Central nervous system (CNS) penetration of homoharringtonine (HHT)

Generally tritiated homoharringtonine ([³H]HHT, 150 Ci, 430 g) was administered intravenously to seven patients at varying times before surgical resection of malignant brain tumor. Plasma, urine, cerebrospinal fluid (CSF), and tumor specimens were obtained during surgery, and the concentrations of HHT, its major metabolite, and [³H]HHT equivalent were determined chromatographically and radiochemically. For [³H]HHT equivalent, the concentration in tumor ranged from 0.6 to 4.3 ng/g and the ratio of tumor to plasma concentration from 0.5 to 1.8. In one patient who had CSF available for drug determination, the CSF to plasma ratio of total [³H]HHT was 0.3 at 45 minutes after drug administration and less than 0.2 ng/ml was unchanged HHT. For unchanged HHT, drug concentration in tumor ranged from undetectable (4 patients) to 1.8 ng/g. A major metabolite of HHT was detectable in the tumor specimens of all the patients. These results indicate that homoharringtonine can penetrate into brain tumors; in 3 patients with brain tumors, the ratios of HHT concentration in the tumor to that in the concurrent plasma were greater than one. address for offprints     

Survival of European patients with central nervous system tumors

We present estimates of population-based 5-year relative survival for adult Europeans diagnosed with central nervous system tumors, by morphology (14 categories based on cell lineage and malignancy grade), sex, age at diagnosis and region (UK and Ireland, Northern, Central, Eastern and Southern Europe) for the most recent period with available data (2000-2002). Sources were 39 EUROCARE cancer registries with continuous data from 1996 to 2002. Survival time trends (1988 to 2002) were estimated from 24 cancer registries with continuous data from 1988. Overall 5-year relative survival was 85.0% for benign, 19.9% for malignant tumors. Benign tumor survival ranged from 90.6% (Northern Europe) to 77.4% (UK and Ireland); for malignant tumors the range was 25.1% (Northern Europe) to 15.6% (UK and Ireland). Survival decreased with age at diagnosis and was slightly better for women (malignant tumors only). For glial tumors, survival varied from 83.5% (ependymoma and choroid plexus) to 2.7% (glioblastoma); and for non-glioma tumors from 96.5% (neurinoma) to 44.9% (primitive neuroectoderm tumor/medulloblastoma). Survival differences between regions narrowed after adjustment for morphology and age, and were mainly attributable to differences in morphology mix; however UK and Ireland and Eastern Europe patients still had 40% and 30% higher excess risk of death, respectively, than Northern Europe patients (reference). Survival for benign tumors increased from 69.3% (1988-1990) to 77.1% (2000-2002); but survival for malignant tumors did not improve indicating no useful advances in treatment over the 14-year study period, notwithstanding major improvement in the diagnosis and treatment of other solid cancers.     

Phase II study of aziridinylbenzoquinone (AZQ) in patients with central nervous system malignancies: a Southwest Oncology Group study

Summary AZQ, an alkylating agent with lipophilic characteristics allowing CNS penetration was studied in patients with primary CNS malignancies refractory to surgical and radiotherapeutic modalities. Responses were evaluated by three criteria: neurologic examination, performance status and CT scan of the brain. Improvement in all three parameters with stable or decreasing doses of decadron was required for a partial response. Thirty-six poor risk (prior chematherapy) patients with Grades III and IV astrocytomas were treated with 30 mg/m². Three patients had a partial response (14, 17, 60 weeks duration). Two patients had mixed responses (worsening of one disease parameter with improvement in another), four had stable disease and one patient had improvement in neurologic parameters with a stable CT scan. Twenty-six patients had increasing disease. Fifteen good risk patients (no prior chemotherapy) with recurrent grades III and IV astrocytomas were treated at a dose of 40 mg/m² intravenously every three weeks. There were no objective responses in this group of patients. Three patients with nonastrocytomas were treated and no responses observed. The drug was well tolerated. Myelosuppression in the form of leukopenia and thrombocytopenia was the major toxicity. Myelosuppression required dose reductions in eight patients and discontinuation of therapy due to repeated treatment delays in two patients. AZQ at doses of 30 and 40 mg/m² given on an intermittent bolus schedule is inactive in patients with Grades III and IV recurrent astrocytoma.Presented in part at the Second International Symposium on Biology of Brain Tumours, London, October 1984.     

