Pressurized Intraperitoneal Aerosol Chemotherapy for Colorectal Peritoneal Metastases

Third-line treatment and beyond in metastatic colorectal cancer: What do we have and what can we expect?

Colorectal cancer remains the third most common cancer worldwide and the second cause of cancer-related death. Treatment advances and precision oncological medicine for these tumours have been stalled in comparison to those for other common tumours such as lung and breast cancer. However, the recent publication of the SUNLIGHT trial results with the trifluridine/tipiracil (TAS-102)-bevacizumab combination and the irruption of new molecular targets with guided treatments have opened new possibilities in third-line metastatic colorectal cancer management. Anti-EGFR rechallenge, anti-HER2 targeted therapies or the promising results of Pressurised Intraperitoneal Aerosol Chemotherapy (PIPAC), are some of the available options that may modify what is presumably third-line colorectal treatment. Hereby, we present the evidence of the different treatment options in third-line colorectal cancer and beyond, as well as the possibilities of sequencing them.

The Future of Interventions for Stage IV Colorectal Cancers

Future options for the management of stage IV colorectal cancer are primarily focused on personalized and directed therapies. Interventions include precision cancer medicine, utilizing nanocarrier platforms for directed chemotherapy, palliative pressurized intraperitoneal aerosol chemotherapy (PIPAC), adjunctive oncolytic virotherapy, and radioembolization techniques. Comprehensive genetic profiling provides specific tumor-directed therapy based on individual genetics. Biomimetic magnetic nanoparticles as chemotherapy delivery systems may reduce systemic side effects of traditional chemotherapy by targeting tumor cells and sparing healthy cells. PIPAC is a newly emerging option for patients with peritoneal metastasis from colorectal cancer and is now being used internationally, showing promising results as a palliative therapy for colorectal cancer. Oncolytic virotherapy is another emerging potential treatment option, especially when combined with standard chemotherapy and/or radiation, as well as immunotherapy. And finally, radioembolization with yttrium-90 ( 90 Y) microspheres has shown some success in treating patients with unresectable liver metastasis from colorectal cancer via selective arterial injection.

Reasons for stopping Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC): A retrospective study to improve future patient selection

To improve the prognosis and maintain quality of life in patients with peritoneal metastasis (PM), a novel treatment has been introduced-pressurized intraperitoneal aerosol chemotherapy (PIPAC). The majority of teams propose at least 3 PIPAC procedures. However, for many patients PIPAC is stopped after only one or two procedures. The aim of this study was to identify the reasons for stopping PIPAC after only one or two procedures and to establish a profile of poor candidates. This retrospective, multicenter cohort study included all patients who underwent PIPAC in three French expert centers between 2015 and 2021. A total of 268 PIPAC procedures were performed in 89 patients. Of them, 48.3% of patients underwent fewer than three procedures: 28.1% had one, 20.2% two and 51.7% three or more PIPAC procedures. The main reason for stopping PIPAC, regardless of the number of procedures, was disease progression, in 55.8% of cases. Other reasons for stopping PIPAC were non-access to the abdominal cavity (7.9%), conversion to cytoreductive surgery (13.5%), post-PIPAC adverse events (7.9%), patients' wishes (10.1%) and death (2.2%). In univariate analysis, patients who received fewer than three PIPACs less frequently had chemotherapy beforehand (91% vs 100%, p = 0.05), less frequently had bimodal treatment (70% vs 87%, p = 0.04), had more ascites (median 80 ml vs 50 ml, p = 0.05) and more frequently had carcinomatosic ascites (48.8% vs 23.9%, p < 0.01). Performing PIPAC alone in chemotherapy-naïve patients with ascites should be avoided.

