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Knowing when to discontinue Temozolomide therapy in responding aggressive pituitary tumors and carcinomas: a systematic review and Padua (Italy) case series. Expert Rev Endocrinol Metab 2023; 18:181-198. [PMID: 36876325 DOI: 10.1080/17446651.2023.2185221] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 02/23/2023] [Indexed: 03/03/2023]
Abstract
INTRODUCTION Pituitary adenomas can show a tendency to grow, despite multimodal treatment. Temozolomide (TMZ) has been used in the last 15 years in patients with aggressive pituitary tumors. TMZ requires a careful balance of different expertise, especially for selection criteria. AREAS COVERED We conducted: (1) a systematic review of the published literature from 2006 to 2022, collecting only cases with a complete description of patient follow-up after TMZ discontinuation; (2) a description of all patients with aggressive pituitary adenoma or carcinoma treated in Padua (Italy). EXPERT OPINION There is considerable heterogeneity in the literature: TMZ cycles duration ranged from 3 to 47 months; the follow-up time after TMZ discontinuation ranged from 4 to 91 months (mean 24 months, median 18 months), at least a stable disease has been reported in 75% of patients after a mean 13 months (range 3-47 months, median 10 months). The Padua (Italy) cohort reflects the literature. Future directions to explore are to understand the pathophysiological mechanism of TMZ resistance escape, to develop predicting factors to TMZ treatment (especially through the delineation of the underlying transformation processes), and to further expand the therapeutic applications of TMZ (as neoadjuvant, combined with radiotherapy).
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399P Role of geriatric assessment and oncological multidimensional prognostic index in elderly patients with metastatic colorectal cancer in a real-world setting. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.07.537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Prognostic value of baseline G8 geriatric assessment in a real-life population of elderly metastatic colorectal cancer patients: The Gold Study. J Clin Oncol 2022. [DOI: 10.1200/jco.2022.40.16_suppl.e24015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e24015 Background: Colorectal cancer (CRC) is the second most frequent malignancy in patients (pts) aged 70. Elderly patients are often excluded by clinical trials; however, improvements in quality of life and comorbidities management led to expand the access to anticancer treatments irrespectively of age per se. Finding new tools to stratify vulnerability in elderly pts is crucial to guide clinicians in therapeutic decisions. G8 and timed up and go test (TUG) have been related to prognosis and functional decline in patients affected by several solid tumors. However, no studies focused on TUG and G8 prognostic value in CRC pts are available. In this study, we assessed the prognostic value of G8 and TUG in a cohort of real-life elderly pts with metastatic CRC (mCRC). Methods: GOLD was a multicentre, observational, prospective study in which pts aged 70 with mCRC and eligible to 1st line therapy were enrolled. G8 and TUG were performed at screening and at the first documented disease progression (PD). G8 cutoff was 14, as reported in literature; TUG8,5 sec (cutoff set with ROC curve using MedCalc software v 20.027). PFS and OS were described with Kaplan-Meyer curve. All analyzed variables were then compared with multivariate models. Primary endpoint of the study was to assess prognostic value of G8 in OS and PFS. Secondary endpoints were to assess prognostic value of TUG in OS and PFS. Results: Since Oct 2017 to Apr 2019, 109 pts were evaluated in 4 different Oncology Units in Veneto (IT); 4 were not eligible to anticancer treatments and where thus excluded. 105 pts were finally enrolled. Clinical, histological and molecular characteristics were well balanced between pts with G814 vs > 14, with the exception of RASmut, more represented in the G8 > 14 group (p = 0,0195). 39 (37%) pts were aged80; 46 (44%) had ECOG PS1; 55 (53%) had RASmut; 15 (15%) had BRAFmut. 81 (77%) had G814; 78 (75%) had TUG8,5. At a median follow up time of 41,2 months, median OS was 19,41 months (95%CI 15,46-23,19) and median PFS 8,78 months (95% CI 7,53-10,07). OS was longer in patients with G814 (HR 0,61; 95%CI 0,39-0,97; p= 0,0584) and TUG8,5 (HR 0,55; 95%CI 0,35- 0,86; p= 0,0201). PFS was not influenced by G8 (HR 0,86; 95%CI 0,55-1,34; p= 0,5125) nor by TUG (HR 0,71; 95%CI 0,47-1,08). G814 and TUG8,5 conferred better OS also in the subgroup of RASmut (respectively p= 0,0133 and p= 0,0088). Worse OS was observed in presence of > 1 metastatic site (HR = 1,71; 95%CI 1,11 to 2,64; p= 0,0161). At the multivariate analysis, G814 ( p= 0,0202) and single metastatic site ( p= 0,0200) were related to better OS; none of the analysed variables had effect on PFS. Conclusions: In our study G814 and TUG8,5 had prognostic value in OS, but not in PFS, in a real-life population of elderly pts affected by mCRC. G8 and single metastatic site involvement were related to better OS, irrespectively of other clinical, histological and molecular variables.
