Targeted next-generation sequencing of circulating-tumor DNA for tracking minimal residual disease in localized colon cancer.

BACKGROUND: A high percentage of patients diagnosed with localized colon cancer (CC) will relapse after curative treatment. Although pathological staging currently guides our treatment decisions, there are no biomarkers determining minimal residual disease (MRD) and patients are at risk of being undertreated or even overtreated with chemotherapy in this setting. Circulating-tumor DNA (ctDNA) can to be a useful tool to better detect risk of relapse. PATIENTS AND METHODS: One hundred and fifty patients diagnosed with localized CC were prospectively enrolled in our study. Tumor tissue from those patients was sequenced by a custom-targeted next-generation sequencing (NGS) panel to characterize somatic mutations. A minimum variant allele frequency (VAF) of 5% was applied for variant filtering. Orthogonal droplet digital PCR (ddPCR) validation was carried out. We selected known variants with higher VAF to track ctDNA in the plasma samples by ddPCR. RESULTS: NGS found known pathological mutations in 132 (88%) primary tumors. ddPCR showed high concordance with NGS (r = 0.77) for VAF in primary tumors. Detection of ctDNA after surgery and in serial plasma samples during follow-up were associated with poorer disease-free survival (DFS) [hazard ratio (HR), 17.56; log-rank P = 0.0014 and HR, 11.33; log-rank P = 0.0001, respectively]. Tracking at least two variants in plasma increased the ability to identify MRD to 87.5%. ctDNA was the only significantly independent predictor of DFS in multivariable analysis. In patients treated with adjuvant chemotherapy, presence of ctDNA after therapy was associated with early relapse (HR 10.02; log-rank P < 0.0001). Detection of ctDNA at follow-up preceded radiological recurrence with a median lead time of 11.5 months. CONCLUSIONS: Plasma postoperative ctDNA detected MRD and identified patients at high risk of relapse in localized CC. Mutation tracking with more than one variant in serial plasma samples improved our accuracy in predicting MRD.

Anastomotic leakage after colon cancer resection: does the individual surgeon matter?

AIM: Anastomotic leakage is one of the most feared complications after colonic resection. Many risk factors for anastomotic leakage have been reported, but the impact of an individual surgeon as a risk factor has scarcely been reported. The aim of this study was to assess if the individual surgeon is an independent risk factor for anastomotic leakage in colonic cancer surgery. METHOD: This was a retrospective analysis of prospectively collected data from patients who underwent elective resection for colon cancer with anastomosis at a specialized colorectal unit from January 1993 to December 2010. Anastomotic leaks were diagnosed according to standardized criteria. Patient and tumour characteristics, surgical procedure and operating surgeons were analysed. A logistic regression model was used to discriminate statistical variation and identify risk factors for anastomotic leakage. RESULTS: A total of 1045 patients underwent elective colon cancer resection with primary anastomosis. Anastomotic leakage occurred in 6.4% of patients. Ileocolic anastomosis had an anastomotic leakage rate of 7.2%, colo-colonic/colorectal anastomosis 5.2% and ileorectal anastomosis 12.7%, with intersurgeon variability. The independent risk factors associated with anastomotic leakage were the use of perioperative blood transfusion (OR 2.83, CI 1.59-5.06, P < 0.0001) and the individual surgeon performing the procedure (OR up to 8.44, P < 0.0001). CONCLUSION: In addition to perioperative blood transfusion, the individual surgeon was identified as an important risk factor for anastomotic leakage. Efforts should be made to reduce performance variability amongst surgeons.

[Hydroxyethyl starch to protect renal function in laparoscopic surgery]. / Uso de hidroxietil almidón (Voluven) como protección de la función renal en cirugía laparoscópica.

