Survival outcomes for patients with colorectal cancer with synchronous liver only metastasis

BACKGROUND

Colorectal cancer with synchronous liver-only metastasis is managed with a multimodal approach, however, optimal sequencing of modalities remains unclear.

METHODS

A retrospective review of all consecutive rectal or colon cancer cases with synchronous liver-only metastasis was conducted from the South Australian Colorectal Cancer Registry from 2006 to 2021. This study aimed to investigate how order and type of treatment modality affects overall survival.

RESULTS

Data of over 5000 cases were analysed (n = 5244), 1420 cases had liver-only metastasis. There were a greater number of colon than rectal primaries (N = 1056 versus 364). Colonic resection was the preferred initial treatment for the colon cohort (60%). In the rectal cohort, 30% had upfront resection followed by 27% that had chemo-radiotherapy as 1st line therapy. For the colon cohort, there was an improved 5-year survival with surgical resection as initial treatment compared to chemotherapy (25% versus 9%, P < 0.001). In the rectal cohort, chemo-radiotherapy as the initial treatment was associated with an improved 5-year survival compared to surgery or chemotherapy (40% versus 26% versus 19%, P = 0.0015). Patients who were able to have liver resection had improved survival, with 50% surviving over 5 years compared to 12 months in the non-resected group (P < 0.001). Primary rectal KRAS wildtype patients who underwent liver resection and received Cetuximab had significantly worse outcomes compared to KRAS wildtype patients who did not (P = 0.0007).

CONCLUSIONS

Where surgery is possible, resection of liver metastasis and primary tumour improved overall survival. Further research is required on the use of targeted treatments in patients undergoing liver resection.

Phase 1 trial of intraperitoneal paclitaxel in combination with intravenous cisplatin and oral capecitabine in patients with advanced gastric cancer and peritoneal metastases (IPGP study)

AIMS

Gastric cancer with peritoneal involvement has a poor prognosis. Intraperitoneal (IP) paclitaxel has shown promising results in these patients. However, this approach has only been studied in the Asian population, and in combination with S-1. We investigated the maximum tolerated dose of IP paclitaxel, with a standard chemotherapy combination, in the Australian population.

METHODS

The study of the population included metastatic human epidermal growth factor receptor 2 (HER2) negative gastric adenocarcinoma with peritoneal involvement. Treatment included six 21-day cycles of cisplatin (80 mg/m² IV, day 1) plus capecitabine (1000 mg/m² PO BD, days 1-14) plus IP paclitaxel (days 1 and 8). IP paclitaxel doses for cohort 1-3 were 10, 20, and 30 mg/m² , respectively, in a 3 + 3 standard dose-escalation design.

RESULTS

Fifteen patients were enrolled of which 6 were female and the median age was 63. Two patients developed dose-limiting toxicities. No grade 4/5 toxicities were recorded. The maximum tolerated dose was not reached. Therefore, as defined by the study protocol, the recommended phase-2 dose for IP paclitaxel was determined to be 30 mg/m² . The 12-month survival rate was 46.7%, and the median survival was 11.5 months (interquartile range [IQR]: 15.3-6.9).

CONCLUSIONS

IP paclitaxel is safe in combination with cisplatin and capecitabine and the recommended phase-2 dose is 30 mg/m² .

Metastasectomy and BRAF mutation; an analysis of survival outcome in metastatic colorectal cancer

BACKGROUND

Resection of oligometastases improves survival in metastatic colorectal cancer (mCRC). It is unclear whether the benefit is consistent for BRAF V600E mutant (MT) and wild type (WT) mCRC. This retrospective analysis explores the influence of BRAF MT on survival after metastasectomy.

METHODS

Overall survival (OS) and recurrence-free survival (RFS) for BRAF MT and WT mCRC were evaluated. Survival was also analyzed in the cohort of BRAF MT with or without metastasectomy.

RESULTS

Five hundred and thirteen patients who had undergone metastasectomy were identified, 6% were BRAF-MT. Median age 63. Median OS in BRAF MT vs WT: 25.7 vs 48.5 months (hazard ratio [HR] 1.95; 1.18-3.22). However, difference was not significant in a multivariate model. Right primary tumor, intact primary, >1 metastatic site, non-R0 resection, peritoneal metastasis, and synchronous metastasis were independent predictors of worse OS. Among 364 patients with RFS data there was no difference between BRAF MT and WT (16 vs 19 months, p=0.09). In another cohort of 158 BRAF-MT patients, OS was significantly better after metastasectomy compared to "no metastasectomy" (HR 0.34; 0.18-0.65, P= 0.001). Proficient mismatch repair status showed a trend toward worse survival after metastasectomy in BRAF MT (HR 1.71, P = 0.08).

