Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in 1000 patients with perforated appendiceal epithelial tumours

PURPOSE

To report early and long term outcomes following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in 1000 patients with perforated appendiceal epithelial tumours, predominantly with pseudomyxoma peritonei (PMP).

METHODS

Retrospective analysis of a prospective database of 1000 consecutive patients undergoing CRS and HIPEC for perforated appendiceal tumours between 1994 and 2014 in a UK National Peritoneal Malignancy unit.

RESULTS

Overall 1000/1444 (69.2%) patients treated for peritoneal malignancy had appendiceal primary tumours. Of these 738/1000 (73.8%) underwent complete cytoreductive surgery (CCRS), 242 (24.2%) had maximal tumour debulking (MTD) and 20 (2%) had laparotomy and biopsies only. Treatment related 30-day mortality was 0.8% in CCRS and 1.7% in MTD group with major postoperative morbidity rates of 15.2% (CCRS) and 14.5% (MTD). Five- and 10-year overall survival was 87.4% and 70.3% in the 738 patients who had CCRS compared with 39.2% and 8.1% respectively in the MTD group. On multivariate analysis, significant predictors of reduced overall survival were male gender (p = 0.022), elevated CEA (p = 0.001), elevated CA125 (p = 0.001) and high tumour grade or adenocarcinoma (p = 0.001).

CONCLUSIONS

Perforated epithelial appendiceal tumours are rare, though may be increasing in incidence and can present unexpectedly at elective or emergency abdominal surgery, often with PMP. CRS and HIPEC results in good long term outcomes in most patients.

A protocol for management of blood loss in surgical treatment of peritoneal malignancy by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

BACKGROUND AND AIMS

The treatment of peritoneal malignancies with cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has been shown to be associated with massive surgical blood loss. Maintaining high fibrinogen levels throughout surgery may reduce blood loss in these patients. The primary aim of the study was to see if Tranexamic Acid (TXA) and cryoprecipitate reduced surgical blood loss and hence red cell transfusions. A comparison was made with a cohort of patients treated with fresh frozen plasma (FFP) alone. The secondary aim was to measure the effect of both protocols on coagulation parameters and the incidence of arterial or venous thrombosis.

METHOD

We used prospectively collected data from 201 patients who had complete CRS with HIPEC for peritoneal malignancy using different protocols during two discrete 12-month time periods.

RESULTS

The new transfusion protocol led to a higher average fibrinogen level intra-operatively and post-operatively, with a significant reduction in average RBC, FFP and platelet transfusion intra-operatively per patient from 4·2 to 1·8 units, 6·2 to 0·2 units and 0·1 to 0 units, respectively. No significant difference in PT or APTT was seen between patients treated with the standard and new protocols. Venous thrombosis occurred in seven patients treated with the standard protocol and five with the new protocol. A single case of arterial thrombosis was seen in both groups.

CONCLUSION

Patients treated with upfront TXA and cryoprecipitate during CRS required less RBC transfusion than those treated with the standard protocol of early FFP.

Procalcitonin levels predict infectious complications and response to treatment in patients undergoing cytoreductive surgery for peritoneal malignancy

BACKGROUND

Cytoreductive-surgery for peritoneal-malignancy (PM) involves extensive intra-abdominal surgery and a massive post-operative systemic-inflammatory-response (SIRS). It is often challenging to differentiate SIRS that are solely surgery-associated from those of post-operative infections. White-Cell-Counts (WCC) and C-Reactive-Protein (CRP) are routinely used as markers for infection, but are non-specific and their elevation is often delayed in PM cases. Other markers need to be evaluated to assist early identification/prediction of post-operative infections.

METHODOLOGY

Prospective evaluation of serum procalcitonin (PCT), CRP and WCC in 50 patients pre-operatively (Day0), and on post-operative days (POD) 1, 3 & 6, following cytoreductive-surgery with or without splenectomy.