OBJECTIVE: To evaluate the effect of prehydration with hydroxyethyl starch 130/0.4 (Voluven) compared to lactated Ringer solution in laparoscopic cholecystectomy. PATIENTS AND METHODS: We performed a randomized single-blind clinical trial on patients classified as ASA 1 and 2. The exclusion criteria were hypertension, kidney failure, treatment with diuretics or other antihypertensive drugs, diabetes, and use of nonsteroidal anti-inflammatory drugs. Balanced general anesthesia with remifentanil and sevoflurane was used. The total volume of administered fluids (including prehydration) was 2 mL x kg(-1) x h(-1) fasting plus 5 mL x kg(-1) x h(-1) during surgery. Group 1 was prehydrated 30 minutes before surgery with 500 mL of lactated Ringer solution in group 1; in group 2 the same quantity of Voluven was used. Ringer solution was used in both groups to provide additional fluids. Blood pressure was kept within 20% above or below baseline values. Standard anesthetic monitoring was performed. Intraoperative diuresis and creatinine clearance were recorded. The groups were compared using the t test; a P value of 05 or less was considered significant. RESULTS: Twenty-nine patients were enrolled in the study. Diuresis and creatinine clearance were significantly higher in the group that received prehydration with Voluven. The mean (SD) creatinine clearance rate was 176.44 (1433) mL x min(-1) in group 1 and 61.90 (6.6) mL x min(-1) in group 2 (P = .036). The mean volume of urine excreted was 1.71 (0.06) mL x kg(-1) x h(-1) in group 1 and 0.47 (0.02) mL x kg(-1) x h(-1) in group 2 (P = .017). CONCLUSION: Prehydration with Voluven can be an effective measure for protecting renal function against the adverse effects of pneumoperitoneum in laparoscopic surgery.

Management of intersphincteric abscesses.

OBJECTIVE: Intersphincteric abscesses are relatively rare, and in some cases of upward extensions in the supralevator plane, can be difficult to manage. The aim of this study was to analyse the type of treatment used in these abscesses. METHODS: Twenty-one intersphincteric abscesses treated by endoanal drainage in our colorectal unit between 1992 and 2004 were reviewed from our database; location and extension of the abscess, type of treatment and recurrence rates and the use of endoanal ultrasound were studied. RESULTS: Ninety per cent of patients were male; 10 had a previous history of surgery for perianal abscess and suppuration (48%); 16 (76%) had a posterior location and five were anterolateral. Twelve patients had low intersphincteric abscesses and were treated by laying open the abscess and dividing the internal sphincter. Nine were found to have high extensions into the intermuscular planes and were treated by staged procedures: a temporary transanal mushroom catheter was used in seven patients. Endoanal ultrasound was used initially in seven patients (33.3%) and for the evaluation of definitive treatment in 11 (52%). CONCLUSIONS: Low intersphincteric abscesses should be treated by de-roofing of the abscess and division of the internal sphincter up to a level of the dentate line. High intersphincteric abscesses are relatively frequent and mostly require staged surgery with a temporary mushroom (de Pezzer) catheter. Accurate anatomical ultrasound localization and proper drainage become important to avoid recurrences or extrasphincteric fistulas.

Pathological features in marine birds affected by the prestige's oil spill in the north of Spain.

A total of 2,465 seabirds, mainly common murres (Uria aalge), razorbills (Alca torda), and puffins (Fratercula arctica) that beached in the northwestern part of Spain after the "Prestige" oil spill on 19 November 2002 were examined by pathological methods. Birds were divided into three groups: dead birds with the body covered (group 1) or uncovered (group 2) by oil and birds recovered alive but which died after being treated at a rescue center (group 3). The main gross lesions were severe dehydration and emaciation. Microscopically, hemosiderin deposits, related to cachexia and/or hemolytic anemia, were observed in those birds harboring oil in the intestine. Severe aspergillosis and ulcers in the ventriculus were found only in group 3 birds, probably because of stress associated with attempted rehabilitation at the rescue center. The mild character of the pathological changes suggests that petroleum oil toxicosis causes multiple sublethal changes that have an effect on the ability of the birds to survive at sea, especially weak and young, inexperienced animals. Dehydration and exhaustion seem to be the most likely cause of death.

A prospective audit of the complications of loop ileostomy construction and takedown.