CONCLUSION

OS did not differ after metastasectomy between BRAF MT and WT in a multivariate model. Median OS was >2 years in this study after metastasectomy among BRAFV600E MT patients suggesting a survival benefit of metastasectomy in this group where systemic therapeutic options are limited. Metastasectomy may be considered in carefully selected BRAF-MT patients.

Treatment effects (TEs) of EGFR monoclonal antibodies (mAbs) in metastatic colorectal cancer (mCRC) patients (pts) with KRAS, NRAS, and BRAF mutation (MT) status: Individual patient data (IPD) meta-analysis of randomized trials from the ARCAD database

4090

Background: EGFR mAbs have become incorporated into clinical practice for the management of mCRC over the last decade. KRAS and NRAS mutations are used as predictive biomarkers and BRAF V600E mutations are associated with an adverse prognosis. The observed TE within biomarker subpopulations has varied between studies. Methods: IPD from randomized trials with head-to-head comparison between EGFR mAb versus no EGFR mAb (chemotherapy alone or BSC) in mCRC, across all lines of therapy (first, second and later), were pooled. Biomarker subpopulations are defined in the table. Overall survival (OS) and progression-free survival (PFS) were compared between groups by Cox model, stratified by studies and adjusted by age, gender, and performance status. TEs were estimated by adjusted hazard ratio (HRadj) and 95% confidence interval (CI). Within each biomarker subgroup, EGFR mAb efficacy was explored according to multiple exploratory factors, including line of therapy, type of backbone chemo, gender, sidedness and site of metastasis. Interaction tests were performed. P-values < 0.01 were considered statistically significant to account for multiple comparisons. Results: 5729 pts from 8 studies with data available for ≥ 1 biomarker were analysed. PFS benefits (median 9.2 mos in EGFR mAbs, 8.0 mos in no EGFR mAbs) were confirmed in triple-WT pts, but not for OS (refer to table). No OS/PFS benefits were observed for pts with any of the MT tumors. Exploratory analyses showed a potential detrimental TE of EGFR mAbs in KRAS MT mCRC with liver metastasis (OS: HRadj 1.22, p = .003, pinteraction .0056; PFS: HRadj 1.24, p = .0009, pinteraction .0008). These results were confirmed within the subgroup of pts with all 3 biomarkers available. Conclusions: This is the largest IPD analysis to explore the predictive value of RAS/BRAF biomarkers in mCRC. Our findings demonstrate that there is no evidence of efficacy of EGFR mAbs in KRAS, BRAF and/or NRAS MT mCRC. EGFR mAbs might have a detrimental effect in KRAS MT mCRC with liver metastases. [Table: see text]

Metastasectomy and BRAF mutation: An analysis of survival outcome in metastatic colorectal cancer

3531

Background: Surgical resection of oligometastases improves survival in metastatic colorectal cancer (mCRC). It is unclear whether such benefit is consistently observed for BRAF V600E mutant (MT) and wild type (WT) mCRC. We conducted a retrospective analysis to explore the influence of BRAF mutation status on survival outcomes after metastasectomy. Methods: Data collected from two large prospective population databases in Australia (Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) and South Australian cancer registry). Overall survival (OS) and recurrence free survival (RFS) for BRAF MT and WT mCRC were evaluated by Kaplan-Meier method and compared by log-rank test. Results: 513 patients who had undergone metastasectomy were identified, 6% were BRAF MT. Median age 63. Metastasectomy rate was lower in BRAF MT (13 v 27%). In BRAF WT, 4% underwent resection of metastases (mets) in >1 organ at diagnosis and 5% had 3 or 4 metastasectomies versus none in BRAF MT. Median OS in BRAF MT v WT: 25.7 v 48.5 months (HR 1.95; 1.18-3.22). In a multivariate model adjusting for variables which were significant on univariate analysis, OS differences were not statistically significant. Right primary tumor, intact primary, >1 metastatic sites at diagnosis, non R0 resection, peritoneal mets and synchronous mets were independent predictors of worse OS. Among 364 patients with RFS data there was no difference between BRAF MT and WT (16 v 19 months, p=0.09). Rate of downsizing was higher with triplet chemo than doublet +/- bevacizumab or doublet/EGFR in BRAF WT (50 v 30%) as well as MT (33 v 11%). Conclusions: Median OS was > 2 years in BRAF MT V600E after metastasectomy in this study consistent with an OS benefit. OS did not differ after metastasectomy between BRAF MT and WT in a multivariate model. Presence of BRAF MT should not impact patient selection for metastasectomy.[Table: see text]