RESULTS

Day0 PCT, CRP and WCC values were within normal limits, but increasing physiologically in post-operative period without infection, with noticeable higher PCT in splenectomized patients. In our cohort post-operative infections were diagnosed in 14 patients, often within 48 h. There was a trend for faster rise in serum PCT on POD1 compared to CRP and WCC, and faster PCT decline following appropriate therapy on POD3 and POD6 when infected cases were clinically resolving while WCC and CRP continued to rise, particularly in non-spelenectomised patients. The AUC on POD1 was significantly higher for PCT (0.689) vs. WCC (0.476) and CRP (0.477) (p = 0.04). Sensitivity, specificity, positive-predictive-value and negative-predictive-values for PCT ranged between (57%-100%), (22%-74%), (33%-47%) & (81%-100%), for CRP (28%-78%), (5.5%-86%), (18%-44.4%) & (40%-75.5%) and for WCC (14%-26.5%), (65.5-80.5%), (22%-25%), (67%-70%) respectively.

CONCLUSION

PCT, like WCC and CRP, needs to be interpreted with extreme cautions in the context of infections post-cytoreductive-surgery and should only be used in association with other clinical and investigational findings.

The results of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in 1200 patients with peritoneal malignancy

AIM

The study determined the outcome of 1200 consecutive patients treated for peritoneal malignancy in one surgical unit over a 20-year period.

METHOD

A retrospective analysis was conducted of a custom designed prospective database of patients undergoing surgery for peritoneal malignancy since 1994. Patient demographics, tumour type, extent of surgery and outcome were recorded.

RESULTS

Between 1994 and January 2014 (when the 1200th case had undergone surgery) 2956 patients were referred with a diagnosis of peritoneal malignancy. Pseudomyxoma peritonei of appendiceal origin was the pathology in 956/1200 (79.7%) patients. Other aetiologies included colorectal peritoneal metastases [89/1200 (7.4%)], abdominal mesothelioma [65/1200 (5.4%)] and miscellaneous [90/1200 (7.5%)]. Overall 863/1200 (71.9%) had complete cytoreduction, 294 (24.5%) had maximal tumour debulking and 43 (3.6%) had laparotomy only. The proportion undergoing complete cytoreduction per quartile of 300 patients was 60.7%, 65.0%, 77.0% and 80.3%. Laparotomy and biopsy fell from 6.4% in the first quartile to 2.7%, 1.7% and 1.3% in subsequent quartiles. The 30-day mortality in the four quartiles was 3.0%, 1.0%, 0.7% and 0.7%. The 5-year survival was 84% in the 636 patients with appendix tumours who had complete cytoreduction, 76% in the 38 with abdominal mesothelioma and 44% in the 60 with colorectal peritoneal metastases.

CONCLUSION

A centralized approach facilitated high volume experience in a single centre with an increase in the completeness of surgical excision rates and a reduction in mortality and morbidity over time.

Venom Concentrations and Clotting Factor Levels in a Prospective Cohort of Russell's Viper Bites with Coagulopathy

BACKGROUND

Russell's viper envenoming is a major problem in South Asia and causes venom induced consumption coagulopathy. This study aimed to investigate the kinetics and dynamics of venom and clotting function in Russell's viper envenoming.

METHODOLOGY/PRINCIPAL FINDINGS

In a prospective cohort of 146 patients with Russell's viper envenoming, we measured venom concentrations, international normalised ratio [INR], prothrombin time (PT), activated partial thromboplastin time (aPTT), coagulation factors I, II, V, VII, VIII, IX and X, and von Willebrand factor antigen. The median age was 39 y (16-82 y) and 111 were male. The median peak INR was 6.8 (interquartile range [IQR]: 3.7 to >13), associated with low fibrinogen [median,<0.01 g/L; IQR: <0.01-0.9 g/L), low factor V levels [median,<5%; IQR: <5-4%], low factor VIII levels [median,40%; IQR: 12-79%] and low factor X levels [median, 48%; IQR: 29-67%]. There were smaller reductions in factors II, IX and VII over time. All factors recovered over 48 h post-antivenom. The median INR remained >3 at 6 h post-antivenom but had reduced to <2, by 24 h. The aPTT had also returned to close to normal (<50 sec) at 24 h. Factor VII, VIII and IX levels were unusually high pre-antivenom, median peak concentrations of 393%, 307% and 468% respectively. Pre-antivenom venom concentrations and the INR (r = 0.20, p = 0.02) and aPTT (r = 0.19, p = 0.03) were correlated (non-parametric Spearman analysis).

