Modern chemotherapy aims to improve long-term survival for selected patients with peritoneal carcinomatosis. Publications suggest promising results, but the spread of these new aggressive treatment ...strategies in the general population is not well known.
The aim of this study was to draw a picture of epidemiology, management, and survival in synchronous and metachronous peritoneal carcinomatosis from colorectal cancer.
The cumulative risk of metachronous peritoneal carcinomatosis was estimated in patients resected for cure. Net survival rates were calculated for synchronous and metachronous peritoneal carcinomatosis.
The study was conducted with the use of the Burgundy Digestive Cancer Registry.
Overall, 9174 primary colorectal cancers registered between 1976 and 2011 by the population-based digestive cancer registry were considered.
In total, 7% of patients were diagnosed with synchronous peritoneal carcinomatosis. The 5-year cumulative risk of metachronous peritoneal carcinomatosis was 6%, and the stage of the colorectal cancer at diagnosis was the major risk factor. Other independent risk factors were mucinous adenocarcinoma, ulceroinfiltrating tumors, and diagnosis after obstruction or perforation. The proportion of patients resected for cure was 11% and 9% for synchronous and metachronous peritoneal carcinomatosis, and 3-year overall net survival was 8% and 5%. The corresponding rates after resection for cure were 21% and 17%. There was a dramatic increase in the proportion of patients receiving systemic chemotherapy: from 11% before 1997 to 48% in 2011 for synchronous peritoneal carcinomatosis and from 3% to 38% for metachronous peritoneal carcinomatosis.
This is a retrospective observational population-based study.
Peritoneal carcinomatosis complicating colorectal cancer is a major reason for treatment failure. This study identified patients at a high risk of developing peritoneal carcinomatosis who may benefit from specific surveillance. New therapeutic modalities are also needed to improve the prognosis.
The early evolution of planetesimals and planets can be constrained using variations in the abundance of neodymium-142 ((142)Nd), which arise from the initial distribution of (142)Nd within the ...protoplanetary disk and the radioactive decay of the short-lived samarium-146 isotope ((146)Sm). The apparent offset in (142)Nd abundance found previously between chondritic meteorites and Earth has been interpreted either as a possible consequence of nucleosynthetic variations within the protoplanetary disk or as a function of the differentiation of Earth very early in its history. Here we report high-precision Sm and Nd stable and radiogenic isotopic compositions of four calcium-aluminium-rich refractory inclusions (CAIs) from three CV-type carbonaceous chondrites, and of three whole-rock samples of unequilibrated enstatite chondrites. The CAIs, which are the first solids formed by condensation from the nebular gas, provide the best constraints for the isotopic evolution of the early Solar System. Using the mineral isochron method for individual CAIs, we find that CAIs without isotopic anomalies in Nd compared to the terrestrial composition share a (146)Sm/(144)Sm-(142)Nd/(144)Nd isotopic evolution with Earth. The average (142)Nd/(144)Nd composition for pristine enstatite chondrites that we calculate coincides with that of the accessible silicate layers of Earth. This relationship between CAIs, enstatite chondrites and Earth can only be a result of Earth having inherited the same initial abundance of (142)Nd and chondritic proportions of Sm and Nd. Consequently, (142)Nd isotopic heterogeneities found in other CAIs and among chondrite groups may arise from extrasolar grains that were present in the disk and incorporated in different proportions into these planetary objects. Our finding supports a chondritic Sm/Nd ratio for the bulk silicate Earth and, as a consequence, chondritic abundances for other refractory elements. It also removes the need for a hidden reservoir or for collisional erosion scenarios to explain the (142)Nd/(144)Nd composition of Earth.