The survival outcome of patients with metastatic colorectal cancer based on the site of metastases and the impact of molecular markers and site of primary cancer on metastatic pattern

BACKGROUND

Pattern of spread in patients with metastatic colorectal cancer (mCRC) is variable and may reflect different biology in subsets of patients. This is a retrospective study to explore the outcome of patients with mCRC based on their site of metastasis at diagnosis and to explore the association between tumor characteristics [KRAS/RAS, BRAF, mismatch repair (MMR) status, site of primary] and the site of metastasis.

METHODS

Patients from two Australian databases were divided into six groups based on site of metastasis at time of diagnosis of metastatic disease; lung-only, liver-only, lymph node-only or any patients with brain, bone or peritoneal metastases. Primary endpoint was overall survival (OS) of each cohort compared with the rest of the population. A Mantel-Haenszel chi-squared test used to explore the association between site of metastasis and selected tumor characteristics.

RESULTS

Five thousand nine hundred and sixty-seven patients were included. In a univariate analysis, median OS was significantly higher when metastases were limited to lung or liver and shorter for those with brain, bone or peritoneal metastases (p < .001) in both datasets. BRAF mutation was strongly associated with peritoneal metastases (relative risk = 1.8, p < .001) with lower incidence of lung (RR = 0.3, p = .004) and liver (RR = 0.7, p = .005) limited metastases. Lung-only metastases were more frequent with KRAS/RAS mutation (RR = 1.4, p = .007). Left colon tumors were associated with bone (RR = 1.6, p < .001) and lung-only metastases (RR = 2.3, p = .001) while peritoneal spread was less frequent compared with right colon tumors (RR = 0.6, p < .001). Rectal cancer was associated with brain, bone and lung metastases (RR = 1.7; p = .002, 1.7; p < .001, 2.0; p < .001). Liver-only metastases were less frequent in deficient MMR tumors (RR = 0.7, p = .01).

CONCLUSION

Survival duration with mCRC is related to the site of metastases with lung limited disease showing a more favorable survival outcome compared to other single metastatic site disease. The BRAF mutation and primary rectal cancer were associated with poor prognostic metastatic sites.

Costs of paying higher prices for equivalent effects on the Pharmaceutical Benefits Scheme

Objective The aims of the present study were to illustrate and discuss the effects of the non-maintenance of equivalent prices when the comparators of pharmaceuticals listed on the Pharmaceutical Benefits Schedule (PBS) on a cost-minimisation basis come off-patent and are subject to statutory price reductions, as well as further potential price reductions because of the effects of price disclosure. Methods Service use, benefits paid, and price data were analysed for a selected sample of pharmaceuticals recommended for listing on a cost-minimisation basis between 2008 and 2011, and their comparators, to estimate the cost savings to the PBS of maintaining equivalent prices. Results Potential cost savings for 12 pharmaceuticals, including alternative compounds and combination products across nine therapeutic groups, ranged from A$570 000 to A$40 million to April 2015. Potential savings increased significantly following recent amendments to the price disclosure process. Conclusions Potential savings from maintaining equivalent prices for all pharmaceuticals listed on the PBS on a cost-minimisation basis could be over A$500 million per year. Actions to reduce these costs can be taken within existing policy frameworks, but legislative and political barriers may need to be addressed to minimise these costs, which are incurred by the taxpayer for no additional benefit. What is known about the topic? Pharmaceuticals listed on the PBS must provide value for money. Many pharmaceuticals achieve this by demonstrating equal effectiveness to an already listed pharmaceutical and requesting the same price as this comparator; that is, listing on a cost-minimisation basis. When the comparator moves off-patent, the price of the still-patented pharmaceutical is protected, whereas the off-patent drug is subject to price disclosure and often steep price reductions. What does this paper add? This paper adds to recent evidence on the costs to government of paying different prices for two or more pharmaceuticals that are equally effective. Between 2008 and 2011, the direct comparators for 68 pharmaceuticals listed on a cost-minimisation basis have moved onto the price disclosure list. Across 12 of these listings, the potential cost savings in the 10 months to April 2015 were A$73 million. What are the implications for practitioners? The PBS costs the Australian government over A$9 billion per year. Annual savings over A$500 million per year could be achieved by maintaining cost-minimisation across equally effective pharmaceuticals. This would improve the efficiency of the PBS at no risk to patients. Legislation is required to remove the existing F1 and F2 categorisation of listed pharmaceuticals, but the proposed changes would remove the need for therapeutic group premiums and simplify the pricing of PBS items.

