Chemotherapy for primary central nervous system lymphoma

Usefulness of carbon-11-labeled methionine positron-emission tomography for assessing the treatment response of primary central nervous system lymphoma

BACKGROUND

Primary central nervous system lymphoma (PCNSL) responds relatively quickly to chemotherapy or radiotherapy. However, determination of a complete response after treatment is often difficult because of extremely light residual contrast enhancement on magnetic resonance images due to the effects of microhemorrhages and scar tissue formation. These small enhancing lesions define an unconfirmed complete response. The aim of this study was to investigate the usefulness of carbon-11-labeled methionine (11C-Met) positron-emission tomography (PET) for determining the treatment response of PCNSL.

METHODS

Data for 36 patients who were treated for PCNSL between 2011 and 2015 and underwent magnetic resonance imaging and 11C-Met PET were reviewed. Magnetic resonance imaging findings were classified as complete response, unconfirmed complete response, and tumor mass (a composite of partial response, stable disease and progressive disease). PET images were evaluated, standardized uptake values were quantified, and the tumor-to-normal tissue count ratio (TNR) was calculated. Receiver operating characteristic curves were generated to determine the optimal cutoff TNRs.

RESULTS

The optimal TNRs for differentiating complete response and unconfirmed complete response from tumor mass were 1.83 (area under the curve, 0.951) and 1.80 (area under the curve, 0.932), respectively. The corresponding sensitivity and specificity values for the diagnosis of tumor mass were 82.4 and 100%, respectively, in the complete response group and 85.3 and 85%, respectively, in the unconfirmed complete response group.

CONCLUSIONS

A TNR of ≥1.80 can aid in the detection of active PCNSL using 11C-Met PET. Thus, 11C-Met-PET may be a useful tool for accurate evaluation of the treatment efficacy in PCNSL.

Primary central nervous system lymphoma at the cerebellopontine angle mimicking a trigeminal schwannoma: A unique case report and literature review

Primary central nervous system lymphoma (PCNSL) is an uncommon extranodal manifestation of non-Hodgkin's lymphoma with those presenting at the cerebellopontine angle (CPA) being rare presentations with limited reported cases in the literature. We report a 60-year old female presenting with PCNSL of the left CPA radiologically mimicking a trigeminal schwannoma with corresponding clinical signs. Imaging showed a left CPA lesion that was biopsied and confirmed as diffuse large B-cell lymphoma. Given its rarity, PCNSL should be considered in the differential diagnosis for all CPA tumours.

Chloroethylating nitrosoureas in cancer therapy: DNA damage, repair and cell death signaling

Chloroethylating nitrosoureas (CNU), such as lomustine, nimustine, semustine, carmustine and fotemustine are used for the treatment of malignant gliomas, brain metastases of different origin, melanomas and Hodgkin disease. They alkylate the DNA bases and give rise to the formation of monoadducts and subsequently interstrand crosslinks (ICL). ICL are critical cytotoxic DNA lesions that link the DNA strands covalently and block DNA replication and transcription. As a result, S phase progression is inhibited and cells are triggered to undergo apoptosis and necrosis, which both contribute to the effectiveness of CNU-based cancer therapy. However, tumor cells resist chemotherapy through the repair of CNU-induced DNA damage. The suicide enzyme O⁶-methylguanine-DNA methyltransferase (MGMT) removes the precursor DNA lesion O⁶-chloroethylguanine prior to its conversion into ICL. In cells lacking MGMT, the formed ICL evoke complex enzymatic networks to accomplish their removal. Here we discuss the mechanism of ICL repair as a survival strategy of healthy and cancer cells and DNA damage signaling as a mechanism contributing to CNU-induced cell death. We also discuss therapeutic implications and strategies based on sequential and simultaneous treatment with CNU and the methylating drug temozolomide.

Effectiveness and safety of thiotepa as conditioning treatment prior to stem cell transplant in patients with central nervous system lymphoma

BACKGROUND

Thiothepa is a cytostatic agent used in managing solid malignancies, and also as conditioning treatment before hematopoietic stem cell transplantation [HSCT]. This systematic review summarizes evidence on its effectiveness and safety, in patients with central nervous system [CNS] lymphoma.

METHODS

We searched 3 databases for clinical studies. When feasible, we performed meta-analyses.

RESULTS

We identified 13 eligible studies, none of which with a priori controls. So data synthesis focused on the 226 patients who received thiotepa. Based on pooled estimates, 75.9% of thiotepa-treated patients achieved a complete remission (95% confidence interval [CI] = 67.5-82.8), and 61.7% had a progression-free survival for up to 125 months post-treatment (95% CI = 49.4-72.7). However, 25.5% relapsed, 24.6% experienced infection, and 13.2% experienced neurotoxicity.

