Treatment and prevention of secondary CNS lymphoma.

Central nervous system (CNS) involvement in non-Hodgkin lymphoma is a serious, potentially preventable complication that can occur in 5 to 10% of patients. Its occurrence is directly correlated with pathologic aggressiveness and ranges from less than 3% in the indolent, less-aggressive histologies to as high as 50% in the very aggressive ones such as Burkitt lymphoma. Aggressive treatment once detected can improve neurologic outcome, but because it is often associated with contemporaneous systemic relapse, is rarely associated with long-term survival. Preventing its occurrence, therefore, remains an important goal of initial treatment. Despite there being some suggestive evidence that the addition of systemic rituximab and several intracerebrospinal fluid chemotherapy regimens may have decreased the incidence of CNS involvement, both optimal selection of those patients who should receive prophylaxis as well as the best prophylactic regimen remain active areas of investigation.

Paclitaxel disposition in plasma and central nervous systems of humans and rats with brain tumors.

BACKGROUND: Paclitaxel (Taxol) has been shown to sensitize some malignant cells to the effects of radiation. A number of clinical protocols, combining paclitaxel with radiation therapy, have been designed to exploit this phenomenon. The radiation-potentiating effect of paclitaxel is likely dependent on the ability of the drug to penetrate the tissue being radiated. Paclitaxel is known to have limited access to the central nervous system (CNS) of rats and mice, but its ability to penetrate malignant tissue in the CNS is inadequately documented. PURPOSE: Our purpose was to examine the concentrations of paclitaxel in the cerebrospinal fluid (CSF) of patients with CNS malignancies and in normal and malignant tissues from the brains of Fischer rats bearing the C6 rat glioma and then to compare those paclitaxel concentrations with concomitant paclitaxel concentrations in the plasma of those same patients and animals. METHODS: Four patients were treated with 3-hour infusions of paclitaxel at doses between 90 and 200 mg/m2. Plasma and CSF were sampled at 0.33, 1.5, 3.25, 5, 6, and 24 hours after initiation of the paclitaxel infusion. Four Fischer rats had 20,000 C6 glioma cells stereotactically implanted into their right frontal lobes; 28 days later, they were given 3-hour infusions of paclitaxel at 10 mg/kg. Plasma was sampled during the paclitaxel infusion. At the completion of the infusion, rats were killed, and portions of their normal and malignant CNS tissues were removed for histologic assessment. Concentrations of paclitaxel in plasma, CSF, and brain tissue were determined with high-pressure liquid chromatography. RESULTS: Plasma pharmacokinetics of paclitaxel in patients with brain tumors were comparable to those previously described in patients with other malignancies. Paclitaxel could be measured in CSF of all patients, but concentrations were very low. Peak paclitaxel concentrations in CSF ranged between 5 and 83 nM and occurred between 3.25 and 5 hours after initiation of the paclitaxel infusion. Peak paclitaxel concentrations in CSF were between 0.12% and 8.3% of those present in concomitant plasma samples. Paclitaxel was not detectable in the normal or malignant CNS tissue of any rat, despite the fact that plasma concentrations of paclitaxel at the time of tissue acquisition ranged from 0.62 to 153 microM. CONCLUSIONS: Paclitaxel has only limited access to the CSF of patients with CNS malignancies and to normal and malignant CNS tissues of rats bearing brain tumors. IMPLICATIONS: The utility of combining paclitaxel with radiation therapy to treat CNS malignancies should be considered in light of the documented limited access of paclitaxel to the CNS.

High-dose intravenous methotrexate for patients with nonleukemic leptomeningeal cancer: is intrathecal chemotherapy necessary?