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Anaplastic Astrocytoma: State of the art and future directions. Crit Rev Oncol Hematol 2020; 153:103062. [PMID: 32717623 DOI: 10.1016/j.critrevonc.2020.103062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 06/17/2020] [Accepted: 07/12/2020] [Indexed: 01/05/2023] Open
Abstract
Anaplastic Astrocytoma(AA) is a malignant, diffusely infiltrating, primary brain tumor. According to the WHO 2016 classification of central-nervous-system tumors, AA has been described as a glial tumor with no co-deletion of 1p/19q, and is divided into IDH mutated tumor, characterized by better prognosis, and IDH wild-type form, with worse prognosis. The standard of care is maximal safe resection followed by radiotherapy and chemotherapy with temozolomide. Several efforts have been made to evaluate, according to molecular selection, which is the best post-surgical treatment. At recurrence, the treatment remains challenging and some trials are ongoing to evaluate new potential drugs, alone or in combination with chemotherapy. We performed a description of the status of the art on diagnosis, molecular characteristics and treatment of AA. In particular, we focused our details on new drugs; indeed, a deeper knowledge of the molecular characteristics of gliomas could lead to to development of active personalized treatments according with precision medicine.
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Prognostic role of Oncological Multidimensional Prognostic Index (Onco-MPI) in elderly patients with urological cancers. J Clin Oncol 2020. [DOI: 10.1200/jco.2020.38.6_suppl.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
66 Background: MPI is an effective tool for geriatric assessment in elderly patients (pts). An oncological version of MPI (Onco-MPI) has been validated by our group in pts with cancer. We evaluate here the prognostic role of Onco-MPI in pts affected by urological cancer. Methods: Pts aged ≥70 years with prostate, renal and urothelial cancer (bladder or upper urinary tract) referred to the Medical Oncology 1 Unit from Jan 2005 to Aug 2019 received a basal comprehensive geriatric assessment (CGA). Onco-MPI was calculated by a validated algorithm as a weighted linear combination of the CGA domains as previously described, identifying 3 different prognostic groups: low (scores 0.0-0.46), intermediate (scores 0.47-0.63) and high risk (scores 0.64-1.0). Results: A total of 643 pts were included; 382 with prostate, 121 renal and 140 urothelial cancer. Median age was 77 years (68-95). ECOG PS was 0 in 44%, 1 in 34.2% and >1 in 21.6%; 19.3% had stage I or II disease, 29.7% stage III and 51% stage IV. Median overall survival (OS) was 35.4 months (95% CI 29.5-41.2). Onco-MPI score (low vs medium vs high risk) was significantly associated with OS in the overall population as well as in the subgroups of patients with prostate, renal or urothelial cancer (table). In pts with prostate cancer the majority of pts were low risk (93%) and only few intermediate (7%), no one was high risk. Conclusions: Onco-MPI confirmed its prognostic role in elderly pts with prostate, renal and urothelial carcinoma. It may be therefore valuable both in clinical practice for driving decision-making, and in geriatric clinical trials thanks to its standardization.[Table: see text]
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Health-related quality of life (HRQoL) evaluation in the REGOMA trial: A randomized, phase II clinical trial analyzing regorafenib activity in relapsed glioblastoma patients. Ann Oncol 2019. [DOI: 10.1093/annonc/mdz243.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Comprehensive geriatric assessment (CGA) can categorize elderly glioblastoma (GBM) patients into three groups predicting survival: A monoinstitutional study. Ann Oncol 2019. [DOI: 10.1093/annonc/mdz243.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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OS7.3 Health-related quality of life (HRQoL) evaluation in the REGOMA trial: a randomized, phase II clinical trial analyzing regorafenib activity in relapsed glioblastoma patients. Neuro Oncol 2019. [DOI: 10.1093/neuonc/noz126.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
BACKGROUND
REGOMA trial showed that regorafenib (REG) significantly improved OS and PFS in patients (pts) with relapsed GBM with respect to lomustine (LOM). REG showed a different toxicity profile compared to LOM. Here, we report final results of the HRQoL assessment, a secondary end point.
