Survival data on timing of resection of liver metastases in colorectal cancer patients

Between 2007 and 2016, 140 consecutive patients who underwent resection of colorectal cancer with simultaneous liver metastases at a single university hospital were retrospectively analysed. In order to gather information regarding potential survival differences for n = 68 simultaneous versus n = 72 staged resections of the colorectal primary tumor and the liver metastases, Clinical, histopathological, serological, and survival data were compared for those two patient groups. The rate of simultaneous tumor resections increased from approximately 25% in 2007 to >75% in 2016. There was no difference in tumor specific survival for patients with simultaneous vs. staged resection (p = 0.631). This effect continued after excluding patients with extrahepatic metastases (p = 0.440). Further, neoadjuvant treatment did not lead to differences in the tumor-specific survival (p = 0.123). Factors associated with an increased tumor-specific survival were low ASA score (p < 0.001), low number of tumor-affected lymph nodes (p < 0.001), histological grading G1/2 (p = 0.001), and a low number of liver metastases (p = 0.044). There was no significant survival difference for the primary tumor stage (pT), the Clavien-Dindo complication rate, the resection status (R0), and minor versus major hepatectomies.


a b s t r a c t
Between 2007 and 2016, 140 consecutive patients who underwent resection of colorectal cancer with simultaneous liver metastases at a single university hospital were retrospectively analysed. In order to gather information regarding potential survival differences for n = 68 simultaneous versus n = 72 staged resections of the colorectal primary tumor and the liver metastases, Clinical, histopathological, serological, and survival data were compared for those two patient groups. The rate of simultaneous tumor resections increased from approximately 25% in 2007 to > 75% in 2016. There was no difference in tumor specific survival for patients with simultaneous vs. staged resection ( p = 0.631). This effect continued after excluding patients with extrahepatic metastases ( p = 0.440). Further, neoadjuvant treatment did not lead to differences in the tumor-specific survival ( p = 0.123). Factors associated with an increased tumorspecific survival were low ASA score ( p < 0.001), low number of tumor-affected lymph nodes ( p < 0.001), histological grading G1/2 ( p = 0.001), and a low number of liver metastases ( p = 0.044). There was no significant survival difference for the primary tumor stage (pT), the Clavien-Dindo complication rate, the resection status (R0), and minor versus major hepatectomies.
© 2020 The Author(s

Value of the data
• Our data report on a large set of consecutive patients, which is not possible to collect in smaller hospitals. The results help to define treatment algorithms for patients with colorectal cancer and hepatic metastases. • Abdominal surgeons, oncologists and patients can benefit from these data • Based on our retrospective analysis, a randomized controlled trial may be conducted in the future regarding the question of simultaneous versus staged resection of colorectal cancer with synchronous liver metastases. • The data may help to reduced lengths of hospital stays, to reduced costs of the health care system, and to a higher satisfaction of patients.

Materials and methods
All medical records of patients who underwent hepatic resections at the Department of Surgery, Klinikum rechts der Isar, Technical University of Munich, Germany, between January 2007 and December 2016, were retrospectively reviewed. Only patients with primary colorectal cancer and synchronous liver metastases were included in this study for further analyses, if a resection of both has been performed, the colorectal primary and the liver metastases, to create a more homogenous study cohort. The decision for simultaneous resection or staged resection was made by evaluation of all available diagnostic findings in the multidisciplinary tumor board, which consisted at least by an oncological HPB surgeon, a gastroenterologist, an oncologist, a radiologist, and a pathologist. The documented data included preoperative performance

Fig. 2.
There was no difference in tumor-specific survival in the complete patient cohort, including n = 68 patients with simultaneous resection of the colorectal primary tumor and n = 72 patients with staged resections ( p = 0.631; see [1] for the graph and for further description of the whole patient cohort). This finding remained unchanged after exclusion of the n = 16 patients who had extrahepatic metastases in addition to the liver metastases ( p = 0.440).  On the other hand, no survival differences were identified regarding the staging of the colorectal primary tumor (pT), the Clavien-Dindo complication rate [2] , the overall resectional status of liver and colorectum (R0), and for minor versus major hepatectomies. status; MELD score; tumor staging, including histopathology; details of the surgical and oncological procedures; perioperative morbidity and mortality; liver function tests at different perioperative time points; complication rate according to Clavien-Dindo [2]; and detailed follow-up data. Follow-up was conducted by reviewing the hospital's archiving system or by contacting the patients and their treating physicians. All analyses were conducted on a deidentified data set.
Statistical analyses were performed with SPSS Statistics Version 24.0.0 (IBM Corporation, New York, United States of America) and GraphPad (GraphPad Software, Inc., San Diego, United States of America). Time-dependent survival probabilities were estimated with the Kaplan-Meier method, and the log-rank test was used to compare subgroups.

Ethics statement
The study was approved by the ethical review board of the Klinikum rechts der Isar of the Technical University of Munich (Ethikkomission an der Technischen Universität München) on March 23th, 2018 ("Datenerhebung von Patienten mit viszeralchirurgischen Erkrankungen", # 93/18 S). Written, informed consent was obtained from each patient included in the study prior to surgery. The study protocol conforms to the ethical guidelines of the 20 0 0 Declaration of Helsinki as reflected in a priori approval by the institution's human research committee.