Transvaginal/transumbilical hybrid--NOTES--versus 3-trocar needlescopic cholecystectomy: short-term results of a randomized clinical trial.

OBJECTIVE: For cholecystectomy, both the needlescopic cholecystectomy (NC) 3-trocar technique using 2 to 3 mm trocars and the umbilical-assisted transvaginal cholecystectomy (TVC) technique have found their way into clinical routine. This study compares these 2 techniques in female patients who are in need of an elective cholecystectomy. BACKGROUND: Natural orifice transluminal endoscopic surgery (NOTES) is a surgical concept permitting scarless intra-abdominal operations through natural orifices, such as the vagina. Because of the lack of an adequately powered trial, we designed this first randomized controlled study for the comparison of TVC and NC. METHODS: This prospective, randomized, nonblinded, single-center trial evaluates the safety and effectiveness of TVC (intervention), compared with NC (control) in female patients with symptomatic cholecystolithiasis. The primary endpoint was intensity of pain until the morning of postoperative day (POD) 2. Secondary outcomes were among others intra- and postoperative complications, procedural time, amount of analgesics used, pain intensity until POD 10, duration of hospital stay, satisfaction with the aesthetic result, and quality of life on POD 10 as quantified with the Eypasch Gastrointestinal Quality of Life Index (GIQLI). RESULTS: Between February 2010 and June 2012, 40 patients were randomly assigned to the interventional or control group. All patients completed follow-up. Procedural time, length of postoperative hospital stay, and the rate of intra- and postoperative complications were similar in the 2 groups. However, significant advantages were found for the transvaginal access regarding pain until POD 2, but also until POD 10 (P = 0.043 vs P = 0.010) despite significantly less use of peripheral analgesics (P = 0.019). In the TVC group, patients were significantly more satisfied with the aesthetic result (P < 0.001) and had a significantly better GIQLI (P = 0.028). CONCLUSIONS: Although comparable in terms of safety, TVC caused less pain, increased satisfaction with the aesthetic result, and improved postoperative quality of life in the short term.

Transvaginal hybrid-NOTES appendectomy in routine clinical use: prospective analysis of 13 cases and description of the procedure.

BACKGROUND: Access-related abdominal wall injury is part of the operative trauma in laparoscopic appendectomy and accounts for complications. Minimizing this trauma by entering the abdominal cavity by means of natural orifice transluminal surgery (NOTES) may be achieved by a hybrid-appendectomy procedure using the transvaginal route plus a single transumbilical trocar. METHODS: Thirteen patients were prospectively analyzed following transvaginal-hybrid NOTES appendectomy. For the procedure, rigid instruments are used with the patient in lithotomy position. The procedure is performed with two transvaginal and one transumbilical access-points. The specimen is retrieved transvaginally. RESULTS: All procedures were performed without additional trocars. No conversions to standard laparoscopy or open surgery were necessary. All procedures were performed in acceptable time (mean 52 min). No intraoperative complications and two (15%) postoperative complications, an infected hematoma and an abscess, occurred. They were smoothly treated with standard techniques including one laparoscopic reoperation (8%). Drain placement or resection of a Meckel's diverticulum was easily managed without conversion. Gynecological short-term follow-up revealed one complication, which was vaginal fungal infection. It occurred after a 7-day course of antibiotics. CONCLUSION: This method is found to be feasible intraoperatively and early postoperatively in terms of possibility to manage a variety of intraoperative findings that may occur during planned appendectomy, low intraoperative complications, and management of postoperative complications using established concepts. We, therefore, consider the procedure safe and continue to offer hybrid-NOTES appendectomy to suitable patients.

Transvaginal hybrid NOTES cholecystectomy--results of a randomized clinical trial after 6 months.

