Additional experience with empiric radiotherapy for presumed human immunodeficiency virus-associated primary central nervous system lymphoma

An unusual and challenging case of HIV-associated primary CNS Lymphoma with Hodgkin-like morphology and HIV encephalitis

HIV-associated primary CNS lymphomas are well-recognized, almost exclusively EBV-driven neoplasms with poor clinical prognosis. We report a challenging, atypical case of an HIV-associated lymphoproliferative disorder with unusual morphologic features reminiscent of Hodgkin Lymphoma, accompanied by HIV encephalitis. A 52-year-old male presented with acute seizures after seven months of progressive neurocognitive decline that was clinically diagnosed as progressive supranuclear palsy. Clinical work-up revealed HIV infection along with two ring-enhancing lesions in the brain on MRI, and negative CSF EBV testing. Subsequent biopsy showed well-demarcated hypercellular regions in the brain comprised of scattered Reed-Sternberg-like cells in a background of small to medium-sized lymphocytes exhibiting focal angiocentricity and geographic necrosis. The atypical cells were positive for CD20, EBV, and CD79a, and negative for CD45, GFAP, CD15, CD30, and p24. These cells were admixed with numerous CD68-positive cells. The adjacent brain showed classic features of HIV encephalitis with perivascular, CD68 and p24-positive multinucleated giant cells. This case illustrates several diagnostic pitfalls in the work-up of HIV-associated brain lesions, as well as reporting a unique histomorphology for an HIV-related primary CNS lymphoproliferative disorder.

Utility of brain biopsy in patients with acquired immunodeficiency syndrome before and after introduction of highly active antiretroviral therapy

OBJECTIVE

This study investigates the changing indications, results, and practice patterns of brain biopsy in patients with acquired immunodeficiency syndrome (AIDS) as treatment evolved with the development of highly active antiretroviral therapy (HAART).

METHODS

We collected data on 246 patients with AIDS who were undergoing brain biopsy of intracranial lesions. Patients were managed in accordance with a uniform protocol. Patients were divided into two groups of those biopsied in the era before (1992-1996) or after (1997-2001) the use of HAART.

RESULTS

The introduction of HAART led to a steep decrease in the number of biopsies performed annually. The protocol functioned well. Diagnoses were obtained for 92.3% of patients. Lymphoma was the most frequent diagnosis (52.9% of patients), followed by progressive multifocal leukoencephalopathy (18.9% of patients) and toxoplasmosis (8.1% of patients). No patient who underwent lesion biopsy for reasons of negative toxoplasmosis titers or atypical radiology evaluation was diagnosed with toxoplasmosis. Nineteen patients who experienced failed toxoplasmosis treatment were diagnosed with toxoplasmosis. Toxoplasmosis titers had a high specificity and a negative predictive value. Patients with progressive multifocal leukoencephalopathy or nondiagnostic biopsies were more likely to have solitary lesions. The average Karnofsky performance score at the time of biopsy was 72.4, which is still within the range of independent functioning. Significant intracerebral hemorrhages were only observed in patients with lymphoma who also had low platelet counts.

CONCLUSION

Although the number of patients with AIDS who require brain biopsy has decreased, the procedure still has merits. The paradigm we developed was useful for selecting patients for early biopsy. Patients with AIDS who also have intracerebral lesions should have toxoplasmosis titers performed, and those whose titers are negative for toxoplasmosis should undergo early brain biopsy.

AIDS malignancies

Among individuals with HIV-infection, coinfection with oncogenic viruses including EBV, HHV-8, and HPV cause significant cancer-related morbidity and mortality. It is clear that these viruses interact with HIV in unique ways that predispose HIV-infected individuals to malignant diseases. In general, treatment directed specifically against these viruses does not appear to change the natural history of the malignant disease, and once the malignancy develops, if their health permits, HIV-infected patients should be treated using similar treatment protocols to HIV-negative patients. However, for the less frequent HIV-related malignancies, such as PEL, or MCD, optimal treatments are still emerging. For certain AIDS-defining malignancies, it is clear that the widespread access to HAART has significantly decreased the incidence, and improved outcomes. However, for other cancers, such as the HPV-related tumors, the role of HAART is much less clear. Further research into prevention and treatment of these oncogenic virally mediated AIDS-related malignancies is necessary.