DISCUSSION

Thiotepa-based conditioning followed by HSCT may be effective in most CNS lymphoma patients, with a manageable toxicity profile. But adequately powered randomized trials are needed to better evaluate and isolate the effects of thiotepa.

High-dose methotrexate, high-dose cytarabine and temozolomide for the treatment of primary central nervous system lymphoma (PCNSL)

Treatment of primary central nervous system lymphoma (PCNSL) associates with low response rates and poor survival using conventional radio and chemotherapy. Due to its favorable toxicity profile, temozolomide has emerged as a new option for treatment of PCNSL in young patients. In this study, we report a series of PCNSL patients treated with an innovative regimen combining high dose of both cytarabine and methotrexate with temozolomide without radiotherapy or intrathecal chemotherapy. To evaluate a new intensive chemotherapy with temozolomide, trying to assess response and progression-free survival rates and if the results are promising, we are aiming at evaluating the overall survival (OS) taking into consideration the toxicity profile. The study was performed at Al Mowassa Charity Hospital in Damascus (Syria). Forty patients with histologically confirmed PCNSL median age 52 years (range 20-65) years were included. Biopsies were cultured, and a karyotyping was made in 32 patients. An induction chemotherapy was started, and methotrexate 3 gr/m² over 12 h on day 1, cytarabine 3 gr/m² every 12 h on day 1 and temozolomide 150 mg/m² from day 2 through day 6 with a total of 6 cycles were given on a monthly basis. Among the 40 patients included in the study, a complete response was observed in 34 patients (85%) and a partial response in the remaining 6 patients (15%). Disease progressed in 8 out of 40 patients (20%) while 32 patients are still living at 5 years making the OS reaching 77%. Grade II nephrotoxicity was observed in 2 patients while grade III and IV hematotoxicity was observed in 5 patients. High dose of both Ara-C and MTX combined with temozolomide appears to be a good choice in the treatment of PCNSL, in the light of good response and OS rates, taking into consideration the acceptable toxicity profile. However, a larger trial is needed to make it an acceptable new combination as a first line for PCNSL patients.

Salvage therapy for refractory AIDS-related primary central nervous system lymphoma

A 27-year-old male patient presented with speech disorders and multiple brain masses on MRI evaluation. He tested positive for HIV. A sterotactic biopsy diagnosed primary central nervous system lymphoma (diffuse large B-cell lymphoma). After two cycles of high-dose metotrexate (HD-MTX-)-based chemotherapy, the tumor progressed. He underwent whole brain radiotherapy achieving complete response. Six cycles of consolidating immunochemotherapy with rituximab-temozolomide were administered after radiation. Forty-three months after remission, he has not recurred and his neurological status is optimal. Younger HIV patients with refractory PCNSL and preserved immune function can face salvage therapy successfully achieving long term remissions with no remarkable neurotoxicity.

Temozolomide and unusual indications: review of literature

Temozolomide (TMZ) was first known to be useful as a radiosensitiser in both primary brain tumours like glioblastoma multiforme and oligodendroglioma. Later, TMZ proved its efficacy in the treatment of melanoma. Multiple publications have demonstrated the benefit of TMZ in terms of efficacy and tolerance (used as mono-therapy or as adjuvant chemotherapy) compared to the "gold standard" treatment of this kind of tumours. Furthermore, several recent clinical trials have shown the particular importance of TMZ in other types of cancer. This publication deals with the use of TMZ in cancers which are not formal indications for TMZ (excluding glioblastoma multiforme, oligodendroglioma and melanoma). It also includes a necessary review of recent literature about the role of TMZ in the treatment of brain metastases, lymphomas, refractory leukaemia, neuroendocrine tumours, pituitary tumours, Ewing's sarcoma, primitive neuroectodermal tumours, lung cancer and other tumours.

Functional reconstitution of human ABCC3 into proteoliposomes reveals a transport mechanism with positive cooperativity

