Clinical Impact of Contouring Variability for Prostate Cancer Tumor Boost

PURPOSE/OBJECTIVE(S)

In the FLAME randomized phase III trial, adding a focal radiotherapy (RT) boost to tumors visible on MRI improved prostate cancer disease-free survival, local control, and regional/distant metastasis-free survival without increasing toxicity. In a prospective study (ReIGNITE RT Boost), we found substantial variability in radiation oncologists' attempts to contour prostate cancer tumors on MRI. Participants' accuracy and reliability improved when they used a quantitative MRI biomarker for cancer called the restriction spectrum imaging restriction score (RSIrs). Here, we measure the impact of radiation oncologists' tumor contour attempts on RT plans and predicted probability of biochemical failure.

MATERIALS/METHODS

A total of 44 radiation oncologists (participants) from multiple institutions contoured prostate tumors on 30 patient cases, some with only conventional MRI and some with conventional MRI plus RSIrs maps. We developed a knowledge-based planning automated algorithm to generate RT plans with focal tumor boost per the FLAME trial protocol: 77 Gy in 35 fractions to prostate and integrated boost up to 95 Gy to the focal target, provided no normal tissue constraints were violated. We applied this algorithm to each participant's tumor contour and compared dosimetric parameters to those achieved when using the expert-defined tumor (consensus of two radiologists and a radiation oncologist). The primary metric was dose covering 98% of the expert-defined tumor (D98%), which was associated with probability of biochemical failure in a model published with the FLAME trial.

RESULTS

In this preliminary analysis, 42 target volumes were analyzed from 20 participants and two patient cases: case 1 was contoured with conventional MRI alone and case 2 with RSIrs. All plans had adequate coverage of the prostate and met all key normal tissue constraints. For case 1 (without RSIrs), the expert's D98% was 87.1 Gy. By comparison, median D98% for participants was 82.2 Gy (IQR 77.8 - 84.6 Gy). Per the FLAME trial model, the predicted probability of biochemical failure at 7 years is 6% for the expert, but participants' plans yielded a median failure probability of 11% (IQR 18 - 9%). For case 2 (with RSIrs), the expert's D98% was 82.8 Gy, while median D98% for participants was 80.6 Gy (IQR 80.0 - 81.0 Gy). Predicted probability of biochemical failure is 12% for the expert-defined target and median 13% (IQR 14 - 13%) for participants.

CONCLUSION

Variability in radiation oncologists' prostate tumor contours can lead to clinically meaningful changes to focal RT boost plans. The probability of biochemical failure for one patient case increased from 6% to a median of 11% when using conventional MRI alone. Use of RSIrs may mitigate this problem by increasing the accuracy and reliability of radiation oncologists' tumor contours.

Effective dose rate coefficients for exposure to contaminated soil

The Oak Ridge National Laboratory Center for Radiation Protection Knowledge has undertaken calculations related to various environmental exposure scenarios. A previous paper reported the results for submersion in radioactive air and immersion in water using age-specific mathematical phantoms. This paper presents age-specific effective dose rate coefficients derived using stylized mathematical phantoms for exposure to contaminated soils. Dose rate coefficients for photon, electron, and positrons of discrete energies were calculated and folded with emissions of 1252 radionuclides addressed in ICRP Publication 107 to determine equivalent and effective dose rate coefficients. The MCNP6 radiation transport code was used for organ dose rate calculations for photons and the contribution of electrons to skin dose rate was derived using point-kernels. Bremsstrahlung and annihilation photons of positron emission were evaluated as discrete photons. The coefficients calculated in this work compare favorably to those reported in the US Federal Guidance Report 12 as well as by other authors who employed voxel phantoms for similar exposure scenarios.