Highly Active Antiretroviral Therapy and Human Immunodeficiency Virus–Associated Primary Cerebral Lymphoma

From a cohort of 9621 human immunodeficiency virus type 1-infected individuals, we identified 61 patients with primary central nervous system lymphoma (PCL) who had a median survival of 1.3 months. We compared clinicopathologic variables of patients who were treated in the pre-highly active antiretroviral therapy (HAART) and HAART eras and investigated whether exposure to antiretroviral agents with differing cerebrospinal fluid penetrations was associated with risk for PCL. All statistical tests were two-sided. Incidence of PCL was lower in the HAART era (1.2 cases per 1000 patient-years, 95% confidence interval [CI] = 0.8 to 1.9) than in the pre-HAART era (three cases per 1000 years, 95% CI = 2.1 to 4.0; P<.001), and overall survival was longer (median survival = 32 days, range = 5-315 days, versus 48 days, range = 15-1136 days; log rank P = .03). In the HAART era, fewer patients had prior acquired immunodeficiency syndrome-defining illnesses than in the pre-HAART era (64% versus 90%; P = .013), and patients were more likely to have the diagnosis of PCL confirmed histologically or by polymerase chain reaction (77% versus 26%; P<.001). Exposure to specific antiretroviral agents was not associated with risk for PCL.

Therapy insight: AIDS-related malignancies--the influence of antiviral therapy on pathogenesis and management

Patients with HIV infection are at an increased risk of a number of malignancies, including Kaposi's sarcoma (KS) and certain B-cell lymphomas. Most of these tumors are caused by oncogenic DNA viruses, including KS-associated herpesvirus and Epstein-Barr virus. HIV contributes to the development of these tumors through several mechanisms, including immunodeficiency, immunodysregulation, and the effects of HIV proteins such as Tat. The development of highly active antiretroviral therapy (HAART) has reduced the incidence of many HIV-associated tumors and has generally improved their responsiveness to therapy. However, the number of people living with AIDS is increasing, and it is possible that the number of AIDS-associated malignancies will rise and the pattern of tumors will change as more people live longer with HIV infection. The goal of KS therapy is long-term tumor control with minimal toxicity. HAART is an important component of this therapy, and some patients do not require other KS-specific therapies. By contrast, the goal of AIDS-related lymphoma therapy in most cases is the attainment of a complete response with curative intent, and the benefits of administering HAART during therapy must be weighed against possible disadvantages. The past decade has seen substantial improvements in the treatment of AIDS-related lymphoma, which is attributed partially to a shift in tumor type and more effective regimens. There is currently an interest in developing new therapies for HIV-associated malignancies, based on viral, vascular or other pathogenesis-based targets.

AIDS-Related Primary Central Nervous System Lymphoma

Primary central nervous system lymphoma (PCNSL) can develop in the setting of profound immunosuppression, including late-stage infection with HIV. The management of such patients has yet to be defined optimally and differs substantially from that of immunocompetent patients who have PCNSL. The clinical features, diagnosis, and management of AIDS-related PCNSL are reviewed. The authors focus on commonly encountered diagnostic and therapeutic dilemmas and explore some promises and pitfalls of Epstein-Barr virus-directed therapies.

Guidelines for the diagnosis and management of neurological complications of HIV infection

The spectrum of neurological complications of HIV-infection has remained unchanged through the years, but its epidemiology changed remarkably as a result of the introduction of highly active antiretroviral therapy (HAART). Guidelines for the diagnosis and treatment of cerebral toxoplasmosis, cryptococcal meningitis, progressive multifocal leukoencephalopathy, CMV encephalitis, CMV polyradiculomyelitis, tuberculous meningitis, primary CNS lymphoma, HIV dementia, HIV myelopathy and HIV polyneuropathy are given with a grading of evidence and recommendations.

Survival is prolonged by highly active antiretroviral therapy in AIDS patients with primary central nervous system lymphoma

OBJECTIVE

To determine the effects of highly active antiretroviral therapy (HAART) on survival in AIDS-related primary central nervous system lymphoma (PCNSL).

METHODS

Survival in consecutive patients with PCNSL at a large county teaching hospital from 1995 to 2001 were analyzed by the log rank test and Cox proportional hazards ratios (HR) were calculated for factors potentially affecting survival.

