3D-SARC: A Pilot Study Testing the Use of a 3D Augmented-Reality Model with Conventional Imaging as a Preoperative Assessment Tool for Surgical Resection of Retroperitoneal Sarcoma.

BACKGROUND: Retroperitoneal sarcomas (RPSs) present a surgical challenge, with complex anatomic relationships to organs and vascular structures. This pilot study investigated the role of three-dimensional (3D) augmented reality (3DAR) compared with standard imaging in preoperative planning and resection strategies. METHODS: For the study, 13 patients who underwent surgical resection of their RPS were selected based on the location of their tumor (right, left, pelvis). From the patients' preoperative computed tomography (CT) scans, 3DAR models were created using a D2P program and projected by an augmented-reality (AR) glass (Hololens). The 3DAR models were evaluated by three experienced sarcoma surgeons and compared with the baseline two-dimensional (2D) contrast-enhanced CT scans. RESULTS: Three members of the surgical team evaluated 13 models of retroperitoneal sarcomas, resulting in a total of 26 responses. When the surgical team was asked to evaluate whether the 3DAR better prepared the surgeon for planned surgical resection, 10 responses favored the 3DAR, 5 favored the 2D CT scans and 11 showed no difference (p = 0.074). According to 15 (57.6 %) of the 26 responses, the 3DAR offered additional value over standard imaging in the preoperative planning (median score of 4; range, 1-5). The median stated likelihood that the surgeons would consult the 3DAR was 5 (range, 2-5) for the preoperative setting and 3 (range, 1-5) for the intraoperative setting. CONCLUSIONS: This pilot study suggests that the use of 3DAR may provide additional value over current standard imaging in the preoperative planning for surgical resection of RPS, and the technology merits further study.

Pleomorphic dermal sarcoma of the scalp - A single-centre experience.

BACKGROUND: Pleomorphic dermal sarcoma (PDS) of the scalp is a rare tumour which is usually slow growing, but occasionally displays rapid growth and has a low rate of local recurrence. Surgical resection is the mainstay of treatment, with or without radiotherapy. The aim of this study is to describe the surgical approach and the additional benefit of radiotherapy to the treatment of these patients. METHODS: Retrospective, single-centre analysis of patients with PDS of the scalp that underwent surgical resection between 2007 and 2021 (n = 24). Treatment variables including depth of resection (superficial or deep to the galea aponeurotica) and adjuvant radiotherapy were investigated. RESULTS: Twenty-four patients were included in this study. Median age was 80 (range, 52-95), with a median ASA score of 3 (2-3). Sixteen (66.6 %) patients underwent surgical resection including the galea, while the rest (n = 8) did not or was not known. Radiotherapy was given in 7 (29 %) patients in which only 3 (12.5 %) were in the galeal resection group. Reasons for radiotherapy administration were concomitant SCC found at the same area of resection and close margins. In a median follow-up of was 26.2 months (range, 13.6-102.5) there was only one recurrence event. CONCLUSIONS: PDS of the scalp can be safely managed with a surgical resection if clear surgical margins are achieved without radiotherapy with good oncological outcomes.

International Expert Consensus on Defining Textbook Oncologic Outcomes in Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Colorectal Peritoneal Metastasis.

BACKGROUND: Textbook oncologic outcome (TOO) is a composite metric shown to correlate with improved survival after curative intent oncologic procedures. Despite increasing use among disciplines in surgical oncology, no consensus exists for its definition in cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). STUDY DESIGN: An international consensus-based study employed a Delphi methodology to achieve agreement. Fifty-four senior surgeons from the peritoneal surface malignancies field received a questionnaire comprising TOO parameters divided into 3 surgical domains: operative, short-term, and long-term postoperative outcomes. Two online meetings with participants defined the new criteria. Consensus was achieved when 75% of agreement rate was reached. Clinical data of patients who underwent CRS and HIPEC for colorectal peritoneal metastasis between 2010 and 2022 from 1 designated center (Sheba Medical Center) were collected, the consensus definition applied and outcomes analyzed. RESULTS: Thirty-eight surgeons (70%) participated. Expert consensus TOO parameters for colorectal peritoneal metastasis CRS and HIPEC included the absence of unplanned reoperations during 30 days postoperation, absence of severe postoperative complications (Clavien-Dindo ≥III), absence of unplanned readmissions during 30 days postoperation, 90-day postoperative mortality, and absence of contraindications for chemotherapy within 12 weeks from operation, and included the achievement of complete cytoreduction (CC0). The study cohort consisted of 251 patients, and 151 (60%) met TOO criteria. Patients who achieved TOO had significantly better overall survival (median 67.5 months, 95% CI) vs patients who did not achieve TOO (median 44.6 months, 95% CI, p < 0.001) and significantly improved disease-free survival (median, 12 months, 95% CI, vs 9 months, 95% CI, p = 0.01). CONCLUSIONS: Achievement of TOO as defined by consensus statement is associated with improved survival.