CONCLUSIONS

Russell's viper coagulopathy results in prolonged aPTT, INR, low fibrinogen, factors V, VIII and X which recover over 48 h. Severity of clotting abnormalities was associated with venom concentrations.

Elevated tumour markers are normalized in most patients with pseudomyxoma peritonei 7 days after complete tumour removal

AIM

Elevation of the preoperative tumour markers in pseudomyxoma peritonei (PMP) is common and is a risk factor for recurrence. There has, however, been no documentation of the effect of complete tumour removal on tumour markers levels after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The aim of the study was to compare the tumour markers 7 days after surgery in patients with elevated preoperative levels.

METHOD

This was an observational prospective study of patients with PMP of appendiceal origin treated in one of the UK National Referral Centres for this condition. Thirty patients [median age = 61 (range: 31-74) years; six men] with an elevated preoperative level of carcinoembryonic antigen (CEA), carbohydrate antigen 125 (CA-125) and/or carbohydrate antigen 19-9 (CA19-9) underwent repeated estimation, 7 days after CRS and HIPEC for PMP.

RESULTS

The median preoperative CEA level of 12 μg/l fell to 0.75 μg/l postoperatively (P < 0.0001), CA-125 fell from 45 to 31 kU/l (P = 0.183) and CA19-9 fell from 134 to 37 kU/l (P = 0.003). The CEA was raised in 22 (73%) of 30 patients preoperatively and in two (7%) of 30 patients 7 days after surgery (P < 0.0001). The corresponding data for CA-125 were 18 (60%) and 13 (43%) (P = 0.196) and for CA19-9 they were 24 (80%) and 16 (53%) (P = 0.028).

CONCLUSION

This is the first documentation of a reduction or normalization of CEA 7 days after CRS, but not for CA19-9 or CA-125. This may indicate completeness of surgical resection and could aid selection for adjuvant therapy and predict prognosis. Long-term follow-up is, however, necessary to determine the significance of this observation.

Population Pharmacokinetics of an Indian F(ab')2 Snake Antivenom in Patients with Russell's Viper (Daboia russelii) Bites

BACKGROUND

There is limited information on antivenom pharmacokinetics. This study aimed to investigate the pharmacokinetics of an Indian snake antivenom in humans with Russell's viper bites.

METHODS/PRINCIPAL FINDINGS

Patient data and serial blood samples were collected from patients with Russell's viper (Daboia russelii) envenoming in Sri Lanka. All patients received Indian F(ab')2 snake antivenom manufactured by VINS Bioproducts Ltd. Antivenom concentrations were measured with sandwich enzyme immunoassays. Timed antivenom concentrations were analysed using MONOLIXvs4.2. One, two and three compartment models with zero order input and first order elimination kinetics were assessed. Models were parameterized with clearance (CL), intercompartmental clearance (Q), central compartment volume (V) and peripheral compartment volume (VP). Between-subject-variability (BSV) on relative bioavailability (F) was included to account for dose variations. Covariates effects (age, sex, weight, antivenom batch, pre-antivenom concentrations) were explored by visual inspection and in model building. There were 75 patients, median age 57 years (40-70 y) and 64 (85%) were male. 411 antivenom concentration data points were analysed. A two compartment model with zero order input, linear elimination kinetics and a combined error model best described the data. Inclusion of BSV on F and weight as a covariate on V improved the model. Inclusion of pre-antivenom concentrations or different batches on BSV of F did not. Final model parameter estimates were CL,0.078 L h(-1), V,2.2L, Q,0.178 L h(-1) and VP,8.33L. The median half-life of distribution was 4.6 h (10-90%iles:2.6-7.1 h) and half-life of elimination, 140 h (10th-90th percentilesx:95-223h).

CONCLUSION

Indian F(ab')2 snake antivenom displayed biexponential disposition pharmacokinetics, with a rapid distribution half-life and more prolonged elimination half-life.

