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© 2002 American Society for Clinical Oncology Importance of Radiotherapy in the Outcome of Patients With Primary CNS Lymphoma: An Analysis of the CHOD/BVAM Regimen Followed by Two Different Radiotherapy TreatmentsByFrom the Department of Clinical Oncology, Nottingham City Hospital, and Department of Neurosurgery, Nottingham University Hospital, Nottingham, United Kingdom; Departments of Hematology, Radiation Oncology, and Neurology, Hospital Clínic, Institut de Recerca Biomèdica August Pi i Sunyer, University of Barcelona, Barcelona; and Services of Radiation Oncology and Hematology, Institut Català dOncologia, lHospitalet, Spain. Address reprint requests to Francesc Graus, MD, Servei de Neurologia, Hospital Clínic, Villarroel 170, Barcelona 08036, Spain; email: fgraus{at}clinic.ub.es
PURPOSE: To assess the effect of a reduced dose of radiotherapy (RT) in patients with primary CNS lymphoma (PCNSL) responding to the cyclophosphamide, doxorubicin, vincristine, and dexamethasone (CHOD)/carmustine, vincristine, methotrexate, and cytarabine (BVAM) regimen. PATIENTS AND METHODS: Patients received one cycle of CHOD and two of BVAM. In the first trial, all 31 patients received 45-Gy whole-brain RT (CHOD/BVAM I). In the second, with 26 patients, RT dose was reduced to 30.6 Gy if there was a complete response (CR) after chemotherapy (CHOD/BVAM II).
RESULTS: Age, performance status, and chemotherapy received were similar in both protocols. CR rate at the end of all treatment was 68% for CHOD/BVAM I and 77% and for CHOD/BVAM II. Treatment modality was the only predictor of relapse, with 3-year relapse risks of 29% and 70% for CHOD/BVAM I and II, respectively. This was specifically important in the 25 patients less than 60 years old (3-year relapse risk, 25% v 83%; P = .01). The 5-year overall survival (OS) was 36%. Age (< 60 v CONCLUSION: Reduction of the RT dose from 45 Gy to 30.6 Gy in patients younger than 60 years old with PCNSL who achieved CR resulted in an increased risk of relapse and lower OS.
THE OPTIMAL TREATMENT for primary CNS lymphoma (PCNSL) is not established. In the last decade, several phase II studies have shown that the 5-year actuarial probability of survival with chemotherapy regimens that include high-dose methotrexate followed by radiotherapy (RT) is approximately 30% to 40%.1,2 This figure is superior to that of 28% at 2 years obtained with RT alone.3 Nevertheless, the combined effect of methotrexate and RT may lead to severe late neurotoxicity.4,5 The risk of this complication is particularly high in patients older than 60 years, in whom the risk of relapse is higher. To avoid this complication, some authors have proposed that chemotherapy should be used alone, with cranial RT reserved for those patients who are not in complete remission (CR) after chemotherapy.6 The risk of this approach is that it reduces the probability of long-term remission if RT is needed to eradicate microscopic disease that persists after chemotherapy. Therefore, the first step before eliminating the RT from a given regimen should be to analyze the impact of reducing the dose of RT on the risk of relapse and on survival of those patients in CR after chemotherapy. This approach has not been systematically studied in the different combined protocols used for PCNSL. In the present study, we report the effect of reducing the RT dose in PCNSL patients who responded to the previously described cyclophosphamide, doxorubicin, vincristine, and dexamethasone (CHOD)/carmustine, vincristine, methotrexate, and cytarabine (BVAM) regimen.7,8
Patient Characteristics Fifty-seven newly diagnosed patients with PCNSL were entered onto two successive phase II trials between 1990 and 1995 (CHOD/BVAM I; 31 patients) and between 1996 and 1999 (CHOD/BVAM II; 26 patients). Both protocols included the same chemotherapy regimen, but in CHOD/BVAM II, the dose of RT was reduced if the patient was in CR after chemotherapy (Table 1). None of the patients had clinical evidence of human immunodeficiency virus type 1 infection, had undergone organ transplantation, or had presented any previous malignancy. Patients older than 70 years were not included in these trials. Thirty-three patients were treated in Nottingham, United Kingdom, 22 patients were treated in Barcelona, Spain, and two patients were treated in Birmingham, United Kingdom. The main initial features of the patients at diagnosis are listed in Table 2. The clinical features, response to therapy, toxicity, and outcome of the 31 patients receiving CHOD/BVAM I have previously been reported.8 The staging studies recommended in the protocol were the following: (1) analytic: WBC count, hemoglobin and platelet count, erythrocyte sedimentation rate, basic biochemistry, including renal and liver function tests, and lactate dehydrogenase levels, (2) cytology of CSF (performed in 33 patients), (3) bone marrow aspiration and/or trephine biopsy (performed in 54 patients), and (4) computed tomography or magnetic resonance imaging of the brain, thorax, abdomen and pelvis (performed in all the cases). Slit-lamp examination of the eye was carried out in 22 patients. No patient had evidence of lymphoma outside of the CNS after the above-mentioned maneuvers.