PURPOSE: Standard treatments for neoplastic meningitis are only modestly effective and are associated with significant morbidity. Isolated reports suggest that concurrent systemic and intrathecal (i.t.) therapy may be more effective than i.t. therapy alone. We present our experience, which includes CSF and serum pharmacokinetic data, on the use of high-dose (HD) intravenous (i.v.) methotrexate (MTX) as the sole treatment for neoplastic meningitis. PATIENTS AND METHODS: Sixteen patients with solid-tumor neoplastic meningitis received one to four courses (mean, 2.3 courses) of HD (8 g/m2 over 4 hours) i.v. MTX and leucovorin rescue. Serum and CSF MTX concentrations were measured daily. Toxicity, response, and survival were retrospectively compared with a reference group of 15 patients treated with standard i.t. MTX during the same time interval. RESULTS: Peak methotrexate concentrations ranged from 3.7 to 55 micromol/L (mean, 17.1 micromol/L) in CSF and 178 to 1,700 micromol/L (mean, 779 micromol/L) in serum. Cytotoxic CSF and serum MTX concentrations were maintained much longer than with i.t. dosing. Toxicity was minimal. Cytologic clearing was seen in 81% of patients compared with 60% of patients treated intrathecally (P = .3). Median survival in the HD i.v. MTX group was 13.8 months versus 2.3 months in the i.t. MTX group (P = .003). CONCLUSION: HD i.v. MTX is easily administered and well tolerated. This regimen achieves prolonged cytotoxic serum MTX concentrations and CSF concentrations at least comparable to those achieved with standard i.t. therapy. Cytologic clearing and survival may be superior in patients treated with HD i.v. MTX. Prospective studies and a reconsideration of the use of i.t. chemotherapy for patients with neoplastic meningitis are warranted.

Phase I study of weekly outpatient paclitaxel and concurrent cranial irradiation in adults with astrocytomas.

PURPOSE: Astrocytomas are extremely resistant to currently available treatments. Cranial irradiation is a mainstay of frontline therapy, but tumor recurrence is nearly universal. Paclitaxel has shown antitumor efficacy against astrocytoma cell lines, and is a potent radiosensitizer. For these reasons, we conducted a phase I study of weekly paclitaxel and concurrent cranial irradiation in patients with newly diagnosed astrocytomas. PATIENTS AND METHODS: Patients with astrocytomas were eligible for this study following initial surgery if they had a Karnofsky performance score (KPS) > or = 60%; normal hematologic, liver, and renal function; and could give informed consent. Beginning on day 1 of treatment, patients received paclitaxel by 3-hour infusion once weekly for 6 weeks, concurrent with standard cranial irradiation. Pharmacokinetic studies were performed on 10 patients. RESULTS: Sixty patients were enrolled; 56 were fully assessable. Forty-eight had glioblastomas (GBMs), 10 anaplastic astrocytomas (AAs), and two astrocytomas. Age ranged from 21 to 81 years (median, 55); KPS ranged from 60 to 100 (median, 70). The paclitaxel dose was escalated from 20 mg/m2 to 275 mg/m2. No clinically significant anemia or thrombocytopenia occurred. Only one patient (175 mg/m2) became neutropenic. Sensory neuropathy was dose-limiting. The maximum tolerated dose (MTD) was 250 mg/m2. Paclitaxel pharmacokinetic profiles in study patients were identical to those of previously reported patients with other solid tumors. CONCLUSION: The MTD of paclitaxel administered weekly for 6 weeks by 3-hour infusion is 250 mg/m2. Since patients with brain tumors often have preexisting neurologic deficits, we suggest 225 mg/m2 as the optimum dose for phase II trials in this group of patients.

Randomized trial of a slow-release versus a standard formulation of cytarabine for the intrathecal treatment of lymphomatous meningitis.