Influenza vaccine immunogenicity in patients with primary central nervous system malignancy

Background

Patients with central nervous system (CNS) malignancies represent an “at-risk” population for contracting influenza, particularly if they are receiving ongoing chemotherapy, radiation, and/or glucocorticoid treatment. The Centers for Disease Control endorses vaccination for these patients, although data are not available to indicate whether they mount an immunologic response adequate to achieve clinical protection.

Methods

A pilot prospective cohort study was designed to evaluate the immunogenicity of the standard-dose trivalent inactivated influenza vaccine in patients with malignant CNS tumors. Baseline data collection included diagnosis, chemotherapy, timing of chemotherapy or radiation relative to vaccination, and glucocorticoid dose. Serum samples were collected at baseline, day 14, day 28, and month 3 following vaccination. Samples were tested using hemagglutinin inhibition to determine seroconversion (4-fold rise in titer) and seroprotection (titer >1:40).

Results

A total of 38 patients were enrolled (mean age, 54 years ±13.5 years, 60.5% male, 94.7% Caucasian, and 5.3% African American). CNS tumor diagnoses included glioblastoma multiforme (55.2%), other high-grade glioma (13.2%), low-grade glioma (15.8%), and primary CNS lymphoma (15.8%). At enrollment, 20 patients (52.6%) were taking glucocorticoids, 25 (65.8%) were on active chemotherapy, and 3 (7.9%) were undergoing radiation. Seroconversion rates at day 28 for the A/H1N1, A/H3N2, and B strains were 37%, 23% and 23%, respectively. Seroprotection was 80%, 69%, and 74%, respectively. All rates were significantly lower than published rates in healthy adults (P < .001).

Conclusion

Influenza vaccine immunogenicity is significantly reduced in patients with CNS malignancies. Future studies are needed to determine the causative etiologies and appropriate vaccination strategies.     

Calmodulin content in human central nervous system tumors

Summary Benign and malignant brain tumors and normal cerebral cortex were assayed for calmodulin content by enzymatic and radioimmunoassay techniques. Normal cerebral cortex contained more (8.31 ± 1.27 vs 3.30 ± 0.42 µg/mg protein) calmodulin than the brain tumors. The contents of calmodulin in the malignant glioblastomas were significantly higher than the meningiomas (5.41 ± 0.31 vs 2.97 ± 0.16 µg/mg protein). These differences were independent of tumor location and persisted when calmodulin content was normalized for DNA rather than protein content. This data supports differences in the tissue calmodulin contents with normal cortex> primary malignant tumors> benign tumors> metastatic tumor tissue.     

原发性中枢神经系统淋巴瘤患者预后的影响因素分析

目的 探讨原发性中枢神经系统淋巴瘤(PCNSL)患者预后的影响因素.方法 收集82例PCNSL患者的临床资料,包括性别、年龄、病灶数量、病灶部位、病灶直径、治疗方法、意识状态、体力状况(PS)评分等一般资料,以及脑脊液(CSF)常规检测指标(CSF蛋白质、CSF氯化物)和生化检测指标[血清乳酸脱氢酶(LDH)、β2微球...     

Second malignancies in patients with primary central nervous system lymphoma

Background

Primary central nervous system lymphoma (PCNSL) is a rare extranodal lymphoma with distinctive biological behaviors. The evolving treatment of PCNSL has greatly improved the outcome for patients with this disease and has stimulated interest in second malignancies (SMs) in patients diagnosed with PCNSL.

Methods

The records of 129 cases of PCNSL at Mayo Clinic, diagnosed between January 1, 1988, and November 26, 2012, were reviewed. Data on clinical characteristics, laboratory parameters, treatments, outcomes, and SMs were collected. The mean follow-up time was 44.8 months (range, 0.5–240 months; median, 28.0 months).

Results

Altogether, 28 cases with 30 (23.26%) SMs were identified. Twenty (15.50%) patients had prior or synchronous SM. Ten (7.76%) patients developed a subsequent primary cancer after PCNSL. The most common sites of prior or synchronous SMs were prostate (4/20), skin (4/20), and gastrointestinal (3/20). The most common site of the subsequent SM was skin (4/10). Two cases were identified with both prior SM and subsequent SM.

