Extremely high peritoneal cancer index in colorectal peritoneal metastases demonstrates safety and overall survival benefit in selected patients undergoing cytoreductive surgery and heated intraperitoneal chemotherapy.

BACKGROUND: Colorectal peritoneal metastases are a devastating consequence of colorectal cancer (CRC) with extremely poor prognosis. Patients that can undergo complete cytoreduction by cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) have a markedly improved overall survival. Traditionally, patients with extremely high peritoneal cancer index (PCI), PCI >20, are not offered CRS/HIPEC. METHODS: We performed a retrospective analysis of our prospectively maintained CRS/HIPEC database and evaluated all patients with CRC peritoneal metastases between 2012 and 2022. We divided the cohorts between those with low operative PCI (PCI<20) and high operative PCI (PCI =>20). We examined demographic, clinicopathologic data, perioperative, and oncological outcomes between the cohorts. RESULTS: Of the 691 patients who underwent CRS/HIPEC, 289 were evaluable with CRC metastases, 234 with PCI <20 and 43 with PCI => 20. Median radiologic preoperative and operative PCI was 4 and 10 versus 7 and 24.5 in the low and high PCI cohorts, respectively. Operative time was longer (6 vs. 4 h) and blood loss higher (500 vs. 400 mL) in the high PCI cohort. All other demographic, clinicopathological, and operative characteristics were similar. Median disease free survival (DFS) was longer in the low PCI cohort (11.5 vs. 7 months) but overall survival (OS) showed benefit (41.3 vs. 31.8 months), (p = 0.001 and p = 0.189, respectively), comparatively with an only chemotherapy strategy. CONCLUSIONS: Appropriately selected patients with CRC metastases and extremely high PCI demonstrate similar perioperative safety outcomes in experienced tertiary referral centers. Despite a shorter median DFS, these carefully selected patients demonstrated similar median OS.

Resection of Recurrent Pelvic Soft Tissue Sarcoma: Is the Risk Worth the Reward?

INTRODUCTION: Soft tissue sarcomas (STS) of the pelvis present a surgical and oncological challenge. We investigated the outcomes of patients undergoing resection of pelvic sarcomas. METHODS: A retrospective analysis of all patients who underwent surgical resection for STS between 2014 and 2021 at a tertiary academic referral center (n = 172). Included all patients with primary or recurrent STS which originated or extended to the pelvic cavity (n = 29). RESULTS: The cohort was divided into primary pelvic sarcomas (n = 18) and recurrent pelvic sarcomas (rPS, n = 11). Complete R0/R1 resection was achieved in 26 patients (89.6%). The postoperative complication rate was 48.3%. The rate of major complications was 27.5%. The median time of follow-up from surgery was 12.3 months (range, 0.6-60.3 months). Disease-free survival was superior in the primary pelvic sarcomas group compared to the rPS group (P = 0.002). However, there was no significant difference in overall survival, (P = 0.52). Univariant and multivariant analyses identified rPS group (Hazard Ratio 8.68, P = 0.006) and resection margins (Hazard Ratio 6.29, P = 0.004) to be independently associated with disease-free survival. CONCLUSIONS: We have demonstrated that achieving R0/R1 resection is feasible. Oncological outcomes are favorable for primary tumors, whereas recurrent tumors exhibit early recurrences. Consideration of resection of recurrent pelvic STS should involve a careful multidisciplinary evaluation.

Natural History and Management of Small-Bowel Obstruction in Patients After Cytoreductive Surgery and Intraperitoneal Chemotherapy.