MATERIAL AND METHODS
HRQoL was measured using the European Organization for Research and Treatment of Cancer (EORTC) core questionnaire (QLQ-C30) and brain module (QLQ-BN20) administered before any MRI assessments, every 8 weeks (+/- 2 weeks) until disease progression. To evaluate treatment impact on HRQoL, questionnaires at progression were excluded. Mixed-effect linear models were fitted for each of the HRQOL domain to examine the change over progression-free time within and between arms. The models included the time of questionnaire assessment, the treatment group and their interaction, as fixed effects, and a compound symmetry covariance structure for the random effects. Differences of at least 10 points were classified as a clinically meaningful change. To correct for multiple comparisons and to avoid type I error, the level of significance was set at P=0.01 (2-sided).
RESULTS
Of 119 randomized pts, 117 partecipated in the HRQoL evaluation, and 114 had a baseline assessment (n=56 REG; n=58 LOM). No statistically significant differences were observed in any generic or cancer specific domain during treatment in the REG and LOM arms, or between the two arms, except for the appetite loss scale which was significantly worse in PTS treated with REG (Global mean 14.7 (SD=28.6) vs 7.6 (SD=16.0); p=0.0081). The rate of pts with a clinically meaningful worsening for appetite loss was not statistically different between the two arms (9 out of 24 and 0 out of 13 in the REG and LOM arm, respectively;p=0.02).
CONCLUSION
In the REGOMA trial, HRQoL did not change during regorafenib treatment. Pts treated with regorafenib and lomustine reported no significant difference in HRQoL.
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Health-related quality of life (HRQoL) evaluation in the REGOMA trial: A randomized, phase II clinical trial analyzing regorafenib activity in relapsed glioblastoma patients. J Clin Oncol 2019. [DOI: 10.1200/jco.2019.37.15_suppl.2045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
2045 Background: REGOMA trial showed that regorafenib (REG) significantly improved OS and PFS in relapsed glioblastoma (GBM) patients (pts) with respect to lomustine (LOM). REG showed a different toxicity profile compared to LOM. Here, we report final results of the HRQoL assessment, a secondary end point. Methods: HRQoL was measured using the European Organization for Research and Treatment of Cancer (EORTC) core questionnaire (QLQ-C30) and brain module (QLQ-BN20) administered before any MRI assessments, every 8 weeks (+/- 2 weeks) until disease progression. To evaluate treatment impact on HRQoL, questionnaires at progression were excluded. Mixed-effect linear models were fitted for each of the HRQOL domain to examine the change over progression-free time within and between arms. The models included the time of questionnaire assessment, the treatment group and their interaction, as fixed effects, and a compound symmetry covariance structure for the random effects. Differences of at least 10 points were classified as a clinically meaningful change. To correct for multiple comparisons and to avoid type I error, the level of significance was set at P = 0.01 (2-sided). Results: Of 119 randomized pts, 117 participated in the HRQoL evaluation, and 114 had a baseline assessment (n = 56 REG; n = 58 LOM). No statistically significant differences were observed in any generic or cancer specific domain during treatment in the REG and LOM arms, or between the two arms, except for the appetite loss scale which was significantly worse in PTS treated with REG (Global mean 14.7 (SD = 28.6) vs 7.6 (SD = 16.0); p = 0.0081). The proportion of pts with a clinically meaningful worsening for appetite loss was not statistically different between the two arms (9 out of 24 and 0 out of 13 in the REG and LOM arm, respectively; p = 0.0146). Conclusions: In the REGOMA trial, HRQoL did not change during REG treatment. Pts treated with REG and LOM reported no significant difference in HRQoL. Clinical trial information: NCT02926222. [Table: see text]
