Undetectable circulating tumor DNA confirms the inability of pseudomyxoma peritonei to systemic dissemination.

The study of circulating tumor DNA (ctDNA) plays a pivotal role in advancing precision oncology, providing valuable information for individualized patient care and contributing to the ongoing effort to improve cancer diagnosis, treatment, and management. However, its applicability in pseudomyxoma peritonei (PMP) remains unexplored. In this multicenter retrospective study involving 21 PMP patients, we investigated ctDNA presence in peripheral blood using three distinct methodologies. Despite mucinous tumor tissues exhibiting KRAS and GNAS mutations, ctDNA for these mutations was undetectable in blood samples. In this pilot study, circulating tumor DNA was not detected in blood when the tumor harbored mutations of known significance. In the future, a study with a larger sample size is needed to confirm these findings and to determine whether ctDNA could identify patients at risk for early recurrence and/or systemic metastases.

Therapeutic effect of adipose-derived mesenchymal stem cells in a porcine model of abdominal sepsis.

BACKGROUND: The term sepsis refers to a complex and heterogeneous syndrome. Although great progress has been made in improving the diagnosis and treatment of this condition, it continues to have a huge impact on morbidity and mortality worldwide. Mesenchymal stem cells are a population of multipotent cells that have immunomodulatory properties, anti-apoptotic effects, and antimicrobial activity. We studied these capacities in a porcine model of peritoneal sepsis. METHODS: We infused human adipose-derived mesenchymal stem cells (ADSCs) into a porcine model of peritoneal sepsis. Twenty piglets were treated with antibiotics alone (control group) or antibiotics plus peritoneal infusion of ADSCs at a concentration of 2 × 106 cells/kg or 4 × 106 cells/kg (low- and high-dose experimental groups, respectively). The animals were evaluated at different time points to determine their clinical status, biochemical and hematologic parameters, presence of inflammatory cytokines and chemokines in blood and peritoneal fluid, and finally by histologic analysis of the organs of the peritoneal cavity. RESULTS: One day after sepsis induction, all animals presented peritonitis with bacterial infection as well as elevated C-reactive protein, haptoglobin, IL-1Ra, IL-6, and IL-1b. Xenogeneic ADSC infusion did not elicit an immune response, and peritoneal administration of the treatment was safe and feasible. One day after infusion, the two experimental groups showed a superior physical condition (e.g., mobility, feeding) and a significant increase of IL-10 and TGF-ß in blood and a decrease of IL-1Ra, IL-1b, and IL-6. After 7 days, all animals treated with ADSCs had better results concerning blood biomarkers, and histopathological analysis revealed a lower degree of inflammatory cell infiltration of the organs of the peritoneal cavity. CONCLUSIONS: Intraperitoneal administration of ADSCs as an adjuvant therapy for sepsis improves the outcome and diminishes the effects of peritonitis and associated organ damage by regulating the immune system and reducing intra-abdominal adhesions in a clinically relevant porcine model of abdominal sepsis.

Extended totally extraperitoneal (eTEP) treatment for lateral primary and incisional hernias. New approach to old problems.

PURPOSE: To describe the eTEP approach for treating lateral primary and incisional hernia and show its results in a prospective series of cases. METHODS: A descriptive prospective study with patients treated surgically for lateral hernias using eTEP approach. Every patient was operated by the same surgeon from November 2018 to December 2021. Inclusion criteria were primary and incisional hernia, lateral and W1 and W2 sized using the EHS classification. Exclusion criteria were W3 hernia, loss of domain, need to remove previous mesh, dystrophic or ulcerative skin, history of previous complex surgery. Details of the surgical technique are described. RESULTS: 34 patients were operated. Median age was 65 years old and BMI, 29.9 (22.1-47.1). There were several locations being the most frequent L3 in 18 patients. The median length was 41 mm (10-129) and width, 44 mm (10-97). The median of defect-mesh ratio was 5.05 (0.9-447.64). TAR was practised in 21 patients (61.8%). Only one patient suffered a clinically relevant complication, being a hematoma (Dindo-Clavien II). 50% of patients were operated in ambulatory surgery. After a median follow-up of 13.5 months, only one recurrence has been reported (2.9%). CONCLUSION: eTEP to treat lateral hernias is feasible and reproducible showing good results in terms of hernia recurrence and complications. A further prospective randomized clinical trial is needed to support these results.

