Primary central nervous system lymphoma: the role of consolidation treatment after a complete response to high-dose methotrexate-based chemotherapy

BACKGROUND: The most effective treatment for a new diagnosis of primary central nervous system lymphoma is high-dose methotrexate (MTX)-based chemotherapy followed by whole-brain radiation therapy (WBRT). However, this combined modality treatment carries an increased risk of delayed neurotoxicity. For patients who achieve a complete response (CR) after induction that uses high-dose MTX-based chemotherapy, it is not clear if consolidation treatment is necessary. Therefore, a retrospective study was conducted to assess the impact of consolidation treatment after a CR to initial induction chemotherapy on disease control and survival. METHODS: The authors retrospectively analyzed 122 patients who achieved a CR after initial MTX-based chemotherapy. The benefit of consolidation WBRT, high-dose cytarabine (HDAC), or both on failure-free (FFS) and overall survival (OS) was assessed. RESULTS: With a median follow-up of 60 months, FFS was longer in patients who received WBRT plus HDAC as consolidation treatment (P = .03 by univariate analysis); there was no difference in OS observed among patients who received no consolidation treatment, HDAC alone, WBRT plus HDAC, or WBRT alone. Age and Karnofsky performance scale (KPS) were the only independent prognostic factors. Patients who received WBRT alone or in combination with HDAC had higher rates of neurotoxicity. CONCLUSIONS: Consolidation treatment with WBRT, HDAC, or both does not appear to improve survival in patients who achieved a CR with induction MTX-based therapy. Age, KPS, and risk of delayed neurotoxicity must be considered in the choice of consolidation regimens.     

半导体激光穴位照射联合局部封闭治疗原发性三叉神经痛57例

目的探讨半导体激光穴位照射联合局部封闭治疗原发性三叉神经痛的临床疗效。方法57例原发性三叉神经痛患者根据不同疼痛部位采用不同穴位接触照射,每一穴位各照射3min,间隔2min;同时用2％利多卡因2．5mL＋25％硫酸镁溶液2．5mL对不同部位局部封闭浸润注射。结果57例患者随访3个月,总有效率为98．2％;随访6个月,总有效率为94．7％;随访1年,总有效率为89．5％;随访2年,总有效率为86．0％。结论半导体激光穴位照射联合局部封闭治疗原发性三叉神经痛,有较好的疗效且可反复多次治疗,尤其对无法进行手术的老年患者采用射频温控热凝治疗更适用。     

全脑放疗对大鼠血-脑脊液屏障功能的影响

目的通过检测顺铂在脑组织中的浓度变化,观察全脑常规分割外照射对血-脑脊液屏障通透性的影响。方法将Wistar大鼠50只随机分为0、10、20、30、40Gy组,每组10只,用6MV的X线加1.0cm厚组织补偿进行全脑常规分割外照射,每次2Gy,每天照射1次,每周照射5d。各组大鼠完成既定照射总量后16h经腹腔注射顺铂（1.0mg/kg）,20min后采集静脉血及脑组织,采用高效液相色谱法测定血清和脑组织中顺铂的浓度。结果各组大鼠血清中顺铂浓度比较差异无统计学意义（F=0.16,P〉0.05）。大鼠脑组织中顺铂的浓度随照射剂量的增加而逐渐增高,各组间比较差异有显著性（F=63.12,q=2.231～18.005,P〈0.05、0.01）。结论放射治疗可增加血-脑脊液屏障通透性,全脑放疗20～30Gy时为加用化疗的最佳时机。     

Identification of tumor suppressive activity by irradiation microcell-mediated chromosome transfer and involvement of alpha B-crystallin in nasopharyngeal carcinoma

In previous studies, we successfully refined nasopharyngeal carcinoma (NPC) critical regions (CRs) mapping to chromosome 11q13 and 11q22-23. The chromosome 11 fragment containing the 1.8 Mb NPC CR at 11q13 (CR1), the CR at 11q22.3 mapped near D11S2000 (CR2), part of the CR at 11q23.1-11q23.2 overlapping with D11S1300 and D11S1391 (CR3), and the CR at cell adhesion molecule 1 (CADM1) locus (CR4), was chosen as the chromosome 11 donor cell line for the present study. Gamma irradiation was applied to cleave this truncated chromosome into smaller fragments and a new panel of donor cells containing further deleted fragments was produced. Subclones XMCH3.2 and XMCH3.4 were chosen for subsequent transfer to HONE1 cells; each contains a single copy of deleted chromosome 11 fragment with or without CR2 and the THY1 locus, previously shown to be involved in NPC. Both resultant chromosome 11 fragments in XMCH3.2 and XMCH3.4 caused tumor suppression. The association of alpha B-crystallin (CRYAB), a gene identified as being differentially expressed by gene profiling of NPC and an immortalized nasopharyngeal epithelial cell line, and which is located near CR3, was found to be associated with tumor suppression in all the tumor-suppressive hybrids. In addition, the expression level of this gene was down-regulated in the 7 NPC cell lines and in 5 out of 14 normal/tumor tissue pairs in the present study. Both promoter hypermethylation and allelic loss may be involved in the inactivation of this gene, suggesting its possible role in NPC development.     