RESULTS

During the study period, 25 patients were diagnosed with PCNSL: 19 definite and 6 probable. At diagnosis, median CD4 cell count was 12 x 10(6) cells/l (range 1-151) and median HIV viral load was 5.3 log(10) copies/ml (range 3.9-5.9). Sixteen patients died (median survival 87 days; range, 0 to > 2112). Longer survival was noted for patients who received HAART after diagnosis [HR for death, 0.06; 95% confidence interval (CI), 0.01-0.48]. Six of seven HAART-treated patients were alive versus 0/18 untreated patients at a median follow-up time of 667 days (P = 0.0007 by log rank test). A survival benefit was seen for patients who had >/= 0.5 log(10) copies/ml decrease in HIV viral load after diagnosis (n = 6; HR, 0.07; 95% CI, 0.01-0.55) and for patients with a significant CD4 cell rebound (increase >/= 50 x 106 cells/l) in response to HAART (n = 6): all survived versus 0/19 survived (P = 0.0003). Cranial radiation therapy (n = 13) prolonged survival (HR, 0.20; 95% CI, 0.07-0.58). Median survival was only 29 days for 11 patients who received neither radiation nor HAART.

CONCLUSIONS

Receipt of HAART after diagnosis is associated with a significantly longer survival in patients with AIDS-related CNS lymphoma.

Treatment options of AIDS-related lymphoma

Recently, the median survival of patients with AIDS-related lymphoma has changed significantly. This effect is mainly because of changes in the use of antiviral (highly active antiretroviral therapy; HAART) or chemotherapy regimens. Several novel treatment options have been explored in patients with lymphoma. It is hoped that innovative strategies will lead to a survival benefit in these patients. In this review, we present an update of current strategies for the treatment of AIDS-related lymphoma.

Management of AIDS-related non-Hodgkin's lymphomas

The incidence of non-Hodgkin's lymphoma in individuals infected with HIV is approximately 60- to 100-fold increased over the general population. The majority of patients with AIDS-related lymphoma (ARL) present with stage III-IV disease and with B-symptoms. They often have multiple extranodal localisations, with a high incidence of central nervous system involvement. Histologically, most tumours are either diffuse large cell lymphomas or Burkitt lymphomas. Several factors, such as disrupted immune surveillance, Epstein-Barr virus infection, chronic antigenic stimulation, cytokine dysregulation and the acquisition of genetic lesions, are thought to contribute to the pathogenesis. Patients with ARL have a poor prognosis: overall survival ranges from 1.5 to 18 months. The most important adverse prognostic factors are poor performance status, a low CD4+ cell count and a history of opportunistic infections. Results of treatment with polychemotherapy compare unfavourably to results in patients without HIV infection. Since the advent of highly active antiretroviral therapy (HAART), there appears to be a decrease in the incidence of ARL. In addition, the use of HAART in combination with chemotherapy and the use of new treatment modalities may improve the outcome of this disease.

Focal neurological disease in patients with acquired immunodeficiency syndrome

Focal neurological disease in patients with acquired immunodeficiency syndrome may be caused by various opportunistic pathogens and malignancies, including Toxoplasma gondii, progressive multifocal leukoencephalopathy (PML), cytomegalovirus (CMV), and Epstein-Barr virus-related primary central nervous system (CNS) lymphoma. Diagnosis may be difficult, because the findings of lumbar puncture, computed tomography (CT), and magnetic resonance imaging are relatively nonspecific. Newer techniques have led to improved diagnostic accuracy of these conditions. Polymerase chain reaction (PCR) of cerebrospinal fluid specimens is useful for diagnosis of PML, CNS lymphoma, and CMV encephalitis. Recent studies have indicated the diagnostic utility of new neuroimaging techniques, such as single-photon emission CT and positron emission tomography. The combination of PCR and neuroimaging techniques may obviate the need for brain biopsy in selected cases. However, stereotactic brain biopsy, which is associated with relatively low morbidity rates, remains the reference standard for diagnosis. Highly active antiretroviral therapy has improved the prognosis of several focal CNS processes, most notably toxoplasmosis, PML, and CMV encephalitis.

Primary central nervous system lymphoma involving the optic chiasm in AIDS

OBJECTIVE

To report visual loss resulting from chiasmal involvement by primary central nervous system lymphoma (PCNSL).

MATERIALS AND METHODS

Case report.

RESULTS

A patient with the acquired immune deficiency syndrome (AIDS) presented with visual loss resulting from PCNSL involving the optic chiasm. The clinical findings, neuroimaging, pathology, and treatment of this patient are described.

CONCLUSIONS

Although rare, clinicians should consider PCNSL in the differential of a hypothalamic/chiasmal mass, especially in a patient with AIDS.

