Risk factors for a permanent stoma after resection of left-sided obstructive colon cancer - A prediction model

INTRODUCTION

In patients with left-sided obstructive colon cancer (LSOCC), a stoma is often constructed as part of primary treatment, but with a considerable risk of becoming a permanent stoma (PS). The aim of this retrospective multicentre cohort is to identify risk factors for a PS in LSOCC and to develop a pre- and postoperative prediction model for PS.

MATERIALS AND METHODS

Data was retrospectively obtained from 75 hospitals in the Netherlands. Patients who had curative resection of LSOCC between January 1, 2009 to December 31, 2016 were included with a minimum follow-up of 6 months after resection. The interventions analysed were emergency resection, decompressing stoma or stent as bridge-to-elective resection. Main outcome measure was presence of PS at the end of follow-up. Multivariable logistic regression analysis was performed to identify risk factors for PS at primary presentation (T₀) and after resection, in patients having a stoma in situ (T₁). These risk factors were used to construct a web-based prediction tool.

RESULTS

Of 2099 patients included in the study (T₀), 779 had a PS (37%). A total of 1275 patients had a stoma in situ directly after resection (T₁), of whom 674 had a PS (53%). Median follow-up was 34 months. Multivariable analysis showed that older patients, female sex, high ASA-score and open approach were independent predictors for PS in both the T₀ and T₁ population. Other predictors at T₀ were sigmoid location, low Hb, high CRP, cM1 stage, and emergency resection. At T₁, subtotal colectomy, no primary anastomosis, not receiving adjuvant chemotherapy and high pTNM stage were additional predictors. Two predictive models were built, with an AUC of 0.74 for T₀ and an AUC of 0.81 for T₁.

CONCLUSIONS

PS is seen in 37% of the patients who have resection of LSOCC. In patients with a stoma in situ directly after resection, 53% PS are seen due to non-reversal. Not only baseline characteristics, but also treatment strategies determine the risk of a PS in patients with LSOCC. The developed predictive models will give physicians insight in the role of the individual variables on the risk of a PS and help in informing the patient about the probability of a PS.

Geodetic evidence for interconnectivity between Aira and Kirishima magmatic systems, Japan

It is not known whether clustered or aligned volcanic edifices at the Earth surface have connected magmatic systems at depth. Previously suggested by geological records of paired eruptions, volcano interconnectivity still lacks proper geodetic evidence. Here we use GPS time-series and deformation modeling to show how Aira caldera and Kirishima, two adjacent volcanic centers in Kagoshima graben (southern Japan), interacted during Kirishima unrest in 2011. Whereas Aira caldera had been inflating steadily for two decades, it deflated during the eruption of Kirishima which started with a large-volume lava extrusion. This deflation, which cannot be explained by stress changes, is interpreted as the result of magma withdrawal from the Aira system during the Kirishima replenishment phase. This study highlights the behavior of connected neighboring volcanic systems before and after a large eruption, and the importance of taking into account volcano interactions in eruption probability models.

Depolymerization of lignosulfonates by submerged cultures of the basidiomycete Irpex consors and cloning of a putative versatile peroxidase

Lignosulfonates are abundantly available byproducts of the paper and pulping industry, and they therefore represent a promising feedstock for new sustainable processes. For industrial applications of lignosulfonates, their molecular weight distribution is a critical factor. In order to decrease the average molecular weight of lignosulfonates, Seventeen basidiomycetes were screened for their capability to depolymerize lignosulfonates from spent sulfite liquor (SSL) in surface and liquid cultures. Five basidiomycetes polymerized the lignosulfonates under the selected conditions. Only Irpex consors was found to efficiently degrade calcium lignosulfonates when SSL (0.5%, w/w) was used as the sole carbon and nitrogen source. The average molecular weight of the lignosulfonates was reduced from ∼26 to ∼4 kDa as determined by size exclusion chromatography (SEC) within two weeks. Various extracellular enzyme activities of I. consors were determined over the culture period. High peroxidase activities were correlating with a high degradation rate and the culture was harvested at the day of highest peroxidase activity. A putative versatile peroxidase was isolated by fast protein liquid chromatography (FPLC) and its encoding cDNA was cloned.

Immunoscintigraphy with positron emission tomography: gallium-68 chelate imaging of breast cancer pretargeted with bispecific anti-MUC1/anti-Ga chelate antibodies