AIM: A prospective review of the complications of ileostomy construction and takedown. MATERIALS AND METHODS: One hundred twenty-seven consecutive patients undergoing construction of a loop ileostomy were included in a prospective nonrandomized computer database. Complications of the loop ileostomy were assessed prior to and after closure. Three closure techniques were performed [enterotomy suture (25.7%), resection and hand sewn (31.2%) or stapled anastomosis (43.1%)] and compared. RESULTS: One hundred twenty-seven (73 male, 54 female) patients, mean age 54 years were included from 1992 to 2002. Seventy-two patients underwent anterior resection for low rectal carcinoma, 30 an ileoanal pouch for ulcerative colitis and 25 for miscellaneous conditions. Fifty-nine pre-takedown complications occurred in 50 (39.4%) patients. The most common were dermatitis (12.6%) and erythema (7.1%). The most severe were dehydration in 1 patient and stomal prolapse in 4 patients. Closure was associated with a complication rate of 33.1% and a mortality rate of 0.9%. Wound infection occurred in 18.3% and small bowel obstruction in 4.6%. Anastomotic leak requiring reanastomosis occurred in 2.8% and enterocutaneous fistula treated conservatively in 5.5%. There were no statistically significant differences in morbidity between closure techniques (p = 0.892). There were no statistically significant differences in complications (p = 0.516) between patients with ulcerative colitis and those with neoplasia (39.29% vs. 32.2%). CONCLUSIONS: Loop ileostomy construction and takedown is associated with considerable morbidity, mostly minor. No differences exist between technique used for closure or the baseline pathology of the patient.

Comparison between two warm ischemic models in experimental liver transplantation in pigs.

BACKGROUND: Experimental models of warm ischemia in liver transplantation have been employed to study the mechanisms and treatment of ischemia reperfusion injury. METHODS: We compared a control group without (group A, n = 10) versus two models of warm ischemia of liver transplants in pigs: namely, occlusion of the hepatic artery and portal vein for 30 minutes (group B, n = 23) and extraction of the liver 60 minutes after cardiac arrest (group C, n = 5). Liver function tests, coagulation studies, and liver biopsies were performed during the first 24 hours post-liver transplant. RESULTS: Clamping of the hepatic vasculature in group B produced a significant liver injury compared with the control group: elevation of the ALT and an abnormal 1-hour post-revascularization biopsy similar to that observed in the cardiac arrest group C. The transaminase levels were lower among group A animals (P <.05). But the hepatic synthetic functions as reflected in the protrombin time (PT) were not affected in group B versus group A. The alteration in PT with respect to the initial value was similar among group A and group B animals, which were significantly less than that in group C (P <.05). CONCLUSIONS: Occlusion of the hepatic artery and portal vein, a simple surgical maneuver, causes moderate damage to a liver graft but less alteration of hepatic synthetic function. Clamping of the hepatic vasculture obtains more long-term survivors after OLT than cardiac arrest.

Impact of surgeon organization and specialization in rectal cancer outcome.

PURPOSE: The present study was designed to assess the differences in the outcome of patients with rectal cancer treated by a group of surgeons before and after being organized as a Coloproctology Unit at the same University Department of Surgery. METHODS: Comparison of two periods of rectal cancer surgery: I (1986-91) and II (1992-95). Period I: 94 patients were operated on by 14 general surgeons. Period II: 108 patients were operated on by only 4 surgeons of the same group organized as a Colorectal Surgery Unit after visiting referral centres abroad, adopting techniques such as total mesorectal excision (TME) for middle and low rectal cancer and washout of rectal stump. Mean follow-up during periods I and II was 69.1 and 42.0 months, respectively. A prospective data base analysis was used. Survival and local recurrence rates were calculated by the actuarial method. For comparison between groups the log rank method was used. RESULTS: The two groups were comparable with respect to mean age, gender, TNM and rectal tumour location. A significant increase in radical resectability and a decrease of the Abdominoperineal resection (APR)/Low anterior resection (LAR) ratio were observed in the second period. The overall pelvic recurrence rate was 25% in the first period and 11 in the second (P < 0.01). Significant differences were also found when the patients with LAR were compared between both periods, 30% vs 9% (P < 0.01) and specially when the 10 cm anal verge distance was considered to divide the LAR groups. No differences were found regarding the APR procedures in both periods. There was improved cancer-specific survival for the LAR group in the second period (P=0.03). CONCLUSION: Specialization and centralization influence the quality of rectal cancer surgery, mainly local recurrence rates and survival after low anterior resection.

Simple technique for the intraoperative detection of Crohn's strictures with a calibration sphere.

Several methods have been used to detect and evaluate small-bowel strictures in Crohn's disease. We describe a simple technique for the calibration of strictures using a 2.5-cm medical plastic sphere. This method provides an aseptic, safe, and effective calibration of the entire small bowel.

Immunohistochemical localisation of rabbit haemorrhagic disease virus VP-60 antigen in early infection of young and adult rabbits.