Primary CNS lymphoma: clinical presentation, pathological classification, molecular pathogenesis and treatment

Primary CNS lymphomas (PCNSL) represent malignant non-Hodgkin's B cell lymphomas, which are confined to the central nervous system. They show a dramatic increase in frequency in the immunocompromised as well as in the immunocompetent population. Recent studies have identified germinal center B cells as the cellular origin of PCNSL; however, the details of their molecular pathogenesis still remain to be elucidated. Treatment recommendations are not clearly established. Radiotherapy (RT) is efficient in terms of tumor response, but not curative. Median survival after RT alone is about 1 year. According to the results of uncontrolled studies the combination of RT and chemotherapy based on high-dose methotrexate (HD-MTX) is most efficient in terms of survival rates. However, long-term neurotoxicity overshadows treatment efficacy, especially in patients over 60 years of age. The authors favor the systematic evaluation of chemotherapy alone with protocols including HD MTX, because unicenter results are promising in terms of both survival as well as quality of life in long term survivors.

Acquired immunodeficiency syndrome-related primary cerebral lymphoma: response to irradiation

Acquired immunodeficiency syndrome-related primary cerebral lymphoma (AIDS-PCL) is uncommon. Fourteen cases of presumed AIDS-PCL between 1986 and 1995 were reviewed retrospectively in order to characterize the natural history, and the response to radiotherapy. The median age was 38 years (range 24-65). The median interval between seropositive diagnosis of HIV and AIDS-PCL was 28 months (range 5-113). The median duration of symptoms was 2 weeks (range 0.2-12). At presentation, the Eastern Cooperative Oncology Group performance status (PS) was PS1 (2/14 patients), PS2 (6/14) and PS3 (6/14). The symptoms and signs were non-specific and depended on the site and extent of cerebral involvement. There was no characteristic pattern of brain imaging in terms of size, number, location or pattern of contrast enhancement of the cerebral lesions. Nine patients received various fractionation-dose schedules (range 8-50 Gy). Complete and partial responses were seen in 2/9 and 3/9 cases, respectively. Clinical stabilization of neurological symptoms was noted in 3/9 cases and disease progression in 1/9. The median survival times (MST) from presentation for irradiated and non-irradiated patients were 9.3 and 2.1 weeks, respectively (range 0.9-43.1). Although patient selection introduced bias, there appears to be a modest improvement in MST for treated patients. The MST with radiotherapy alone remains poor, but radiotherapy may provide palliation. For some selected patients, a prolonged response is possible.

AIDS-related central nervous system lymphomas

PURPOSE

To evaluate combined radio-chemotherapy in patients with AIDS-related lymphomatous meningitis (LM) or primary central nervous system lymphoma (PCNSL).

PATIENTS AND METHODS

Eighteen men and 2 women with AIDS had cytologically documented LM. Fifteen patients had systemic non-Hodgkin's lymphoma with LM and 5 patients had PCNSL with CSF dissemination. Standardized pre-treatment evaluations included contrast cranial MRI, placement of an intraventricular reservoir, contrast spine MRI, ophthalmologic evaluation and 111Indium-DTPA CSF flow studies. Regions of bulky or symptomatic disease were treated with limited-field irradiation. Concurrent systemic chemotherapy was administered in 18 patients. All patients were scheduled to receive intraventricular methotrexate (MTX) according to a concentration x time (C x T) drug schedule. In cytologic or clinical failures, patients were treated with salvage therapy using intraventricular ara-C and in a similar manner, patients were treated with intraventricular thio-TEPA following cytologic relapse or clinical failure intraventricular following intraventricular ara-C. Sixty-seven patients (63 men; 4 women) with PCNSL underwent a standardized pre-treatment evaluation as in patients with LM and were treated according to 3 schedules. In the first group (n = 15), comfort care was offered. In the second group (n = 45), whole brain radiotherapy was administered. In the third group (n = 7), patients were treated with combined radio- and chemotherapy using systemic procarbazine, CCNU and vincristine (PCV-3). The third group was selected based on a Karnofsky performance status > or =60, no evidence of disseminated PCNSL, a CD4 count >200, no concurrent opportunistic infection and a patient's desire for aggressive therapy.

RESULTS

In the LM patient group, 16 patients were evaluable as 4 patients subsequently withdrew consent for treatment. Median time to tumor progression/survival were as follows: not-treated (n = 4) 12 days/ month; treated non-responding (n = 6) 30 days/2 months; and treated responding (n = 10) 130 days/6 months. In the PCNSL patient group, median range survival were as follows: comfort care (n = 15) 1.5/0.5-3 months; whole brain radiotherapy (n = 45) 4/1.5-5 months; and combined radio-chemotherapy (n = 7) 13/10-18 months.