Comparing patient reported abdominal pain between patients treated with oxaliplatin-based pressurized intraperitoneal aerosol chemotherapy (PIPAC-OX) and primary colorectal cancer surgery

Oxaliplatin-based pressurized intraperitoneal aerosol chemotherapy (PIPAC-OX) is an emerging palliative treatment for patients with unresectable colorectal peritoneal metastases. Previously, our study group reported that patients experienced abdominal pain for several weeks after PIPAC-OX. However, it is unknown how this compares to abdominal pain after regular colorectal cancer surgery. To provide some perspective, this study compared the presence of abdominal pain after PIPAC-OX to the presence of abdominal pain after primary tumor surgery. Patient reported abdominal pain scores (EORTC QLQ-CR-29), from two prospective, Dutch cohorts were used in this study. Scores ranged from 0 to 100, a higher score represents more abdominal pain. Abdominal pain at baseline and at four weeks after treatment were compared between the two groups. Twenty patients who underwent PIPAC-OX and 322 patients who underwent primary tumor surgery were included in the analysis. At baseline, there were no differences in abdominal pain between both groups (mean 20 vs. 18, respectively; p = 0.688). Four weeks after treatment, abdominal pain was significantly worse in the PIPAC group (39 vs 15, respectively; p < 0.001; Cohen's d = 0.99). The differential effect over time for abdominal pain differed significantly between both groups (mean difference: 19 vs - 3, respectively; p = 0.004; Cohen's d = 0.88). PIPAC-OX resulted in significantly worse postoperative abdominal pain than primary tumor surgery. These results can be used for patient counseling and stress the need for adequate analgesia during and after PIPAC-OX. Further research is required to prevent or reduce abdominal pain after PIPAC-OX.Trial registration CRC-PIPAC: Clinicaltrails.gov NCT03246321 (01-10-2017).

PIPAC for Gastrointestinal Malignancies

The peritoneum is a common site of metastases for gastrointestinal tumors that predicts a poor outcome. In addition to decreased survival, peritoneal metastases (PMs) can significantly impact quality of life from the resulting ascites and bowel obstructions. The peritoneum has been a target for regional therapies due to the unique properties of the blood-peritoneum barrier. Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) have become accepted treatments for limited-volume peritoneal disease in appendiceal, ovarian, and colorectal malignancies, but there are limitations. Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) improves drug distribution and tissue penetration, allowing for a minimally invasive application for patients who are not CRS/HIPEC candidates based on high disease burden. PIPAC is an emerging treatment that may convert the patient to resectable disease, and may increase survival without major morbidity, as indicated by many small studies. In this review, we discuss the rationale and benefits of PIPAC, as well as sentinel papers describing its application for gastric, colorectal, appendiceal, and pancreatobiliary PMs. While no PIPAC device has yet met FDA approval, we discuss next steps needed to incorporate PIPAC into neoadjuvant/adjuvant treatment paradigms, as well as palliative settings. Data on active clinical trials using PIPAC are provided.

Peritoneal regression grading score (PRGS): first evidence for independent predictive and prognostic significance

Objectives

The peritoneal regression grading score (PRGS) is a four-tied pathologic score measuring tumor regression in biopsies from patients with peritoneal metastasis (PM) receiving chemotherapy.

Methods

This retrospective analysis of a prospective registry (NCT03210298) analyses 97 patients with isolated PM under palliative chemotherapy. We examined the predictive value of the initial PRGS for overall survival (OS) and the prognostic value of PRGS in repeated peritoneal biopsies.

Results

The 36 (37.1 %) patients with an initial mean PRGS≤2 had a longer median OS (12.1 months, CI 95 % 7.8-16.4) vs. 8.0 months (CI 95 % 5.1-10.8 months) in 61 (62.9 %) patients with PRGS≥3 (p=0.02) After stratification, the initial PRGS was an independent predictor of OS (Cox-regression, p<0.05). Out of 62 patients receiving≥two chemotherapy cycles, 42 (67.7 %) had a histological response (defined as a lower or stable mean PRGS in successive therapy cycles), and 20 (32.3 %) progressed (defined as an increasing mean PRGS). PRGS response was associated with a longer median OS (14.6 months, CI 5-95 % 6.0-23.2) vs. 6.9 (CI 5-95 % 0.0-15.9) months. PRGS response was prognostic in the univariate analysis (p=0.017). Thus, PRGS had both a predictive and prognostic significance in patients with isolated PM receiving palliative chemotherapy in this patient cohort.

Conclusions

This is the first evidence for the independent predictive and prognostic significance of PRGS in PM. These encouraging results need validation in an adequately powered, prospective study.