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.

Practical Management of Adult Ultra-Rare Primary Retroperitoneal Soft Tissue Sarcoma: A Focus on Perivascular Epithelioid Tumours and Extraosseous Ewing Sarcoma.

With the exception of well-differentiated liposarcoma, dedifferentiated liposarcoma, leiomyosarcoma, solitary fibrous tumour, malignant peripheral nerve sheath tumour, and undifferentiated pleomorphic sarcoma, the majority of the ≈70 histologic subtypes of retroperitoneal sarcoma are defined as 'ultra-rare' sarcomas, with an incidence of ≤1-5/1,000,000 persons/year. For most of these ultra-rare RPS subtypes, diagnosis and treatment follows international guidelines for the management of more common RPS histologies, with en bloc surgical resection as the mainstay of curative treatment, and enrolment in clinical trials where possible. Because the treatment of RPS is heavily driven by histology, the surgeon must be familiar with specific issues related to the diagnosis and management of ultra-rare sarcoma subtypes. Expert radiological and surgeon reviews are required to differentiate similarly presenting tumours where surgery can be avoided (e.g., angiomyolipoma), or where upfront systemic therapy is indicated (e.g., extraosseous Ewing's sarcoma). Thus, the management of all retroperitoneal sarcomas should occur at a sarcoma referral centre, with a multidisciplinary team of experts dedicated to the surgical and medical management of these rare tumours. In this focused review, we highlight how diagnosis and management of the ultra-rare primary RPS histologies of malignant perivascular epithelioid cell tumour (PEComa), extraosseous Ewing sarcoma (EES), extraosseous osteosarcoma (EOS), and rhabdomyosarcoma (RMS) critically diverge from the management of more common RPS subtypes.

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.

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.

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.

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.

The increasing role of abdominal metastesectomy for malignant melanoma in the era of modern therapeutics.

BACKGROUND: Metastatic spread of malignant melanoma to the abdomen presents a therapeutic challenge. Targeted and Immune-therapies dramatically improve patients' survival, yet some patients may still benefit from surgical intervention. This study investigates the outcomes of surgical treatment of abdominal metastatic melanoma in the era of modern therapy. METHODS: This is a retrospective study of all patients who underwent surgical resection for abdominal metastatic melanoma between the years 2009-2021 (n = 80). We examined the clinical, operative, perioperative, and oncological outcomes of these patients. RESULTS: The cohort included a therapeutic group (T, n = 43) and palliative group (P, n = 37). The rate of overall post-operative complications was lower in the T group (n = 3, 9.3%) compared to the P group (n = 10, 27.1%) (p = 0.04), but no difference in major complications rate (p = 0.41). The median follow-up was 13.4 months (range, 0.5-107), with an estimated 2- and 5-years survival of 66.5% and 45.3% respectively. The estimated 2- and 5-years survival of the T group was 76.61% and 69.65%, and 49.01% and 28.01% in the P group (p = 0.005). Univariate analysis identified Therapeutic resection (HR 3.2, p = 0.008), isolated lesions (HR 1.47, p = 0.033) and major complication score (HR 1.8, p=<0.001) to be correlated with survival. On multivariate analysis, Therapeutic resection (HR 2.53, p = 0.042) and major complication score (HR 1.62, p = 0.004) remained significant independent factors correlated with survival. In patients who progressed on treatment, and their progression was treated with surgical resection 46.1% where able to be maintained on the same preoperative treatment strategy. CONCLUSION: We have demonstrated that abdominal metastesectomy is a safe and oncologically efficacious therapy in selected patients. Especially in the era of modern therapeutics, patients with isolated disease site, limited resectable progression on therapy, or patients with symptomatic metastases should be considered for surgical resection.

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.