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NCOG-12. COMPREHENSIVE GERIATRIC ASSESSMENT (CGA) FOR OUTCOME PREDICTION IN ELDERLY PATIENTS (PTS)WITH GLIOBLASTOMA (GBM): A MONO-INSTITUTIONAL EXPERIENCE. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy148.727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Comprehensive geriatric assessment (CGA) for outcome prediction in elderly patients (PTS) with glioblastoma (GBM): A mono-institutional experience. Ann Oncol 2018. [DOI: 10.1093/annonc/mdy273.369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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OS2.3 Updated results of REGOMA: A randomized, multicenter, controlled open-label phase II clinical trial evaluating regorafenib in relapsed glioblastoma <GBM> patients <PTS>. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy139.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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P01.021 Comprehensive Geriatric Assessment (CGA) for outcome prediction in elderly patients (PTS)with glioblastoma (GBM): a mono-institutional experience. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy139.063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Updated results of REGOMA: A randomized, multicenter, controlled open-label phase II clinical trial evaluating regorafenib in relapsed glioblastoma (GBM) patients (PTS). J Clin Oncol 2018. [DOI: 10.1200/jco.2018.36.15_suppl.2047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Prevalence of malnutrition in patients at first medical oncology visit: the PreMiO study. Oncotarget 2017; 8:79884-79896. [PMID: 29108370 PMCID: PMC5668103 DOI: 10.18632/oncotarget.20168] [Citation(s) in RCA: 208] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/20/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND In cancer patients, malnutrition is associated with treatment toxicity, complications, reduced physical functioning, and decreased survival. The Prevalence of Malnutrition in Oncology (PreMiO) study identified malnutrition or its risk among cancer patients making their first medical oncology visit. Innovatively, oncologists, not nutritionists, evaluated the nutritional status of the patients in this study. METHODS PreMiO was a prospective, observational study conducted at 22 medical oncology centers across Italy. For inclusion, adult patients (>18 years) had a solid tumor diagnosis, were treatment-naive, and had a life expectancy >3 months. Malnutrition was identified by the Mini Nutritional Assessment (MNA), appetite status with a visual analog scale (VAS), and appetite loss with a modified version of Anorexia-Cachexia Subscale (AC/S-12) of the Functional Assessment of Anorexia-Cachexia Therapy (FAACT). FINDINGS Of patients enrolled (N=1,952), 51% had nutritional impairment; 9% were overtly malnourished, and 43% were at risk for malnutrition. Severity of malnutrition was positively correlated with the stage of cancer. Over 40% of patients were experiencing anorexia, as reported in the VAS and FAACT questionnaire. During the prior six months, 64% of patients lost weight (1-10 kg). INTERPRETATION Malnutrition, anorexia, and weight loss are common in cancer patients, even at their first visit to a medical oncology center.