BACKGROUND: Small-bowel obstruction (SBO) after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is a common complication associated with re-admission that may alter patients' outcomes. Our aim was to characterize and investigate the impact of bowel obstruction on patients' prognosis. METHODS: This was a retrospective analysis of patients with SBO after CRS/HIPEC (n = 392). We analyzed patients' demographics, operative and perioperative details, SBO re-admission data, and long-term oncological outcomes. RESULTS: Out of 366 patients, 73 (19.9%) were re-admitted with SBO. The cause was adhesive in 42 (57.5%) and malignant (MBO) in 31 (42.5%). The median time to obstruction was 7.7 months (range, 0.5-60.9). Surgical intervention was required in 21/73 (28.7%) patients. Obstruction eventually resolved (spontaneous or by surgical intervention) in 56/73 (76.7%) patients. Univariant analysis identified intraperitoneal chemotherapy agents: mitomycin C (MMC) (HR 3.2, p = 0.003), cisplatin (HR 0.3, p = 0.03), and doxorubicin (HR 0.25, p = 0.018) to be associated with obstruction-free survival (OFS). Postoperative complications such as surgical site infection (SSI), (HR 2.2, p = 0.001) and collection (HR 2.07, p = 0.015) were associated with worse OFS. Multivariate analysis maintained MMC (HR 2.9, p = 0.006), SSI (HR 1.19, p = 0.001), and intra-abdominal collection (HR 2.19, p = 0.009) as independently associated with OFS. While disease-free survival was similar between the groups, overall survival (OS) was better in the non-obstruction group compared with the obstruction group (p = 0.03). CONCLUSIONS: SBO after CRS/HIPEC is common and complex in management. Although conservative management was successful in most patients, surgery was required more frequently in patients with MBO. Patients with SBO demonstrate decreased survival.

Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy in Elderly is Safe and Effective.

INTRODUCTION: An increasing proportion of elderly patients (EP) are undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS/HIPEC). They have increased comorbidities and perioperative risk. Current literature is deficient in describing the outcomes of EP undergoing CRS/HIPEC. MATERIALS AND METHODS: A retrospective review of our prospectively maintained CRS/HIPEC database analyzed perioperative and oncological outcomes of EP (>70 y) compared to younger patients (YP) (<60 y). RESULTS: Of 500 CRS/HIPEC patients, 62 EP and 210 YP were included. Median age was 73 y in EP and 46 y in YP. Demographic, clinical, operative, and perioperative outcomes were similar between groups. American Society of Anesthesiologists > 3 was more prevalent in the EP with 88.2% versus 54.8% in the YP (P < 0.001). Comorbidities were higher in the EP with 87.1% versus 39.0% in the YP (P < 0.001). Peritoneal Cancer Index score was similar with a median of 9. All postoperative and severe complications were similar with 55.2% and 17.1% in the YP and 64.5% and 21.0% in the EP (P = 0.242; P = 0.448). Postoperative mortality was similar with 1.5% in the YP and 5.0% in the EP (P = 0.134). In colorectal primary patients, median overall and disease-free survival was 61.8 and 12.9 mo in the YP and 64.6 and 11.3 mo in the EP (P = 0.363; P = 0.845). CONCLUSIONS: Despite a significant age difference, increased comorbidities, worse American Society of Anesthesiologists, and similar Peritoneal Cancer Index burden, we found no significant differences in perioperative complications or oncological benefit in elderly CRS/HIPEC patients. EP appear to have similar perioperative and oncological outcomes as YP.

Repeat Cytoreductive Surgery and Intraperitoneal Chemotherapy for Colorectal Cancer Peritoneal Recurrences is Safe and Efficacious.

BACKGROUND: Cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) for colorectal cancer peritoneal metastases (CRPM) is associated with improved survival in patients with historically dismal prognosis. Nonetheless, peritoneal recurrences remain common and represent a difficult challenge in these patients' management. Repeat CRS/HIPEC is associated with even greater morbidity and its survival benefit has not yet been clearly demonstrated. METHODS: We retrospectively reviewed our prospectively maintained database and aimed to assess the safety and oncological efficacy of repeat CRS/HIPEC. RESULTS: Two hundred thirty-two patients underwent an initial CRS/HIPEC, whereas 30 subsequently had repeat CRS/HIPEC for CRPM. Groups were similar in demographics, comorbidities, and peritoneal cancer index (PCI). No significant difference in morbidity, hospital stay, or reoperation rate was noted between initial and repeat procedures. Patients who underwent repeat CRS/HIPEC had a median overall survival of 68 months versus 51 months in patients who did not undergo repeat procedure for their peritoneal recurrence (p = 0.03). Disease-free survival (DFS) in patients after repeat and after initial procedure were similar with median of 9.6 versus 12 months, respectively (p = 0.083). Univariate analysis demonstrated that PCI, DFS, and repeat procedure displayed significant factors on outcomes in patients with peritoneal recurrences, whereas PCI > 16 and DFS remained independent predictors on multivariable analysis. CONCLUSIONS: Our analysis, which represents the largest series to date of repeat CRS/HIPEC for CRPM, indicates that this approach as a part of multimodal therapy is both safe and efficacious in appropriately selected patients.