Outcomes of Stable Lung Colorectal Metastases on Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) have demonstrated benefit in patients with colorectal peritoneal metastases (CRPM). Traditionally, extraperitoneal disease is considered a contraindication to CRS/HIPEC. Stable lung metastases in patients with colorectal cancer often have an indolent course, while the presence of untreated peritoneal metastases poorly affects short-term survival. We sought to evaluate the outcomes of patients undergoing CRS/HIPEC for peritoneal disease with known stable lung metastases. METHODS: We retrospectively reviewed our prospectively maintained CRS/HIPEC database. In 2017, we adopted a policy of considering patients with stable lung metastases for CRS/HIPEC as part of multidisciplinary treatment. We compared the oncologic outcome and safety of CRS/HIPEC with peritoneal only (PM) against patients with peritoneal and lung metastases (PLM). RESULTS: Our database includes 570 patients with CRS/HIPEC of which 174 with CRPM that underwent CRS/HIPEC, 18 with preoperatively diagnosed peritoneal and lung metastases. The demographics of the PM and PLM group were similar with the exception of operative time that was longer in the PLM group. Median PCI of the cohort was 7, similar in both groups (p = 0.89). Three-year overall survival (OS) of PLM patients was 68%, compared to 71% in PM (p = 0.277). Three-year progression-free survival (PFS) rate was 20% in PLM and 23% in PM (p = 0.688). CONCLUSIONS: Presence of stable lung metastases from colorectal cancer in patients with CRPM does not appear to affect the outcomes of CRS/HIPEC. Patients with stable lung disease should be considered for CRS/HIPEC after multidisciplinary discussion.

The pattern of peritoneal colorectal metastasis predicts survival after cytoreductive surgery and hyperthermic intra-peritoneal chemotherapy.

BACKGROUND: Peritoneal cancer index (PCI) has been used reliably to prognosticate patients with peritoneal metastasis, however, it fails to describe the patterns of peritoneal spread and to correlate these patterns to survival outcomes. We aim to define the scattered peritoneal spread (SPS) as a pattern associated with worse survival in colorectal peritoneal metastasis. METHODS: A retrospective analysis of metastatic colorectal cancer patients from a prospectively maintained database of peritoneal surface malignances (n = 280) between 2015 and 2020. SPS was defined by the presence of at least two distant and non-contiguous PCI regions. We compared patients with SPS (n = 73) and clustered peritoneal spread (CPS) (n = 88) for demographics, perioperative and survival outcomes. RESULTS: No difference in demographics or post-operative course was noted between the groups. The median follow-up was 15.4 months (0.4-70.8 months). Worse disease-free survival (DFS) in the SPS group with an estimated median of 8.2 months compared to 22.5 months in the CPS spread group, (p = 0.001). The estimated median overall survival (OS) for SPS group was 35.7 months whereas in the CPS group the median was not reached (p = 0.025). The same effect of SPS was preserved even after stratification of PCI. CONCLUSIONS: We defined and described the association of the peritoneal spread pattern to survival outcomes. SPS patients exhibit worse DFS and OS independent of the PCI level. Integration of malignant spread pattern into prognostication models along with PCI may aid in predicting oncological outcomes.

The impact of gastrointestinal anastomotic leaks on survival of patients undergoing cytoreductive surgery and heated intraperitoneal chemotherapy.

BACKGROUND: Gastrointestinal (GI) leaks after cytoreductive surgery and hyperthermic Intraperitoneal Chemotherapy (CRS/HIPEC) is a known life-threatening complication that may alter patients' outcomes. Our aim is to investigate risk factors associated with GI leaks and evaluate the impact of GI leaks on patient's oncological outcomes. METHODS: A retrospective analysis of perioperative and oncological outcomes of patients with and without GI leaks after CRS/HIPEC. RESULTS: Out of 191 patients included in this study, GI leaks were identified in 17.8% (34/191) of patients. Small bowel anastomoses were the most common site (44%). Most of the GI leaks were managed conservatively and re-operation was needed in 44.1% of cases. Univariate analysis identified higher PCI (p = 0.03), higher number of packed cells transfused (p = 0.036), pelvic peritonectomy (p = 0.013), high number of anastomoses (p = 0.003) and colonic resection (p = 0.042) as factors associated with GI leaks. Multivariate analysis identified stapled anastomoses (OR 2.59, p = 0.001) and pelvic peritonectomy (OR 2.33, p = 0.044) as independent factors associated with GI leaks. Disease-free survival tended to be worse in the leak group but did not reach statistical significance (p = 0.235). The 3- and 5-year OS was 73.2% and 52.9% in the leak group compared to 75.8% and 73.2% in the non-leak group (p = 0.236). CONCLUSIONS: GI leak showed no impact on overall and disease free survival after CRS/HIPEC.Avoidance of stapled reconstruction in high risk patients with high tumor burden and large number of anastomoses may yield improved outcomes.

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.