PURPOSE: To evaluate the efficacy and safety of a slow-release formulation of cytarabine (DepoCyt; Chiron Corp, Emeryville, CA, and Skye Pharma, Inc, San Diego, CA) that maintains cytotoxic concentrations of cytarabine (ara-C) in the CSF of most patients for more than 14 days. PATIENTS AND METHODS: Twenty-eight patients with lymphoma and a positive CSF cytology were randomized to receive DepoCyt 50 mg once every 2 weeks or free ara-C 50 mg twice a week for 1 month. Patients whose CSF cytology converted to negative and who did not have neurologic progression received an additional 3 months of consolidation therapy and then 4 months of maintenance therapy. All patients received dexamethasone 4 mg orally bid on days 1 through 5 of each 2-week cycle. RESULTS: The response rate was 71% for DepoCyt and 15% for ara-C on an intent-to-treat basis (P =.006). All of the patients on the DepoCyt arm but only 53% of those on the ara-C arm were able to complete the planned 1-month induction therapy regimen. Time to neurologic progression and survival trend in favor of DepoCyt (median, 78.5 v 42 days and 99.5 v 63 days, respectively; P >.05). DepoCyt treatment was associated with an improved mean change in Karnofsky performance score at the end of induction (P =.041). The major adverse events on both arms were headache and arachnoiditis, which were often caused by the underlying disease. CONCLUSION: DepoCyt injected once every 2 weeks produced a high response rate and a better quality of life as measured by Karnofsky score relative to that produced by free ara-C injected twice a week.

A randomized controlled trial comparing intrathecal sustained-release cytarabine (DepoCyt) to intrathecal methotrexate in patients with neoplastic meningitis from solid tumors.

Standard treatment for neoplastic meningitis requires frequent intrathecal (IT) injections of chemotherapy and is only modestly effective. DepoCyt is a sustained-release formulation of cytarabine that maintains cytotoxic concentrations of the drug in the cerebrospinal fluid (CSF) for more than 14 days after a single 50-mg injection. We conducted a randomized, controlled trial of DepoCyt versus methotrexate in patients with solid tumor neoplastic meningitis. Sixty-one patients with histologically proven cancer and positive CSF cytologies were randomized to receive IT DepoCyt (31 patients) or IT methotrexate (30 patients). Patients received up to six 50-mg doses of DepoCyt or up to sixteen 10-mg doses of methotrexate over 3 months. Treatment arms were well balanced with respect to demographic and disease-related characteristics. Responses occurred in 26% of DepoCyt-treated and 20% of methotrexate-treated patients (P = 0.76). Median survival was 105 days in the DepoCyt arm and 78 days in the methotrexate arm (log-rank P = 0.15). The DepoCyt group experienced a greater median time to neurological progression (58 versus 30 days; log-rank P = 0.007) and longer neoplastic meningitis-specific survival (log-rank P = 0.074; median meningitis-specific survival, 343 versus 98 days). Factors predictive of longer progression-free survival included absence of visible central nervous system disease on neuroimaging studies (P<0.001), longer pretreatment duration of CSF disease (P<0.001), history of intraparenchymal tumor (P<0.001), and treatment with DepoCyt (P = 0.002). The frequency and grade of adverse events were comparable between treatment arms. In patients with solid tumor neoplastic meningitis, DepoCyt produced a response rate comparable to that of methotrexate and significantly increased the time to neurological progression while offering the benefit of a less demanding dose schedule.

The role of paclitaxel in the treatment of primary and metastatic brain tumors.

The rationale for the use of paclitaxel to treat brain tumors includes impressive activity in a wide array of chemotherapy-resistant solid tumors, in vitro and in vivo evidence of cytotoxicity against primary brain tumors, and a paucity of effective alternative agents. A review of published studies evaluating paclitaxel alone or in combination with other chemotherapeutic agents suggests that paclitaxel alone is not highly active against newly diagnosed or recurrent glioblastoma multiforme. However, additional prospective trials are warranted to evaluate the efficacy of paclitaxel plus conventional cranial irradiation or stereotactic radiosurgery. Single-agent paclitaxel appears to be active against gliomas with an oligodendroglial component and may prove useful both as a component of initial therapy and for recurrent disease. Activity against anaplastic gliomas and brain metastases also should be explored. With radiation, a weekly paclitaxel administration schedule is particularly appealing from pharmacologic, safety, and dose-intensity perspectives. In addition, the dose of paclitaxel must be increased in patients who are concurrently receiving medications that induce the P-450 drug metabolizing system. Primary and metastatic brain tumors constitute a very difficult problem in oncology. Future investigations should be directed at evaluating paclitaxel-based chemotherapy regimens in selected brain tumor types, combining paclitaxel with stereotactic radiosurgery, and determining the importance of other proposed mechanisms of action of paclitaxel (eg, inhibition of angiogenesis and tumor invasion).