Pressurized intraperitoneal aerosol chemotherapy, reasons for interrupting treatment: a systematic review of the literature

Objectives

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) gives encouraging results in the treatment of peritoneal metastasis (PM). The current recommendations require at least 3 sessions of PIPAC. However, some patients do not complete the full treatment course and stop after only 1 or 2 procedures, hence the limited benefit. A literature review was performed, with search terms including "PIPAC" and "pressurised intraperitoneal aerosol chemotherapy."

Content

Only articles describing the causes for premature termination of the PIPAC treatment were analysed. The systematic search identified 26 published clinical articles related to PIPAC and reporting causes for stopping PIPAC.

Summary

The series range from 11 to 144 patients, with a total of 1352 patients treated with PIPAC for various tumours. A total of 3088 PIPAC treatments were performed. The median number of PIPAC treatments per patient was 2.1, the median PCI score at the time of the first PIPAC was 19 and the number of patients who did not complete the recommended 3 sessions of PIPAC was 714 (52.8%). Disease progression was the main reason for early termination of the PIPAC treatment (49.1%). The other causes were death, patients' wishes, adverse events, conversion to curative cytoreductive surgery and other medical reasons (embolism, pulmonary infection, etc…).

Outlook

Further investigations are necessary to better understand the causes for interrupting PIPAC treatment and also improving the selection of patients who are most likely to benefit from PIPAC.

Safety and Feasibility of High-Pressure/High-Dose Pressurized Intraperitoneal Aerosol Chemotherapy (HP/HD-PIPAC) for Primary and Metastatic Peritoneal Surface Malignancies

OBJECTIVE

The aim of this study was to evaluate the feasibility and perioperative safety of high-pressure/high-dose pressurized intraperitoneal aerosol chemotherapy (HP/HD-PIPAC) to manage peritoneal surface malignancies (PSM).

METHODS

Retrospective analysis of a prospective database of about 130 consecutive patients scheduled for HP/HD-PIPACs for PSM. Doxorubicin plus cisplatin (PIPAC-C/D) or oxaliplatin (PIPAC-Ox) were nebulized into a constant capnoperitoneum of 20 mmHg at doses of 6, 30, or 120 mg/m² of body surface area (BSA). Outcome criteria were perioperative complications (Clavien-Dindo).

RESULTS

The median age of patients was 62 years (range 9-82), and the primary tumor site was of colorectal (CRC), upper gastrointestinal tract (UGI), unknown primary (CUP), malignant epithelioid mesothelioma of the peritoneum (MPM), hepato-pancreatic-biliary tract (HPB), and other origin in 30 (23.1%), 27 (20.8%), 16 (12.3%), 16 (12.3%), 6 (4.6%), and 35 (26.9%) patients, respectively. Abdominal access failed for a first, second, third, and fourth or more HP/HD-PIPAC in 12/130 (9.2%), 4/64 (6.3%), 6/40 (15.0%), and 2/33 (6.1%) patients. A total of 243 procedures were performed in 118 patients. No intraoperative complications related to increased capnoperitoneal pressure occurred, but an intraoperative bleeding complication was observed in 1/243 (0.4%) patients. The overall rate of postoperative procedure-related complications was 19.3% (47/243), while 15.3% (37/243), 1.6% (6/243), 1.6% (1/243), 0.4% (1/243), and 0.4% (1/243) were Grade I, II, III, IV, and V complications, respectively.

CONCLUSIONS

Perioperative complications of HP/HD-PIPAC are comparable with standard pressure/dose PIPAC treatment protocols. Prospective studies are warranted to examine potential improvement in therapy outcomes.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with peritoneal surface malignancies (PSM): a prospective single-center registry study

PURPOSE

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new, palliative approach for patients with peritoneal surface malignancies (PSMs). Its main goals are to control symptoms and ascites. For this experimental procedure, treatment efficacy and patient safety need to be closely monitored.

METHODS

We performed a prospective registry study for patients with PSMs. Cisplatin (C) (7.5 mg/m² body surface) and doxorubicin (D) (1.5 mg/m²) were administered laparoscopically via PIPAC.