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Worsening of quality of life (QoL), cognitive functions (CF) and psychological status (PSY) can predict radiologic progressive disease (RPD) in glioblastoma (GBM) patients (PTS) treated with radiation therapy (RT) and temozolomide (TMZ): a mono-institutional prospective study. Ann Oncol 2017. [DOI: 10.1093/annonc/mdx431.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Worsening of quality of life (QoL), cognitive functions (CF) and psychological status (PSY) can predict radiologic progressive disease (RPD) in glioblastoma (GBM) patients (PTS) treated with radiation therapy (RT) and temozolomide (TMZ): A mono-institutional prospective study. Ann Oncol 2017. [DOI: 10.1093/annonc/mdx366.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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REGOMA: A randomized, multicenter, controlled open-label phase II clinical trial evaluating regorafenib activity in relapsed glioblastoma patients. Ann Oncol 2017. [DOI: 10.1093/annonc/mdx440.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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A prospective analysis of quality of life (QoL), cognitive functions (CF) and psychological status (PSY) in glioblastoma (GBM) patients (PTS) treated with RT and temozolomide (TMZ). Ann Oncol 2016. [DOI: 10.1093/annonc/mdw367.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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A prospective analysis of quality of life (QoL), cognitive functions (CF) and psychological status (PSY) in glioblastoma (GBM) patients (PTS) treated with RT and Temozolomide (TMZ). Ann Oncol 2016. [DOI: 10.1093/annonc/mdw345.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Cognitive Rehabilitation in Patients with Gliomas and Other Brain Tumors: State of the Art. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3041824. [PMID: 27493954 PMCID: PMC4963561 DOI: 10.1155/2016/3041824] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/26/2016] [Accepted: 06/02/2016] [Indexed: 01/01/2023]
Abstract
Disease prognosis is very poor in patients with brain tumors. Cognitive deficits due to disease or due to its treatment have an important weight on the quality of life of patients and caregivers. Studies often take into account quality of life as a fundamental element in the management of disease and interventions have been developed for cognitive rehabilitation of neuropsychological deficits with the aim of improving the quality of life and daily-life autonomy of patients. In this literature review, we will consider the published studies of cognitive rehabilitation over the past 20 years.
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Neurocognitive functions and health-related quality of life in glioblastoma patients: a concise review of the literature. Eur J Cancer Care (Engl) 2015; 28:e12410. [PMID: 26531122 DOI: 10.1111/ecc.12410] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2015] [Indexed: 11/29/2022]
Abstract
The maintenance of quality of life in patients with high-grade glioma is an important endpoint during treatment, particularly in those with glioblastoma multiforme, given its dismal prognosis; thus, the primary aims of treatments are to reduce morbidity, restore or preserve neurological functions, and the capacity to perform daily activities. This review aims to summarise what is currently known about neurocognitive outcome and quality of life in patients with high-grade glioma, particularly in glioblastoma patients. We considered all the variables that can influence neurocognitive functions, the perception of quality of life and their role as predictors for treatment outcomes.
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Alternative schedule of Fotemustine in elderly patients with recurrent glioblastoma: a phase II prospective study. Ann Oncol 2015. [DOI: 10.1093/annonc/mdv348.38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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2921 Low-dose Fotemustine in elderly patients with recurrent glioblastoma: A phase II prospective study. Eur J Cancer 2015. [DOI: 10.1016/s0959-8049(16)31636-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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2916 A prospective study analyzing quality of life and cognitive function in patients with glioblastoma treated with RT and Temozolomide: Impact of age and gender. Eur J Cancer 2015. [DOI: 10.1016/s0959-8049(16)31631-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Photoinhibition of Chlamydomonas reinhardtii in State 1 and State 2: damages to the photosynthetic apparatus under linear and cyclic electron flow. J Biol Chem 2001; 276:22251-7. [PMID: 11294855 DOI: 10.1074/jbc.m011376200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The relationship between state transitions and photoinhibition has been studied in Chlamydomonas reinhardtii cells. In State 2, photosystem II activity was more inhibited by light than in State 1. In State 2, however, the D1 subunit was not degraded, whereas a substantial degradation was observed in State 1. These results suggest that photoinhibition occurs via the generation of an intermediate state in which photosystem II is inactive but the D1 protein is still intact. The accumulation of this state is enhanced in State 2, because in this State only cyclic photosynthetic electron transport is active, whereas there is no electron flow between photosystem II and the cytochrome b(6)f complex (Finazzi, G., Furia, A., Barbagallo, R. P., and Forti, G. (1999) Biochim. Biophys. Acta 1413, 117-129). The activity of photosystem I and of cytochrome b(6)f as well as the coupling of thylakoid membranes was not affected by illumination under the same conditions. This allows repairing the damages to photosystem II thanks to cell capacity to maintain a high rate of ATP synthesis (via photosystem I-driven cyclic electron flow). This capacity might represent an important physiological tool in protecting the photosynthetic apparatus from excess of light as well as from other a-biotic stress conditions.