Adult medulloblastoma: multiagent chemotherapy.

In this study, the records of 17 adult patients with medulloblastoma treated with craniospinal radiation and 1 of 2 multiagent chemotherapy protocols were reviewed for progression-free survival, overall survival, and toxicity, and the patients were compared with each other and with similarly treated children and adults. Records of patients treated at 3 institutions were reviewed. Seventeen medulloblastoma patients (11 female, 6 male) with a median age of 23 years (range, 18-47 years) were treated with surgery, craniospinal radiation (CSRT) plus local boost, and 1 of 2 adjuvant chemotherapy regimens. All tumors were infratentorial (10 in 4th ventricle and 7 in left or right hemisphere). Ten patients presented with hydrocephalus, and 7 of them were shunted. Eight patients had gross total resection, 7 had subtotal resection (>50% removed), and 2 had partial resection (<50% removed). Postoperatively, 3 patients had positive cytology and 3 had positive spinal MRI. Five patients were classified as good risk and 12 were classified as poor risk (Chang staging system). Ten patients were treated with the "Packer protocol," consisting of CSRT plus weekly vincristine followed by 8 cycles of cisplatin, lomustine, and vincristine. Seven patients were treated with the Pediatric Oncology Group (POG) protocol, consisting of alternating courses of cisplatin/etoposide and cyclophosphamide/vincristine, followed by CSRT. Eight of 17 patients relapsed, with all 8 relapsing at the primary site. Other relapse sites included the leptomeninges (5), bone (1), and brain (1). The estimated median relapse-free survival (Kaplan-Meier) for all patients was 48 months (95% confidence interval, >26 months to infinity). Median relapse-free survival for patients on the Packer protocol was 26 months, and for those on the POG regimen was 48 months (P = 0.410). Five of 10 on the Packer protocol were relapse-free, while 4 of 7 were relapse-free on the POG regimen. Two patients relapsed during chemotherapy and 6 relapsed after completing all therapy at 18, 18, 26, 30, 40, and 48 months. The estimated median survival of all patients was 56 months (95% confidence interval, 27 to infinity) with 11 patients alive; for the Packer protocol, median survival was 36 months, and for the POG protocol, it was 57 months (P = 0.058). The hazard ratio was 0 (95% confidence interval, 0 to infinity). Toxicity during the Packer protocol was moderately severe, with only 1 of 10 patients able to complete all therapy. Two patients had severe abdominal pain during CSRT + vincristine, and 5 had peripheral neuropathy during vincristine therapy. Hearing loss (>20 dB) occurred in 7, neutropenia (<500 microl) in 6, thrombocytopenia (<50,000 microl) in 6, nephrotoxicity (>25% decrease by creatinine clearance) in 2, and decreased pulmonary function (diffusing capacity for carbon monoxide decrease >40%) in 1. On the POG protocol, only 1 patient had persistent nausea and vomiting, 2 had peripheral neuropathy, and 3 had hearing deficit (>20 dB) or tinnitus. The POG and Packer protocols did not have a statistically significant difference in relapse-free or overall survival because of the small sample size. The POG protocol seemed to have less nonhematologic toxicity. Adults on the Packer protocol appeared to have shorter median survival and greater toxicity than did children. To know whether adding adjuvant chemotherapy to craniospinal radiation in adult therapy increases relapse-free and overall survival, we must await the results of a larger randomized controlled clinical trial.

A comparison between ventricular and lumbar cerebrospinal fluid cytology in adult patients with leptomeningeal metastases.