Role of biomarkers of nephrotoxic acute kidney injury in deliberate poisoning and envenomation in less developed countries

Acute kidney injury (AKI) has diverse causes and is associated with increased mortality and morbidity. In less developed countries (LDC), nephrotoxic AKI (ToxAKI) is common and mainly due to deliberate ingestion of nephrotoxic pesticides, toxic plants or to snake envenomation. ToxAKI shares some pathophysiological pathways with the much more intensively studied ischaemic AKI, but in contrast to ischaemic AKI, most victims are young, previously healthy adults. Diagnosis of AKI is currently based on a rise in serum creatinine. However this may delay diagnosis because of the kinetics of creatinine. Baseline creatinine values are also rarely available in LDC. Novel renal injury biomarkers offer a way forward because they usually increase more rapidly in AKI and are normally regarded as absent or very low in concentration, thereby reducing the need for a baseline estimate. This should increase sensitivity and speed of diagnosis. Specificity should also be increased for urine biomarkers since many originate from the renal tubular epithelium. Earlier diagnosis of ToxAKI should allow earlier initiation of appropriate therapy. However, translation of novel biomarkers of ToxAKI into clinical practice requires better understanding of non-renal factors in poisoning that alter biomarkers and the influence of dose of nephrotoxin on biomarker performance. Further issues are establishing LDC population-based normal ranges and assessing sampling and analytical parameters for low resource settings. The potential role of renal biomarkers in exploring ToxAKI aetiologies for chronic kidney disease of unknown origin (CKDu) is a high research priority in LDC. Therefore, developing more sensitive biomarkers for early diagnosis of nephrotoxicity is a critical step to making progress against AKI and CKDu in the developing world.

Mechanisms underlying early rapid increases in creatinine in paraquat poisoning

Background

Acute kidney injury (AKI) is common after severe paraquat poisoning and usually heralds a fatal outcome. The rapid large increases in serum creatinine (Cr) exceed that which can be explained by creatinine kinetics based on loss of glomerular filtration rate (GFR).

Methods and Findings

This prospective multi-centre study compared the kinetics of two surrogate markers of GFR, serum creatinine and serum cystatin C (CysC), following paraquat poisoning to understand and assess renal functional loss after paraquat poisoning. Sixty-six acute paraquat poisoning patients admitted to medical units of five hospitals were included. Relative changes in creatinine and CysC were monitored in serial blood and urine samples, and influences of non-renal factors were also studied.

Results

Forty-eight of 66 patients developed AKI (AKIN criteria), with 37 (56%) developing moderate to severe AKI (AKIN stage 2 or 3). The 37 patients showed rapid increases in creatinine of >100% within 24 hours, >200% within 48 hours and >300% by 72 hours and 17 of the 37 died. CysC concentration increased by 50% at 24 hours in the same 37 patients and then remained constant. The creatinine/CysC ratio increased 8 fold over 72 hours. There was a modest fall in urinary creatinine and serum/urine creatinine ratios and a moderate increase in urinary paraquat during first three days.

Conclusion

Loss of renal function contributes modestly to the large increases in creatinine following paraquat poisoning. The rapid rise in serum creatinine most probably represents increased production of creatine and creatinine to meet the energy demand following severe oxidative stress. Minor contributions include increased cyclisation of creatine to creatinine because of acidosis and competitive or non-competitive inhibition of creatinine secretion. Creatinine is not a good marker of renal functional loss after paraquat poisoning and renal injury should be evaluated using more specific biomarkers of renal injury.

Detection of venom after antivenom is not associated with persistent coagulopathy in a prospective cohort of Russell's viper (Daboia russelii) envenomings

BACKGROUND

Venom recurrence or persistence in the circulation after antivenom treatment has been documented many times in viper envenoming. However, it has not been associated with clinical recurrence for many snakes, including Russell's viper (Daboia spp.). We compare the recovery of coagulopathy to the recurrence or persistence of venom in patients with Russell's viper envenoming.