ABCC3 (MRP3) is a member of the family of multidrug resistance-associated proteins (MRP), which belong to the largest family of membrane transport proteins, namely, the ATP binding cassette (ABC) transporters. Members of this family contribute to the excretion of several organic anions from cells and play a critical role in conferring resistance against drugs used in the treatment of cancer. The overexpression of ABCC3 in the yeast Pichia pastoris and its subsequent purification made possible the study of substrate-dependent ATPase activity [Chloupkova, M., et al. (2007) Biochemistry 46, 7992-8003]. Here we describe the successful reconstitution of purified ABCC3 in proteoliposomes and ABCC3-dependent uptake of the anticancer drug methotrexate (MTX), as well as the physiological substrate leukotriene C(4) (LTC(4)). Our results show specific transport in a cell-free environment and in the absence of other proteins, revealing positive allosteric cooperativity for ABCC3-mediated substrate translocation. The ABCC3-mediated transport of MTX indicates a Hill coefficient of 2.3 +/- 1.7, a maximum transport rate (V(max)) of >2 micromol min(-1) mg(-1), and a K(M) in the millimolar range, whereas the translocation of LTC(4) into proteoliposomes displayed a Hill coefficient of 2.3 +/- 0.5 with a maximum transport rate of 4.7 +/- 0.8 nmol min(-1) mg(-1), and a K(M) in the micromolar range (1.7 +/- 0.3 microM). The transport of both substrates, MTX and LTC(4), was inhibited by etoposide, confirming a higher affinity of ABCC3 for LTC(4) than for MTX. The technical advances described in this report represent the basis for the extended and detailed kinetic characterization of ABCC3 with a wide range of implications for the investigation of other human ABC transporters.

Increasing incidence and continued dismal outcome of primary central nervous system lymphoma in Norway 1989-2003 : time trends in a 15-year national survey

BACKGROUND

The incidence of primary central nervous system lymphoma (PCNSL) appears to be increasing in some countries, whereas it is stable in others. Many reports the last decades have suggested that there have been improvements in the treatment of PCNSL. The objective of this study was to analyze time trends in the incidence, clinical features, histologic diagnosis, treatment, and outcome of nonacquired immunodeficiency syndrome (non-AIDS) PCNSL in Norway from 1989 to 2003.

METHODS

Patients were identified by a chart review of all patients who had a recorded diagnosis of PCNSL from 1989 to 2003 in The Norwegian Cancer Registry. The histologic and cytologic material from each patient was re-examined by pathologists. Time trends were analyzed according to year of diagnosis grouped into 3 5-year periods: 1989-1993, 1994-1998, and 1999-2003.

RESULTS

There were 98 patients who had confirmed, newly diagnosed non-AIDS PCNSL in Norway from 1989 to 2003. The incidence rate increased during the consecutive 5-year periods from 0.89 per million during 1989 to 1993, to 1.74 per million during 1994 to 1998, and to 1.82 per million during 1999 to 2003 (P = .013). Diagnostic delay and overall survival did not improve with time. Survival decreased from 1999 to 2003 compared with survival from 1994 to 1998, which was explained in part by reduced performance status and fewer patients receiving combined chemotherapy and radiotherapy during 1999 to 2003. In multivariate analysis, age </=50 years, a good performance status, and active treatment (especially combined chemotherapy and radiotherapy) significantly improved survival.

CONCLUSIONS

The incidence of PCNSL is increasing in Norway. Despite diagnostic and therapeutic advances over the last decades, neither a reduction in diagnostic delay nor any improvement in overall survival with time was observed. The search for improved understanding of etiology and treatment should be intensified.

Temozolomide and methotrexate for primary central nervous system lymphoma in the elderly

BACKGROUND

Treatment for primary CNS lymphoma (PCNSL) in the elderly is associated with lower response rates and higher risks of acute and late delayed toxicity as compared to younger patients. Temozolomide has emerged as a new alternative treatment for PCNSL and constitutes an attractive option for the elderly because of its favorable toxicity profile. In this study we report outcomes of a consecutive series of PCNSL elderly patients initially treated with an innovative regimen combining methotrexate and temozolomide without radiotherapy or intra-thecal chemotherapy.

METHODS

Histologically confirmed newly-diagnosed PCNSL patients older than 60 years were included. An induction chemotherapy was initially given (methotrexate 3 g /m(2) on days 1, 10, and 20, and temozolomide 100 mg/m(2) on days 1-5). Patients achieving a partial or complete response proceeded to a maintenance phase (up to 5 monthly cycles of methotrexate 3 g/m(2) on day 1, and temozolomide 100 mg/m(2 )days 1-5). Non-responders were treated on an individual basis.

RESULTS

Among the 23 included patients, a complete response was observed in 55%, and disease progressed in the other 45%. Median event-free survival was 8 months, and median overall survival was 35 months. Grades 3 or 4 toxicities included nephrotoxicity in three patients, and hematotoxicity in five; no neurotoxicity has been observed to date. One patient died while on treatment from complications of intestinal obstruction.

CONCLUSION

Our efficacy results are comparable to other reported regimens, with the advantages of a favorable toxicity profile, and absence of intra-thecal chemotherapy. Prospective, controlled studies are warranted to confirm such results.