ICRP Publication 133: The ICRP computational framework for internal dose assessment for reference adults: specific absorbed fractions

Dose coefficients for assessment of internal exposures to radionuclides are radiological protection quantities giving either the organ equivalent dose or effective dose per intake of radionuclide following ingestion or inhalation. In the International Commission on Radiological Protection’s (ICRP) Occupational Intakes of Radionuclides (OIR) publication series, new biokinetic models for distribution of internalised radionuclides in the human body are presented as needed for establishing time-integrated activity within organs of deposition (source regions). This series of publications replaces Publications 30 and 68 (ICRP, 1979, 1980, 1981, 1988, 1994b). In addition, other fundamental data needed for computation of the dose coefficients are radionuclide decay data (energies and yields of emitted radiations), which are given in Publication 107 (ICRP, 2008), and specific absorbed fraction (SAF) values – defined as the fraction of the particle energy emitted in a source tissue region that is deposited in a target tissue region per mass of target tissue. This publication provides the technical basis for SAFs relevant to internalised radionuclide activity in the organs of Reference Adult Male and Reference Adult Female as defined in Publications 89 and 110 (ICRP, 2002, 2009). SAFs are given for uniform distributions of mono-energetic photons, electrons, alpha particles, and fission-spectrum neutrons over a range of relevant energies. Electron SAFs include both collision and radiative components of energy deposition. SAF data are matched to source and target organs of the biokinetic models of the OIR publication series, as well as the Publication 100 (ICRP, 2006) Human Alimentary Tract Model and the Publication 66 (ICRP, 1994a) Human Respiratory Tract Model, the latter as revised within Publication 130 (ICRP, 2015). This publication further outlines the computational methodology and nomenclature for assessment of internal dose in a manner consistent with that used for nuclear medicine applications. Numerical data for particle-specific and energy-dependent SAFs are given in electronic format for numerical coupling to the respiratory tract, alimentary tract, and systemic biokinetic models of the OIR publication series.

[Natural orifice transluminal endoscopic surgery in Germany: Data from the German NOTES registry]

BACKGROUND

The German NOTES registry (GNR) was initiated by the German Society for General and Visceral Surgery (DGAV) as a treatment and outcome database for natural orifice transluminal endoscopic surgery (NOTES).

AIM

The aim of this study was the descriptive analysis of all GNR data collected over a 5-year period since its start in 2008 with more than 3000 interventions.

MATERIAL AND METHODS

The GNR is an online database with voluntary participation available to all German-speaking clinics. Demographic data, therapy details, complications and data on the postoperative course of patients are recorded. All cases in the GNR between March 2008 and November 2013 were included in the analysis.

RESULTS

From a total of 3150 data sets 2992 (95 %) were valid and suited for the analysis. Hybrid transvaginal cholecystectomy was the most frequently used procedure (88.7 %), followed by hybrid transvaginal/transgastric appendectomy (6.1 %) and hybrid transvaginal/transrectal colon procedures (5.1 %). Intraoperative complications occurred in 1.6 %, postoperative complications in 3.7 % and conversions were reported in 1.5 %. Intraoperative bladder injuries and postoperative urinary tract infections were identified as method-specific complications of transvaginal procedures. Bowel injuries occurred as a rare (0.2 %) but potentially serious complication of transvaginal operations.

CONCLUSION

The German surgical community ensures a safe and responsible introduction of the new NOTES operation techniques with its active participation in the GNR. Despite an overall low complication rate, the high number of procedures in the GNR permitted the identification of method-specific complications. This knowledge can be used to further increase the safety of NOTES in practice.

Heavy metals, lipid peroxidation, and ciguatera toxicity in the liver of the Caribbean barracuda (Sphyraena barracuda)

Human consumption of over 400 species of tropical fish containing polyether toxins (e.g. ciguatoxins, maitotoxins) causes ciguatera fish poisoning. The Caribbean barracuda (Sphyraena barracuda) is one of the most potent ciguatoxic fish. The objective of this study was to determine whether toxicity of 14 barracuda livers was correlated with lipid peroxidation. A significant correlation (p = 0.015, Pearson's correlation) between lipid peroxidation and toxicity of barracuda liver was found. Because iron and copper are well-known catalysts of hydroxyl radical production and lipid peroxidation in biological systems, the correlation between the concentrations of these metals in barracuda liver and lipid peroxidation and toxicity was also investigated. Cadmium was significantly correlated (p = 0.014) with the toxicity of barracuda livers. This study provides the first data concerning the concentration of iron, copper, and cadmium in the liver of the Caribbean barracuda. Of the three metals studied in barracuda liver, iron was the most abundant, followed by copper and cadmium. Lipid peroxidation was highly variable and detected in five (36%) of the liver samples. Lipid peroxidation was not statistically significantly correlated (p > 0.05) with concentrations of iron, copper, and cadmium in barracuda liver. Collectively, these findings provide additional evidence that lipid peroxidation can be a mechanistic component of ciguatera toxicity in the Caribbean barracuda.

