation sensitivity phenomenon but has not been used in the clinical setting. On the basis of the demonstrated synergy between chemotherapy and low-dose fractionated RT, a novel neoadjuvant therapy was designed using low-dose fractionated RT as a chemopotentiator for locally advanced SCCHN.

METHODS AND MATERIALS

Forty patients with locally advanced SCCHN received paclitaxel (225 mg/m2), carboplatin (area under the curve of 6), and four 80-cGy fractions of radiotherapy (two each on Days 1 and 2). This sequence was repeated on Days 22 and 23.

RESULTS

Of the 40 patients enrolled, 39 were assessable. Grade 3 or worse toxicities included neutropenia (50%), infection (13%), arthralgias/myalgias (3%), skin (8%), lung (3%), and allergic reaction (3%), with no Grade 5 toxicity. The response was assessed radiographically and by panendoscopy. At the primary site, 11 patients (28%) had a complete response, 24 (62%) had a partial response, and 4 (10%) had stable disease. Of those with lymph node involvement, 10 (31%) had a complete response, 12 (38%) a partial response, 9 (28%) had stable disease, and 1 (3%) had progressive disease. The overall response rate was 82%.

CONCLUSION

Low-dose fractionated RT combined with paclitaxel and carboplatin is effective in SCCHN and has a similar toxicity profile to chemotherapy alone. This novel approach provided a response rate of 90% at the primary site and a nodal response rate of 69%. Additional scientific investigation of this new treatment paradigm is warranted.

Gamma knife stereotactic radiosurgery for synchronous versus metachronous solitary brain metastases from non-small cell lung cancer

A retrospective study was conducted analyzing the clinical outcome and various prognostic factors in patients treated with gamma knife stereotactic radiosurgery (GK-SRS) for solitary brain metastasis from non-small cell lung carcinoma (NSCLC). A total of 72 patients from June of 1992 to January of 1999 were treated. All patients received GK-SRS to a median dose of 18Gy, with 45 patients receiving additional whole-brain radiation therapy. No one had evidence of extra-cranial metastasis at the time of diagnosis of brain metastases. The median follow-up was 15.7 months for the entire population and 99.5 months for those who were alive at the last follow-up. Univariate and multivariate analyses were used to test the impact of various prognostic factors on survival. The median and 5-year actuarial survivals for the entire cohort were 15.7 months and 10.4%, respectively. The presence of a metachronous versus a synchronous brain metastasis was the only factor significant in the univariate (P=0.045) and multivariate (P=0.002) analyses. Patients with metachronous solitary brain metastases had a significant median survival advantage compared to those with synchronous metastases (33.3 months versus 8.6 months, P=0.001). However, there was no statistically significant difference in median survival from the time of metastasis when treated with GK-SRS in these groups (12.5 months versus 8.4 months, P=0.50). The addition of WBRT did not improve overall survival (12.0 months versus 7.7 months, P=0.73). The 5-year actuarial survival for the metachronous and synchronous groups were 13.2 and 8.1%, respectively. In conclusion, patients presenting with a solitary metachronous brain metastasis from NSCLC achieved longer survivals than those with a synchronous metastasis. The tail in the survival curves demonstrates that a prolonged survival may be attained in patients with solitary metastases from NSCLC. This study adds to the growing body of literature that supports the use of SRS in the management of this patient population.

Clinical research in pancreatic cancer: the Radiation Therapy Oncology Group trials