Toxicity study in a pig model of intraperitoneal collagenase as an "enzymatic scalpel" directed to break stroma in order to generate a new perspective for peritoneal carcinomatosis approach: an experimental research.

BACKGROUND: This study aimed to measure the toxicity resulting from collagenase administration to the peritoneal cavity in a pig model as a preliminary step to break down the stroma surrounding tumors. METHODS: Eight pigs were treated with 2 different collagenase concentrations previously tested in rats by our group. Time and temperature were controlled using a peritoneal lavage system (PRS System, Combat Medical Ltd.) identical to that used in human surgeries through hyperthermic intraperitoneal chemotherapy (HIPEC); 2 additional pigs were treated with peritoneal lavage only. Samples of blood and peritoneal fluid were collected pre-treatment, immediately after treatment, and 24 h postoperatively. In addition, histological studies and blood collagenase levels were measured. RESULTS: No complications were observed during the surgeries. Intraoperative images evidenced the release of peritoneal tissue during collagenase treatment. After surgery, the animals showed no signs of pain. Diet and mobility were normal at 4 h postoperatively, and there were no significant differences in hematologic or biochemical parameters. Quantification of MMP1 and MMP2 in all samples as measured by absorbance showed no differences in blood collagenase levels between pre-treatment, post-treatment, and 24 h postoperatively. None of the animals treated with collagenase showed peritoneal adhesions during the second surgery. Histologically, peritoneal organs and serous structures did not show any microscopic alterations associated with collagenase treatment in any group. CONCLUSION: Lavage of the peritoneal cavity with doses of up to 100,000 collagen digestion units/animal for 30 min is safe and removes connective tissue from the peritoneal cavity.

Intraperitoneal collagenase as a novel therapeutic approach in an experimental model of colorectal peritoneal carcinomatosis.

The usefulness of local collagenase in therapeutic approaches to solid tumors has been tested recently. In this study, we evaluate the safety and efficacy of intraperitoneal collagenase associated or not to mitomycin for treatment of colorectal peritoneal metastases in an experimental rat model. Using a fixed-dose procedure, we found that a dose of collagenase of 37 IU/mL administered for 15 min with a hyperthermia pump at 37.5 °C, both in isolation or associated to sequential treatment with intraperitoneal mitomycin, led to a macroscopic decrease in tumor volume as evaluated by the modified peritoneal cancer index (mPCI). Concerning the safety of the procedure, the animals showed no physiological or behavioral disorders during 8 weeks of follow-up. Local treatment for peritoneal metastases of colorectal origin with intraperitoneal collagenase has proved safe and effective in an experimental murine model. Therefore, the stroma-first approach by enzymatic breakdown of collagen from the tumor's extracellular matrix provides a new therapeutic target for colorectal peritoneal metastases.

Complete laparoscopic pelvic peritonectomy plus hyperthermic intraperitoneal chemotherapy.

BACKGROUND: The aim of our study was to present the technique for, and early results of complete laparoscopic pelvic peritonectomy (LPP) plus hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: We conducted a study on consecutive patients who had LPP for limited peritoneal carcinomatosis (peritoneal carcinomatosis index < 10) from ovarian cancer, colon cancer and benign multicystic mesothelioma, from January 2017 to November 2019 at 2 referral centers in Spain. Perioperative, pathologic, 30-day major morbidity and mortality characteristics were analyzed. The surgical technique is shown in the attached video. RESULTS: Twelve LPP + HIPEC were performed. Complete cytoreduction was achieved in 100% of the patients, the median duration of the operation was 450 min (range 360-600 min). There were 2 cases (16%) of IIIa morbidity (trocar hernia and pleural effusion), and no mortality. The median length of hospital stay was 5.5 days (range 4-10 days). The median length of follow-up was 10 months (range 2-30 months). There was a recurrence at the splenic hilum in 1 patient which was treated by laparoscopic splenectomy and one nodal recurrence at 13 months while all other patients are alive and free of disease at last follow-up. CONCLUSIONS: This is the first technical video of a minimally invasive approach for complete pelvic peritonectomy plus omentectomy associated with HIPEC. For highly selected patients, this procedure presents a feasible and safe alternative to the maximally invasive approach.

RAS Mutation Decreases Overall Survival After Optimal Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy of Colorectal Peritoneal Metastasis: A Modification Proposal of the Peritoneal Surface Disease Severity Score.