Primitive meteorites preserve the chemical and isotopic composition of the first aggregates that formed from dust and gas in the solar nebula during the earliest stages of solar system evolution. ...Gradual increase in the size of solid bodies from dust to aggregates and then to planetesimals finally led to the formation of planets within a few to tens of million years after the start of condensation. Thus the rocky planets of the inner solar system are likely the result of the accumulation of numerous smaller primitive as well as differentiated bodies. The chemically most primitive known meteorites are chondrites and they consist mostly of metal and silicates. Chondritic meteorites are derived from distinct primitive planetary bodies that experienced only limited element fractionation during formation and subsequent differentiation. Different chondrite classes show distinct chemical and isotopic characteristics, which may reflect heterogeneities in the solar nebula and the slightly different pathways of their formation. To a first approximation the chemical composition of the bulk Earth bears great similarities to primitive meteorites. However, for some elements there are striking and significant differences. The Earth shows a much stronger depletion of the moderate to highly volatile elements compared to chondrites. In addition, mixing trends of specific isotopes reveal that the Earth is most enriched in
s
-process isotopes compared to all other analysed bulk solar system materials. It is currently not possible to fully define and quantify the different chemical and isotopic materials that formed the Earth, because a major component seems missing in the extant collections of extraterrestrial samples. Variations in nucleosynthetic isotope compositions as well as the strong depletion of moderately and strongly volatile elements points towards a source in the inner solar system for this missing material. It is conceivable that Venus and Mercury contain a much larger fraction of this missing component. Thus, for a complete reconstruction of the conditions that led to the formation of the inner solar system planets (Mercury to Mars) samples from the inner planets Venus and Mercury are of great interest and importance. High precision chemical and isotopic analyses in the laboratory of rocky material from inner solar system bodies could complete the knowledge on the chemical, isotopic and mineralogical make-up of the solar nebula just prior to planet formation and enhance our understanding of the evolution of the solar nebula in general and the formation of the rocky planets in particular.
It is generally accepted that the parental magmas of the Lesser Antilles arc were generated by partial melting of a mid-ocean ridge basalt (MORB)-type mantle source modified by slab-derived ...components. To determine the nature of these components, the H2O, S, Cl, F, Li and B contents and δ7Li, δ11B, δ18O and δ34S compositions were systematically determined in olivine-hosted melt inclusions from St. Vincent (southern part of the arc). Both the geochemical and isotopic data define a broad compositional spectrum. On the whole, the melt inclusions have basaltic to CaO-rich (>15·0 wt %), SiO2-poor (< 45·7 wt %) compositions. Most of the entrapped melts result from ∼10–20% batch partial melting of a MORB-type mantle source modified initially by dehydration fluids with low solute contents and a seawater-like chemical signature. As a result, the melt inclusions are enriched in B, Cl and H2O compared with MORB and have δ11B up to + 15‰, δ34S of ∼2‰ and δ18O down to + 3‰. In contrast, some others record initial magmatic heterogeneities that require input of fluids derived from (1) the dehydration of altered oceanic crust in agreement with the selective B enrichment (up to 53 ppm) in the melt and negative lithium isotopic compositions, and (2) the dehydration of sediments resulting in distinctive δ11B and δ34S (down to –20‰ and –8‰, respectively) and high Li contents in the melts. The CaO-rich melt inclusions cannot be distinguished from the others on the basis of their isotopic signatures. They possibly reflect magma interactions with CaO-rich, amphibole-bearing lithologies. Combination of our results with literature experimental data leads to the conclusion that St. Vincent basaltic melt inclusions—whose water content varies from 2·2 to 3·6 wt %—represent magmas derived from a rather limited portion of the mantle wedge, by partial melting at between 13 and 14·5 kbar and a restricted temperature range (1220–1190°C).
Grenada Island is located at the southern end of the Lesser Antilles. Grenada lavas display a large range in compositions which includes picrites, representing the parental melt of all Grenada ...suites. We present here an extensive study of major, light and volatile elements combined with δD, δ11B and δ7Li determinations of melt inclusions hosted in olivines (Fo86–91) from picritic scoriae. The major element compositions of melt inclusions encompass those of Grenada basalts. Their H2O contents typically range from 0.2 to 4.1 wt% (one value at 6.4 wt%). Such extreme range stands in contrast with typical arc magmas for a single volcanic center. The high H2O contents are associated with strongly negative values of δD (on average −140‰). Melt inclusions display a wide range in B (1.7–47 ppm) and Li (1.1–12 ppm) contents as well as in δ7Li and δ11B, which vary from −24 to 8.2‰ and from −20 to 8.9‰, respectively. Both B and Li compositions of Grenada melt inclusions suggest (i) the involvement of dehydration fluids or hydrous silicate melts derived from buried carbonate‐bearing sediments, (ii) the contribution of aqueous fluids generated during the dehydration of hydrothermally altered oceanic crust, and (iii) melting of a mantle metasomatized by the addition of high δ11B, high‐Cl, Li‐poor fluids derived from the early dehydration of serpentinized peridotite above the slab beneath Grenada.