Leptomeningeal metastases (LMs) are common metastatic complications, occurring in at least 5% of patients with disseminated cancer. Cerebrospinal fluid (CSF) cytology remains the standard for diagnosis and assessment of treatment response, but may be inadequate. Our objective was to compare ventricular and lumbar CSF cytology in patients who had cytologically proven LM and were receiving intra-CSF chemotherapy. Sixty patients with LM, positive lumbar CSF cytology documented at diagnosis, limited extent of CNS disease, and no evidence of CSF flow obstruction were treated with a variety of intra-CSF chemotherapies. All patients underwent a single simultaneous ventricular and lumbar CSF sampling (mean volume of CSF per site examined, 10 ml) to assess response to therapy at either 1 or 2 months after treatment initiation. Ventricular CSF cytology was positive in 44 patients (73%), 35 of whom were also positive by lumbar CSF cytology. Lumbar CSF cytology was positive in 45 patients (75%), of which 35 were also positive by ventricular CSF cytology. Samples were negative at both ventricular and lumbar sites in 6 patients (10%). Paired CSF cytologies were discordant in 19 (32%) patients. The lumbar cytology was negative in 9, whereas the ventricular cytology was positive (lumbar false-negative rate of 17%); the ventricular cytology was negative in 10, whereas the lumbar cytology was positive (ventricular false-negative rate of 20%). In the presence of spinal signs or symptoms of LM, the lumbar CSF cytology was more likely to be positive than was the ventricular (odds ratio = 2.86; 95% confidence interval, 0.86-9.56). Conversely, in the presence of cranial signs or symptoms, the ventricular CSF cytology was more likely to be positive than was the lumbar (odds ratio = 2.71; 95% confidence interval, 0.76-9.71). In this cohort of patients, whose LM was documented initially by positive lumbar CSF cytology, ventricular and lumbar CSF samples obtained during treatment had similar false-negative rates, depending on the site of clinical or radiologic disease. This suggests that both lumbar and ventricular sites must be sampled when assessing treatment response. If clinical or radiographic disease is present only at 1 site, then CSF from that site is more likely to be positive than is CSF obtained from the more distant site.

Influence of the type of surgery on the histologic diagnosis in patients with anaplastic gliomas.

Stereotactic biopsy of CNS tumors provides a small amount of tissue for pathologic diagnosis. This potentially leads to inaccurate grading of gliomas because of their histologic heterogeneity. We compared histologic diagnoses in a consecutive series of 329 patients with newly diagnosed anaplastic gliomas whose diagnoses were established by either stereotactic biopsy or open resection. Of 262 patients undergoing resection, 214 (82%) had glioblastomas and 48 (18%) had anaplastic astrocytomas (AAs). Of 67 patients undergoing stereotactic biopsy, 33 (49%) had glioblastomas and 34 (51%) had AAs. This difference suggests that some AAs diagnosed by stereotactic biopsy are actually glioblastomas and has important implications for the design and interpretation of clinical trials.

Treatment of radiation-induced nervous system injury with heparin and warfarin.

When radiation is used to treat nervous system cancer, exposure of adjacent normal nervous system tissue is unavoidable, and radiation-induced injury may occur. Acute injury is usually mild and transient, but late forms of radiation-induced nervous system injury are usually progressive and debilitating. Treatment with corticosteroids, surgery, and antioxidants is often ineffective. We treated 11 patients with late radiation-induced nervous system injuries (eight with cerebral radionecrosis, one with a myelopathy, and two with plexopathies, all unresponsive to dexamethasone and prednisone) with full anticoagulation. Some recovery of function occurred in five of the eight patients with cerebral radionecrosis, and all the patients with myelopathy or plexopathy. Anticoagulation was continued for 3 to 6 months. In one patient with cerebral radionecrosis, symptoms recurred after discontinuation of anticoagulation and disappeared again after reinstitution of treatment. We hypothesize that anticoagulation may arrest and reverse small-vessel endothelial injury--the fundamental lesion of radiation necrosis--and produce clinical improvement in some patients.