CONCLUSIONS

Combined radio- and chemotherapy is appropriate for a small subset of patients with AIDS and either LM or PCNSL. This approach results in meaningful palliation not strikingly dissimilar from that seen in non-AIDS patients.

Treatment outcome in presumed and confirmed AIDS-related primary cerebral lymphoma

A retrospective analysis identified 38 HIV seropositive patients with a diagnosis of presumed (n = 26) or confirmed (n = 12) primary cerebral lymphoma (PCNSL). All patients had failed to respond to empirical antitoxoplasma therapy and the clinical diagnosis of PCNSL was confirmed by brain biopsy (n = 4), cerebrospinal fluid (CSF) examination for Epstein-Barr virus (EBV) by PCR (n = 7) or postmortem examination (n = 1). There was no difference in the age, performance status, CD4 counts, antiretroviral usage or interval since first HIV serodiagnosis between patients with presumed or confirmed PCNSL. 16 patients received either radiotherapy (n = 14) or chemotherapy (n = 2). Patients with confirmed or presumptive PCNSL were equally likely to receive treatment. The median overall survival, which was measured from the end of unsuccessful antitoxoplasma therapy, was 1.2 months for the whole cohort. There was no difference in overall survival between patients with presumptive (median 0.8 months) and confirmed (median 1.3 months) PCNSL (logrank P = 0.69). This suggests that there may be little value in positively diagnosing PCNSL in the current diagnostic algorithm. Recent improvements in outcome have been reported with systemic chemotherapy in HIV-PCNSL and may influence the need for earlier definitive diagnosis in the future.

Minimally invasive diagnosis of acquired immunodeficiency syndrome-related primary central nervous system lymphoma

BACKGROUND

The detection of Epstein-Barr virus (EBV)-DNA in cerebrospinal fluid (CSF) by means of the polymerase chain reaction (PCR) has been revealed, in retrospective studies, to be a good marker of primary central nervous system lymphoma (PCNSL) related to acquired immunodeficiency syndrome (AIDS); however, the technique's usefulness in the management of AIDS patients with focal brain lesions is still unknown. We studied the clinical usefulness of testing CSF obtained by lumbar puncture for the presence of EBV-DNA as a minimally invasive approach to the diagnosis of AIDS-PCNSL in patients with focal brain lesions.

METHODS

Human immunodeficiency virus (HIV)-infected patients with focal brain lesions, observed prospectively during a 30-month period, underwent lumbar puncture if not contraindicated; otherwise, ventricular CSF was obtained at brain biopsy. The presence of EBV-DNA was determined by means of PCR.

RESULTS

We evaluated 122 patients: 42 diagnosed with brain lymphoma and the remaining 80 diagnosed with other brain disorders. Cerebrospinal fluid was collected from 101 patients--by lumbar puncture in 95, including 40 patients with AIDS-PCNSL. The sensitivity and specificity of PCR for EBV-DNA detection in lumbar CSF were 80% (95% confidence interval [CI] = 60.9%-91.6%) and 100% (95% CI = 92.6%-100%), respectively. Lumbar puncture and subsequent assessment of EBV-DNA would have allowed a correct diagnosis in 63.2% (95% CI = 46.0%-77.7%) of patients with AIDS-PCNSL and excluded this diagnosis in 76.3% (95% CI = 65.2%-84.8%) of patients without lymphoma (because EBV-DNA was not detected).

CONCLUSIONS

The presence of EBV-DNA in lumbar CSF is a sensitive and highly specific diagnostic marker of AIDS-PCNSL, and EBV-DNA detection in this fluid may allow a minimally invasive diagnosis in a large percentage of patients with brain lymphomas.

Intravenous methotrexate for primary central nervous system non-Hodgkin's lymphoma in AIDS

OBJECTIVE

To evaluate high-dose intravenous methotrexate in primary central nervous system (CNS) lymphoma in HIV-infected patients.

DESIGN

An uncontrolled pilot trial.

SETTING

An infectious diseases department in Paris, France.

PATIENTS

All consecutive AIDS patients with primary CNS lymphoma attending the same unit from August 1994 to March 1996.