The isotopic composition of Cl, a highly hydrophilic and incompatible element, can provide new insights into the processes of element recycling in subduction zone settings. Samples from 13 localities ...in Guatemala, El Salvador, Nicaragua and Costa Rica, representing a ca. 1000 km long NW-SE segment along the Central American Volcanic Arc (CAVA), were selected. Ninety-seven melt inclusions, hosted by olivine Fo90−70, were measured for Cl isotope ratios and trace element concentrations. Melt inclusions from samples from Guatemala to northwest Nicaragua have a restricted range of δ37Cl values (range < 1‰ within a sample) with values decreasing from Santa Maria (Guatemala) to San Miguel (El Salvador), whereas melt inclusions from Nicaragua and Costa Rica display larger variation within a sample (δ37Cl value range >1‰, up to 3.8‰) and do not show any systematic variation along the arc. For some samples, the δ37Cl in the melt inclusions is shifted by up to 2‰ to higher values compared to bulk rock data from the same volcanic center, for which the extent of Cl degassing is not known. The combination of δ37Cl values in melt inclusions with trace elements and the existing knowledge about the slab contributions along the arc allows us to elucidate the Cl isotope composition of different endmembers in this subduction zone. From Guatemala to northwest Nicaragua, a fluid component, originating from serpentinite, has a δ37Cl value close to +0.6‰. This value, similar to lithospheric serpentinites, confirms that despite the aqueous fluid migration through the entire slab, Cl isotopes do not fractionate significantly during transport. A melt-like component, present in the southern part of the arc, has negative δ37Cl, possibly down to −2.5‰. This component has lower δ37Cl than values of the oceanic crust but similar to sediments currently subducting beneath CAVA. Finally, a common component, most likely amphibole-bearing metasomatized mantle, is identified in samples with the highest δ37Cl values (up to +3.0‰). The melting of amphibole, a mineral concentrating 37Cl over 35Cl, could explain the high δ37Cl values. The difference between melt inclusions and bulk rock δ37Cl in some volcanic centers probably results from late-stage processes such as mixing of different batches of magma at shallower levels after melt inclusions entrapment. Melt inclusions thus give a more comprehensive picture of Cl isotope systematics along the CAVA and in primitive subduction-related magmas.
•Chlorine isotopes were measured in melt inclusions along CAVA.•Melt inclusions have on average higher δ37Cl than bulk rocks.•Aqueous fluids, melt-like component and metasomatized mantle form three distinct signatures.•The high δ37Cl of the metasomatized mantle wedge suggests the presence of amphibole.•The amphibole signature in bulk rocks is diluted by late-stage processes.
The exsolution of a magmatic volatile phase in the plumbing systems of volcanoes plays a key role in controlling growth dynamics of subvolcanic reservoirs and eruptive styles. By using common ...petrological proxies found in volcanic deposits, such as melt inclusions and apatite crystals, the presence of such an exsolved magmatic volatile phase can be traced, specifically the exsolution of water from silicate melt. To monitor variations in the water saturation state of magmas from the Aso volcanic complex (Kyushu, Japan) prior to and during the catastrophic Aso-4 caldera-forming event (at ∼86 ka BP), we investigate a set of pre-Aso-4 and Aso-4 deposits, combining volatile budgets (F, Cl, OH, S) of melt inclusions, matrix glasses, and apatite crystals, with sulfur isotope signatures in apatite. F-Cl-OH partitioning in apatite along with melt inclusion data from pre-Aso-4 units indicate water-undersaturated conditions during magma evolution until around 10 ka prior to the Aso-4 event. In contrast, eruptions occurring within the last ∼10 ka prior to the Aso-4 event indicate the presence of a water-rich exsolved magmatic volatile phase in the eruptible portions of the subvolcanic reservoir. Likewise, sulfur systematics in apatite and melt inclusions from the Aso-4 event suggest the exsolution of a water-rich magmatic volatile phase at some point prior to the caldera-forming event. Recharge of mafic magmas shortly before the Aso-4 eruption induced chemical hybridization in the resident upper crustal mush, bringing the reservoir back to less evolved compositions and water-undersaturated conditions. This hybridization event is recorded by volatile contents of both apatite and matrix glasses from late-erupted, crystal-rich products of the Aso-4 event, all yielding water-undersaturated signatures. During this hybridization event, chemical dilution and partial redissolution of the exsolved volatile phase reduced the magma compressibility significantly, so that additional magma influx from depth might have allowed a sharply increasing overpressurization in the subvolcanic reservoir and served as a potential trigger for the cataclysmic Aso-4 eruption. Drawing from our observations made on Aso, we propose that recharging of large silicic upper-crustal reservoirs with increased volumes of drier and more mafic melts can influence their water saturation states and associated physical properties. Such changes could contribute to the triggering of large-scale caldera-forming events.
