Evaluation of a new histological grading system for assessing the response to chemotherapy of peritoneal metastases from colorectal cancer: A mouse model study

Tumoral and circulating genomic landscape inform survival differences in colorectal carcinomatosis

Colorectal peritoneal metastases (CPM) are the third most common site of metastatic spread of colorectal cancer and are associated with worse survival than other sites of metastatic disease. In recent years tumoral circulating tumoral DNA (ctDNA) mutational status has been increasingly utilized in clinical decision making for metastatic colorectal cancer patients despite its utility in CPM being poorly understood. Here we describe standard of care performed mutational profiles and associated outcomes for unresectable CPM patients, with a contextual comparison to 160 unresected colorectal liver metastases (CLM) patients. Of 508 patients, 288 (57 %) had CPM alone and 220 (43 %) had CPM with extraperitoneal metastases. Patients with synchronous CPM and CLM had worse overall survival (HR 1.67 [95 %CI 1.26-2.22]). Mutations in ctDNA were noted in 110/145 (75.9 %) of CPM patients, with mutations in KRAS or PIK3CA ctDNA being associated with worse survival. Importantly, the association between tumoral mutational profile and survival differed by site of metastatic disease. The prognostic significance of specific mutations, particularly BRAF and KRAS, differs between patients with CPM and CLM, and supports the distinct biology of these metastatic sites and the importance of tissue and circulating genomic profiling to risk-stratify these patients according to site of metastasis.

Evaluation of the prognostic impact of pathologic tumor regression grade on patients with colorectal cancer after preoperative chemoradiotherapy

BACKGROUND

The prognostic value of the pathological response to preoperative chemoradiotherapy (CRT) in rectal cancer (RC) remains unknown.

OBJECTIVES

We aimed to assess the predictive value of the response to CRT that was derived from an evaluation of the histological findings (whole-section vs. representative-section sampling) and attempted to determine an objective cut-off value for the tumor regression grade (TRG).

METHODS

We examined the association of the TRG with the outcomes (recurrence-free survival [RFS] and overall survival [OS]) of 78 patients with RC. Patients with RC treated with preoperative CRT were divided into development (30 cases) and validation (48 cases) cohorts. The TRG was classified as grades I (Ia, Ib), II, and III. The cut-off value was determined by receiver operating characteristic (ROC) curve analysis.

RESULTS

The TRG determined from whole-section sampling versus representative-section sampling was more strongly correlated with patient survival. We found that in both cohorts, patients with a cut-off value of <73% had a poor prognosis. Finally, the cut-off value was found to be an independent predictive factor in both univariate and multivariate analysis.

CONCLUSIONS

The TRG that was used to evaluate patients with RC who underwent preoperative CRT was an independent prognostic factor for outcome.

Thermosensitive methyl-cellulose-based injectable hydrogel carrying oxaliplatin for the treatment of peritoneal metastasis in colorectal cancer

Advanced colorectal cancer (CRC) with peritoneal metastasis (PM) is a highly aggressive malignancy with poor prognosis. Systematic chemotherapy and local treatments are the primary therapeutic approaches. However, systemic chemotherapy is limited by low accumulation of drugs at the tumor site and systemic toxicity. Local treatments include cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). However, CRS faces challenges related to incomplete tumor resection, while HIPEC is restricted by the uneven distribution of drugs and potential complications. Herein, a thermosensitive methyl-cellulose-based injectable hydrogel carrying oxaliplatin (OXA) was synthesized to improve this situation. Specifically, methyl cellulose (MC) coagulated into a hydrogel, and OXA was loaded into the MC hydrogel to construct the OXA-MC hydrogel. We explored the OXA-MC hydrogel for the treatment of PM in CRC. The results demonstrated that the OXA-MC hydrogel had favorable biocompatibility and thermo-sensitivity and could act as a local slow-release drug carrier. Moreover, in a CT-26 tumor-bearing model, it showed a remarkable anti-tumor effect by inhibiting proliferation and promoting apoptosis. Additionally, transcriptome analysis indicated that the OXA-MC hydrogel might be involved in the regulation of the PI3K-AKT signaling pathway. In summary, we successfully prepared the OXA-MC hydrogel and provided a valid approach in the treatment of PM in CRC, which lays a foundation for other PM treatments.

Histological tumor response predicts clinical outcome in patients with colorectal peritoneal metastasis treated with preoperative chemotherapy followed by cytoreduction and HIPEC

Objectives

Up to one quarter of the patients with colorectal cancer (CRC) develop peritoneal carcinomatosis (PM). The aims of this retrospective study were to characterize the histological response of the PM of CRC to preoperative chemotherapy and evaluate the potential prognostic value, in terms of survival.

Methods

This retrospective unicentric study evaluated a group of 30 patients treated between 2010 and 2020 at the São João University Hospital Center with preoperative chemotherapy, followed by cytoreduction surgery plus hyperthermic intraperitoneal chemotherapy. The evaluation of the histological response was done using two scores: the tumor regression grading (TRG) and the peritoneal regression grading score (PRGS).