RESULTS

Between November 2015 and June 2020, we recorded data from 108 patients and 230 scheduled procedures. Tumor burden, patient fitness, quality of life, operating time and in-hospital stay remained stable over consecutive procedures. We recorded 21 non-access situations and 14 intraoperative complications (11 intestinal injuries, and three aspirations while inducing anesthesia). Three or more previous abdominal surgeries or cytoreductive surgery (CRS) with intraperitoneal hyperthermic chemoperfusion (HIPEC) were risk factors for non-access and intestinal injuries (χ², p ≤ 0.01). Five Grade IV and three Grade V postoperative complications according to the Clavien-Dindo Classification (CDC) occurred. Median overall survival was 264 days (interquartile range 108-586). Therapies were primarily discontinued because of death (34%), progressive (26%), or regressive (16%) disease.

CONCLUSION

PIPAC is effective in stabilizing PSMs and retaining quality of life in selected patients. Earlier abdominal surgeries and CRS with HIPEC should be considered when determining the indication for PIPAC. Randomized controlled studies are needed to evaluate PIPAC's therapeutic benefits compared to systemic chemotherapy (sCHT) alone.

TRIAL REGISTRATION

NCT03100708 (April 2017).

10 Years of Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC): A Systematic Review and Meta-Analysis

BACKGROUND

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel intraperitoneal drug delivery method of low-dose chemotherapy as a pressurized aerosol in patients affected by peritoneal cancer of primary or secondary origin. We performed a systematic review and meta-analysis with the aim of assessing the feasibility, safety, and efficacy of PIPAC.

METHODS

A systematic literature search was performed using Medline and Web of Science databases from 1 January 2011, to inception, to 31 December 2021. Data were independently extracted by two authors. The Newcastle-Ottawa Scale was used to assess the quality and risk of bias of studies. Meta-analysis was performed for pathological response, radiological response, PCI variation along treatment, and for patients undergoing three or more PIPAC. Pooled analyses were performed using the Freeman-Tukey double arcsine transformation, and 95% CIs were calculated using Clopper-Pearson exact CIs in all instances.

RESULTS

A total of 414 papers on PIPAC were identified, and 53 studies considering 4719 PIPAC procedure in 1990 patients were included for analysis. The non-access rate or inability to perform PIPAC pooled rate was 4% of the procedures performed. The overall proportion of patients who completed 3 or more cycles of PIPAC was 39%. Severe toxicities considering CTCAE 3-4 were 4% (0% to 38.5%). In total, 50 studies evaluated deaths within the first 30 postoperative days. In the included 1936 patients were registered 26 deaths (1.3%). The pooled analysis of all the studies reporting a pathological response was 68% (95% CI 0.61-0.73), with an acceptable heterogeneity (I² 28.41%, p = 0.09). In total, 10 papers reported data regarding the radiological response, with high heterogeneity and a weighted means of 15% (0% to 77.8%). PCI variation along PIPAC cycles were reported in 14 studies. PCI diminished, increased, or remained stable in eight, one and five studies, respectively, with high heterogeneity at pooled analysis. Regarding survival, there was high heterogeneity. The 12-month estimated survival from first PIPAC for colorectal cancer, gastric cancer, gynecological cancer and hepatobiliary/pancreatic cancer were, respectively, 53%, 25%, 59% and 37%.

CONCLUSIONS

PIPAC may be a useful treatment option for selected patients with PM, with acceptable grade 3 and 4 toxicity and promising survival benefit. Meta-analysis showed high heterogeneity of data among up-to-date available studies. In a subset analysis per primary tumor origin, pathological tumor regression was documented in 68% of the studies with acceptable heterogeneity. Pathological regression seems, therefore, a reliable outcome for PIPAC activity and a potential surrogate endpoint of treatment response. We recommend uniform selection criteria for patients entering a PIPAC program and highlight the urgent need to standardize items for PIPAC reports and datasets.

Response Evaluation in Patients with Peritoneal Metastasis Treated with Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC)

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) directed therapy emerged as a treatment of peritoneal metastasis (PM) a decade ago. The response assessment of PIPAC is not uniform. This narrative review describes non-invasive and invasive methods for response evaluation of PIPAC and summarizes their current status. PubMed and clinicaltrials.gov were searched for eligible publications, and data were reported on an intention-to-treat basis. The peritoneal regression grading score (PRGS) showed a response in 18-58% of patients after two PIPACs. Five studies showed a cytological response in ascites or peritoneal lavage fluid in 6-15% of the patients. The proportion of patients with malignant cytology decreased between the first and third PIPAC. A computed tomography showed stable or regressive disease following PIPAC in 15-78% of patients. The peritoneal cancer index was mainly used as a demographic variable, but prospective studies reported a response to treatment in 57-72% of patients. The role of serum biomarkers of cancer or inflammation in the selection of candidates for and responders to PIPAC is not fully evaluated. In conclusion, response evaluation after PIPAC in patients with PM remains difficult, but PRGS seems to be the most promising response evaluation modality.