Conclusions

Second malignancies in cases with PCNSL were not uncommon and occurred in nearly a quarter of our cohort. Nonmelanoma skin cancers were frequently seen. Therefore, screening for SMs should also be considered in long-term follow-up of patients with PCNSL. In addition, the high incidence of subsequent cancer, synchronous cancer, and frequently seen nonmelanoma skin cancers may all indicate an immunosuppressed state in patients with PCNSL.     

Proton magnetic resonance spectroscopy in immunocompetent patients with primary central nervous system lymphoma

Background: Magnetic resonance spectroscopy imaging (MRSI) non-invasively evaluates the metabolic profile of normal and abnormal brain tissue. Primary central nervous system lymphoma (PCNSL) is a highly aggressive tumor responsive to high-dose methotrexate based regimens. Patients often have complete responses but relapses are common. We characterized the MR spectra of PCNSL patients, correlated MRSI with MRI and evaluated whether early recurrence could be detected by MRSI.Methods: Patients with PCNSL had multi-voxel MRSI before, during, and after treatment. The region of interest was defined using axial FLAIR images. Metabolites assessed were N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr), lipid, and lactate. Ratios of Cho/Cr, NAA/Cho, and NAA/Cr were calculated and correlated with MRI. Overall survival (OS), progression free survival (PFS), and relative risks of each of the ratios were determined.Results: MRSI was performed on 11 men and seven women; median age of 59. Sixty-seven MRSI studies were performed, 17 baseline and 48 follow-up studies. Median ratios in 16 pretreated patients were Cho/Cr-1.90, NAA/Cho-0.39, and NAA/Cr-1.27. Two patients had lipid at baseline, five had lactate and two had both. MRSI correlated with tumor response or progression on MRI; in three patients MRSI suggested disease progression prior to changes on MRI. Univariate analysis of metabolite ratios, lipid, and lactate revealed that none significantly affected PFS or OS. Kaplan–Meier analysis of the presence or absence of lipid, lactate or both revealed a trend for increased PFS.Conclusion: MRSI and MRI correlate with tumor response or progression and may allow early detection of disease recurrence. The presence or absence of lipid and/or lactate may have prognostic significance. Further research using MRSI needs to be done to validate our findings and determine the role of MRSI in PCNSL.Presented in part at the 1999 Annual Meeting of the American Academy of Neurology; April 12, 1999.     

原发性中枢神经系统淋巴瘤35例临床及预后分析

目的：探讨原发中枢神经系统淋巴瘤（PCNSL）临床特点、诊治方案及临床疗效。方法：总结2001年1月-2008年1月收治的35例PCNSL患者,均经病理证实为B细胞来源非霍奇金淋巴瘤并接受放疗,其中25例放疗后接受化疗。结合文献对原发性中枢神经系统淋巴瘤患者的临床特点、病理学检查、影像学表现、治疗及预后进行回顾性分析。结果：本病以中老年人多见,发病急,病程短,病情进展快。临床表现复杂,颅内高压为主要表现之一。CT、MRI增强扫描病灶多呈均匀明显强化,可单发或多发。35例患者中位生存时间23月,1年生存率74．3％,3年生存率25．7％,5年生存率5．71％。肿瘤全切及局部切除者,生存率未见明显统计学差异（P=0．053）,加化疗疗效优于不加化疗（P=0．012）。结论：PCNSL临床表现多样,影像学缺乏特异性,极易误诊,确诊需要依靠病理学检查,最佳治疗方案是手术加放疗、化疗的联合治疗。PCNSL侵袭性强,生存期短,其预后主要与发病年龄、多灶性、一般状态有关。     

Characteristics and outcomes of elderly patients with primary central nervous system lymphoma

BACKGROUND:

Approximately 50% of all patients with primary central nervous system lymphoma (PCNSL) are aged ≥65 years; however, this group is relatively understudied, and to the authors's knowledge, optimal treatment for older patients is not well defined.

METHODS:

This was a retrospective review of PCNSL patients aged ≥65 years who were treated at Memorial Sloan‐Kettering Cancer Center between 1986 and 2008. A multivariate analysis of demographic and clinical variables on prognosis and receipt of treatment was performed.