Results

Mean post-procedure survival is higher in the PRGS 1–2 group (74.19 months) vs. the PRGS 3–4 group (25.27 months) (p=0.045), as well as in the TRG 1–2 group (74.58 months) vs. TRG 4–5 (25.27 months) (p=0.032). As for progression-free survival (PFS), the PRGS 1–2 group had a mean value of 58.03 months vs. PRGS 3–4 which had 11.67 months (p=0.002). Similar was observed with the TRG 1–2 group, which had a mean PFS of 61.68 months vs. TRG 4–5 with 11.67 months (p=0.003).

Conclusions

A better histological response to preoperative chemotherapy, represented as a lower PRGS and TRG value, is associated with longer post-procedure survival and progression-free survival in this group of patients. That is, these two scores have prognostic value.

Effect of 5-Fluoro-Uracile + Oxaliplatin chemotherapy on the histological response of PEritoneal and hePatIc corectal metasTases in a mOuse model: PEPITO experimental study

BACKGROUND

The histological responses (HRs) after systemic chemotherapy should be used to determine the optimal management of patients with peritoneal and liver metastasis from colorectal cancer (cPM, cLM), in curative intent. We aimed to compare HRs of cPM and cLM in metastatic mice model after chemotherapy.

METHODS

Colon carcinoma CT26-luc cells were transplanted into syngeneic BALB/c mice by intraperitoneal (leading to cPM), intrasplenic (leading to cLM), or intraperitoneal + intrasplenic (leading to cPM cLM) injections and follow up using bioluminescence during 21 days. Bi-chemotherapeutic treatment (5-fluorouracil at D11, D17, and D20, and oxaliplatin at D13 and D19) was administered. The peritoneal cancer index (PCI) and HRs using Peritoneal Regression Grading Score (PRGS) and Tumor Regression Grade (TRG) classifications were analyzed at day 21.

RESULTS

Unlike bioluminescence rate, PCI was reduced after chemotherapy in all treated groups with cPM comparatively to controls (33 ± 9.5 vs. 19.8 ± 5, p = 0.002 for cPM groups; 37.7 ± 3.6 vs. 25.2 ± 10.8, p = 0.0003 for the cPM + cLM groups). The complete or major HR rates were higher in all treated groups compared to the non-treated mice (cPM, 2.29 ± 0.55 vs. 3.56 ± 1.01; cLM, 2.43 ± 1.89 vs. 4.86 ± 0.378; cPM + cLM, 2.73 ± 1.03 and 2.2 ± 0.65 vs. 3.79 ± 0.75 and 4.36 ± 0.43). The complete or major HR rates after chemotherapy were similar across the metastatic sites in 60% for cPM + cLM group.

CONCLUSIONS

The efficacy of chemotherapeutic treatment did not differ between the metastatic sites. Murine models are suitable in histological analyses to study tumor development and regression but clinical study will be performed to confirm these results.

Phase I study of intraperitoneal aerosolized nanoparticle albumin based paclitaxel (NAB-PTX) for unresectable peritoneal metastases

Background

Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a novel method to treat patients with peritoneal metastases (PM). We aimed to study the tolerability, safety, pharmacokinetics, and tumour response of nanoparticle albumin bound paclitaxel (NAB-PTX) during PIPAC in a Phase I study.

Methods

Eligible patients with biopsy-proven PM from ovarian, breast, gastric, hepatobiliary, or pancreatic origin underwent three PIPAC treatments using NAB-PTX with a four-week interval. The dose of NAB-PTX was escalated from 35 to 140 mg/m² using a Bayesian design to estimate the maximum tolerated dose (MTD).

Findings

Twenty-three patients were included; thirteen (65%) patients combined PIPAC therapy with continued systemic chemotherapy. The most frequent toxicities were liver toxicity and anaemia. Treatment resulted in seven (35%) responders, six (30%) non-responders and seven (35%) patients with stable PM. Systemic absorption of NAB-PTX was slow, with median peak plasma concentrations reached after 3 to 4 h. Median NAB-PTX tumour tissue concentrations suggested accumulation: 14.6 ng/mg, 19.2 ng/mg and 40.8 ng/mg after the first, second and third PIPAC procedure respectively. EORTC QoL and VAS scores remained stable. Overall survival after one year was 57%.

Interpretation

PIPAC with NAB-PTX results in a favourable PK profile and promising anticancer activity in patients with unresectable PM. The MTD and recommended Phase II clinical trial dose are 140 mg/m². In patients with impaired hepatobiliary function, a dose of 112.5 mg/m² is recommended.

Funding

Kom op tegen Kanker (Flemish League against Cancer).

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.