Feasibility and Safety of Oxaliplatin-Based Pressurized Intraperitoneal Aerosol Chemotherapy With or Without Intraoperative Intravenous 5-Fluorouracil and Leucovorin for Colorectal Peritoneal Metastases: A Multicenter Comparative Cohort Study

BACKGROUND

This retrospective multicenter cohort study compared the feasibility and safety of oxaliplatin-based pressurized intraperitoneal aerosol chemotherapy (PIPAC-Ox) with or without intraoperative intravenous 5-fluorouracil (5-FU) and leucovorin (L).

METHODS

Our study included consecutive patients with histologically proven unresectable and isolated colorectal peritoneal metastases (cPM) treated with PIPAC-Ox in seven tertiary referral centers between January 2015 and April 2020. Toxicity events and oncological outcomes (histological response, progression-free survival, and overall survival) were compared between patients who received intraoperative intravenous 5-FU/L (PIPAC-Ox + 5-FU/L group) and patients who did not (PIPAC-Ox group).

RESULTS

In total, 101 patients (263 procedures) were included in the PIPAC-Ox group and 30 patients (80 procedures) were included in the PIPAC-Ox + 5-FU/L group. Common Terminology Criteria for Adverse Events v4.0 grade 2 or higher adverse events occurred in 48 of 101 (47.5%) patients in the PIPAC-Ox group and in 13 of 30 (43.3%) patients in the PIPAC-Ox + 5-FU/L group (p = 0.73). The complete histological response rates according to the peritoneal regression grading score were 27% for the PIPAC-Ox + 5-FU/L group and 18% for the PIPAC-Ox group (p = 0.74). No statistically significant differences were observed in overall or progression-free survival between the two groups.

CONCLUSIONS

The safety and feasibility of PIPAC-Ox + 5-FU/L appears to be similar to the safety and feasibility of PIPAC-Ox alone in patients with unresectable cPM. Oncological outcomes must be evaluated in larger studies.

Patient-reported outcomes during repetitive oxaliplatin-based pressurized intraperitoneal aerosol chemotherapy for isolated unresectable colorectal peritoneal metastases in a multicenter, single-arm, phase 2 trial (CRC-PIPAC)

BACKGROUND

CRC-PIPAC prospectively assessed repetitive oxaliplatin-based pressurized intraperitoneal aerosol chemotherapy (PIPAC-OX) as a palliative monotherapy (i.e., without concomitant systemic therapy in between subsequent procedures) for unresectable colorectal peritoneal metastases (CPM). The present study explored patient-reported outcomes (PROs) during trial treatment.

METHODS

In this single-arm phase 2 trial in two tertiary centers, patients with isolated unresectable CPM received 6-weekly PIPAC-OX (92 mg/m²). PROs (calculated from EQ-5D-5L, and EORTC QLQ-C30 and QLQ-CR29) were compared between baseline and 1 and 4 weeks after the first three procedures using linear mixed modeling with determination of clinical relevance (Cohen's D ≥ 0.50) of statistically significant differences.

RESULTS

Twenty patients underwent 59 procedures (median 3 [range 1-6]). Several PROs solely worsened 1 week after the first procedure (index value - 0.10, p < 0.001; physical functioning - 20, p < 0.001; role functioning - 27, p < 0.001; social functioning - 18, p < 0.001; C30 summary score - 16, p < 0.001; appetite loss + 15, p = 0.007; diarrhea + 15, p = 0.002; urinary frequency + 13, p = 0.004; flatulence + 13, p = 0.001). These PROs returned to baseline at subsequent time points. Other PROs worsened 1 week after the first procedure (fatigue + 23, p < 0.001; pain + 29, p < 0.001; abdominal pain + 32, p < 0.001), second procedure (fatigue + 20, p < 0.001; pain + 21, p < 0.001; abdominal pain + 20, p = 0.002), and third procedure (pain + 22, p < 0.001; abdominal pain + 22, p = 0.002). Except for appetite loss, all changes were clinically relevant. All analyzed PROs returned to baseline 4 weeks after the third procedure.