BACKGROUND: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are currently the most accepted treatment for peritoneal metastases from colorectal cancer. Restrictive selection criteria are essential to obtain the best survival benefits for this complex procedure. The most widespread score for patient selection, the peritoneal surface disease severity score (PSDSS), does not include current biological factors that are known to influence on prognosis. We investigated the impact of including RAS mutational status in the selection criteria for these patients. METHODS: We studied the risk factors for survival by multivariate analysis using a prospective database of consecutive patients with carcinomatosis from colorectal origin treated by CRS and HIPEC in our unit from 2009 to 2017. The risk factors obtained were validated in a multicentre, international cohort, including a total of 520 patients from 15 different reference units. RESULTS: A total of 77 patients were selected for local análisis. Only RAS mutational status (HR: 2.024; p = 0.045) and PSDSS stage (HR: 2.90; p = 0.009) were shown to be independent factors for overall survival. Early PSDSS stages I and II associated to RAS mutations impaired their overall survival with no significant differences with PSDSS stage III overall survival (p > 0.05). These results were supported by the international multicentre validation. CONCLUSIONS: By including RAS mutational status, we propose an updated RAS-PSDSS score that outperforms PSDSS alone providing a quick and feasible preoperative assessment of the expected overall survival for patients with carcinomatosis from colorectal origin undergone to CRS + HIPEC.

HIPECT4: multicentre, randomized clinical trial to evaluate safety and efficacy of Hyperthermic intra-peritoneal chemotherapy (HIPEC) with Mitomycin C used during surgery for treatment of locally advanced colorectal carcinoma.

BACKGROUND: Local relapse and peritoneal carcinomatosis (PC) for pT4 colon cancer is estimated in 15,6% and 36,7% for 12 months and 36 months from surgical resection respectively, achieving a 5 years overall survival of 6%. There are promising results using prophylactic HIPEC in this group of patients, and it is estimated that up to 26% of all T4 colon cancer could benefit from this treatment with a minimal morbidity. Adjuvant HIPEC is effective to avoid the possibility of peritoneal seeding after surgical resection. Taking into account these results and the cumulative experience in HIPEC use, we will lead a randomized controlled trial to determine the effectiveness and safety of adjuvant treatment with HIPEC vs. standard treatment in patients with colon cancer at high risk of peritoneal recurrence (pT4). METHODS/DESIGN: The aim of this study is to determine the effectiveness and safety of adjuvant HIPEC in preventing the development of PC in patients with colon cancer with a high risk of peritoneal recurrence (cT4). This study will be carried out in 15 Spanish HIPEC centres. Eligible for inclusion are patients who underwent curative resection for cT4NxM0 stage colon cancer. After resection of the primary tumour, 200 patients will be randomized to adjuvant HIPEC followed by routine adjuvant systemic chemotherapy in the experimental arm, or to systemic chemotherapy only in the control arm. Adjuvant HIPEC will be performed simultaneously after the primary resection. Mitomycin C will be used as chemotherapeutic agent, for 60 min at 42-43 °C. Primary endpoint is loco-regional control (LC) in months and the rate of loco-regional control (%LC) at 12 months and 36 months after resection. DISCUSSION: We assumed that adjuvant HIPEC will reduce the expected absolute risk of peritoneal recurrence from 36% to 18% at 36 months for T4 colon-rectal carcinoma. TRIAL REGISTRATION: NCT02614534 ( clinicaltrial.gov ) Nov-2015.

Marjolin's ulcer arising from a laparostomy scar.

Marjolin's ulcer is the malignant transformation of a scar, usually as a squamous cell carcinoma. An uncommon presentation form is from a laparostomy scar. A 49-year-old patient that had a laparostomy during the treatment of a necrohemorrhagic pancreatitis in 1987 complained 13 years later of a 20-cm ulcer on the laparostomy scar. A resection of the abdominal wall including the ulcer and a segmental transverse colectomy were performed because of infiltration by an invasive squamous cell carcinoma. Ten months later, axillary lymphadenectomy was performed because of lymph node metastasis. Currently, the patient is free of disease. Lymph node infiltration is frequent in squamous cell carcinoma on Marjolin's ulcer and survival is not good. Prophylaxis of this disease includes meticulous care of wounds, with early skin grafts when required and treatment of infections.