PRIMARY TUMOR RESECTION OR SYSTEMIC THERAPY AS PALLIATIVE TREATMENT FOR PATIENTS WITH ISOLATED SYNCHRONOUS COLORECTAL CANCER PERITONEAL METASTASES IN A NATIONWIDE COHORT STUDY
Anouk Rijken*1,2, Vincent C. van de Vlasakker1, Geert A. Simkens1, Koen P. Rovers1, Felice N. van Erning2, Miriam Koopman3, Cornelis Verhoef4, Johannes H. de Wilt5, Ignace H. de Hingh1,2,6
1Catharina Ziekenhuis, Eindhoven, North Brabant, Netherlands; 2Netherlands Comprehensive Cancer Organization, Utrecht, Netherlands; 3Universitair Medisch Centrum Utrecht, Utrecht, Utrecht, Netherlands; 4Erasmus MC, Rotterdam, Zuid-Holland, Netherlands; 5Radboudumc, Nijmegen, Gelderland, Netherlands; 6Maastricht University School for Oncology & Developmental Biology, Maastricht, Limburg, Netherlands
Background: To date, limited data are available to guide the decision-making process for clinicians and their patients regarding the different palliative treatment options for patients with isolated synchronous colorectal cancer peritoneal metastases (CRC-PM). Therefore, the aim of this study is to analyze the outcome of the different palliative treatment options for patients with isolated synchronous CPM in a population-based cohort.
Material and Methods: A cohort from the Netherlands Cancer Registry (NCR) was used, in which all patients diagnosed with isolated synchronous CRC-PM between 2009 and 2020 were screened for eligibility. All patients diagnosed with isolated synchronous CPM who underwent elective palliative therapy were included. Follow-up was completed until January 31st, 2022. Patients who underwent an emergency resection or curative intent therapy such as cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) were excluded. Patients were categorized into upfront palliative primary tumor resection (with or without systemic therapy) and palliative systemic therapy only. Overall survival (OS) was compared between both groups with the log-rank test. Multivariable cox regression analysis was performed to correct for tumor histology, tumor differentiation and tumor stage.
Results: In total, 1054 patients were included in this study. Of those, 387 (37%) patients underwent palliative primary tumor resection and 667 (63%) patients underwent palliative systemic therapy only. Older age, a right-sided tumor and positive lymph nodes and primary tumor diagnosis between 2009 and 2012 were more frequently present in patients who underwent primary tumor resection than in those who received palliative systemic therapy. Sixty-day mortality was 9% in the palliative primary tumor resection group and 5% in the palliative systemic therapy group (P=0.02). Median OS was 13.8 (interquartile range [IQR], 6.5-29.4) months in the palliative primary tumor resection group and 10.3 (IQR 5.5-17.0) months in the palliative systemic therapy group (P<0.001). Multivariable analysis showed that palliative primary tumor resection was significantly associated with improved OS (hazard ratio, 0.67; 95%CI 0.56-0.80; P<0.001).
Conclusions: In this study, palliative primary tumor resection appeared to be associated with improved survival compared to palliative systemic therapy alone in patients with isolated synchronous CRC-PM despite a higher 60-day mortality. This finding must be interpreted with care as residual bias is likely to have played a significant role. Nevertheless, it is highly unlikely that a randomized controlled trial will address this issue in the near future. Therefore, this option may be considered in the decision-making process by clinicians and their patients regarding the different palliative therapy options.
Figure 1. Overall survival of palliative primary tumor resection group and palliative systemic therapy group (Log-rank: <0.001).
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