Pretargeting techniques that are based on the sequential administrations of bispecific antitumor/antimetal chelate antibodies (BS-MAbs), a blocker to saturate the anti-chelate binding sites of the BS-MAb still present in the circulation, and the radiolabeled chelate are suitable to increase tumor-to-normal tissue contrasts and enable positron emission tomography (PET) as an imaging method. As demonstrated in the nude mouse model, a combination of pretargeted immunoscintigraphy and PET markedly improved the detection of tumor xenografts. With the presented preliminary clinical trial, we attempted to assess the efficacy of pretargeting and PET for breast cancer localization in patients. The BS-MAb used for pretargeting was synthesized from the F(ab')(2) fragments of the anti-MUC1 MAb 12H12, which reacts with the vast majority of breast tumors, and the F(ab') fragments of an anti-gallium (Ga) chelate MAb via a mixed functional chemical linker. For labeling of the Ga-chelate, we used the short-lived positron emitter Ga-68 (t(1/2), 68 min; beta(+), 88%). The dose and time schedule of pretargeting was deduced from previous animal experiments. Ten patients with biopsy-proven, primary breast carcinoma were infused with 10 mg of the BS-MAB: Eighteen h later, they received i.v. injections of 10.7 mg of a blocker and, 15 min later, 9.6 microg of the Ga chelate labeled with 230-300 MBq of (68)GA: PET imaging was started 60-90 min after injection of the (68)Ga chelate. Average tumor-to-blood and tumor:normal breast tissue ratios were 0.9 and 3.0 at 1 h postinjection. Tumor uptake amounted to approximately 0.003% iD/g corresponding to a standard uptake value of approximately 2. Blood clearance of the (68)Ga chelate showed a t(1/2) beta of approximately 100 min. Fourteen of 17 known lesions, averaging 25 +/- 16 mm in size, were clearly visualized as foci of increased activity with PET. No false-positive but three false-negative readings were obtained. An enhanced, bilateral activity uptake in the whole breast parenchyma, found in 4 of the 10 patients, compromised the recognition of these tumor sites. Although the shedding of the MUC1 antigen and the comparatively low tumor affinity of the BS-MAb, common to all anti-mucin MAbs, proved not to be optimal for increasing tumor:tissue ratios with a pretargeting technique, PET imaging offered better sensitivity for the detection of breast cancer at low tumor contrasts than conventional immunoscintigraphy. This could be demonstrated by the clear visualization of tumor sites 10 mm in size, which contrasted only by a factor of 2 from surrounding normal breast tissue.

Carcinogenicity assays of wood dust and wood additives in rats exposed by long-term inhalation

OBJECTIVE

This study evaluates whether wood dust and/or wood preservatives develop a carcinogenic potential against the tissues of the airways of rats.

METHODS

The formation of tumors of the respiratory tract after exposure to wood dust was studied in six groups of approximately 60 female Fischer 344 rats exposed by long-term inhalation to mean concentrations of (1) 18 mg/m3 of untreated oak wood dust, (2) wood preservatives containing ca. 1 microgram/m3 lindane and 0.2 microgram/m3 of pentachlorophenol (PCP) in the exposure air, or lindane and 18 micrograms/m3 of PCP (group lindane/PCP vapors, and group oak wood treated with lindane/PCP), (3) 21 or 39 micrograms/m3 of sodium dichromate (calculated as CrO3, group chromate aerosol and group oak wood with chromate), and 72 micrograms/m3 of N-nitrosodimethylamine vapors as positive control. The negative control group consisted of 115 animals (sham-exposed).

RESULTS

Tumors of the nasal cavity developed in two rats exposed to chromate aerosol or in combination with wood dust (2/102, 2%). Malignant tumors of the lower respiratory tract were induced only in exposed groups of rats (three adenocarcinomas of the lung and four bronchiolar lung carcinomas, 7/254, 2.8%). More respiratory tract tumors were observed in rats exposed to chromate or wood with chromate (5/102, 5%), also in groups exposed to oak wood dust (oak untreated, oak + chromate, oak + lindane/PCP; together 5/155, 3.2%). Analysis of 'unpreserved' oak wood dust revealed up to 5 micrograms/m3 of chromate. When this exposure was taken into account, eight of nine animals with respiratory tract tumors (including nasal cavity) had exposure to chromate, while only one tumor occurred in the group lindane/PCP. Otherwise the incidence of systemic tumors was increased in animals exposed to lindane/PCP, due in particular to a significantly increased incidence of liver tumors (OR = 3.7; 1.24-11.3; P = 0.019). Fatal (mucoepidermoid) tumors were induced by N-nitrosodimethylamine (NDMA) in the positive control (14/46, 30%). No such tumors of the respiratory tract were observed in the negative control.

CONCLUSIONS

Tumors in the respiratory tract were found only in exposed animals, predominantly in the groups which inhaled oak wood dust and chromate stain. Chromate may play a decisive role for the etiology of tumors of the nasal cavity in wood workers. This assumption should be supported by further dose-response studies.

Widespread uplift and 'trapdoor' faulting on Galápagos volcanoes observed with radar interferometry

Volcanic uplift, caused by the accumulation of magma in subsurface reservoirs, is a common precursor to eruptions. But, for some volcanoes, uplift of metres or more has not yet led to an eruption. Here we present displacement maps of volcanoes in the Galápagos Islands, constructed using satellite radar interferometry, that might help explain this dichotomy. We show that all but one of the seven volcanoes on the islands of Isabela and Fernandina deformed during 1992-99. Cerro Azul and Fernandina erupted during the observation period and show evidence of inflation, co-eruptive deflation and shallow dyke intrusion. In contrast, the largest volcano, Sierra Negra, has not erupted, yet exhibits spatially and temporally variable deformation, with a maximum uplift of 2.7 m between 1992 and 1999, which can be modelled by a shallow inflating sill. Inflation during 1997-98, however, was accompanied by 'trapdoor' faulting on a steeply dipping fracture system within the caldera. Repeated trapdoor faulting over geological time has formed an arcuate intra-caldera ridge within Sierra Negra and may have acted to relax stresses above the magma chamber, inhibiting summit eruptions. Similar processes may help explain large uplift unaccompanied by eruptive activity at other volcanoes.