Transgene expression in dendritic cells to induce antigen-specific cytotoxic T cells in healthy donors

Immunization with specific tumor-associated antigen (Ag) (TAA)-pulsed dendritic cells (DC) has proven to be efficacious in a variety of animal models and is being investigated for the treatment of cancer patients. Use of DC pulsed with specific peptides or transfected with TAA genes has been a focused area of investigation for the induction of potent tumor and viral immune responses. In this study we demonstrate transgene expression, including expression of the MART-1 gene, in DC transfected with plasmid DNA and cationic liposome complexes. These transiently transfected DC, derived from healthy donor monocytes cultured with granulocyte macrophage colony-stimulating factor and interleukin-4, express the transgene and can stimulate naive CD8+ T cells to elicit an antitumor immune response. These cytotoxic T lymphocytes (CTL) were capable of recognizing both known and unknown TAA epitopes and were able to exhibit cytolytic activity against human histocompatibility leukocyte Ag-matched tumor cells expressing the Ag. In addition to their cytolytic function, the CTL displayed an oligoclonal T-cell receptor repertoire, indicating that the presented Ag induced alterations in the T-cell population. The ability to induce tumor-specific CTL in vitro using gene-modified DC transiently expressing TAAs demonstrates the potential use of these Ag-presenting cells to generate future in vivo cancer vaccine strategies.

Dendritic cells pulsed with CEA peptide induce CEA-specific CTL with restricted TCR repertoire

The human carcinoembryonic antigen (CEA), which is expressed in several cancer types is a potential target for antigen-specific immunotherapy. In this study, we show that dendritic cells (DC) pulsed with an HLA class I restricted CEA cytotoxic T lymphocyte (CTL) peptide epitope can stimulate T cells to kill CEA peptide loaded T2 target cells as well as CEA expressing tumor lines in the presence of interleukin-7 (IL-7) in an HLA-restricted manner. This has been demonstrated for carcinoma patients as well as healthy donors. The DC-CEA + IL-7 stimulated cultures contained predominantly CD3+CD8+CD56- cells indicative of MHC class I restricted CTL. In addition, DC-CEA + IL-7 stimulated cells showed higher levels of CD69 expression compared with cells stimulated with IL-7 alone, implying an activated phenotype. When the T-cell receptor (TCR) from CTL cultures stimulated with DC-CEA + IL-7 was analyzed, an oligoclonal pattern of expression was found for certain V beta subfamilies compared with the polyclonal patterns shown by IL-7 or phytohemagglutinin stimulated T cells from the same donors. This TCR restriction appeared to be maintained and enhanced after additional rounds of restimulation with DC-CEA + IL-7. The association between cytotoxicity and TCR restriction suggests that TCR analysis may be useful as an in vitro indicator to monitor alterations in the T-cell population in response to antigen-specific immunotherapies.

Gene modification of primary tumor cells for active immunotherapy of human breast and ovarian cancer

We have previously shown that cationic liposomes facilitate adeno-associated virus (AAV) plasmid transfections of primary and cultured cell types. To test the clinical feasibility of using genetically modified tumor vaccines for the treatment of breast and ovarian cancers, we have constructed an expression plasmid pMP6IL2 and investigated the use of liposome-mediated gene delivery into primary, uncultured human breast and ovarian tumor cells to produce interleukin 2 (IL-2)-secreting tumor cells. We have demonstrated significant levels of IL-2 expression in tumor cell lines and primary breast and ovarian tumor cells using this AAV-based expression plasmid complexed to cationic liposomes. Transfections with the non-AAV plasmid containing the identical expression cassette as the AAV plasmid induced IL-2 expression in the tumor cell line but failed to produce IL-2 in primary tumor cells. Significant levels of IL-2 were induced with the AAV plasmid regardless of liposome compositions used for transfection. The transfected breast cell line and primary tumor cells were able to express the transgene product for up to 28 days after lethal radiation. The transfection efficiency was comparable for both the tumor cell line and primary tumor cells and ranged from 20 to 50% for both cell types as assessed by intracellular IL-2 staining. Although the primary tumor cell preparations consist of mixed population of cells, at least 40% of the tumor cells expressed the transgene as assessed by immunostaining for IL-2. The ability to efficiently express transgenes in freshly isolated, nondividing tumor cells may potentiate active immunotherapy strategies for gene-based cancer treatment.