The depolymerization of polymers by enzymes is of great interest for biodegradable plastics, a group of materials which has been developed as an answer to increasing problems in plastics waste ...management. Polyesters play the dominant role in biodegradable polymers and recently a model of polyester degradation by hydrolyses (lipases) has been published. The chain mobility of the polymer chains proved to be the most relevant factor controlling polyester biodegradability, usually excluding many aromatic polyesters such as PET from biodegradation. Recently a new thermophilic hydrolase (activity optimum at 65
°C) from
Thermobifida fusca (TfH) was isolated, characterized and expressed in recombinant
Escherichia coli. This enzyme is especially active in degrading polyesters containing aromatic constituents, and exhibits a 65% sequence similarity to a lipase from
Streptomyces albus and combines characteristics of lipases and esterases. TfH is even capable to degrade commercial PET from beverage bottles. Specific modification of the active site of enzymes like TfH may open the door for enzymatic PET recycling in the future.
This European Organisation for Research and Treatment of Cancer phase III trial assesses whether adjuvant whole-brain radiotherapy (WBRT) increases the duration of functional independence after ...surgery or radiosurgery of brain metastases.
Patients with one to three brain metastases of solid tumors (small-cell lung cancer excluded) with stable systemic disease or asymptomatic primary tumors and WHO performance status (PS) of 0 to 2 were treated with complete surgery or radiosurgery and randomly assigned to adjuvant WBRT (30 Gy in 10 fractions) or observation (OBS). The primary end point was time to WHO PS deterioration to more than 2.
Of 359 patients, 199 underwent radiosurgery, and 160 underwent surgery. In the radiosurgery group, 100 patients were allocated to OBS, and 99 were allocated to WBRT. After surgery, 79 patients were allocated to OBS, and 81 were allocated to adjuvant WBRT. The median time to WHO PS more than 2 was 10.0 months (95% CI, 8.1 to 11.7 months) after OBS and 9.5 months (95% CI, 7.8 to 11.9 months) after WBRT (P = .71). Overall survival was similar in the WBRT and OBS arms (median, 10.9 v 10.7 months, respectively; P = .89). WBRT reduced the 2-year relapse rate both at initial sites (surgery: 59% to 27%, P < .001; radiosurgery: 31% to 19%, P = .040) and at new sites (surgery: 42% to 23%, P = .008; radiosurgery: 48% to 33%, P = .023). Salvage therapies were used more frequently after OBS than after WBRT. Intracranial progression caused death in 78 (44%) of 179 patients in the OBS arm and in 50 (28%) of 180 patients in the WBRT arm.
After radiosurgery or surgery of a limited number of brain metastases, adjuvant WBRT reduces intracranial relapses and neurologic deaths but fails to improve the duration of functional independence and overall survival.
This phase III trial compared adjuvant whole-brain radiotherapy (WBRT) with observation after either surgery or radiosurgery of a limited number of brain metastases in patients with stable solid ...tumors. Here, we report the health-related quality-of-life (HRQOL) results.
HRQOL was a secondary end point in the trial. HRQOL was assessed at baseline, at 8 weeks, and then every 3 months for 3 years with the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire C30 and Brain Cancer Module. The following six primary HRQOL scales were considered: global health status; physical, cognitive, role, and emotional functioning; and fatigue. Statistical significance required P ≤ .05, and clinical relevance required a ≥ 10-point difference.
Compliance was 88.3% at baseline and dropped to 45.0% at 1 year; thus, only the first year was analyzed. Overall, patients in the observation only arm reported better HRQOL scores than did patients who received WBRT. The differences were statistically significant and clinically relevant mostly during the early follow-up period (for global health status at 9 months, physical functioning at 8 weeks, cognitive functioning at 12 months, and fatigue at 8 weeks). Exploratory analysis of all other HRQOL scales suggested worse scores for the WBRT group, but none was clinically relevant.
This study shows that adjuvant WBRT after surgery or radiosurgery of a limited number of brain metastases from solid tumors may negatively impact some aspects of HRQOL, even if these effects are transitory. Consequently, observation with close monitoring with magnetic resonance imaging (as done in the EORTC trial) is not detrimental for HRQOL.
In patients with early unfavorable Hodgkin's lymphoma (HL), combined modality treatment with four cycles of ABVD (adriamycin, bleomycin, vinblastine, and dacarbazine) and 30 Gy involved-field ...radiotherapy (IFRT) results in long-term tumor control of approximately 80%. We aimed to improve these results using more intensive chemotherapy.
Patients with newly diagnosed early unfavorable HL were randomly assigned to either four cycles of ABVD or an intensified treatment consisting of two cycles of escalated BEACOPP (bleomycin, etoposide, adriamycin, cyclophosphamide, vincristine, procarbazine, and prednisone) followed by two cycles of ABVD (2 + 2). Chemotherapy was followed by 30 Gy IFRT in both arms. The primary end point was freedom from treatment failure (FFTF); secondary end points included progression-free survival (PFS) and treatment-related toxicity.