Tumor induction and prophylaxis following different forms of intestinal urinary diversion in a rat model

Eighty Wistar rats were randomized into two groups. In group 1 vesicosigmoidostomy with proximal colostomy was performed, in group 2, vesicosigmoidostomy. The total tumor incidence did not significantly (group 1 10/40, 25%; group 2 13/40, 32.5%). The tumor spectrum differed, with more adenocarcinomas in group 2 (11/40, 27.5% vs 4/40, 10%; P = 0.047) and urothelial carcinomas only in group 1 (5/40, 2.5%). One hundred and ten other Wistar rats were randomized into three groups. Animals in group A received vesicoileosigmoidostomy, group B, two-step vesicosigmoidostomy with initial separation of urine and the urocolonic anastomosis, group C, vesicosigmoidostomy. Significantly fewer adenocarcinomas were observed in group A (2/40, 5%) than in group B (16/40, 40%; P < 0.002) and group C (9/30, 30%; P < 0.007). These results indicate a similar cancer risk in all continent forms of urinary diversion, at least via colon. Ileal interposition seems to be an effective carcinoma prophylaxis following ureterosigmoidostomy. The proliferative instability at the urointestinal anastomosis is crucial for the pathogenesis and prophylaxis of this form of carcinogenesis, whereas urine seems to play only a minor role.

Tumor induction in a rat model for ureterosigmoidostomy without evidence of nitrosamine formation

Twenty rats were randomized into a vesicosigmoidostomy and an unoperated control group. In both groups the 24 hour excretion of secondary amines, nitrate, nitrite and nitrosamines was measured before and after gavage of proline and nitrate, piperazine and nitrate, N-nitrosoproline, mono-N-nitrosopiperazine. The urinary nitrosamine concentrations were not significantly different between both groups neither before nor after application of the several substances. Thirty rats were randomized into two vesicosigmoidostomy groups with and without antibiotic coverage and an unoperated control group. After ligation of distal rectum and mesosigmoid the rectosigmoids were removed. No significant concentrations of volatile nitrosamines could be measured in the rectosigmoid contents of the three groups. One hundred and twenty rats randomized into three groups following vesicosigmoidostomy received the potential nitrosamine antidotes sodium-2-mercaptoethane sulfonate or sodiumpentosan-polysulfate or acted as controls. 12/118 (10.2%) developed adenomas and 25/118 (21.2%) adenocarcinomas at the vesico-colonic anastomosis with no significant differences between the three groups concerning tumor incidence or mortality. The results show that colon carcinomas occur in a rat model for ureterosigmoidostomy without evidence for thus induced nitrosamine formation. This and the missing effect of nitrosamine antidotes suggest that other factors than nitrosation must be responsible for colon carcinogenesis following urinary diversion via intestine.

Therapeutic efficacy of two different cytostatic-linked phosphonates in combination with razoxane in the transplantable osteosarcoma of the rat

Two new compounds, 4-[4-[bis-(2-chloroethyl)-amino-]phenyl]-1- hydroxybutane-1,1-bisphosphonic acid (BAD) and aminotris-(methylenephosphonato)-diamminoplatinum(II) (ADP) that both have cytostatic and osteotropic properties, have shown good therapeutic efficacy against an osteosarcoma which metastasizes and kills by lung metastases. We therefore combined each of these drugs with the antimetastic agent razoxane. Razoxane (20 mg/kg i.p., 5 days/week for 6 weeks) was administered in combination with either BAD (30 mg/kg i.p.) or ADP (37.5 mg/kg i.v.) twice weekly for 3 weeks. Tumour volumes, body weight, survival time and occurrence of metastases were recorded, in addition to the measurement of the metastasis area compared to the total lung area in serial histological lung samples. In both experiments, razoxane effected a significant increase in life span while being ineffective in tumour inhibition. Razoxane in combination with BAD displayed an enhanced anticancer activity which was not significant. ADP had a good antineoplastic activity and a large increase in survival time (144 per cent ILS). Razoxane used in combination with ADP did not influence antitumour efficacy. Median survivals of both ADP-treated groups were significantly longer than the razoxane-treated group. Analysis of the lung metastasis area showed a maximum of 57 per cent for the controls while all treated groups occupied a lesser area. The lowest metastases area was found with the combination treatment BAD + RAZ (18 per cent). This was considered an antimetastatic effect, while ADP treatment effected a time delay only. No change in metastatic pattern was observed in any of the treatment groups. Histological examination showed no effect on the capillaries in the proliferating region of the tumours that could account for the lower occurrence of metastases.