INTRODUCTION: For cholecystectomy (CHE), both the needlescopic three-trocar technique with 2-3-mm instruments (needlescopic cholecystectomy (NC)) and the umbilically assisted transvaginal technique with rigid instruments (transvaginal cholecystectomy (TVC)) have been established for further reduction of the trauma remaining from laparoscopy. METHODS: To compare the further outcome of both techniques for elective CHE in female patients, we analyzed the secondary end points of a prospective randomized single-center trial (needlescopic versus transvaginal cholecystectomy (NATCH) trial; ClinicalTrials.gov Identifier: NCT0168577), in particular, satisfaction with aesthetics, overall satisfaction, abdominal pain, and incidence of trocar hernias postoperatively at both 3 and 6 months. After 3 months, the domains "satisfaction" and "pain" of the German version of the Female Sexual Function Index (FSFI-d) were additionally evaluated to detect respective complications. A gynecological control examination was conducted in all TVC patients after 6 months. RESULTS: Forty patients were equally randomized into the therapy and the control groups between February 2010 and June 2012. No significant differences were found for overall satisfaction with the surgical result, abdominal pain, sexual function, and the rate of trocar hernias. However, aesthetics were rated significantly better by TVC patients both after 3 and after 6 months (P = 0.004 and P < 0.001). There were no postoperative pathological gynecological findings. CONCLUSIONS: Following TVC, there is a significantly better aesthetic result as compared to NC, even at 3 and 6 months after the procedure. No difference was found for sexual function.

Appendectomy in Germany-an analysis of a nationwide survey 2011/2012.

INTRODUCTION: Although appendectomies are frequently performed and new procedural techniques have emerged, no nationwide analysis exists after the cessation of the German quality control in 2004. METHODS: One thousand eight hundred seventy surgical hospitals in Germany were asked to answer questions anonymously concerning the size of the department, applied procedural techniques, various technical details, as well as the approach to the intraoperative finding of an inconspicuous appendix. RESULTS: We received 643 questionnaires (34.4 %) for evaluation. Almost all hospitals (95.5 %) offer laparoscopic appendectomy (LA), 15.4 % offer single-port (SPA), and 2.2 % (hybrid-) NOTES technique (NA). LA is the standard procedure in 85.2 % of male and in 89.1 % for female patients. In an open procedure (OA), the appendix and mesoappendix are mostly ligated (93.8 and 91.5 %). A Veress needle and open access are employed equally for LA. In 66.6 % of LA, the appendix is divided using an Endo-GIA, the mesoappendix in 45.5 % with bipolar coagulation. Almost half of the hospitals routinely flush the site in OA and LA. In open surgery with an inconspicuous appendix but a pathological finding elsewhere in the abdomen, it is resected "en principe" in 64.7 % and in the absence of any pathological finding in 91.2 %. For laparoscopic procedures, the numbers are 54.8 and 88.4 %. CONCLUSIONS: Most German hospitals perform appendectomies laparoscopically regardless of patients' gender. Usage of an Endo-GIA is widely established. SPA has not gained much acceptance, nor is NA widely used yet. In the absence of any pathological findings in particular, the macroscopically inconspicuous appendix results in an appendectomy "en principe" in most German hospitals.

Less pain after transvaginal/transumbilical cholecystectomy than after the classical laparoscopic technique: short-term results of a matched-cohort study.

BACKGROUND: Natural orifice surgery (NOS) is gaining acceptance as an alternative to the traditional laparoscopic technique, especially for cholecystectomy through the transvaginal route. However, NOS remains controversial concerning expected advantages in terms of short- and long-term outcomes and potential side effects. This study was designed to compare short-term outcomes between transvaginal/transumbilical and classical laparoscopic cholecystectomy (LC). METHODS: A prospective matched-cohort study compared the authors' first 50 transvaginal/transumbilical cholecystectomies (TVC) with a group of 50 classical LCs from the corresponding period matched in terms of age, body mass index, and American Society of Anesthesiology classification. In both groups, elective surgery was performed for symptomatic cholecystolithiasis. In the NOS group, a hybrid procedure was performed with one transumbilical rigid instrument and two transvaginal rigid instruments. A numeric rating scale was used for daily pain assessment, initiated postoperatively in the recovery room. Both groups were compared with regard to length of surgery, intra- and postoperative complications, length of hospital stay, postoperative pain, and consumption of analgesics. RESULTS: The length of surgery and the rate of complications were similar in the two groups. But significant advantages were found for the transvaginal access in terms of pain using Numeric Rating Scale (NRS) on the day of surgery (NRS, 1.5/10 vs 3.1/10; p = 0.003) as well as in the morning (NRS, 1.9/10 vs 2.8/10; p = 0.047) and in the evening (NRS, 1.1/10 vs 1.8/10; p = 0.025) of postoperative day 1, and with regard to the length of the postoperative hospital stay (2.7 vs 3.4 days; p = 0.035). CONCLUSIONS: The findings show that TVC is a safe procedure for female patients. It has a risk comparable with that of classic LC, causes significantly less pain in the early postoperative period, and leads to a significantly shorter hospital stay. Prospective randomized trials are necessary to confirm these results.