With a total of 1,528 qualified patients included, the 2 + 2 regimen demonstrated superior FFTF compared with four cycles of ABVD (P < .001; hazard ratio, 0.44; 95% CI, 0.30 to 0.66), with a difference of 7.2% at 5 years (95% CI, 3.8 to 10.5). The difference in 5-year PFS was 6.2% (95% CI, 3.0% to 9.5%). There was more acute toxicity associated with 2 + 2 than with ABVD, but there were no overall differences in treatment-related mortality or secondary malignancies.
Intensified chemotherapy with two cycles of BEACOPP escalated followed by two cycles of ABVD followed by IFRT significantly improves tumor control in patients with early unfavorable HL.
Eight cycles of BEACOPP(escalated) (escalated dose of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone) followed by radiotherapy (RT) to initial bulk or ...residual tumor mass is the German Hodgkin Study Group standard of care for advanced-stage Hodgkin's lymphoma (HL). However, treatment-related toxicity is a concern, and the role of RT in this setting is unclear. The HD12 study thus aimed to reduce toxicity while maintaining efficacy.
In this prospectively randomized multicenter trial, eight cycles of BEACOPP(escalated) was compared with four cycles of BEACOPP(escalated) followed by four cycles of the baseline dose of BEACOPP (BEACOPP(baseline); 4 + 4), and RT with no RT in the case of initial bulk or residual disease. The study was designed to exclude a difference in 5-year freedom from treatment failure (FFTF) rate of 6%.
Between January 1999 and January 2003, 1,670 patients age 16 to 65 years were enrolled onto the HD12 study. At 5 years, FFTF was 86.4% in the BEACOPP(escalated) arm and 84.8% in the 4 + 4 arm (difference, -1.6%; 95% CI, -5.2% to 1.9%), and overall survival was 92% versus 90.3% (difference, -1.7%; 95% CI, -4.6% to 1.1%). Deaths related to acute toxicity of chemotherapy were observed in 2.9% of patients (BEACOPP(escalated), n = 19; 4 + 4, n = 27). FFTF was inferior without RT (90.4% v 87%; difference, -3.4%; 95% CI, -6.6% to -0.1%), particularly in patients who had residual disease after chemotherapy (difference, -5.8%; 95% CI, -10.7% to -1.0%), but not in patients with bulk in complete response after chemotherapy (difference, -1.1%; 95% CI, -6.2% to 4%).
The reduction of BEACOPP to the 4 + 4 regimen did not substantially reduce severe toxicity but might decrease efficacy. Our results do not support the omission of consolidation RT for patients with residual disease. Alternative strategies for improving the risk-to-benefit ratio for patients with advanced HL are needed.
Cure rates of early Hodgkin lymphoma (HL) are high, and avoidance of late complications and second malignancies have become increasingly important. This comparative treatment planning study analyzes ...to what extent target volume reduction to involved-node (IN) and intensity-modulated (IM) radiotherapy (RT), compared with involved-field (IF) and three-dimensional (3D) RT, can reduce doses to organs at risk (OAR).
Based on 20 computed tomography (CT) datasets of patients with early unfavorable mediastinal HL, we created treatment plans for 3D-RT and IMRT for both the IF and IN according to the guidelines of the German Hodgkin Study Group (GHSG). As OAR, we defined heart, lung, breasts, and spinal cord. Dose-volume histograms (DVHs) were evaluated for planning target volumes (PTVs) and OAR.
Average IF-PTV and IN-PTV were 1705 cm(3) and 1015 cm(3), respectively. Mean doses to the PTVs were almost identical for all plans. For IF-PTV/IN-PTV, conformity was better with IMRT and homogeneity was better with 3D-RT. Mean doses to the heart (17.94/9.19 Gy for 3D-RT and 13.76/7.42 Gy for IMRT) and spinal cord (23.93/13.78 Gy for 3D-RT and 19.16/11.55 Gy for IMRT) were reduced by IMRT, whereas mean doses to lung (10.62/8.57 Gy for 3D-RT and 12.77/9.64 Gy for IMRT) and breasts (left 4.37/3.42 Gy for 3D-RT and 6.04/4.59 Gy for IMRT, and right 2.30/1.63 Gy for 3D-RT and 5.37/3.53 Gy for IMRT) were increased. Volume exposed to high doses was smaller for IMRT, whereas volume exposed to low doses was smaller for 3D-RT. Pronounced benefits of IMRT were observed for patients with lymph nodes anterior to the heart. IN-RT achieved substantially better values than IF-RT for almost all OAR parameters, i.e., dose reduction of 20% to 50%, regardless of radiation technique.