CHOD/BVAM I and II Treatment Regimens The CHOD/BVAM regimen, previously described in detail,7,8 is shown in Table 1. The chemotherapy protocol was identical for both the CHOD/BVAM I and II regimens. Patients included in CHOD/BVAM I received 45-Gy whole-brain irradiation (to the C2/C3 interspace) in 25 fractions during a 5-week period, plus a boost to the site of the single lesion (10 Gy in five fractions in 1 week). In the CHOD/BVAM II regimen, the whole-brain irradiation dose was reduced to 30.6 Gy in 17 fractions during a 3-week period in those patients who had achieved a CR after chemotherapy with no boost to single lesions. Patients who did not reach CR after chemotherapy received 45 Gy as in CHOD/BVAM I. Additional spinal irradiation (35 Gy in 25 fractions in 5 weeks) was performed in both trials when CSF cytology was positive. All patients gave informed consent according to the ethics committee guidelines of the participating institutions. Computed tomography or magnetic resonance scans of the brain were repeated after surgery, chemotherapy, and RT. Further scans were performed every 6 months during follow-up evaluations for the first 2 years and annually thereafter. Assessment of response was performed as suggested by Macdonald et al.9
Statistical Methods
Completion of Therapy and Toxicity The main characteristics at diagnosis of the 57 patients included in the CHOD/BVAM I (31 cases) and II (26 cases) treatments are detailed in Table 2. No significant differences were found between the two regimens, with the exception of the number of CNS lesions: patients receiving CHOD/BVAM I presented with multiple mass lesions in 29% of cases, whereas those included in CHOD/BVAM II showed multiple lesions in 62% of cases (P = .01).
The majority of patients completed chemotherapy as planned (23 patients [74%] of CHOD/BVAM I and 21 [81%] of CHOD/BVAM II). One patient in the CHOD/BVAM II study received a single dose of methotrexate due to renal toxicity and the PCNSL progressed during chemotherapy. The major acute toxicity was myelosuppression with World Health Organization/Eastern Cooperative Oncology Group grade 3 or 4 neutropenia documented in almost all patients (82%). Thirty-four patients (60%) experienced at least one episode of neutropenic fever, but only 15 patients had positive blood cultures. The only other toxicities apart from alopecia and bone marrow toxicity were hepatic (grade
Response to Therapy
Risk of Relapse Sixteen of the 41 patients eventually relapsed during the follow-up period, with a risk of relapse at 3 years of 44% (95% confidence interval [CI], 27% to 61%). Patients in the CHOD/BVAM I trial had a lower risk of relapse than those receiving the CHOD/BVAM II treatment, with 3-year risks of relapse of 29% (95% CI, 9% to 49%) and 70% (95% CI, 40% to 100%), respectively (P = .02) (Fig 1A). This was particularly important in the 25 patients younger than 60 years old (3-year risk of relapse, 25% v 83% for protocols I and II, respectively; P = .01) (Fig 1B), whereas no difference between treatments was observed in the 16 patients aged 60 years and older. No other initial variable reached statistical significance in predicting relapse.
The risk of relapse was analyzed in the group of 36 patients who reached CR after chemotherapy, since these patients received a different dose of RT in the CHOD/BVAM I (45 Gy) and II (30 Gy) protocols. In the CHOD/BVAM I group, a trend for a lower risk of relapse was observed both in the whole series (3-year risk of relapse, 30% v 65%; P = .08) and in patients younger than 60 years old (3-year risk of relapse, 25% v 79%; P = .06).
OS
The baseline features were analyzed for OS. Patients 60 years (P = .02), patients with poor performance status (Eastern Cooperative Oncology Group > 2) (P = .05), and those with cognitive deficits (P = .02) had an unfavorable outcome. The lack of response to corticosteroids before surgery showed a trend for poor survival (P = .07). The number of lesions (single v multiple lesions) had no predictive value for OS. No significant difference in OS was found in the whole series with regard to treatment modality (CHOD/BVAM I v II). In the multivariate analysis with the above-mentioned significant variables, only age (< 60 v 60 years) maintained statistical significance for OS (relative risk, 2.1; 95% CI, 1.4 to 2.8). The prognostic study for OS was also performed in the group of 41 patients who achieved CR after all treatment (21 on the CHOD/BVAM I protocol and 20 on the CHOD/BVAM II protocol). No variable reached a significant predictive value, with only the treatment modality (P = .09) and dose of RT (P = .07) having marginal importance. However, when this analysis was performed in younger patients (< 60 years old), those receiving full-dose RT had a better outcome than the remainder (3-year OS, 92% v 60%; P = .04) (Fig 3).
Late Neurotoxicity The 35 patients who survived for longer than 1 year in CR after completion of all treatment were assessed for late neurotoxicity. Thirteen received the reduced dose of RT (30.6 Gy), with no patient developing cognitive dysfunction during the follow-up period. Twenty-two were treated with the standard RT dose (45 Gy): only one (8%) of 12 patients aged less than 60 years at diagnosis showed mild cognitive dysfunction. In contrast, six (60%) of the 10 patients aged 60 to 69 years developed dementia (P = .02).