Preemptive endoluminal vacuum therapy with the VACStent-A pilot study to reduce anastomotic leakage after Ivor Lewis hybrid esophagectomy.

Introduction: Endoscopic treatment by vacuum therapy (EVT) or covered stents has emerged as an improved treatment option for upper gastrointestinal wall defects and is regarded as an improved treatment option for anastomotic leakage (AL) after esophagectomy. However, endoluminal EVT devices may lead to obstruction of the GI tract; and a high rate of migration and missing functional drainage has been shown for covered stents. The recently developed VACStent, a combination of a fully covered stent within a polyurethane sponge cylinder may overcome these issues allowing EVT while stent passage is still open. Initial clinical applications have demonstrated efficacy, practicability and safety in the treatment of esophageal leaks (AL). Methods: In this pilot study, 9 patients with high-risk anastomosis after neoadjuvant therapy undergoing hybrid esophagectomy received the VACStent in a preemptive setting for the assessment of the reduction of the AL rate, postoperative morbidity and mortality. Results: Technical success of the application of the VACStent® was achieved in all interventions. One patient experienced anastomotic leakage 10 days after esophagectomy and was successfully treated with two consecutive VACStents and a VAC Sponge. In summary, mortality in-hospital was 0% and anastomotic healing was uneventful without septic episodes. No severe device-related adverse events (SADE) nor significant local bleeding or erosion could be observed. Oral intake of liquids or food was documented in all patients. The device handling was regarded uncomplicated. Discussion: The preemptive application of the VACStent offers a promising new option for improved clinical treatment avoiding of critical situations in hybrid esophagectomy, which should be validated in a large clinical study.

Restorative restproctectomy as single-port surgery through the ostomy site in a three-stage procedure.

PURPOSE: Single-port laparoscopic surgery as an alternative to traditional laparoscopic technique is anticipated to be beneficial in the early postoperative course. We describe restorative restproctectomy as single-port surgery through the ostomy site in a three-stage procedure for refractory ulcerative colitis 12 weeks after laparoscopic subtotal colectomy. SURGICAL TECHNIQUE: After release of the terminal ileostomy, creating the ileal J pouch extra-abdominally, a single-port device was placed. Through this, the rectal stump was mobilized and extracorporeally closed. The ileal pouch anal anastomosis was created using circular double-stapling technique. The single-port device was removed, and the loop ileostomy was placed at the same site. RESULTS: We employed this technique in a 54 year-old patient who had suffered from ulcerative colitis. No postoperative complications were observed. CONCLUSIONS: Restorative restproctectomy as single-port surgery through the ostomy site is safe and feasible. No additional incision is necessary. The trauma of conventional laparoscopic access can be further reduced.

VACStent: Combining the benefits of endoscopic vacuum therapy and covered stents for upper gastrointestinal tract leakage.

Background and study aims Endoscopic treatment has markedly improved the high morbidity and mortality in patients with upper gastrointestinal tract leakage. Most procedures employ either covered self-expanding metal stents (SEMS) or endoscopic vacuum therapy (EVT), both with good clinical success but also with concomitant significant shortcomings inherent in each technique. A newly developed device, the VACStent, combines the fully covered SEMS with a polyurethane sponge cylinder anchored on the outside. This allows endoluminal EVT while keeping the intestinal lumen patent. The benefit is prevention of stent migration because the suction force of the sponge-cylinder immobilizes the VACStent on the intestinal wall, while at the same time, the attached external vacuum pump suctions off any secretions and improves healing with negative-pressure wound treatment (NPWT). Patients and methods In this pilot study, the first patients to receive the VACStent were assessed. Outcomes included the applicability and stability of the VACStent system together with the clinical course. Results Three patients with different clinical courses were managed with the VACStent. The first patient suffered anastomotic leakage following subtotal esophagectomy and was successfully treated with two postoperative VACStents for 12 days. The second patient received a covered SEMS for 14 days for acute Boerhaave syndrome. Due to persistent leakage, management was converted to EVT. Seven days, later a VACStent was inserted to allow oral nutrition while the leak finally closed. In the third patient, a LINX Reflux Management System had to be removed for erosion, leaving the gastroesophageal junction (GEJ) with a full-thickness gap. After VACstent insertion, successful closure was achieved within 4 days. Conclusions These clinical cases demonstrate the applicability and efficacy of the VACstent in management of esophageal and anastomotic leakage. With its vacuum sponge, the stent fosters wound healing while the covered SEMS keeps the passage patent for nutrition.