Perioperative and Oncological Outcomes of Combined Hepatectomy with Complete Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy for Metastatic Colorectal Cancer.

BACKGROUND: Synchronous peritoneal and liver metastasis in colorectal cancer is a relative contraindication for curative surgery. We aimed to evaluate the safety and oncological outcomes of combined treatment of peritoneal and liver metastasis. METHODS: We conducted a retrospective analysis of metastatic colorectal cancer patients from two prospective databases: peritoneal surface malignancy (n = 536) and hepatobiliary (n = 286). We compared 60 patients treated with cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) and hepatectomy; 80 patients treated with cytoreduction and HIPEC only; and 63 patients treated with hepatectomy alone. RESULTS: No differences in demographics were observed between the groups. Median hospital and intensive care unit (ICU) stay was shorter in group C (7 and 1 days, respectively) versus groups A and B (13 and 1 days, and 12 and 1 days, respectively; p < 0.001). Postoperative complications were not significantly different. Median follow-up was 18.6, 23.1, and 30.6 months for groups A, B, and C, respectively. Estimated 5-year overall survival (OS) was 48.8% (group A), 55.4% (group B), and 60.2% (group C) [p = 0.043 for group A vs. group C], and estimated 5-year disease-free survival (DFS) was 14.2% (group A), 23.0% (group B), and 18.6% (group C). Five-year OS was superior in group C compared with group A (p = 0.043), and DFS was superior in group C compared with groups A and B (p = 0.043 and 0.03, respectively). The peritoneum was the site of first recurrence in groups A and B (23.3% and 32.5%, respectively), and the liver was the site of first recurrence in group C (44.4%). CONCLUSIONS: We report favorable perioperative and oncological outcomes in combined cytoreduction/HIPEC and hepatectomy for patients with peritoneal and liver metastasis. Surgical intervention after multidisciplinary discussion should be considered in patients with both peritoneal and hepatic lesions when complete cytoreduction is feasible.

Ratio of Pathological Response to Preoperative Chemotherapy in Patients Undergoing Complete Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy for Metastatic Colorectal Cancer Correlates with Survival.

BACKGROUND: Pathological response of colorectal peritoneal metastasis (CRPM) may affect prognosis. We investigated the relationship between oncological outcomes and pathological response to chemotherapy of CRPM following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: We conducted a retrospective analysis of a prospectively maintained Peritoneal Surface Malignancies database between 2015 and 2020. Analysis included patients with CRPM who underwent a CRS/HIPEC procedure (n = 178). The cohort was divided into three groups according to the response ratio (ratio of tumor-positive specimens to the total number of specimens resected): Group A, complete response; Group B, high response ratio, and Group C, low response ratio. RESULTS: The group demographics were similar, but the overall complication rate was higher in Group C (65.2%) compared with Groups A (55%) and B (42.8%) [p = 0.03]. Survival correlated to response ratio; the estimated median disease-free survival of Group C was 9.1 months (5.97-12.23), 14.9 months (4.72-25.08) for Group B, and was not reached in Group A (p = 0.001). The estimated median overall survival in Group C was 35 months (26.69-43.31), and was not reached in Groups A and B (p = 0.001). CONCLUSIONS: The pathological response ratio to systemic therapy correlates with survival in patients undergoing CRS/HIPEC. This study supports the utilization of preoperative therapy for better patient selection, with a potential impact on survival.

[CYTOREDUCTIVE SURGERY AND HYPERTHERMIC INTRAPERITONEAL CHEMOTHERAPY (HIPEC) FOR PERITONEAL METASTASIS OF GASTRO-INTESTINAL ORIGIN].

INTRODUCTION: The management of peritoneal surface malignancies has changed dramatically. Moving, in less than two decades, from a nihilistic approach offering limited palliation and a short median survival into an aggressive surgical approach combining resection of all tumor deposits (cytoreductive surgery (CRS) combined with hyperthermic intra-peritoneal chemotherapy (HIPEC). This novel approach dramatically changed the outcome of this group of disorders offering a long term survival with curative intent to selected patients. The aim of the current review is to describe, based on current medical literature and our experience, current treatment options with CRS+HIPEC in various peritoneal surface malignancies of gastrointestinal origin, namely, colorectal cancer and appendiceal cancer, indications, technique, and outcomes.

Comparison between laparoscopic and open Hartmann's reversal: results of a decade-long multicenter retrospective study.