RESULTS:

One hundred seventy‐four patients between the ages of 65 and 89 years were identified; there was a slight predominance of women (52.9%). One hundred forty‐eight patients were treated with chemotherapy at the time of diagnosis (98% with methotrexate‐based therapy) and 31 of these patients also received whole‐brain radiotherapy (WBRT). Sixteen patients received WBRT alone. A radiographic response to chemotherapy was noted in 76% of patients. Ninety patients developed disease progression after initial treatment; 74 received salvage therapy and 48% of these patients responded to salvage treatment. The median overall survival was 25 months (range, 18‐33 months), and the 3‐year survival rate was 36%. Approximately 20.1% of patients were alive for ≥11 years. WBRT was delivered more frequently before 1998, and patients with a history of prior malignancy were less likely to receive WBRT. Age and performance status were identified as the most important predictors of survival. Treatment‐related neurotoxicity at 2 years was strongly associated with receipt of WBRT (P = .0002).

CONCLUSIONS:

PCNSL in the elderly remains sensitive to methotrexate‐based chemotherapy and aggressive treatment may be warranted both at the time of diagnosis and disease recurrence. Cancer 2010. © 2010 American Cancer Society.     

Fluctuation of serum phenytoin concentrations during autologous bone marrow transplant for primary central nervous system tumors

Summary We reviewed our experience for adult patients receiving oral anticonvulsant therapy during high-dose chemotherapy and autologous bone marrow re-infusion for primary malignant tumors of the central nervous system. Nineteen patients received either iv carmustine (BCNU) 900–1050 mg/m² and 6120 cGy cranial irradiation (N = 10), iv carmustine 900–1050 mg/m2 and iv cisplatin 200 mg/m² (N = 8), or iv carmustine 600 mg/m², iv cisplatin 200 mg/m², and iv etoposide 2400 mg/m² (N = 1). Anticonvulsant therapy consisted of phenytoin alone (N = 8), phenobarbital alone (N = 4), carbamazepine alone (N = 2), phenytoin and carbamazepine (N = 2), carbamazepine and phenobarbital (N = 1), and no anticonvulsant therapy (N = 2). Serum anticonvulsant concentrations were monitored frequently and doses adjusted to keep values in the therapeutic range. While phenobarbital and carbamazepine doses remained relatively stable, all patients required increased doses of phenytoin anticonvulsant therapy after beginning chemotherapy (mean onset 3.7 days after initiation of chemotherapy). The increase in phenytoin dose ranged from 50% to 300% above baseline (mean 134%). By the time of discharge from the hospital (approximately 3–4 weeks after the start of chemotherapy) anticonvulsant dose was decreased to near pre-therapy levels. These swings coincided with the initiation of dexamethasone therapy for antiemetic effect and were more pronounced in patients also receiving cisplatin therapy. Due to close monitoring of serum phenytoin concentrations, no instances of toxicity due to excessive drug concentration, or seizures due to subtherapeutic doses, were noted in patients with primary CNS malignancies. Serum phenytoin concentrations fluctuate markedly during high-dose chemotherapy and must be analyzed frequently during the course of therapy.     

原发性中枢神经系统淋巴瘤35例临床及预后分析

目的:探讨原发中枢神经系统淋巴瘤(PCNSL)临床特点、诊治方案及临床疗效。方法:总结2001年1月-2008年1月收治的35例PCNSL患者,均经病理证实为B细胞来源非霍奇金淋巴瘤并接受放疗,其中25例放疗后接受化疗。结合文献对原发性中枢神经系统淋巴瘤患者的临床特点、病理学检查、影像学表现、治疗及预后进行回顾性分析。结果:本病以中老年人多见,发病急,病程短,病情进展快。临床表现复杂,颅内高压为主要表现之一。CT、MRI增强扫描病灶多呈均匀明显强化,可单发或多发。35例患者中位生存时间23月,1年生存率74.3%,3年生存率25.7%,5年生存率5.71%。肿瘤全切及局部切除者,生存率未见明显统计学差异(P=0.053),加化疗疗效优于不加化疗(P=0.012)。结论:PCNSL临床表现多样,影像学缺乏特异性,极易误诊,确诊需要依靠病理学检查,最佳治疗方案是手术加放疗、化疗的联合治疗。PCNSL侵袭性强,生存期短,其预后主要与发病年龄、多灶性、一般状态有关。     