To summarize the clinical research activities of the Radiation Therapy Oncology Group program in the treatment of patients with locally advanced, as well as resected, pancreatic cancer. Phase II and III clinical trials are underway, examining novel cytotoxic and targeted agents with irradiation (RT) for patients with locally advanced and resected pancreatic cancer.A Phase II study incorporating concurrent paclitaxel with external beam radiotherapy in the locally advanced setting has been completed and recently analyzed. This experience has served as the foundation of a Phase II study using concurrent paclitaxel and gemcitabine with RT followed by R115777, a farnesyltransferase inhibitor, as maintenance therapy. In the adjuvant treatment of pancreatic cancer, an Intergroup Phase III trial has compared "conventional" postoperative chemoirradiation (5-fluorouracil before, after, and during RT) and gemcitabine before and after RT (with 5-fluorouracil during RT). This study has recently closed, meeting its accrual goal. The successor study will evaluate the use of gemcitabine given concurrently with RT, as well as in a maintenance schedule. This report summarizes current and future Radiation Therapy Oncology Group clinical trials in the treatment of patients with localized pancreatic cancer.

Brain injury: current management and investigations

Radiation, surgery, and chemotherapy, singly or combined, are modalities that are frequently used for the treatment of primary brain malignancies and metastases that secondarily spread to the brain. Each of the 3 modalities continues to improve with time; likewise the efficacy in management of malignant brain tumors has gradually improved. As cancer therapies become more effective with regard to disease control and survival, the potential impact of each modality on brain injury, either alone or when combined, becomes even more significant. In addition, with increasing survival, the likelihood of observing long-term injury is likely to increase. Thus, the expression of acute and long-term brain injury is becoming a more important factor in the management of patients with brain malignancies. This review presents current management and investigations associated with these modality-related injuries.

Spinal cord and peripheral nerve injury: current management and investigations

Treatment of patients having malignancy near or within the spinal cord can be more challenging or limited than in patients with brain tumors. This is largely because of the near total lack of noneloquent neural tissue associated with the spinal cord and/or intimately associated peripheral nerves. The adverse effects of surgery, radiation therapy, and chemotherapy or multimodality therapy can be acute or chronic, insidious, and often permanent in nature. Because cancer therapies (particularly combination therapies) have become more effective with regard to tumor control, the potential impact of each modality on spine and peripheral nerve injury has become even more significant. Similarly, with increasing survival, the likelihood of observing long-term injury is likely to increase. Thus, the expression of acute and long-term spine and peripheral nerve injury is becoming a more important factor in the management of patients with spine malignancies. This review presents current management and investigations associated with these modality-related injuries.

Stereotactic radiosurgery for meningiomas

Meningiomas are benign tumors attached to the dura that typically have a slow growth rate. After gliomas, they are the most common primary tumor of the brain. They are ideal radiobiological targets because single-fraction radiation has a high biologically effective dose. Furthermore, a highly conformal radiation plan can provide effective treatment to the tumor while sparing the surrounding brain. Meningioma control rates range from 90 to 95%, and the risk of morbidity is low. Radiosurgery is an excellent treatment for asymptomatic, small- to moderate-sized meningiomas. It is also ideal for patients with incompletely resected meningiomas, recurrent meningiomas, and risk factors precluding conventional surgery.

Neurologic complications of bladder carcinoma: a review of 359 cases

BACKGROUND

Carcinoma of the urinary bladder accounts for approximately 2% of all malignant tumors and usually spreads through both local invasion and hematogenous dissemination. In the current study, the authors reviewed a large series of patients to determine the nature and frequency of neurologic complications.

METHODS

In the current study, the authors reviewed the records of 359 patients with bladder carcinoma who were treated at the study institution between 1962-2001.

RESULTS

Fifty-two patients (14%) were reported to have neurologic complications. Complications resulting from neurologic metastases were relatively infrequent (5%). Seven patients (2%) had lumbosacral plexopathies and 6 patients (2%) had metastatic epidural spinal cord compression. Brain metastases were present in only 4 patients (1%). Nonmetastatic complications were more common than metastatic complications and were comprised of metabolic encephalopathies in 24 patients (7%), peripheral neuropathies in 9 patients (2.5%), cerebral infarctions in 6 patients (2%), and seizures in 5 patients (1%). No cases of neurologic infection or carcinomatous meningitis were reported.