Collaborative evaluation of a method for the detection of Norwalk virus in shellfish tissues by PCR

A multicenter, collaborative trial was performed to evaluate the reliability and reproducibility of a previously described method for the detection of Norwalk virus in shellfish tissues with the PCR (R.L. Atmar, F. H. Neill, J. L. Romalde, F. Le Guyader, C. M. Woodley, T. G. Metcalf, and M. K. Estes, Appl. Environ. Microbiol. 61:3014-3018, 1995). Virus was added to the stomachs and hepatopancreatic tissues of oysters or hard-shell clams in the control laboratory, the samples were shipped to the participating laboratories, and viral nucleic acids were extracted and then detected by reverse transcription-PCR. The sensitivity and specificity of the assay were 85 and 91%, respectively, when results were determined by visual inspection of ethidium bromide-stained agarose gels; the test sensitivity and specificity improved to 87 and 100%, respectively, after confirmation by hybridization with a digoxigenin-labeled, virus-specific probe. We have demonstrated that this method can be implemented successfully by several laboratories to detect Norwalk virus in shellfish tissues.

Developing a centre for health information and promotion

Following the successful application for nursing development unit funding, the children's outpatient department within the Child Health Directorate of the University Hospital, Southampton, has developed a number of ambitious plans to promote nursing initiatives, one of which was the creation of a centre for health information and promotion. This article describes this development.

Tumor cell retention of antibody Fab fragments is enhanced by an attached HIV TAT protein-derived peptide

Two peptide analogs of the 37-62 sequence region of the HIV TAT protein bind tightly to the surface of A431 breast carcinoma cells. After conjugation to either of two poorly internalized anti-tumor antibody Fab fragments, the analogs enhanced the in vitro cell surface retention and internalization of the Fab fragments to the level of the whole antibodies. This was at the expense of some binding specificity in the case of 1.6 peptides/NRLU-10 Fab, but not in the case of 1.1 peptides/Fab. Enhanced retention may occur by enhanced bivalent binding of the Fab fragments. The internalized fraction of free peptide, but not of the Fab conjugates, is enhanced by chloroquine. The conjugates which were less specific for tumor cell binding may be useful for enhanced retention/internalization of specifically acting agents, for use at specific sites of injection, or against pre-separated target cell populations, while the more specific conjugate may be of interest for further development.

Enhanced in vitro tumor cell retention and internalization of antibody derivatized with synthetic peptides

The Fab fragments of two antitumor monoclonal antibodies, NR-ML-05 and NR-LU-10, have been covalently derivatized with synthetic peptides designed to provide secondary sites of attachment to enhance their retention on tumor cells. Analogs of the peptide "GALA", an amphipathic peptide previously reported to interact with uncharged lipid bilayers, gave antibody conjugates of different molecular weight and bound peptide stoichiometry when attached to Fab fragments using the heterobifunctional cross-linker sulfo-SMCC. This attached peptide enhanced the retention and internalization of Fab fragments of NR-ML-05 on FEMX human melanoma cells, but not of NR-LU-10 on HT-29 human colon carcinoma cells, indicating that this effect might be specific for individual tumor antigen-antibody systems. This peptide appeared to increase nonspecific interactions of the conjugate with antigen-negative cells. Other membrane-active peptides were also tested. None were as effective as the "GALA" analogs. A synthetic ion channel peptide attached to NR-ML-05 Fab exhibited the greatest enhanced internalization of these tested peptides.

Immunoconjugates of Pseudomonas exotoxin A: evaluation in mice, monkeys, and man

Immunotoxins of PE were constructed with stable thioether linkages using two monoclonal antibodies to ovarian cancer, OVB-3 and NR-LU-10. Antigens recognized by both antibodies have limited normal tissue distribution and are expressed on virtually all ovarian cancers. Both antibodies form highly potent conjugates (ID50 = 100 pg/ml) with high selectivity (greater than or equal to 4 logs) and can eliminate greater than or equal to 5 logs of tumor cells in vitro. The conjugates have been evaluated for efficacy in both ovarian and colon carcinoma ascites xenografts. In the ovarian model, the conjugates produce an increase in life span (ILS) of 200 to 300 with some cures against established but low tumor burden ascites. Increasing the tumor burden decreases efficacy and duration of responses. A lower ILS of 150 to 200 is achieved in the more aggressive colon model. However, the combination of immunotoxin with chemotherapy, which is ineffective on its own, demonstrated enhanced activity (ILS = 300). Toxicity of the conjugates is hepatic and easily monitored by liver function tests (LDH). Antitoxin responses are highly variable, but typically have a rapid onset and appear to be predicted by preexisting levels. Pilot clinical evaluation in ovarian cancer (intraperitoneal) is ongoing.