A randomized, blinded, placebo-controlled trial of divalproex sodium prophylaxis in adults with newly diagnosed brain tumors.

BACKGROUND: Seizures occur after the diagnosis of brain tumors in up to 40% of patients. Prophylactic anticonvulsants are widely advocated despite a lack of convincing evidence of their efficacy in preventing first seizures. We conducted a randomized, double-blind, placebo-controlled study comparing the incidence of first seizures in divalproex sodium- and placebo-treated patients with newly diagnosed brain tumors. PATIENTS AND METHODS: Patients who had not previously had a seizure were randomized within 14 days of diagnosis of their brain tumor to receive either divalproex sodium or placebo. All patients had at least one supratentorial brain lesion, a Karnofsky Performance Score (KPS) > or = 50%, and no previous anticonvulsant use or other brain disease. Compliance and adequacy of dosing were assessed by pill counts and monthly blood levels. RESULTS: Seventy-four of 75 consecutive eligible patients were entered in this study. Median follow-up was 7 months. The drug and placebo groups did not differ significantly in age, sex, KPS, primary tumor type, number or location of brain lesions, frequency of brain surgery, or pretreatment EEG. Thirteen of 37 patients (35%) receiving divalproex sodium and 9 of 37 patients (24%) on placebo had seizures. The odds ratio for a seizure in the divalproex sodium arm relative to the placebo arm was 1.7 (95% CI 0.6 to 4.6; p = 0.3). The hypothesis that anticonvulsant prophylaxis provides a reduction in the frequency of first seizure as small as 30% was rejected (p = 0.05). CONCLUSIONS: Anticonvulsant prophylaxis with divalproex sodium is not indicated for patients with brain tumors who have not had seizures.

Prophylactic cranial irradiation in small cell lung cancer: rationale, results, and recommendations.

The utility of prophylactic cranial irradiation (PCI) in patients with small cell lung cancer (SCLC) constitutes one of the longest running debates in oncology. Despite dozens of prospective and retrospective studies and decades of individual experience, a consensus has been reached on only two issues: (1) when administered to all patients with SCLC, PCI decreases the likelihood of developing brain metastases by about half, but (2) PCI does not significantly prolong survival. Uncertainty persists over many critical questions, including whether, when, and how to administer PCI; whether identifiable subgroups of patients benefit more tangibly from PCI; how frequent and severe the long-term side effects of PCI are; whether withholding treatment until brain metastases are diagnosed is clinically responsible and cost effective; and how newer forms of treatment for brain metastases should be integrated into the picture. In this review, we discuss the epidemiology and natural history of brain metastases in patients with SCLC, the results of studies examining the efficacy of PCI, data on the early and late toxicities of PCI, and the status of alternative therapies for patients with brain metastases from SCLC. Based on this information, an approach to newly diagnosed patients is suggested, and recommendations for future study are made.

Weekly, outpatient paclitaxel and concurrent cranial irradiation in adults with brain tumors: preliminary results and promising directions.

In a phase I study, paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) was given weekly by 3-hour infusion for 6 weeks concurrent with daily cranial irradiation as initial treatment for patients with newly diagnosed astrocytic brain tumors. The primary goal of the study was to establish the maximum tolerated dose of paclitaxel when administered by this schedule. Sixty patients were entered into the study and received at least one course of therapy. Fifty-six patients completed treatment. The treatment regimen was well tolerated, with minimal hematologic toxicity. Peripheral neuropathy was dose-limiting. Median survival was 9.2 months for patients with glioblastoma multiforme and has not been reached for patients with anaplastic astrocytoma or astrocytoma. The maximum tolerated dose of paclitaxel in this study was 250 mg/m2 administered weekly. However, because five of six patients receiving this dose of paclitaxel developed peripheral neuropathy, and because patients with brain tumors may adapt to a superimposed neuropathy less well than patients without pre-existing nervous system dysfunction, we propose 225 mg/m2 as the recommended dose for subsequent phase II trials.