This study evaluated the time course distribution of rabbit haemorrhagic disease virus (RHDV) structural protein VP60 in tissues from experimentally infected rabbits from three different age groups. Viral VP60 antigen could not be detected in tissue samples from animals under four weeks, and only a few hepatocytes (0.01 to 0.2 per cent) were stained in the 6-week-old animals. A 6-week-old rabbit euthanised at 72 hpi showed VP60-labelling in hepatocytes and macrophages close to areas of inflammation. Viral VP60 antigen was detected as early as 12 hpi in a few hepatocytes (0.03 per cent) from adult animals. Within this age group, the extent of hepatocyte labelling considerably increased at 18 (3.0 per cent), 24 (25.5 per cent), 36 (50 per cent) and 48 (60 per cent) hpi. Extrahepatic viral VP60 antigen was also detected at 36 and 48 hpi in spleen macrophages and lymphocytes from adult rabbits. These findings support the hypothesis that the hepatocyte is the only cell type in the liver able to support RHDV replication almost immediately after viral infection.

[Role of surgery in the treatment of primary gastric lymphoma]. / Papel de la cirugía en el tratamiento del linfoma gástrico primario.

Primary gastric lymphoma's optimum management remains controversial. We reviewed our series of 23 patients with primary gastric lymphoma treated in our hospital between 1976 and 1998 with surgery as main therapy. Ten patients underwent surgical resection alone, whereas 13 also received postoperative adjuvant therapy, depending on the oncologist-haematologist's recommendations. No differences were found between treatments regarding mortality and morbidity. Clinical-histological features and patients, follow-up are analyzed. No patient died because of lymphoma and there wasn't either local or distant recurrence. We consider that surgery remains a valid option for the primary gastric lymphoma treatment. The introduction of combined modalities of radiation therapy and chemotherapy will depend on the final stage, the tumor histological features, and the feasibility of getting a radical resection.

Therapeutic effects of different doses of botulinum toxin in chronic anal fissure.

PURPOSE: The aim of this study was to evaluate the clinical and manometric results of three different doses of botulinum toxin and two methods of injection for the treatment of chronic idiopathic anal fissure. METHODS: Sixty-nine patients with chronic anal fissure were included in a non-randomized, prospective trial of intrasphincteric injection of botulinum toxin. All patients reported postdefecatory anal pain lasting more than two months. Scoring systems were developed for anal pain, bleeding, and defecatory difficulty. Maximum resting and squeeze anal pressures were determined before and one month after treatment. Twenty-three patients undergoing a 5-U injection of diluted botulinum toxin A (BOTOX) on each side of the anal sphincter (total dose, 10 U) constituted the first group. In a second group 27 patients were injected as previously described, with an additional 5-U injection below the fissure (total dose, 15 U). The 19 patients constituting the third group received a 7-U injection on each side of the anus and below the fissure (total dose, 21 U). All patients were followed up for at least six months. RESULTS: Pain relief one month after treatment was more evident in the second and the third group (48 percent of patients in the first group, 74 percent in the second group, and 100 percent in the third group). A significant reduction of the mean resting pressure was demonstrated only in Groups II and III (P < 0.05), whereas the mean squeeze pressure significantly decreased in the three groups (P < 0.01 in Group I and P < 0.001 in Groups II and III). Fifty-two percent of the patients in the first group, 30 percent in the second group, and 37 percent in the third group were reinjected during the follow-up period, because of persistence of symptomatology or early relapse. The need for surgery was similar in the first and the second group (17 and 19 percent, respectively) and clearly lower in the last group (5 percent). No serious complications or incontinence attributable to this therapeutic modality developed in any patient. CONCLUSIONS: Intrasphincteric injection of botulinum toxin is a reliable new option in the treatment of uncomplicated chronic anal fissure. The healing rate is related to the dose and probably to the number of puncture sites. No permanent damage to the continence mechanism was detected in these patients.

[Follow-up of breast cancer: review of 750 cases after 5 years]. / Seguimiento del cáncer de mama: revisión de 750 casos a 5 años.

Recurrence of breast cancer can present in very small tumors even 20 years after initial treatment. Periodic revision of all the operated population during a long time will be necessary to detect all the recurrences. For this the cost-benefit relation of follow-up in breast cancer is a controversial topic. We present our results in 750 cases of breast cancer operated from 1980 and submitted to a follow-up protocol during five years. We analyzed the value of follow-up for the discovery of metastases, local recurrence after conservative treatment and after mastectomy. Finally we considered the usefulness of early diagnosis of familial breast cancer and cancer in the contralateral breast. Metastases was discovered in asymptomatic patients in 68%, which could improve the survival. Recurrence after mastectomy was seen in 1.3% of the patient and a half of these after treatment presented survival superior to 3 years. Follow-up favours early diagnosis and could have influence on survival.