Late neurotoxicity is a major problem in PCNSL patients who survive for longer than 1 year.4,5 Cognitive impairment, urinary incontinence, and gait disorders are progressive and dramatically reduce the quality of life of patients who may be cured of the PCNSL. This complication is related to age (it occurs in up to 83% of patients older than 60 years), to RT dose, and to chemotherapy if chemotherapy is given after RT.4,8 To decrease the incidence of this complication, chemotherapy alone has been used in a few studies, with cranial RT deferred until relapse of PCNSL.6,13-15 Whether avoiding RT after initial chemotherapy would have a negative impact on survival of patients with PCNSL is unknown and a matter of controversy. Our results indicate that a reduction in the RT dose to the whole brain from 45 Gy to 30.6 Gy in PCNSL patients younger than 60 years achieving CR after the CHOD/BVAM regimen is associated with a higher risk of relapse and a poorer outcome in terms of survival. This association was not been observed in patients aged 60 years and older, but the number of patients evaluated in this age group was small (16 patients). Therefore, the possibility of finding different results in a larger sample cannot be completely ruled out. There was no patient selection in that all eligible patients were included in these two protocols, but patients included in the CHOD/BVAM II treatment presented more often with multiple, contrast-enhanced lesions. This may be due in part to the routine use of magnetic resonance imaging in the second protocol, which may have resulted in the increase of multiple lesions observed. Nevertheless, this feature showed no predictive value for response to therapy, relapse, and OS in either univariate or multivariate analyses that, in line with previous studies,3,4,16,17 identified age as an important predictor for survival. Treatment modality was the only factor that predicted for relapse, especially in younger patients. Similarly, the number of patients who completed chemotherapy as planned was not different in the two protocols; therefore, no other variable could explain the differences found between the two treatments except the reduction in the RT dose. The 5-year OS of PCNSL patients receiving the CHOD/BVAM protocol was 36%, with a median survival time of 40 months. These figures are similar to those obtained with other combined treatments that include methotrexate at doses of 1.5 g/m2 or higher.2,4,5,18-20 The addition of other drugs to methotrexate in combined protocols with RT has not as yet shown better results than the use of methotrexate as monotherapy.21,22 However, the rationale for using multidrug regimens is to achieve long-lasting remissions that are unlikely to be obtained by methotrexate alone (based on the experience with treating systemic lymphoma) and to avoid the use of subsequent RT. The present results suggest that the multidrug regimen CHOD/BVAM is probably more effective when combined with RT. This finding has also been observed in localized, high-grade, systemic lymphomas, where chemotherapy with cyclophosphamide, hydroxydaunomycin, vincristine, and prednisone (CHOP) followed by RT may be superior to CHOP alone.23 A novel approach in the management of PCNSL is to use chemotherapy alone upfront and reserve RT for those patients with residual disease or who relapse after treatment.6,13-15 This strategy has also been used in patients with CNS germ cell tumors.24 The study showed that CNS germ cell tumors that relapsed after chemotherapy could be successfully salvaged with RT and that 50% of the patients could be effectively treated without RT.24 The experience with chemotherapy as exclusive treatment in patients with PCNSL is limited to a few series with a relative short follow-up. The frequency of relapse after the initial treatment ranged from 38% to 63%, and a substantial number of patients received cranial RT for relapse.2,13-15 In the largest series, 31 patients were initially treated with methotrexate alone, but at the end of the study, 17 (55%) had received RT either because CR was not achieved or the tumor relapsed.25 In our study, patients younger than 60 years old who achieved CR with the CHOD/BVAM I treatment had a 5-year probability of survival of above 60%, and no patient treated with 45 Gy to the whole brain, even with a boost to 55 Gy, developed dementia after a median follow-up of 59 months. Only one of 18 patients younger than 60 years old showed mild late neurotoxicity. These data, along with our finding that the RT dose reduction caused an increased risk of relapse, suggest that the CHOD/BVAM regimen alone, and probably any other methotrexate-based chemotherapy regimen, will not offer the best results if RT is withheld. Therefore, one should be extremely cautious when designing randomized trials comparing chemotherapy regimens with and without RT in PCNSL patients younger than 60 years old. In a previous study,5 survival in PCNSL patients aged 60 years and older was not shortened when RT was deferred at relapse after chemotherapy. However, the causes of death were different. Patients treated upfront with combined therapy usually died from complications derived from severe neurotoxicity, whereas those initially treated with chemotherapy alone died from progressive PCNSL. We did not observe any late neurotoxicity in the patients who received the reduced RT dose of 30.6 Gy, but the number of patients is too small and the follow-up is still too short to make any definite conclusion. However, since total RT dose is an important predictor of delayed neurotoxicity, a decrease in the incidence of this complication should be expected if the total RT dose is reduced. If one assumes that RT is not a good salvage treatment for PCNSL patients who relapse after chemotherapy, a sound strategy for these older patients could be to treat those who achieve a CR after chemotherapy with a reduced dose of cranial RT.
Both E.M.B. and A.L.-G. contributed equally to the study.
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Copyright © 2002 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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