BACKGROUND: Hartmann's reversal is a challenging surgical procedure with significant postoperative morbidity rates. Various surgical methods have been suggested to lower the risk of postoperative complications. In this study, we aimed to compare the postoperative results between open and laparoscopic techniques for Hartmann's reversal. METHODS: A retrospective study of all patients who underwent Hartmann's reversal in five centers in central Israel between January 2004 and June 2015 was conducted. Medical charts were reviewed, analyzing preoperative and operative parameters and short-term postoperative outcomes. RESULTS: 260 patients were included in the study. 76 patients were operated laparoscopically with a conversion rate of 26.3% (20 patients). No differences were found between patients operated laparoscopically and those operated in an open technique regarding gender (p = 0.785), age (61.34 vs. 62.64, p = 0.521), body mass index (26.6 vs. 26.2, p = 0.948), Charlson index score (1.79 vs. 1.95, p = 0.667), and cause for Hartmann's procedure (neoplastic vs. non-neoplastic, p = 0.644). No differences were seen in average time from the Hartmann's procedure to reversal (204.89 vs. 213.60 days, p = 0.688) and in overall complication rate (46.4 vs. 46.5%, p = 1). The Clavien-Dindo score for distinguishing between minor (0-2 score, p = 1) and major complications (3-5 score, p = 0.675) failed to demonstrate an advantage to laparoscopy, as well as to average length of stay (10.91 days in the laparoscopic group vs. 11.72 days in the open group, p = 0.529). An analysis based on the intention-to-treat with laparoscopy, including converted cases in the laparoscopic group, showed similar results, including overall complication rate (48.6 vs. 45.6%, p = 0.68) and Clavien-Dindo score in both minor (p = 0.24) and major complications (p = 0.44). Length of stay (10.92 vs. 11.81 days, p = 0.45) was also similar between the two groups. CONCLUSION: In this series, a laparoscopic approach to Hartmann's reversal did not offer any short-term advantage when compared to an open surgical approach.

Hospital readmission rates and risk factors for readmission following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal surface malignancies.

BACKGROUND: Cytoreductive surgery and Hyperthermic intra-peritoneal chemotherapy (CRS/HIPEC) for peritoneal surface malignancies is associated with high morbidity. The increased numbers of patients undergoing CRS/HIPEC in recent years mandates risk analysis and quality assurance. However, only scarce data exist regarding causative parameters for readmission. The aim of this study was to assess readmission rates and risk factors associated with readmission. METHODS: A retrospective-cohort study including patients from two high-volume centers who underwent CRS/HIPEC surgery between the years 2007-2016 was performed. Patients' demographics, peri-operative data and readmission rates were recorded. RESULTS: 223 patients were included in the study. The 7 and 30-day readmission rates were 3.5% (n = 8) and 11% (n = 25), respectively. Late readmission rates (up to 90 days) were 11% (n = 25). The most common causes of readmission were surgical related infections (35%), small bowel obstruction (17.5%) and dehydration (14%). Post-operative complications were associated with higher readmission rates (p = 0.0001). PCI score was not associated with higher rates of readmission. CONCLUSION: Readmissions following CRS/HIPEC occur mainly due to infectious complications and dehydrations. Patients following CRS/HIPEC should be discharged after careful investigation to a community based continuing care with access for IV fluid replacement or antibiotics administration when required.

Considerations for Hartmann's reversal and Hartmann's reversal outcomes-a multicenter study.

PURPOSE: Hartmann's procedure is commonly practiced in emergent cases with the restoration of bowel continuity planned at a second stage. This study assessed the rate of restorations following Hartmann's procedure and evaluated factors affecting decision-making. METHODS: Data on patient demographics, comorbidities, causes for Hartmann's procedure, reversal rate, and complications were collected in a multicenter retrospective cohort study of patients who underwent Hartmann's procedure in five medical centers. RESULTS: Six hundred forty patients underwent Hartmann's procedure for diverticular disease (36.1%), obstructing malignancy (31.8%), benign obstruction (5%), and other reasons (23.1%). Overall, 260 (40.6%) patients underwent subsequent restoration of bowel continuity. One hundred twenty-one (46.5%) patients had post-reversal complications, with an average Clavien-Dindo score of 1.4 and a mortality rate of 0.77%. Decision to avoid reversal was mostly related to comorbidities (49.7%) and metastatic disease (21.6%). Factors associated with the decision to restore bowel continuity included male gender (P = 0.02), patient age (62.3 years in Hartmann's reversal patients vs 73.5 years in non-reversal patients; P < 0.0001), number of comorbidities (1.1 vs 1.58; P < 0.001), average Charlson score (1.93 vs 3.44; P < 0.001), and a neoplastic etiology (P < 0.0001). A sub-analysis excluding all patients who died in the 30 days following Hartmann's procedure showed similar factors associated with ostomy closure. CONCLUSION: Many patients do not have restoration of bowel continuity after undergoing Hartmann's procedure. Hartmann's reversal is associated with a significant postoperative morbidity. Surgeons and patients should be aware of the possibility that the colostomy might become permanent.