Pharmacokinetics, immunogenicity and bioactivity of the therapeutic antibody catumaxomab intraperitoneally administered to cancer patients.

AIMS: Catumaxomab is the first EMEA approved trifunctional anti-EpCAMxanti-CD3 antibody for the treatment of cancer patients with malignant ascites. A phase II pharmacokinetic study was conducted to determine local and systemic antibody concentrations and anti-drug antibody (ADA) development. METHODS: Thirteen cancer patients with symptomatic malignant ascites were treated with four ascending doses of 10, 20, 50, and 150 microg catumaxomab intraperitoneally (i.p.) infused on days 0, 3, 6 or 7 and 10. The pharmacokinetics of catumaxomab were studied by implementation of supportive data from a non clinical mouse tumour model. Additionally, ADA development was monitored. RESULTS: Ten out of 13 patients were evaluable for pharmacokinetic analysis. Catumaxomab became increasingly concentrated in ascites during the course of treatment, attaining effective concentrations in the ng ml(-1) range. Catumaxomab remained immunologically active even after several days in the circulation. The observed systemic catumaxomab exposure was low (<1%), with a maximal median plasma concentration (C(max)) of 403 pg ml(-1). The mean elimination half-life in the plasma was 2.13 days. All patients developed ADA, but not before the last infusion. High observed inter-individual variability and low systemic exposure may be explained by the inverse correlation between tumour burden, effector cell numbers and systemic antibody bioavailability as demonstrated in a defined mouse tumour model. CONCLUSIONS: Based on the high and effective local concentrations, low systemic exposure and acceptable safety profile, we confirmed that the i.p. application scheme of catumaxomab for the treatment of malignant ascites is appropriate.

Effective relief of malignant ascites in patients with advanced ovarian cancer by a trifunctional anti-EpCAM x anti-CD3 antibody: a phase I/II study.

PURPOSE: Malignant ascites in ovarian carcinoma patients is associated with poor prognosis and reduced quality of life. The trifunctional antibody catumaxomab (anti-EpCAM x anti-CD3) enhances the antitumor activity by redirecting T cells and Fcgamma receptor I/III--positive accessory cells to the tumor. This multicenter phase I/II dose-escalating study investigated tolerability and efficacy of i.p. catumaxomab application in ovarian cancer patients with malignant ascites containing epithelial cell adhesion molecule (EpCAM)--positive tumor cells. EXPERIMENTAL DESIGN: Twenty-three women with recurrent ascites due to pretreated refractory ovarian cancer were treated with four to five i.p. infusions of catumaxomab in doses of 5 to 200 microg within 9 to 13 days. RESULTS: The maximum tolerated dose was defined at 10, 20, 50, 200, and 200 microg for the first through fifth doses. Side effects included transient fever (83%), nausea (61%), and vomiting (57%), mostly CTCAE (Common Terminology Criteria for Adverse Events) grade 1 or 2. A total of 39 grade 3 and 2 grade 4 treatment-related adverse events (AE), 9 of them after the highest dose level (200 microg), were observed in 16 patients. Most AEs were reversible without sequelae. Treatment with catumaxomab resulted in significant and sustained reduction of ascites flow rate. A total of 22/23 patients did not require paracentesis between the last infusion and the end of study at day 37. Tumor cell monitoring revealed a reduction of EpCAM-positive malignant cells in ascites by up to 5 log. CONCLUSION: I.p. immunotherapy with catumaxomab prevented the accumulation of ascites and efficiently eliminated tumor cells with an acceptable safety profile. This suggests that catumaxomab is a promising treatment option in ovarian cancer patients with malignant ascites.

The current status of immunotherapy in peritoneal carcinomatosis.

INTRODUCTION: Peritoneal carcinomatosis (PC) is a cancer disease with an urgent need for effective treatment. Conventional chemotherapy failed to show acceptable results. Cytoreductive surgery and hyperthermic chemoperfusion (HIPEC) are only beneficial in few patients with resectable peritoneal metastasis. Immunotherapy could be attractive against PC, as all requirements for immunotherapy are available in the peritoneal cavity. AREAS COVERED: This review analyzes the present literature for immunotherapy of PC. Advances from immune stimulators, radionucleotide-conjugated- and bispecific antibodies to future developments like adoptive engineered T-cells with chimeric receptors are discussed. The clinical development of catumaxomab, which was the first intraperitoneal immunotherapy to be approved for clinical treatment, is discussed. The requirements for future developments are illustrated. Expert commentary: Immunotherapy of peritoneal carcinomatosis is manageable, showing striking cancer cell killing. Improved profiles of adverse events by therapy-induced cytokine release, enhanced specific killing and optimal treatment schedules within multimodal treatment will be key factors.