Selective elimination of breast cancer cells from human bone marrow using an antibody-Pseudomonas exotoxin A conjugate

A pancarcinoma monoclonal antibody (NR-LU-10), homogeneously reactive with human breast cancer cells, was conjugated to Pseudomonas exotoxin A. The immunotoxin was evaluated for its potential for purging breast cancer cells from human bone marrow. The immunotoxin NR-LU-10 antibody did not react with normal bone marrow preparations yet readily detected 1% contamination of bone marrow by MCF-7 breast cancer cells added to normal bone marrow without significantly inhibiting the colony-forming ability of bone marrow progenitor cells. NR-LU-10-Pseudomonas exotoxin A has potential for purging bone marrow of breast cancer cells without impairing the growth of bone marrow progenitor cells.

Enhanced therapeutic efficacy of an immunotoxin in combination with chemotherapy against an intraperitoneal human tumor xenograft in athymic mice

A mouse IgG2b anti-pan carcinoma monoclonal antibody, NR-LU-10, was shown to bind homogeneously to ascites xenografts of both ovarian and colon carcinoma. Following linkage to a highly potent holotoxin, Pseudomonas exotoxin A (PE), NR-LU-10 demonstrated high potency and selectivity in vitro (ID50 = 100 pg/ml; elimination of greater than or equal to 4.5 logs of cells). The conjugate was evaluated for therapeutic efficacy against a human colon tumor (HT-29) transplantable in the peritoneal cavity of nude mice. Beginning 3 days after HT-29 injection, mice received either three or six i.p. injections of 0.5 micrograms of unconjugated NR-LU-10 or immunotoxin conjugate (NR-LU-10/PE) every other day. Mice that received three or six treatments of NR-LU-10 alone had median survival times (MSTs) of 39 and 40 days, respectively, which did not differ significantly from the MST observed for the untreated control groups (MST = 35 days). In contrast, treatment with three or six injections of 0.5 micrograms NR-LU-10/PE exhibited significantly increased MSTs (P = 0.002) of 50 and 60 days, respectively. Coinjection of unconjugated NR-LU-10 (20 micrograms) and 0.5 micrograms of NR-LU-10/PE blocked the therapeutic effect of the immunotoxin (MST = 33 days). The therapeutic efficacy of NR-LU-10/PE was further enhanced against HT-29 when administered i.p. during and after cytoreductive chemotherapy. The i.p. administration of 300 mg/lg of cyclophosphamide plus 100 mg/kg of the chemoprotective drug, WR-2721, 10 and 17 days posttumor cell inoculation induced a significant increase in MST from 36 days to 59 days (P = 0.002). Interestingly, groups of mice that received either two, four, or seven treatments of NR-LU-10/PE following cytoreductive therapy exhibited a further significant increase (P = 0.001) in MSTs of 89, 97, and 105 days, respectively. Therefore, the use of immunotoxin therapy following cytoreductive chemotherapy significantly prolonged survival time of mice bearing the HT-29 colon tumor over that observed with chemotherapy or NR-LU-10/PE alone.

Transformation by the oncogene v-fms: the effects of castanospermine on transformation-related parameters

The effects of castanospermine on various parameters associated with transformation were examined in cells expressing the viral oncogene v-fms. Fischer rat embryo (FRE) cells transformed by the oncogene v-fms and grown in the presence of castanospermine reverted to a more normal cell morphology and accumulated fms protein within the endoplasmic reticulum. Treated cells attained contact inhibition of cell growth at a much lower cell density compared to the untreated controls. No effect of castanospermine on cell growth was observed for FRE cells transformed by a different oncogene v-fgr. Castanospermine-treated SM-FRE (v-fms transformed) cells reexpressed extracellular matrix fibronectin and exhibited an extensive actin-containing cytoskeleton similar to that of normal nontransformed FRE cells. Castanospermine treatment of SM-FRE cells resulted in a sixfold decrease in [3H]deoxyglucose uptake compared to that of the nonreverted SM-FRE cells. Again, no effect was observed in FRE cells transformed by the oncogene v-fgr (GR-FRE). These results further characterize the reversion caused by castanospermine and indicate that cell surface expression coordinately controls anchorage independent growth, cell morphology, contact inhibition of growth, and hexose uptake.