INTERVENTIONS

Methotrexate was intravenously administered at a dose of 3 g/m2 every 14 days with leucovorin rescue. A maximum of six cycles was planned. Steroids were given to all patients and haematological growth factors were administered as required.

MAIN OUTCOME MEASURES

Rate of response, time to response and survival.

RESULTS

Fifteen patients (10 with histological documentation) were recruited. The median time since clinical onset was 27 days (range, 7-69 days), median Karnofsky score was 51 (range, 30-70), and mean CD4+ cell count was 30 +/- 19 x 10(6)/l (range, 7-69 x 10(6)/l). Complete responses, defined as clinical improvement and disappearance of contrast-enhancing brain abnormalities on computed tomography or magnetic resonance imaging, were obtained in seven out of 15 patients (three out of 10 patients with histological diagnosis and four out of five patients without histological confirmation). The Karnofsky score of these seven patients improved to 80 +/- 10 (range, 70-100). The mean time taken to respond was 62 +/- 20 days (range, 45-90 days). One patient relapsed at 6 months. Six patients failed to respond, and two died of severe sepsis on days 15 and 45. The median survival time was 290 days (range, 11-570 days): 73 days (range, 11-570 days) in the 10 patients with histological diagnosis, and 347 days (range, 286-409 days) in the five patients without histological confirmation. Side-effects occurred in 10 patients, with gastrointestinal disorders in five, mucositis and skin rash in two, and fever in three patients; however, these events were mild and did not require cycle postponement or dose changes. No cognitive dysfunction occurred.

CONCLUSION

Methotrexate appears to be an attractive alternative to radiation therapy for primary CNS lymphoma and is associated with a far greater improvement in quality of life relative to historical series of radiation therapy.

Palliation of AIDS-related primary lymphoma of the brain: observations from a multi-institutional database

PURPOSE

To catalogue the presenting symptoms of patients with AIDS who are presumed to have primary central nervous system lymphoma (PCNSL). To document the palliative efficacy of cranial irradiation (RT) relative to the endpoints of complete and overall response for the respective symptoms.

METHODS

An analysis of 163 patients with AIDS-related PCNSL who were evaluated at nine urban hospitals was performed. These patients were treated for PCNSL after the establishment of a tissue diagnosis or on a presumptive basis after failing empiric treatment for toxoplasmosis. All patients were treated between 1983 and 1995 with radiotherapy (median dose-fractionation scheme = 3 Gy x 10) and steroids (>90% dexamethasone). Because multiple fractionation schemes were used, prescriptions were converted to biologically effective doses according to the formula, Gy10 = Total Dose x (1 + fractional dose/alpha-beta); using an alpha-beta value of 10.

RESULTS

The overall palliative response rate for the entire group was 53%. In univariate analysis, trends were present associating complete response rates with higher performance status (KPS > or = 70 vs. KPS < or = 60 = 17% vs. 5%), female gender (women vs. men = 29% vs. 8%), and the delivery of higher biologically effective doses (BED) of RT (Gy10 > 39 vs. < or = 39 = 20% vs. 5%). In multivariate analysis of factors predicting complete response, both higher KPS and higher BED retained independent significance. A separate univariate analysis identified high performance status (KPS > or = 70 vs. KPS < or = 60 = 71% vs. 47%), and young age (< or = 35 vs. > 35 = 61% vs. 40%) as factors significantly correlating with the endpoint of the overall response. In multivariate analysis, high performance status and the delivery of higher biologically effective doses of irradiation correlated significantly with higher overall response rates.

CONCLUSION

Most AIDS patients who develop symptoms from primary lymphoma of the brain can achieve some palliation from a management program that includes cranial irradiation. Young patients with excellent performance status are most likely to respond to treatment. The delivery of higher biologically effective doses of irradiation also may increase the probability of achieving a palliative response.

Biology and management of AIDS-associated primary CNS lymphomas

Primary central nervous system (CNS) lymphoma is the most common brain tumor in patients with AIDS and occurs in about 10% of this population. CT/MR scan usually demonstrates single or multiple contrast enhancing masses that are radiographically indistinguishable from other CNS processes such as toxoplasmosis. Brain biopsy, positive cerebrospinal fluid (CSF) cytology, or possibly the demonstration of Epstein-Barr viral DNA in the CSF can establish the diagnosis. Cranial radiotherapy (RT) has been the cornerstone of therapy and produces responses in most patients, but their median survival is still only a few months. The addition of chemotherapy to RT may prolong survival in a sub-group of patients.