CONCLUSIONS

Patients receiving repetitive PIPAC-OX monotherapy for unresectable CPM had clinically relevant but reversible worsening of several PROs, mainly 1 week after the first procedure.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT03246321; Netherlands trial register: NL6426.

Histological regression of gastrointestinal peritoneal metastases after systemic chemotherapy

Objectives

Peritoneal metastases (PM) are relatively resistant to systemic chemotherapy, and data on histological response to therapy is rare. The aim of this study was to quantify the treatment response of PM after systemic chemotherapy.

Methods

Retrospective monocentric cohort study of 47 consecutive patients with PM from gastrointestinal origin undergoing surgery (cytoreduction: CRS + Hyperthermic IntraPEritoneal Chemotherapy [HIPEC] or Pressurized IntraPeritoneal Aerosol Chemotherapy [PIPAC]) after prior systemic chemotherapy from 1.2015 to 3.2019. Tumor response was assessed using the 4-scale Peritoneal Regression Grading System (PRGS) (4: vital tumor to 1: complete response).

Results

Patients had a median of 2 (range: 1-7) lines and 10 (3-39) cycles of prior systemic chemotherapy. A median of four biopsies (range: 3-8) was taken with a total of 196 analyzed specimens. Twenty-four biopsies (12%) showed no histological regression (PRGS4), while PRGS 3, two and one were diagnosed in 37 (19%), 39 (20%), and 69 (49%) specimens, respectively. A significant heterogeneity was found between peritoneal biopsies in 51% patients. PRGS correlated strongly with peritoneal spread (PCI, p<0.0001), and was improved in patients with more than nine cycles of systemic chemotherapy (p=0.04). Median survival was higher in patients with PRGS < 1.8 (Quartiles one and 2) than higher (Q3 and Q4), but the difference did not reach significance in this small cohort.

Conclusions

PRGS is an objective too to describe histological response of PM of GI origin after systemic chemotherapy. This response differs significantly between patients, allowing to distinguish between chemosensitive and chemoresistant tumors.

Clinical Outcome for Patients Managed with Low-Dose Cisplatin and Doxorubicin Delivered as Pressurized Intraperitoneal Aerosol Chemotherapy for Unresectable Peritoneal Metastases of Gastric Cancer

BACKGROUND

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is increasingly used to manage gastric cancer peritoneal metastasis (GCPM).

METHODS

This study analyzed a prospective database of GCPM patients treated with cisplatin and doxorubicin PIPAC (PIPAC-C/D). The outcome criteria were adverse events, pathologic response [peritoneal regression grading score (PRGS)], and overall survival (OS).

RESULTS

The PIPAC-C/D procedure was scheduled for 144 patients with a median age of 57 years (range 22-88 years). Access to the abdominal cavity for the first PIPAC failed in 11 patients (7.7 %). A total of 296 procedures were performed for 131 patients. Of the 144 patients, 52 (36.1%) underwent one PIPAC, 32 (22.2%) underwent two PIPACs, 24 (16.7%) underwent three PIPACs, and 21 (14.6%) underwent four or more PIPACs. The overall morbidity/mortality was grade 1 for 22 patients (15.3%), grade 2 for 32 patients (22.2%), grade 3 for 7 patients (4.9%), grade 4 for no patients (0%), and grade 5 for 2 patients (1.4%). Of the 37 patients who had three or more PIPACs eligible for histopathologic response analysis, 27 (73%) had major or complete regression (PRGS 1/2). A median OS of 11 months (range 0-61 months) for the total study population and 16 months (range 2-61 months) for the patients with three or more PIPACs was observed. For 10 patients (7%) who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, the median OS was 15 months (minimum, 4 months; maximum, 27 months). Multivariate analysis showed three or more PIPACs to be an independent prognostic factor for improved OS (hazard ratio, 0.36; p < 0.0001).

CONCLUSIONS

Repetitive PIPAC-C/D ± systemic chemotherapy is associated with low morbidity and mortality rates. Prospective randomized trials are needed to confirm whether three or more PIPAC-C/Ds improve clinical outcome.