Inflammatory Bowel Disease in Cytoreductive Surgery and Heated Intraperitoneal Chemotherapy.

BACKGROUND: Inflammatory bowel diseases (IBDs) pose an increased risk of gastrointestinal cancer with especially worse prognosis. Cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) improves outcomes in selected patients with colorectal peritoneal metastases. Little published data describes the outcomes of CRS/HIPEC in IBD patients. METHODS: We performed a retrospective review of a prospectively maintained CRS/HIPEC database. Outcomes in patients with and without IBD were compared for short-term outcomes such as hospital/intensive care unit stay, blood loss/transfusions, complications, and reoperations. We also examined oncological outcomes including recurrence, overall (OS), and disease-free survival (DFS). RESULTS: We identified 232 patients that underwent CRS/HIPEC for colorectal or small bowel adenocarcinoma, of which 10 were with IBD. Patients with IBD had lower ASA (p=0.005), less hypertension (p=0.033), and 30% small bowel primary compared to none in the non-IBD cohort (p<0.001). Otherwise, demographic and perioperative characteristics were similar between the groups. The median peritoneal cancer index (PCI) was 7 and similar between the cohorts (p=0.422). Extent of organ resections and peritonectomies performed were similar. Complications occurred in 60.3% of patients (21.2% major), similar between the groups (p=0.744 and p=0.444, respectively). Reoperation rate of 27% was similar between groups (p=0.097). The median OS in the IBD cohort was 19.6 vs 53.2 months in the non-IBD cohort (p = 0.056). The median DFS in the IBD cohort was 4.9 vs 9.4 months in the non-IBD cohort (p=0.174). DISCUSSION: Cytoreductive surgery and heated intraperitoneal chemotherapy in patients with IBD has similar complication profile and trended towards poorer oncological outcomes as CRS/HIPEC in non-IBD patients.

Predisposing factors for high output stoma in patients with a diverting loop ileostomy after colorectal surgeries.

PURPOSE: One of the most common ileostomy-related complications is high output stoma (HOS) which causes significant fluids and electrolytes disturbances. We aimed to analyze the incidence, severity, and risk factors for readmission for HOS. METHODS: We reviewed all patients who underwent loop ileostomy closure in a single institution between 2010 and 2020. Patients that were readmitted for dehydration due to HOS during the time interval between the creation and the closure of the stoma were identified and divided into a study (HOS) group. The remaining patients constructed the control group. RESULTS: A total of 307 patients were included in this study, out of which, 41 patients were readmitted 73 times (23.7% readmission rate) for the HOS group, and the remaining 266 patients constructed the control group. Multivariate analysis identified; advanced American Society of Anesthesiologists (ASA) physical status (PS) classification, elevated baseline creatinine, and open surgery as risk factors for HOS. Renal function worsened among the entire cohort between the construction of the stoma to its closure (mean creatinine of 0.82 vs. 0.96, P<0.0001). CONCLUSION: Loop ileostomy formation is associated with a substantial readmission rate for dehydration as a result of HOS, and increasing the risk for renal impairment during the duration of the diversion. We identified advanced ASA PS classification, open surgery, and elevated baseline creatinine as predictors for HOS.

Increased risk for incisional hernia following cytoreductive surgery with hyperthermic intraperitoneal chemotherapy.