Minimal residual disease in gastric cancer: evidence of an independent prognostic relevance of urokinase receptor expression by disseminated tumor cells in the bone marrow.

PURPOSE: To study the invasion-related molecule urokinase-type plasminogen activator receptor (u-PAR) expressed by disseminated tumor cells as a biologic predictor of poor survival in a large prospective series of patients with gastric cancer. PATIENTS AND METHODS: In 156 gastric cancer patients (prospective series), disseminated tumor cells in the bone marrow and the u-PAR expressed by these tumor cells were determined by cytokeratin (CK) 18 immunocytochemistry and u-PAR/CK18 double immunocytochemistry. RESULTS: In contrast to the mere detection of disseminated tumor cells at primary surgery, the additional evidence of u-PAR on these cells correlated significantly with pathologic T stage (P =.0474) and the expression of u-PAR (P =.0093) and plasminogen-activator inhibitor 1 (P =.0145) in the primary tumor (immunohistochemistry, chi(2)). Kaplan-Meier analysis revealed no association with prognosis for the mere detection of disseminated tumor cells. In contrast, a significant association was seen between detection of u-PAR on these cells and shorter disease-free (P <.0001) and overall survival (P <.0001). Multivariate analysis revealed that u-PAR on disseminated tumor cells at the time of primary surgery is an independent prognostic factor for disease-free (95% confidence interval [CI], 1.72 to 3.21; P =.024) and overall survival (P =.0049; relative risk, 2.89; 95% CI, 1.92 to 4.30). CONCLUSION: This is the first large study to show that u-PAR, detected on disseminated tumor cells in the bone marrow, is an independent prognostic parameter in gastric cancer, in contrast to the mere detection of minimal residual disease (MRD). u-PAR may be a promising marker to define a critical subpopulation of disseminated tumor cells and a target to eliminate MRD. Molecular phenotyping of MRD is critical for defining its individual clinical relevance.

Relative lymphocyte count is a prognostic parameter in cancer patients with catumaxomab immunotherapy.

BACKGROUND: Catumaxomab (anti-EpCAM × anti-CD3) treatment in peritoneal carcinomatosis (PC) of EpCAM-positive cancers was effective in phase I and II studies. Recently, it was approved in the EU for treatment of peritoneal carcinomatosis and malignant ascites. Aim of this hypothesis-generating study was to identify predictive or prognostic biomarkers with relevance for overall survival. METHODS: 34 patients with PC in phase I/II studies with catumaxomab treatment were assessed for age, Karnofsky Index (KI), relative (RLC) and absolute lymphocyte count, relative and absolute granulocyte count, T-cell subsets, NK cells, and monocytes before catumaxomab therapy. Disease control (responder) was defined by stable disease, partial response or complete response (RECIST v1.0) >3 months or survival >6 months. Correlation analysis, Kaplan-Meier curves, ROC calculation, and multivariate regression were used for statistical analysis. RESULTS: Mean RC values significantly differed between the non-responder (14.0%) and the responder group (23.9%; p=0.001). RLC was correlated with overall survival (p=0.03). RLC of >12% defined by ROC calculation was associated with prolonged survival (p=0.035; hazard ratio of 2.775 for patients with RLC <12%). Patients with RLC >12% showed a mean survival of 15.6 versus 5.6 months in patients with RLC ≥ 12% (p=0.001). Multivariate analysis found the individual RLC before therapy (p=0.039) and the KI performance status (p=0.002) to be independent prognostic parameters. Increasing KI by 1% resulted in a risk decrease of 10.1%. Increasing RLC by 1% resulted in a risk decrease of 4.6%. Age and the extent of PC did not significantly influence survival. CONCLUSIONS: RLC and KI were identified as potential prognostic parameters for superior disease control and overall survival after catumaxomab treatment. RLC may be used as a biomarker to indicate a suitable immune status for catumaxomab therapy. The predictive impact has to be confirmed in further studies.