Weekly paclitaxel with and without concurrent radiation therapy: toxicity, pharmacokinetics, and response.

Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has shown in vitro and clinical activity against non-small cell lung cancer and astrocytic brain tumors, tumors traditionally thought of as relatively resistant to chemotherapy and radiotherapy. Because of its ability to block dividing cells in the G2/M portion of the cell cycle (the most radiosensitive phase of the cell cycle), paclitaxel is also a potentially potent radiosensitizer. To exploit these and other properties of paclitaxel, we explored a weekly, outpatient administration schedule, with and without concurrent radiation therapy, in patients with non-small cell lung cancer and astrocytic brain tumors. Our experience has shown that weekly outpatient administration is feasible, that remarkably high dose intensities can be achieved with acceptable toxicity, and that the specific dose-limiting toxicity appears to depend on administration schedule, type of concurrent radiotherapy, and certain patient characteristics. Preliminary response data are very encouraging. At the same time, pharmacokinetic studies have suggested possible reasons for our ability to use such exorbitant dose intensities safely, and also have shown that sustained plasma paclitaxel levels above the putative radiosensitizing threshold can be achieved continuously during a 6-week course of radiotherapy. Specific results, dosing recommendations, and plans for future studies are discussed.

National survey on prophylactic cranial irradiation: differences in practice patterns between medical and radiation oncologists.

PURPOSE: Prophylactic cranial irradiation (PCI) in the treatment of small cell lung cancer (SCLC) patients remains controversial in the oncology community because of its potential for long-term toxicity and unproven survival benefit in randomized trials. A national survey of 9176 oncologists was conducted to characterize the use of PCI with regard to physician demographics, patient characteristics, and oncologists' beliefs. METHODS: Data was collected via a questionnaire letter survey. Biographical data, treatment patterns, and clinical impressions were analyzed by the generalized linear model and generalized estimating equations method. RESULTS: There were 1231 responders overall (13.4% of those surveyed), including 628 (51%) radiation oncologists (RO), 587 (48%) medical oncologists (MO), 8 (0.6%) surgical oncologists, and 8 (0.6%) from other oncology subspecialties. Of respondents, 74% overall recommend PCI in limited-stage patients, including 65% of MO and 82% RO (p = 0.001). Of responders who recommend PCI in limited-stage patients, 67% do so only after complete response to initial therapy. Only 30% of respondents recommend PCI for extensive-stage SCLC patients (p = 0.001), and 94% of these recommend PCI only when those patients have a complete response after initial therapy. Interestingly, 38% of responding MO feel that PCI improves survival of limited-stage patients, but only 11% believe PCI improves quality of life. Of the RO, 48% believe PCI improves survival in limited-stage SCLC, and 36% feel PCI improves quality of life (p < 0.05 and p < 0.01, respectively). MO responders believe PCI causes late neurological sequelae more often than do RO responders (95% vs. 84%, p < 0.05), with impaired memory (37%), chronic fatigue (19%), and loss of motivation (13%) as most commonly seen side effects. Only 1.5% overall, however, routinely obtain neuropsychiatric testing in PCI patients, and 42% overall never obtain them. CONCLUSION: Results confirm that oncologic subspecialists have statistically significant differences in opinion regarding the use of PCI. However, these differences may not translate into large differences in clinical practice. Most oncologists continue to recommend PCI in limited-stage SCLC patients, despite many believing PCI may not provide a survival advantage nor improve quality of life.

Studies of primary central nervous system lymphoma with fluorine-18-fluorodeoxyglucose positron emission tomography.