Phase 2 study of temozolomide in children and adolescents with recurrent central nervous system tumors: a report from the Children's Oncology Group

BACKGROUND: Effective chemotherapy is lacking for most types of central nervous system (CNS) tumors in children. Temozolomide, an agent with activity against adult brain tumors, was investigated in children and adolescents with recurrent CNS tumors. METHODS: Temozolomide was administered orally as monthly 5-day courses at doses of 200 mg/m(2)/d (patients with no prior craniospinal irradiation [CSI]) or 180 mg/m(2)/d (prior CSI). Patients with a complete (CR) or partial (PR) response or stable disease (SD) could continue temozolomide for up to 12 cycles. RESULTS: The cohort comprised 122 patients, including 113 with CNS tumors. Median age was 11 years (range, 1-23 years). Among 104 evaluable patients with CNS tumors, 5 PRs and 1 CR were observed. PRs occurred in 1 of 23 evaluable patients with high-grade astrocytoma, 1 of 21 with low-grade astrocytoma, and 3 of 25 with medulloblastoma/primitive neuroectodermal tumor (PNET). The CR occurred in an additional patient with medulloblastoma/PNET. No responses were observed in patients with ependymoma, brain-stem glioma, or other CNS tumors. Notably, 41% of patients with low-grade astrocytoma had SD through 12 courses. The most frequent toxicities were grade 3 or 4 neutropenia (19%) and thrombocytopenia (25%); nonhematologic toxicity was infrequent. CONCLUSIONS: Although overall objective responses were limited, further exploration of temozolomide may be warranted in children with medulloblastoma and other PNETs, or in patients with low-grade astrocytoma, perhaps in a setting of less pretreatment than the patients in the current study, or in the context of multiagent therapy.     

原发中枢神经系统淋巴瘤放疗作用观察

目的 探索放疗在原发中枢神经系统淋巴瘤治疗中的作用。方法 回顾分析2010年9月至2017年12月确诊的免疫功能正常的原发中枢神经系统淋巴瘤60例资料,其中50例经由手术或立体定向活检后病理诊断,10例影像学临床诊断。52例患者接受了化疗,其中45例为大剂量甲氨喋呤为主方案,25例为含利妥昔单抗方案。27例患者行计划性放疗,33例未行计划性放疗,其中治疗失败后9例接受了挽救性放疗。结果 中位随访时间28个月(5~70个月)。全组中位生存、中位无进展生存期分别为22个月(5~65个月)、13个月(5~55个月),4年总生存率、无进展生存率分别为61%、33%。计划性放疗组、非计划性放疗组4年总生存率分别为68%、54%(P=0.083),无进展生存率分别为47%、20%(P=0.014)。挽救性放疗组与计划性放疗组4年总生存率差异无统计学意义(P=0.398),全脑放疗≤36Gy、>36Gy组4年总生存率差异也无统计学意义(P=0.136)。结论 放疗是原发中枢神经系统淋巴瘤的综合治疗的一部分,计划性放疗可能使患者在综合治疗中获益,较高的照射剂量不能使患者获益。     

利妥昔单抗联合大剂量甲氨蝶呤在原发性中枢神经系统淋巴瘤患者中的应用效果

目的 探讨利妥昔单抗联合大剂量甲氨蝶呤在原发性中枢神经系统淋巴瘤患者中的应用效果.方法 按照入院顺序将84例原发性中枢神经系统淋巴瘤患者分为对照组和观察组,每组42例,对照组接受大量甲氨蝶呤治疗,观察组患者接受利妥昔单抗联合大剂量甲氨蝶呤治疗.比较两组患者的临床疗效、不良反应、生存期和生活质量.结果 观察组患者的治疗总...     