INTRODUCTION: The incidence of incisional hernias (IH) after midline laparotomy varies from 11% to 20%. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is potentially prone to hernias because a Xiphoid to pubis laparotomy incision performed on patients who have undergone previous abdominal surgeries with the addition of chemotherapy and its related adverse effects. METHODS: We performed a retrospective analysis on a prospectively maintained single institution database from March 2015 to July 2020. The inclusion criteria were patients who underwent CRS-HIPEC and had at least 6 months postoperative follow-up with post-operative cross-sectional imaging study. RESULTS: Two hundred and one patients were included in the study. All patients underwent CRS-HIPEC with resection of previous scar and umbilectomy. Fifty-four patients were diagnosed with IH (26.9%). The major risk factors for IH in multivariate analysis were higher American society of Anesthesiologists score (ASA) (OR 3.9, P = 0.012), increasing age (OR 1.06, P = 0.004) and increasing BMI (OR 1.1, P = 0.006). Most of the hernia sites were median (n = 43, 79.6%). Eleven (20.4%) patients had lateral hernias due to stoma incisions or drain sites. Most of the median hernias were at the level of the resected umbilicus 58.9% (n = 23). Five (9.3%) of the patients with IH necessitated an urgent surgical repair. CONCLUSION: We have demonstrated that more than a quarter of the patients after CRS-HIPEC suffer from IH and up to 10% of them may require surgical intervention. More research is needed to find the appropriate intraoperative interventions to minimize this sequela.

Perioperative and Oncological Outcomes of Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Metastasis of Rectal Origin.

BACKGROUND: The peritoneum is a common metastatic site of colorectal cancer (CRC) and associated with worse oncological outcomes. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) has been shown to improve outcomes in selected patients. Studies have demonstrated significant difference in survival of patients with primary colon and rectal tumors both in local and in metastatic setting; but only few assessed outcomes of CRS/HIPEC for rectal and colon tumors. We studied the perioperative and oncological outcomes of patients undergoing CRS/HIPEC for rectal cancer. METHODS: A retrospective analysis of a prospectively maintained database between 2009 and 2021 was performed. RESULTS: 199 patients underwent CRS/HIPEC for CRC. 172 patients had primary colon tumors and 27 had primary rectal tumors. Primary rectal location was associated with longer surgery (mean 4.32, hours vs 5.26 h, p = 0.0013), increased blood loss (mean 441cc vs 602cc, p = 0.021), more blood transfusions (mean 0.77 vs 1.37units, p = 0.026) and longer hospitalizations (mean 10 days vs 13 days, p = 0.02). Median disease-free survival (DFS) was shorter in rectal primary group; 7.03 months vs 10.9 months for colon primaries (p = 0.036). Overall survival was not statistically significant; 53.2 months for rectal and 60.8 months for colon primary tumors. Multivariate analysis indicated origin (colon vs rectum) and Peritoneal Cancer Index to be independently associated with DFS. CONCLUSIONS: Patients with rectal carcinoma undergoing CRS/HIPEC for peritoneal metastasis had worse peri-operative and oncological outcomes. Overall survival was excellent in both groups. This data may be used for risk stratification when considering CRS/HIPEC for patients with rectal primary.

Pelvic Peritonectomy Poorly Affects Outcomes in Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Colorectal Metastases.

BACKGROUND: Constraints of pelvic anatomy render complete cytoreduction (CRS) challenging. The aim of this study is to investigate the impact of pelvic peritonectomy during CRS/HIPEC on colorectal peritoneal metastasis (CRPM) patients' outcomes. METHODS: This is a retrospective analysis of a prospectively maintained CRS/hyperthermic intraperitoneal chemotherapy (HIPEC) database. The analysis included 217 patients with CRPM who had a CRS/HIPEC between 2014 and 2021. We compared perioperative and oncological outcomes of patients with pelvic peritonectomy (PP) (n = 63) to no pelvic peritonectomy (non-PP) (n = 154). RESULTS: No differences in demographics were identified. The peritoneal cancer index (PCI) was higher in the PP group with a median PCI of 12 vs. 6 in the non-PP group (p < 0.001). Operative time was 4.9 vs. 4.3 h in the PP and non-PP groups, respectively (p = 0.63). Median hospitalization was longer in the PP group at 12 vs. 10 days (p = 0.007), and the rate of complications were higher in the PP group at 57.1% vs. 39.6% (p = 0.018). Pelvic peritonectomy was associated with worse disease-free (DFS) and overall survival (OS) with 3-year DFS and OS of 7.3 and 46.3% in the PP group vs. 28.2 and 87.8% in the non-PP group (p = 0.028, p .> 0.001). The univariate OS analysis identified higher PCI (p = 0.05), longer surgery duration (p = 0.02), and pelvic peritonectomy (p < 0.001) with worse OS. Pelvic peritonectomy remained an independent prognostic variable, irrespective of PCI, on the multivariate analysis (p < 0.001). CONCLUSIONS: Pelvic peritonectomy at the time of CRS/HIPEC is associated with higher morbidity and worse oncological outcomes. These findings should be taken into consideration in the management of patients with pelvic involvement.