Urokinase system expression in gastric carcinoma: prognostic impact in an independent patient series and first evidence of predictive value in preoperative biopsy and intestinal metaplasia specimens.

BACKGROUND: The prognostic relevance of urokinase-type plasminogen activator (u-PA), u-PA receptor (u-PAR), and plasminogen activator inhibitor 1 (PAI-1) in gastric carcinoma was demonstrated in an independent patient series. To the authors' knowledge,the roles of these activators as predictors of aggressive phenotypes in preoperative biopsies, Helicobacter pylori infection, and intestinal metaplasia have to date not been investigated simultaneously in resected tumors. The objectives of the current study were 1) to demonstrate the prognostic relevance of u-PA, u-PAR, and PAI-1 in an independent series; 2) to evaluate u-PA system expression in preoperative biopsy specimens compared with resected tumors; and 3) to evaluate u-PA system expression in intestinal metaplasias and samples with H. pylori infection. METHODS: In 104 patients with gastric carcinoma (median follow-up, 68 mos), u-PA, u-PAR, and PAI-1 in tumors and metaplasias were evaluated immunohistochemically. Preoperative biopsies were evaluated in a subset of patients. Patients were screened for H. pylori (urease) and tumor cells in bone marrow (u-PAR/CK18). RESULTS: u-PA and PAI-1 were confirmed as independent prognostic parameters, and u-PAR was associated with a trend toward a poor prognosis. u-PA system tumor expression was found to be correlated significantly with u-PAR in disseminated tumor cells and H. pylori-infected tumors, implicating a role of H. pylori in protease induction. There was a significant correlation noted between u-PA system staining between preoperative biopsies and the results in resected tumors. The expression of u-PAR and PAI-1 in intestinal metaplasias was found to be associated significantly with advanced tumor stage (depth of invasion; pathologic tumor status) and lymph node involvement (pathologic lymph node status) and was correlated significantly with u-PA system expression in tumors. CONCLUSIONS: To the author's know the current study is the first to date to demonstrate that u-PA system expression may serve as a predictor of risk in intestinal metaplasias and preoperative biopsies, implicating consequences for neoadjuvant therapy. The independent impact on recurrence and survival and a correlation with u-PAR-expression of minimal residual disease were identified in this independent series.

Induction of cytotoxicity against autologous tumour cells by interleukin-12: evidence for intrinsic anti-tumor immune capacity in curatively resected gastrointestinal tumour patients.

The aim of this study was to investigate the cell-mediated immune response in 14 patients undergoing curative resection for a gastrointestinal tumor by the induction of peripheral blood mononuclear cell (PBMC)-mediated immune activity against autologous tumour cells. PBMC were stimulated by interleukin-12 (IL-12; 100 IU/ml) and IL-2 (1,000 IU/ml) without contact with tumour cells for 36 h. Specific cytotoxic activity against autologous tumour cells (auTu), natural killer (NK)-sensitive cells (K562) and allogeneic tumour cells (RF48/HT29) was determined by fluorescence cytotoxicity assay. Additionally, inhibition experiments using the mononuclear antibodies (mAb) FMC16 and W6/32 against major histocompatibility complex I (MHC I) on autologous tumour cells were performed in order to determine the involvement of specific T lymphocytes. The cytotoxic activity of unstimulated PBMC did not differ between the three target cells. IL-12 caused a 3.2-fold increase in activity against auTu ( P=0.002). In contrast, after stimulation with IL-2, only a slight increase in activity was observed. After IL-12 stimulation, cytotoxic activity against auTu was 2.5- to 2.7-fold higher than the corresponding activity against K562/allogeneic tumour cells ( P=0.002/ P=0.006). After blocking of the MHC I complex on auTu by FMC 16 or W6/32 mAb, a 62.9%/74.4% reduction in the specific cytotoxicity of IL-12-stimulated PBMC was found. In summary, IL-12 induced an effective immune response against auTu, which was partly mediated by specific cytotoxic T lymphocytes (CTL). It was considered that de novo generation of this activity during 36 h incubation without antigen contact was hardly possible, but that the observed induction of effective anti-tumor cytotoxicity was rather based on the re-activation of a pre-existing immune potential from the tumour-host interaction. These findings indicate the existence of an autologous anti-tumor immune response following curative resection in patients undergoing surgery for solid tumours, which might influence the development of tumour recurrence from disseminated tumour cells. Making use of this capacity could constitute an attractive immunotherapeutical approach for curatively operated tumour patients.