CONCLUSIONS

The results of the current study demonstrate that neurologic complications are relatively uncommon in patients with bladder carcinoma and that local extension into peripheral nerves or bone, rather than hematogenous dissemination, is the most common cause of neurologic complications resulting from bladder carcinoma.

The rationale for adjuvant whole brain radiation therapy with radiosurgery in the treatment of single brain metastases

Randomized trials have established the efficacy of focal treatment (either stereotactic radiosurgery or conventional surgery) for single brain metastases. In the past, adjuvant whole brain radiation therapy (WBRT) was routinely given with focal therapy. Recently, the utility of adjuvant WBRT has been called into question. This paper examines the scientific evidence and the arguments, pro and con, concerning the use of adjuvant WBRT in association with stereotactic radiosurgery or conventional surgery.

Low-dose fractionated radiation potentiates the effects of Paclitaxel in wild-type and mutant p53 head and neck tumor cell lines

This study was designed to: (a) evaluate the induction of hyper-radiation sensitivity (HRS), a phenomenon observed at low doses of radiation (<1 Gy); (b) compare the potentiating effects of single dose radiation (2 Gy) versus the effect of low-dose fractionated radiation (LDFRT; <1 Gy) on Paclitaxel; and (c) understand the molecular mechanism of LDFRT-mediated chemo-potentiating effects, in wild-type p53 SCC-61 and p53 mutant SQ-20B head and neck squamous cell carcinoma cell lines. Both cell lines exhibited the HRS phenomenon at low radiation doses. Compared with SCC-61 cells, SQ-20B cells were resistant to radiation and Paclitaxel alone. A significant enhancement of radiation sensitization by Paclitaxel (0.5 or 1 nM) was observed in both cell lines. Chemo-potentiation of Paclitaxel by single 2-Gy radiation was observed in SCC-61 cells but not in SQ-20B cells. However, LDFRT (0.5 Gy in four fractions) significantly chemo-potentiated the effect of Paclitaxel in both cell lines. The cell cycle regulator p53 and its target genes p21(waf1/cip1) and BAX were induced in SCC-61 cells treated with 2 Gy, Paclitaxel, or in combination, but not in SQ-20B cells. These treatments elevated the antiapoptotic BCL-2 protein in SQ-20B cells but not in SCC-61 cells. Interestingly, LDFRT treatment in both cell lines with or without Paclitaxel down-regulated nuclear factor kappa B activity and BCL-2 protein expression and simultaneously up-regulated BAX protein. These findings strongly suggest that LDFRT (at these doses, HRS phenomenon is observed) can be used in combination with Paclitaxel to overcome the antiapoptotic effects of BCL-2 and nuclear factor kappa B.

Dosimetric characteristics with spatial fractionation using electron grid therapy

Recently, promising clinical results have been shown in the delivery of palliative treatments using megavoltage photon grid therapy. However, the use of megavoltage photon grid therapy is limited in the treatment of bulky superficial lesions where critical radiosensitive anatomical structures are present beyond tumor volumes. As a result, spatially fractionated electron grid therapy was investigated in this project. Dose distributions of 1.4-cm-thick cerrobend grid blocks were experimentally determined for electron beams ranging from 6 to 20 MeV. These blocks were designed and fabricated at out institution to fit into a 20 x 20-cm(2) electron cone of a commercially available linear accelerator. Beam profiles and percentage depth dose (PDD) curves were measured in Solid Water phantom material using radiographic film, LiF TLD, and ionometric techniques. Open-field PDD curves were compared with those of single holes grid with diameters of 1.5, 2.0, 2.5, 3.0, and 3.5 cm to find the optimum diameter. A 2.5-cm hole diameter was found to be the optimal size for all electron energies between 6 and 20 MeV. The results indicate peak-to-valley ratios decrease with depth and the largest ratio is found at Dmax. Also, the TLD measurements show that the dose under the blocked regions of the grid ranged from 9.7% to 39% of the dose beneath the grid holes, depending on the measurement location and beam energy.