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Ultraviolet B exposure of whole leaves of barley affects structure and functional organization of photosystem II. J Biol Chem 2000; 275:10976-82. [PMID: 10753898 DOI: 10.1074/jbc.275.15.10976] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This study examines the effects of ecologically important levels of ultraviolet B radiation on protein D1 turnover and stability and lateral redistribution of photosystem II. It is shown that ultraviolet B light supported only limited synthesis of protein D1, one of the most important components of photosystem II, whereas it promoted significant degradation of proteins D1 and D2. Furthermore, dephosphorylation of photosystem II subunits was specifically elicited upon exposure to ultraviolet B light. Structural modifications of photosystem II and changes in its lateral distribution between granum membranes and stroma-exposed lamellae were found to be different from those observed after photoinhibition by strong visible light. In particular, more complete dismantling of photosystem II cores was observed. Altogether, the data reported here suggest that ultraviolet B radiation alone fails to activate the photosystem II repair cycle, as hypothesized for visible light. This failure may contribute to the toxic effect of ultraviolet B radiation, which is increasing as a consequence of depletion of stratospheric ozone.
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Effects of ultraviolet-B light on photosystem II phosphoproteins in barley wild type and its chlorophyll b-less mutant chlorina f2. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1999; 48:189-93. [PMID: 10343404 DOI: 10.1016/s1011-1344(99)00027-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effects of ultraviolet-B light on the level and steady-state phosphorylation of photosystem II proteins have been studied in barley wild type and its chlorophyll b-less mutant chlorina f2. In the wild type, ultraviolet-B radiation is found to promote dephosphorylation of all thylakoid phosphoproteins. In addition, for reaction-centre proteins D1 and D2, dephosphorylation is paralleled by degradation. Photosystem II core proteins in the mutant are not found to be significantly phosphorylated in any experimental conditions, and loss of D1 and D2 reaction-centre proteins is slightly faster than in the wild type. These results are consistent with the possibility that phosphorylation of reaction-centre proteins affects their stability, possibly by slowing down the rate of degradation, as in the case of visible light.
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Diagnosis by random amplified polymorphic DNA polymerase chain reaction of four cryptic species related to Anopheles (Nyssorhynchus) albitarsis (Diptera: Culicidae) from Paraguay, Argentina, and Brazil. JOURNAL OF MEDICAL ENTOMOLOGY 1995; 32:697-704. [PMID: 7473625 DOI: 10.1093/jmedent/32.5.697] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) analysis was applied to samples from widespread populations of the poorly characterized Anopheles (Nyssorhynchus) albitarsis Lynch-Arribálzaga species complex, and 4 genetically differentiated species were distinguished. A screen of 65 random decamer oligonucleotide primers identified 12 primers, which produced 19 reproducible species-specific genetic markers and 4 markers common to 2 or more species. These markers were correlated in nearly all individuals of each species throughout the ranges sampled, including populations as far apart as 2,500 km. Each individual analyzed was from a different isofemale progeny brood, with associated morphological specimens. These specimens will facilitate studies to relate these species to previously reported chromosomal and enzymatic variation as well as to their feeding behavior and potential as malaria vectors. We hypothesize that 3 of the species have recognized valid names: An. (Nys.) albitarsis Lynch-Arribálzaga, An. (Nys.) marajoara Galvão and Damasceno, and An. (Nys.) deaneorum Rosa-Freitas, whereas the 4th is undescribed.
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