细胞核DNA含量与神经系统良恶性肿瘤关系的研究

目的：探讨DNA含量定量分析在中枢神经良、恶性肿瘤的判定及星形细胞瘤分级诊断中的应用价值。方法：运用计算机辅助图象分析并结合组织细胞化学技术测定肿瘤细胞核的DNA含量及DNA倍体细胞分布情况。结果：星形细胞瘤按WHO分级标准分为Ⅰ～Ⅳ级，其DNA相对含量和DNA指数分别为1级4．11±0．75，1．44±0．28；Ⅱ级4．52±1．20，1．71±0．34；Ⅲ级6．35±1．82，2．54±0．44；Ⅳ级7．07±1．32，3．13±0．59。髓母细胞瘤与听神经瘤与DNA相对含量和DNA指数分别为5．61±2．10，2．33±0．83；3．18±0.94，1．35±0．26，方差分析显示组间存在显著差异（P＜0．01），运用Q值法两两比较，髓母细胞瘤与Ⅲ级星形细胞瘤组间、听神经瘤与Ⅰ级星形细胞瘤组间、Ⅰ级星形细胞瘤与Ⅱ级星形细胞瘤组间均无显著差异（P均＞0．05），余各组间均差异显著（P均＜0．01）。结论：DNA含量测定是判定中枢神经肿瘤良、恶性程度及辅助星形细胞瘤分级诊断的良好手段。     

A new prognostic model using absolute lymphocyte count in patients with primary central nervous system lymphoma

PurposePrimary central nervous system lymphoma (PCNSL) is an aggressive and rare extranodal non-Hodgkin lymphoma (NHL). Absolute lymphocyte count (ALC) has been suggested to have a prognostic value in several subtypes of NHL. We evaluated the prognostic significance of clinical factors, including ALC, in patients with PCNSL to develop a new prognostic model.MethodsWe analysed prognostic factors, including ALC, at diagnosis in 81 PCNSL patients receiving high-dose methotrexate-based therapy.ResultsThe median ALC at diagnosis was 1210 × 10⁶/L (range, 210–3610), with lymphopenia (≤875 × 10⁶/L) being detected in 27 (33.3%) patients. In the multivariate analysis, Eastern Cooperative Oncology Group performance status (ECOG PS) >1 (hazard ratio [HR] 3.18, P = 0.003), age >50 years (HR 4.23, P = 0.012), and lymphopenia at diagnosis (HR 2.83, P = 0.008) remained independent prognostic factors for low overall survival (OS). Lymphopenia was also a significant prognostic factor for progression-free survival (HR 3.17, P = 0.001). By means of a new three-factor prognostic model using ECOG PS >1, age >50 years, and presence of lymphopenia, with 1 point assigned to each factor, we successfully classified the patients into three risk groups: low (0 and 1), intermediate (2), and high (3). The 5-year OS rates of the patients in the low-, intermediate-, and high-risk groups were 74.3%, 21.7%, and 12.5%, respectively (P < 0.001).ConclusionsLow ALC is a useful indicator of poor prognosis in patients with PCNSL. The proposed three-factor model should be validated in large-scale studies.     

原发中枢神经系统恶性淋巴瘤的诊断及治疗

目的：探讨原发中枢神经系统恶性淋巴瘤（PCNSL）的临床、影像学表现,治疗方案选择和预后。方法：对24例PCNSL的诊断、治疗过程、预后进行回顾性分析。结果：PCNSL的临床表现以颅内压增高、局灶占位性病变损伤症状为主,肿瘤可单发或多发;肿瘤影像学缺乏特异性,确诊依靠病理学诊断。结论：PCNSL恶性度高,预后不良,手术全切率低;对确诊病例采用个体化的手术方案结合术后放、化疗是治疗本病的关键,可显著延长患者生存时间。     

Primary central nervous system lymphoma presenting as autonomic dysfunction

Summary We describe a patient with primary central nervous system lymphoma (PCNSL) who presented with symptoms of subacute onset of dysautonomia. Autonomic testing indicated a peripheral autonomie neuropathy while magnetic resonance imaging revealed brainstem involvement. We propose that this patient's autonomie dysfunction could be the result of a paraneoplastic syndrome and PCNSL should be considered in the differential diagnosis of dysautonomia.     

原发中枢神经系统恶性淋巴瘤的诊断及治疗

目的:探讨原发中枢神经系统恶性淋巴瘤(PCNSL)的临床、影像学表现,治疗方案选择和预后. 方法: 对24例PCNSL的诊断、治疗过程、预后进行回顾性分析. 结果: PCNSL的临床表现以颅内压增高、局灶占位性病变损伤症状为主,肿瘤可单发或多发;肿瘤影像学缺乏特异性,确诊依靠病理学诊断. 结论: PCNSL恶性度高,预后不良,手术全切率低;对确诊病例采用个体化的手术方案结合术后放、化疗是治疗本病的关键,可显著延长患者生存时间.