Reduction of target volume to IN most effectively improves OAR sparing, but is still considered investigational. For the time being, IMRT should be considered for large PTVs especially when the anterior mediastinum is involved.
In the HD15 trial of the German Hodgkin Study Group, the negative predictive value (NPV) of positron emission tomography (PET) using 18F-fluorodeoxyglucose in advanced-stage Hodgkin lymphoma (HL) was ...evaluated. A total of 817 patients were enrolled and randomly assigned to receive BEACOPP-based chemotherapy. After completion of chemotherapy, residual disease measuring more than or equal to 2.5 cm in diameter was assessed by PET in 311 patients. The NPV of PET was defined as the proportion of PET− patients without progression, relapse, or irradiation within 12 months after PET review panel. The progression-free survival was 96% for PET− patients (95% confidence interval CI, 94%-99%) and 86% for PET+ patients (95% CI, 78%-95%, P = .011). The NPV for PET in this analysis was 94% (95% CI, 91%-97%). Thus, consolidation radiotherapy can be omitted in PET− patients with residual disease without increasing the risk for progression or early relapse compared with patients in complete remission. The impact of this finding on the overall survival at 5 years must be awaited. Until then, response adapted therapy guided by PET for HL patients seems to be a promising approach that should be further evaluated in clinical trials. This trial is registered at http://isrctn.org study as #ISRCTN32443041.
Liver-specific overexpression of the insulin-like growth factor 2 (IGF2) mRNA binding protein p62/IGF2BP2-2 induces a fatty liver, which highly expresses IGF2. Because IGF2 expression is elevated in ...patients with steatohepatitis, the aim of our study was to elucidate the role and interconnection of p62 and IGF2 in lipid metabolism. Expression of p62 and IGF2 highly correlated in human liver disease. p62 induced an elevated ratio of C18:C16 and increased fatty acid elongase 6 (ELOVL6) protein, the enzyme catalyzing the elongation of C16 to C18 fatty acids and promoting nonalcoholic steatohepatitis in mice and humans. The p62 overexpression induced the activation of the ELOVL6 transcriptional activator sterol regulatory element binding transcription factor 1 (SREBF1). Recombinant IGF2 induced the nuclear translocation of SREBF1 and a neutralizing IGF2 antibody reduced ELOVL6 and mature SREBF1 protein levels. Concordantly, p62 and IGF2 correlated with ELOVL6 in human livers. Decreased palmitoyl-CoA levels, as found in p62 transgenic livers, can explain the lipogenic action of ELOVL6. Accordingly, p62 represents an inducer of hepatic C18 fatty acid production via a SREBF1-dependent induction of ELOVL6. These findings underline the detrimental role of p62 in liver disease.
We sought to quantitatively and objectively evaluate histomorphologic tumor regression and establish a relevant prognostic regression classification system for esophageal cancer patients receiving ...neoadjuvant radiochemotherapy.
Eighty-five consecutive patients with localized esophageal cancers (cT2-4, Nx, M0) received standardized neoadjuvant radiochemotherapy (cisplatin, 5-fluorouracil, 36 Gy). Seventy-four (87%) patients were resected by transthoracic en bloc esophagectomy and 2-field lymphadenectomy. The entire tumor beds of the resected specimens were evaluated histomorphologically, and regression was categorized into grades I to IV based on the percentage of vital residual tumor cells (VRTCs). A major response was achieved when specimens contained either less than 10% VRTCs (grade III) or a pathologic complete remission (grade IV).
Complete resections (R0) were performed in 66 of 74 (89%) patients with 3-year survival rates of 54% +/- 7.05% for R0-resected cases and 0% for patients with incomplete resections or tumor progression during neoadjuvant therapy (P < 0.01). Minor histopathologic response was present in 44 (59.5%) and major histopathologic response in 30 (40.5%) tumors. Significantly different 3-year survival rates (38.8% +/- 8.1% for minor versus 70.7 +/- 10.1% for major response) were observed. Univariate survival analysis identified histomorphologic tumor regression (P < 0.004) and lymph node category (P < 0.01) as significant prognostic factors. Pathologic T category (P < 0.08), histologic type (P = 0.15), or grading (P = 0.33) had no significant impact on survival. Cox regression analysis identified dichotomized regression grades (minor and major histomorphologic regression, P < 0.028) and lymph node status (ypN0 and ypN1, P < 0.036) as significant independent prognostic parameters. A 2-parameter regression classification system that includes histomorphologic regression (major versus minor) and nodal status (ypN0 versus ypN1) was established (P < 0.001).
Histomorphologic tumor regression and lymph node status (ypN) were significant prognostic parameters for patients with complete resections (R0) following neoadjuvant radiochemotherapy for esophageal cancer. A regression classification based on 2 parameters could lead to improved objective evaluation of the effectiveness of treatment protocols, accuracy of staging and restaging modalities, and molecular response prediction.
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