Localization of the feline sarcoma virus fgr gene product (P70gag-actin-fgr): association with the plasma membrane and detergent-insoluble matrix

The v-fgr oncogene codes for a unique transforming protein (P70gag-actin-fgr) that contains virus-specific determinants and cell-derived sequences for both a tyrosine-specific kinase domain and an actin domain. We examined the subcellular distribution of the v-fgr protein by immunofluorescence microscopy and various cell fractionation techniques. By immunofluorescence, the v-fgr protein was localized in a diffuse cytoplasmic pattern within transformed cells. The v-fgr protein was not detectable at substratum adhesion sites. Crude membrane preparations (P100) obtained from fgr-transformed cells contained elevated levels of P70gag-actin-fgr. Further analysis of membranes on discontinous sucrose gradients revealed that P70gag-actin-fgr cofractionated with plasma membranes. Using an alternate method of fractionation, we found that the majority of the v-fgr protein remained with the insoluble matrix obtained by treating cells with a buffer containing Triton X-100. When membranes were similarly treated with detergent, nearly all of v-fgr protein remained with the residual insoluble matrix. These results suggest that the transforming activity of P70gag-actin-fgr may be directed to subcellular cytoskeletal targets at or near the cytoplasmic face of the plasma membrane.

Transformation by the v-fms oncogene product: role of glycosylational processing and cell surface expression

The effect of glycosylational-processing inhibitors on the synthesis, cell surface expression, endocytosis, and transforming function of the v-fms oncogene protein (gp140fms) was examined in McDonough feline sarcoma virus-transformed Fischer rat embryo (SM-FRE) cells. Swainsonine (SW), a mannosidase II inhibitor, blocked complete processing, but an abnormal v-fms protein containing hybrid carbohydrate structures was expressed on the cell surface. SW-treated SM-FRE cells retained the transformed phenotype. In contrast, two glucosidase I inhibitors (castanospermine [CA] and N-methyl-1-deoxynojirimycin [MdN]) blocked carbohydrate remodeling at an early stage within the endoplasmic reticulum and prevented cell surface expression of v-fms proteins. CA-treated SM-FRE cells reverted to the normal phenotype. Neither SW, CA, nor MdN affected either endocytosis or the tyrosine kinase activity associated with the v-fms gene product in vitro. These results demonstrate the necessity of carbohydrate processing for cell surface expression of the v-fms gene product and illustrate the unique ability to modulate the transformed state of SM-FRE cells with the glycosylational-processing inhibitors CA and MdN.

Cell surface expression of the McDonough strain of feline sarcoma virus fms gene product (gp 140fms)

The unique oncogene carried by the McDonough strain of feline sarcoma virus (SM-FeSV), called v-fms, directs the synthesis of a set of related glycoproteins, called gP 180gag-fms, gp 140fms, and gp 120fms. We have prepared antibodies to these proteins and used indirect immunofluorescence techniques on viable SM-FeSV transformed cells to demonstrate that fms-specific determinants are expressed on the external surface. The fms-specific fluorescence co-localized with clathrin and was detectable in clathrin-coated pits and endocytotic vesicles. Two cell surface labeling methods indicated that gp140fms was the only fms-related protein on the cell surface. In view of the relationship between the erbB oncogene product and the epidermal growth factor receptor, and the fact that growth factor receptors utilize clathrin-coated pits in endocytosis, we believe the gp140fms transforming protein of SM-FeSV also could function as an analog of a growth factor receptor.

[Causes of outpatient dropouts in the dispensary care of a chest clinic (author's transl)]

An investigation was made to point out, why 397 of total 2773 patients with 5524 consultations failed the fixed next consultation. 29 patients had died meanwhile. A special invitation was necessary in 368 (= 13%) of 2744 patients. The further behaviour of these patients after suitable advice and the importance of the diagnosis of their diseases in this connection were investigated. Failing of the patients can be diminished by systematical instructions.