IOeRT in retroperitoneal sarcoma: Towards more organ preservation with comparable oncological outcomes.

BACKGROUND: Retroperitoneal sarcomas (RPS) present a surgical challenge with high rates of local recurrence (LR). We investigated the role of intraoperative electron radiotherapy (IOeRT) in reducing LR after surgical resection of RPS. METHODS: A retrospective analysis of all patients who underwent surgical resection for RPS between 2014 and 2021 at a tertiary academic referral center (n = 172). Patients included underwent surgical resection of their RPS and received IOeRT (n = 36) and were compared by case control matching to patients with similar tumor characteristics (recurrence status and tumor grade) that did not receive IOeRT (n = 36). RESULTS: The median length of hospitalization was 8 days (range, 4-34) in the IOeRT group and 10 days (range, 2-42) in the non-IOeRT group (p = 0.25). The mean operating room (OR) time was 4h (±1.3) and 4h (±1.9) in the IOeRT and non-IOeRT groups respectively, (p = 0.37). Complete resection with R0 margins was achieved in 30 patients (83.3%) and 24 patients (66.6%) in the IOeRT and non-IOeRT groups, respectively (p = 0.1). R1 resection was achieved in 6 patients (16.6%) and 12 patients (33.3%) respectively, (p = 0.1). The resected organ weighted score was significantly different between the groups; score 0 observed in 19 (52.7%) patients in the IOeRT group and 3 (8.3%) in the non-IOeRT group (p < 0.001), score 1 observed in 7 (19.4%) in the IOeRT group and 17 (47.2%) in the non-IOeRT group (p = 0.012). The rate of severe complications (CD score>3) did not differ between the groups, 5 (13.8%) patients in the IOeRT group and 9 (25%) patients in the non-IOeRT group (p = 0.23). No radiation associated complications were noted. The 2-year local recurrence free survival (LRFS) was 75.9% in the IOeRT group and 60.3% in the non-IOeRT group (p = 0.4). The 2-year IOeRT field recurrent free survival (IRFS) was 88.4% in the IOeRT group and 60.3% in the non-IOeRT group (p = 0.04). CONCLUSIONS: The use of IOeRT did not increase the rate of surgical complications and was associated with superior local control in the radiation field, improved organ preservation without an impact on overall survival.

PET-CT underestimates the true pathological extent of disease at lymphadenectomy for melanoma patients after systemic therapy.

INTRODUCTION: Modern systemic therapy has revolutionized the treatment of melanoma. Currently, patients with clinically involved lymph nodes require lymphadenectomy with associated morbidities. Positron Emission Tomography - Computed Tomography (PET-CT) has demonstrated accuracy in melanoma detection and response to therapy. We aimed to identify whether a PET-CT directed lymphatic resection after systemic therapy is oncologically sound. MATERIALS AND METHODS: Retrospective review of patients who underwent lymphadenectomy after systemic therapy for melanoma with a preoperative PET-CT. Examined demographic, clinical, and perioperative parameters including extent of disease, systemic therapy and response, and PET-CT findings compared to pathological outcomes. We compared patients with "as or less than expected" outcomes on pathology against those with "more than expected" pathological outcomes. RESULTS: Thirty-nine patients met inclusion criteria. In 28 (71.8%), pathological outcomes were "as or less than expected" by PET-CT, and in 11 (28.2%) pathological outcome were "more than expected". "More than expected" occurred more frequently with advanced disease at presentation with 75% presenting with regional/metastatic disease versus only 42.9% in the "as or less than expected" group (p = 0.015). Poor response to therapy also trended towards the "more than expected" group with only 27.3% favorable response versus 53.6% favorable response in the "as or less than expected" group, not statistically significant. Extent of disease on imaging failed to predict pathological concordance. CONCLUSION: PET-CT underestimates pathological extent of disease in the lymphatic basin in 30% of patients after systemic therapy. We failed to identify predictors of more extensive disease and warn against limited PET-CT directed lymphatic resections.