[Breast cancer: value of various examinations in the diagnosis of the primary lesion]. / Cáncer de mama: valor de distintas exploraciones en el diagnóstico de la lesión primaria.

Breast physical examination which is enormous help in clinical diagnosis of cancer of the breast is not useful in the diagnosis of early lesions. We analized in this study different complementary examinations we do for the diagnosis of the cancer of the breast. Mammography, though maintaining a 5-7% false negative results is the examination of choice of the breast. Not with standing its simplicity, its contribution with respect to breast and neoplastic biology makes it a useful investigation. The diagnosis obtained through mammography in non palpable tumors permit the use of conservative therapeutic techniques at the same time allowing improvement in curation and survival rates when we deal preferently with Stage I cancer. It is still necessary in our means an information-sensibilization of the female population about breast autoexamination and the need for early specialized medical consultation. Any abnormal breast sign should alert us that more than 2.5 months delay would suppose a difference from a T1 to a T2 tumor.

Relationship of curative surgery on natural killer cell activity in colorectal cancer.

PURPOSE: Aim of this study has been to evaluate natural killer (NK) activity in patients with colorectal tumors before and after curative surgery. METHODS: Forty colorectal cancer patients without distant metastases were stratified according to American Joint Committee on Cancer/International Union Against Cancer staging system into three categories: Stage I (n = 12), Stage II (n = 15), and Stage III (n = 13). All of them underwent curative resection, and there were no major postoperative complications. Venous blood samples were obtained preoperatively, at surgical wound closure, and on the 1st, 7th, and 21st postoperative days. Mononuclear cells were isolated over Ficoll-Hypaque (Lymphoprep, Nycomed Pharma AS, Oslo, Norway) gradients, and NK activity was assayed by evaluation of cytotoxic response against K562 cells. Normal NK activity was achieved from 15 healthy donors. Percentage relative increments in relation to preoperative levels were calculated for every postoperative sample, and t-test was used for statistical evaluation. RESULTS: Before surgery, Stages II and III patients had lower levels of NK activity than healthy people (P < 0.05 and P < 0.001, respectively). NK activity always fell after surgery (Stage I: -18.48 +/- 11.42; Stage II: -16.93 +/- 13.57; Stage III: -35.29 +/- 12.03, at day 1 postsurgery) and appeared to rise slightly by the 21st postoperative day in Stage I patients (+4.87 +/- 12.41). Stage II, and especially Stage III, patients did show a significant recovery by the 21st postoperative day (+23.63 +/- 9.36 and +43.19 +/- 13.34, respectively). At this time, NK activity in these two groups was not significantly lower than in normal subjects (P > 0.05). CONCLUSION: NK activity is depressed in colorectal cancer patients in relation to progression of illness, even at locoregional stages. Curative resection of tumors at Stages II and III has promoted a recovery of NK activity in patients with uneventful postoperative courses.

Acute necrotizing pancreatitis: a multicenter study.

A multicenter study of acute necrotizing pancreatitis (ANP) classified in accordance with the Balthazar criteria (grades D and E), has been performed in 12 teaching hospitals. A total of 233 patients were reviewed, and the mortality rate was 26.6%. The most common etiology was biliary pancreatitis (45.5%). Among the complications, shock, renal insufficiency, pulmonary insufficiency and hemorrhagic gastritis were associated with a mortality rate of 51-66%. Diffuse fluid collections were associated with a higher mortality rate (26.8%) than localized fluid collections (14.5%). In 106 patients with gallstone pancreatitis, early surgery was performed in 17, and 5 patients (29.4%) died. No mortality was observed in 32 patients with delayed surgery. Sphincterotomy was performed in 13 patients, and 4 (30.7%) died. Early surgery (necrosectomy and closed peritoneal lavage) was undertaken in 75 patients, with a mortality rate of 39%. In conclusion, the morbidity and mortality rates of ANP can be improved with proper monitoring, adequate supportive care and the judicious use of surgery based on clinical and morphological findings.