Comparison of FDG-PET/CT and CT for delineation of lumpectomy cavity for partial breast irradiation

PURPOSE: The success of partial breast irradiation critically depends on proper target localization. We examined the use of fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) for improved lumpectomy cavity (LC) delineation and treatment planning. METHODS AND MATERIALS: Twelve breast cancer patients underwent FDG-PET/CT on a GE Discovery scanner with a median time from surgery to PET/CT of 49 days. The LC was contoured on the CT scan by a radiation oncologist and, together with a nuclear medicine physician, on the PET/CT scan. The volumes were calculated and compared in each patient. Treatment planning target volumes (PTVs) were calculated by expanding the margin 2 cm beyond the LC, maintaining a 5-mm margin from the skin and chest wall, and the treatment plans were evaluated. In addition, a study with a patient-like phantom was conducted to evaluate the effect that the window/level settings might have on contouring. RESULTS: The margin of the LC was well visualized on all FDG-PET images. The phantom results indicated that the difference between the known volume and the FDG-PET-delineated volume was <10%, regardless of the window/level settings. The PET/CT volumes were larger than the CT volumes in all cases (median volume ratio, 1.68; range, 1.24-2.45; p = 0.004). The PET/CT-based PTVs were also larger than the CT-based PTV (median volume ratio, 1.16; range, 1.08-1.64; p = 0.006). In 9 of 12 patients, a CT-based treatment plan did not provide adequate coverage of the PET/CT-based PTV (99% of the PTV received <95% of the prescribed dose), resulting in substantial cold spots in some plans. In these cases, treatment plans were generated which were specifically designed to cover the larger PET/CT-based PTV. Although these plans showed an increased dose to the normal tissues, the increases were modest: the non-target breast volume receiving > or =50 Gy, lung volume receiving > or =30 Gy, and heart volume receiving > or =5 Gy increased by 5.7%, 0.8%, and 0.2%, respectively. The normal tissue dose-volume objectives were still met with these plans. CONCLUSION: The results of our study have shown that FDG-PET/CT can be used to define the LC volume. The increased FDG uptake was likely a result of postoperative inflammation in the LC. The targets defined using PET/CT were significantly larger than those defined with CT alone. Our results have shown that treatment plans can be generated to cover these larger PET/CT target volumes with only a modest increase in irradiated tissue volume compared with CT-determined PTVs.     

Radiation dose to the lens during craniospinal irradiation-an improvement in proton radiotherapy technique

PURPOSE: To evaluate the effect of angle modification of cranial field proton beam therapy on the radiation dose delivered to the lens during craniospinal irradiation (CSI). METHODS AND MATERIALS: Thirty-nine patients with central nervous system tumors who received CSI with a posterior fossa boost were analyzed for the radiation dose to the lens. Thirteen patients received cranial field treatment using standard opposed-lateral proton beams, and 26 patients received treatment with angled posterior-oblique proton beams. The lens dose in a test case also was evaluated by comparing conventional X-rays with the two proton beam planning methods by using a CMS/Xio three-dimensional planning system. RESULTS: Substantial lens dose sparing was realized with the angling of the cranial proton beams 15 degrees -20 degrees to the posterior. In the 39 treated patients who were analyzed (median age, 7 years), average dose delivered to the lens was decreased by approximately 50% by angling of the proton beams, with the average maximum dose decreasing from 74% to 40% of the prescribed dose (p < 0.0001). Significant lens sparing was seen in patients 10 years and younger (median age, 6 years; p < 0.0001), whereas an insignificant decrease was seen in older patients (median age, 16 years; p = 0.14). With the opposed-lateral technique (median age, 6 years), the lens dose increased significantly with decreasing age (p = 0.002), whereas there was no effect of age on lens dose in the angled beam-treated group (median age, 8.5 years; p = 0.73). CONCLUSION: The present study clearly shows an advantage in sparing of the lens dose by angling the beams used during proton beam CSI. This effect is most pronounced in patients 10 years and younger because of anatomic effects of sinus development.     

放射诱导鼠脑神经元凋亡

目的 探讨X射线诱导鼠脑神经元凋亡与照射剂量的关系及时间规律。方法 将大鼠分为不同剂量照射组和对照组,以双标法计数凋亡的神经元数。结果 X射线能诱导的鼠脑神经元的凋亡,凋亡率在照射前后有显著性差异(P<0.0001),在各剂量组间亦有显著性差异(P<0.005),同剂量组在照射后不同时间点间亦有显著性差异。结论 低、中剂量X射线可诱导鼠脑神经元凋亡,凋亡率有剂量依赖性并具有时间规律性。     

X射线对血管平滑肌细胞作用机制的实验研究

目的：研究X射线外照射对体外原代培养的大鼠血管平滑肌细胞（VSMC）生长、增殖的影响及作用机制。方法：体外培养VSMC,给予单次8MVX射线照射,源皮距为100cm,剂量率400cGy/min。按照射剂量分为2、5、10、20Gy组,以0Gy为对照组,分别采用细胞计数法,克隆形成实验、四唑盐（MIT）比色实验、伊红排斥实验,流式细胞术及末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）技术,动态观察对VSMC生长、增殖、死亡率、凋亡的影响。结果：①照射后24hVSM数降低,72h后明显恢复（P＜0．05）。②照射后48h内VSMC吸光度（A570）值降低,72h2、5Gy组A570值升高,而10、15、20Gy组各高不明显（P＜0．05）。③72h内10、15、20Gy组VSMC死亡率较高,6d后,各剂量组死亡率下降至较低水平（P＜0．05）。④克隆形成实验提示X坶照射可直接导致NA链断裂,引起细胞死亡。⑤碘化丙啶（PI）染色流式细胞仪直方图上可见亚二倍体峰,TUNEL法阳性细胞核呈棕黄色,荧光镜下可见凋亡小体。结论：X射线外照射可抑制VSMC的生长和增殖,可能通过两种不同的机制即致死性和（或）亚致死性损伤及诱导凋亡导致SMC死亡。为应用放射治疗防治血管成形术后再狭窄提供了理论依据。