METHODOLOGY/PRINCIPAL FINDINGS

The study included patients with Russell's viper (D. russelii) envenoming presenting over a 30 month period who had Russell's viper venom detected by enzyme immunoassay. Demographics, information on the snake bite, and clinical effects were collected for all patients. All patients had serum collected for venom specific enzyme immunoassay and citrate plasma to measure fibrinogen levels and prothrombin time (international normalised ratio; INR). Patients with venom recurrence/persistence were compared to those with no detectable recurrence of venom. There were 55 patients with confirmed Russell's viper envenoming and coagulopathy with low fibrinogen concentrations: 31 with venom recurrence/persistence, and 24 with no venom detected post-antivenom. Fibrinogen concentrations increased and INR decreased after antivenom in both the recurrence and non-recurrence patients. Clinical features, laboratory parameters, antivenom dose and length of hospital were similar for both groups. Pre-antivenom venom concentrations were higher in patients with venom recurrence/persistence with a median venom concentration of 385 ng/mL (16-1521 ng/mL) compared to 128 ng/mL (14-1492 ng/mL; p = 0.008).

CONCLUSION

Recurrence of Russell's viper venom was not associated with a recurrence of coagulopathy and length of hospital stay. Further work is required to determine if the detection of venom recurrence is due to the venom specific enzyme immunoassay detecting both venom-antivenom complexes as well as free venom.

Recurrence and outcome after complete tumour removal and hyperthermic intraperitoneal chemotherapy in 512 patients with pseudomyxoma peritonei from perforated appendiceal mucinous tumours

BACKGROUND

Pseudomyxoma peritonei (PMP) usually originates from perforated mucinous appendiceal tumours and may present unexpectedly at surgery, or be suspected at cross sectional imaging. The optimal treatment involves macroscopic tumour removal by cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). The 10-year Kaplan-Meier predicted disease-free survival is 61%. Some patients with recurrence are amenable to further CRS and HIPEC.

AIM

To evaluate the outcomes of re-do surgery in a large single centre series of reoperation for recurrence of peritoneal surface malignancy.

METHOD

Retrospective analysis of prospective database of 752 patients undergoing CRS for perforated appendiceal tumours analysed. Routine follow up involved annual CT scans and serum tumour marker measurement. The survival and recurrence in the 512/752 (68.1%) who had complete cytoreduction between March 1994 and January 2012 was calculated by Kaplan-Meier univariate analysis.

RESULTS

Overall 137/512 (26.4%) developed recurrence and of those 35/137 (25.5%) underwent repeat surgery. Complete tumour removal was again achieved in 20/35 (57.1%). There were no postoperative deaths and no significant difference in early postoperative complications and length of stay compared to primary CRS surgery. The 5-year survival in the 375 without recurrence, the 35 who had re-do surgery and the 102 who had recurrence with no surgery was 90.9%, 79.0% and 64.5% respectively.

CONCLUSION

Approximately one in four patients develops recurrence after complete CRS and HIPEC for PMP of appendiceal origin. Selected patients can undergo salvage surgery with good outcomes.

Morphological Investigation of Alumina Asymmetric Membrane by Manipulating the Sintering Temperature Profile

Ceramic materials have been widely utilized due to its attractive properties including high resistance to extremely harsh environments; chemical and heat, and its durability to the remarkable mechanical strength. Inorganic flat sheet films in this study were prepared by dry-wet phase inversion process followed by sintering method, which expected to produce very unique micro-structures leading to improvement in performance for various applications including catalytic reactions and filtration processes. Aluminium oxide was chosen as the main material due its known capability in filtration processes, membrane reactors and membrane catalysis applications. Polyethersulfone (PES) was used as an organic binder in the membrane dope formulation. Besides alumina and PES, the dope solution was consisted of N-methyl-2-pyrrolidone (NMP) and arlacel as solvent and additive, respectively. The main aim of this study is to investigate the effect of sintering temperature on the morphology and structure of the prepared membranes. Scanning electron microscope (SEM) was used to examine the membrane structure. Since the morphology of a membrane highly influences its mechanical properties, the membrane strength was measured using tensile test. From the SEM, preliminary cast membrane structure displayed a long finger-like near the outer and inner walls sandwiched a sponge-like structure that provided the membrane strength.