•Apatite and melt inclusions can track water saturation states of magma reservoirs.•The Aso system remained water-undersaturated for most of its last caldera cycle.•Water saturation in the reservoir occurs only <10 ka prior to the caldera formation.•Redissolution in melt of an exsolved volatile phase as potential eruption trigger.
Zircon occasionally crystallizes in evolved melt pockets in mafic large igneous province (LIP) magmas, and in these cases, it is used to provide high-precision age constraints on LIP events. The ...precision and accuracy of high-precision ages from LIPs are crucially important, because they may be implicated in mass extinctions. However, why zircon crystallizes in these magmas is not clearly understood, since their mafic compositions should limit zircon saturation. Here, we investigate the occurrence of zircon (and baddeleyite) in intrusive and extrusive mafic rocks from Central Atlantic Magmatic Province (CAMP) using petrography, trace-element analysis, Ti temperatures, Hf and oxygen isotopes, and high-precision U–Pb geochronology, along with petrological and thermal modeling. We provide new ages for CAMP sills that intruded into Paleozoic sediments in Brazil, indicating that the high and low Ti magmatism in this area occurred synchronously over 264 ± 57 ka. We show that upper crustal assimilation, especially of shales, during the emplacement of the CAMP likely led to zircon saturation. Assimilation of upper crustal sediments is also supported by high δ
18
O values and some rare negative εHf values in the zircon crystals. The only extrusive sample analyzed was the North Mountain basalt in Nova Scotia, Canada. This sample contains a large age variation in its zircon crystals (up to 4 Ma), and the older crystals have slightly more negative εHf values suggesting the presence of small (micron scale) xenocrystic cores associated with very late-stage sediment assimilation. However, the CAMP dataset as a whole suggests that the presence of xenocrystic cores is rare. Assuming no xenocrystic cores, and considering the zircon undersaturated nature of LIP mafic melts, the oldest zircon age clusters in a population should record the magma emplacement (or time when assimilation occurred), and the younger ages in a population are more likely to reflect Pb loss, especially given the high U concentrations of LIP zircon. Our identification of heterogeneous isotopic and elemental compositions in LIP zircon indicates that zircon in these magmas saturate in isolated minute melt pockets just before the system cools below its solidus.
•Ti diffusion in zircon is highly anisotropic.•Ti diffusion parallel to the c-axis in zircon is facilitated through aligned interstitial sites.•Ti-in-zircon temperatures do not always reflect ...crystallization conditions.
Ti-in-zircon thermometry has become a widely used tool to determine zircon crystallization temperatures, in part due to reports of extremely sluggish Ti diffusion perpendicular to the crystallographic c-axis in this mineral. We have conducted Ti-in-zircon diffusion experiments, focusing on diffusion parallel to the c-axis, at 1 atm pressure between 1100 and 1540°C, with oxygen fugacities equivalent to air and the Ni-NiO buffer. There is no resolvable dependence of Ti diffusion in zircon upon silica or zirconia activity, or upon oxygen fugacity. The diffusion coefficient of Ti in zircon is found to be a weak function of its own concentration, spanning less than 0.5 log units across any profile induced below 1300°C. Ti diffusion in zircon, parallel to the c-axis at 1 atm pressure, is well described using:log10DTi=1.34(±1.44)−555425(±44820)Jmol−12.303RT(K)m2s−1 where R is the gas constant in J/(mol⋅K). In conjunction with diffusion coefficients for Ti in zircon perpendicular to the c-axis reported by Cherniak and Watson (2007), strong diffusion anisotropy for Ti in zircon is observed. Diffusion parallel to the c-axis is ∼4-5 orders of magnitude faster than diffusion perpendicular to the c-axis within the experimentally constrained temperature range shared between these two studies (1540-1350°C). This difference increases if the data are extrapolated to lower temperatures and reaches ∼7.5-11 orders of magnitude between 950-600 °C, a typical range for zircon crystallization. Diffusion of Ti in natural zircons will predominantly occur parallel to the c-axis, and the Ti-in-zircon thermometer appears susceptible to diffusive modification under some crustal conditions. Temperatures calculated using this system should therefore be evaluated on a case-by-case basis, particularly when considering high-T, slowly cooled, reheated and/or small zircons.
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