10 ns PEFs induce a histological response linked to cell death and cytotoxic T-lymphocytes in an immunocompetent mouse model of peritoneal metastasis

PURPOSE

The application of nanosecond pulsed electric fields (nsPEFs) could be an effective therapeutic strategy for peritoneal metastasis (PM) from colorectal cancer (CRC). The aim of this study was to evaluate in vitro the sensitivity of CT-26 CRC cells to nsPEFs in combination with chemotherapeutic agents, and to observe the subsequent in vivo histologic response.

METHODS

In vitro cellular assays were performed to assess the effects of exposure to 1, 10, 100, 500 and 1000 10 ns pulses in a cuvette or bi-electrode system at 10 and 200 Hz. nsPEF treatment was applied alone or in combination with oxaliplatin and mitomycin. Cell death was detected by flow cytometry, and permeabilization and intracellular calcium levels by fluorescent confocal microscopy after treatment. A mouse model of PM was used to investigate the effects of in vivo exposure to pulses delivered using a bi-electrode system; morphological changes in mitochondria were assessed by electron microscopy. Fibrosis was measured by multiphoton microscopy, while the histological response (HR; hematoxylin-eosin-safran stain), proliferation (KI67, DAPI), and expression of immunological factors (CD3, CD4, CD8) were evaluated by classic histology.

RESULTS

10 ns PEFs exerted a dose-dependent effect on CT-26 cells in vitro and in vivo, by inducing cell death and altering mitochondrial morphology after plasma membrane permeabilization. In vivo results indicated a specific CD8+ T cell immune response, together with a strong HR according to the Peritoneal Regression Grading Score (PRGS).

CONCLUSIONS

The effects of nsPEFs on CT-26 were confirmed in a mouse model of CRC with PM.

Prognostic impact of combined progression index based on peritoneal grading regression score and peritoneal cytology in peritoneal metastasis

AIMS

The peritoneal regression grading score (PRGS) and peritoneal cytology (PC) assess response to chemotherapy in peritoneal metastasis (PM) in a setting of palliative treatment by pressurized intraperitoneal aerosol chemotherapy (PIPAC). Progression has been defined as an increase of PRGS between first and third PIPAC procedures (iPRGS). iPRGSand positive peritoneal cytology were not associated with prognostic impact. These results may be explained by a lack of statistical power. Also, it is not known whether the mean or the highest PRGS among taken peritoneal biopsies bears the highest clinical value. We therefore conducted the largest prospective study to investigate the prognostic impact of PGRS, PC, and their combination, designated as combined progression index (CPI).

METHODS AND RESULTS

Patients with PM who underwent >3 PIPAC (n = 112) between December 2016 and February 2019 were prospectively included. A significant difference in OS and PFS according to CPI (used highest value of PRGS) was found (OS: CPI-, 83.3, 95% CI [49.8; NA] vs. CPI+, 48.1, 95% CI [38.5; 66.4] months; and PFS (respectively, 59.7, 95% CI [43.0; 96.0] vs. 33.7, 95% CI [30.4; 44.2] months). PRGS or PC had no independent prognostic impact. CPI+ was an independent predictor of worse prognosis, in OS (HR = 5.24, 95% CI [2.07; 13.26]), and PFS (HR = 4.41, 95% CI [1.40; 13.88]).

CONCLUSIONS

The CPI based on highest PRGS and PC was found to be independently associated with a worse prognosis for OS and for PFS in the setting of peritoneal metastasis. These results indicate that it should be of interest to systematically take peritoneal fluid for cytological examination and to implement the CPI in the therapeutic decision-making process in the context of PIPAC.

Systematic review of patient reported outcomes (PROs) and quality of life measures after pressurized intraperitoneal aerosol chemotherapy (PIPAC)

Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) constitutes a recently described surgical technique to administer chemotherapy directly to the peritoneum, under pressure, for patients with peritoneal metastasis (PM). The purpose of an oncological treatment is to improve survival but without altering the patient's quality of life. The aim of this review was to evaluate patient-reported outcomes (PRO) after PIPAC for patients with PM. This systematic review was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Between January 1, 2013, and January 1, 2020, studies were selected according to the following criteria: "pressurized intraperitoneal aerosol chemotherapy" OR "PIPAC" AND "patient-reported outcomes" OR "PRO" OR "Quality of life". In this review, 959 PIPAC and five PITAC (Pressurized IntraThoracic Aerosol Chemotherapy) were performed in 425 patients. We highlight the prominent application of generic EORTC QLQ-C30 followed by SF-36 in this review. The PROs according to the EORTC-QLQ-C30 global health score and based on symptom and function scores were stable across most studies. Moreover, PIPAC has improved the PRO of altered patients in two studies. Among 425 patients, the mortality rate was 0.7% and adverse events of Common Terminology Criteria of Adverse Events grade 3 and grade 4 were 9.6% and 1.6%, respectively. We synthesised current research on PROs among patients with PM. This review increases our understanding of the PIPAC strategy from the patient perspective. The implementation of PROs can be complex but will be essential in delivering quality care.