Primary CNS lymphoma is a rare and highly malignant primary brain tumor. Ten patients with biopsy-proven primary CNS lymphoma were studied with 18F-2-fluoro-2-deoxy-D-glucose (FDG) and positron emission tomography (PET) to demonstrate the findings in patients with this tumor. The accumulation of FDG in primary CNS lymphoma is similar to that seen in anaplastic gliomas and is significantly more prominent than in low grade astrocytomas (p = 0.001). Steroid therapy substantially reduced the amount of FDG uptake in the one case studied both before and after its administration. The difference in FDG uptake between steroid-treated and untreated cases of primary CNS lymphoma, however, did not reach statistical significance (p = 0.40). Primary CNS lymphoma, like gliomas, suppresses the metabolism of both contiguous and distant but functionally linked areas of the brain. This study thus shows that the metabolic behavior of primary CNS lymphoma, as monitored by FDG-PET, resembles that of malignant glial tumors.

Distribution and dosimetry of I-123-labeled monoclonal antibody 81C6 in patients with anaplastic glioma.

RATIONALE AND OBJECTIVES: Monoclonal antibody 81C6 reacts with the extracellular matrix antigen, tenascin, present on gliomas and other tumors, as well as several normal tissues, including spleen and liver tissue. Single photon emission computed tomography (SPECT) and I-123-labeled 81C6 at various protein doses were used to maximize tumor to normal tissue uptake ratios. METHODS: The distribution of I-123-labeled monoclonal antibody 81C6 was determined in 16 patients with recurrent gliomas, using SPECT: Between 3.5 and 11.5 mCi of I-123 were administered to each patient, and the antibody doses were between 10.0 and 100.0 mg. Blood was obtained for pharmacokinetic studies, and patients were imaged 1 hour and 18 hours after antibody administration. RESULTS: All tumors were visualized readily on the SPECT study in areas that corresponded to the contrast, enhancing abnormalities on anatomic neuroimaging studies. The half-life in blood of the I-123 81C6 ranged from 16 to 37 hours. Radiation dosimetry calculations suggest that it might be possible to administer more than 700 cGy to intracranial glioma with I-131 labeled 81C6 under optimal conditions with acceptable non-neurologic organ radiation exposure. CONCLUSIONS: SPECT imaging with I-123 81C6 identified all tumors and suggests that, with this antibody, more favorable tumor-to-liver and tumor-to-spleen radiation dose ratios are obtained at higher protein doses.

Metastatic carcinoid tumor to the orbit and brain.

Carcinoid tumors constitute an uncommon source of metastatic lesions to the brain. We report the case of a 63-year-old man who initially sought treatment for proptosis 15 years before coming to our attention with a metastatic intracerebral left parietal carcinoid. The pathological features of the exenterated orbital mass were interpreted as undifferentiated carcinoma, and a lesion of the left lower lobe of the lung that had been removed 6 years earlier had been reported as metastatic malignant melanoma. The long duration between the initial diagnosis and the onset of neurological symptoms brought into question the original diagnosis, which, in retrospect, was most consistent with metastatic carcinoid. Staining for cytokeratin, neuron-specific enolase, and synaptophysin in the absence of staining for S-100 and HMB-45 supported the revised pathological diagnosis. Metastatic intracerebral carcinoid from an unrecognized bronchogenic source is a rare event, particularly after an orbital metastasis, but should be suspected when the clinical course is inconsistent with the more common causes of metastatic disease.

Concurrent chemotherapy and radiotherapy in patients with brain tumors.

Because treatment for most brain tumors remains inadequate, there has been a sustained interest in using concurrent chemotherapy and radiotherapy to improve local control, prolong overall survival, and reduce treatment-related toxicity. Unfortunately, many currently available radiosensitizers are either ineffective against brain tumors or have a reduced ability to cross the blood-brain barrier when administered systemically. Many agents also have overlapping toxicities with cranial irradiation or enhance the toxicity of radiation in a way that potentially compromises care. Finally, the addition of chemotherapy to cranial irradiation complicates the assessment of tumor response. Despite these barriers, trials with a number of promising agents are currently under way. These trials have already provided crucial insights into the pharmacokinetics, clinical pharmacology, and practical management of brain tumor patients with concurrent chemotherapy and radiotherapy. These findings should rapidly lead to the safer and more effective use of combined-modality therapy in patients with central nervous system cancer.