Positive Margins After Resection of Metastatic Colorectal Cancer in the Liver: Back to the Drawing Board?

The effects of resection margin and KRAS status on outcomes after resection of colorectal liver metastases

BACKGROUND

The aim of this study was to investigate the influence of resection margin status in patients with KRAS mutations (mt-KRAS) when compared to those with wild-type KRAS (wt-KRAS) on long-term outcomes in patients with resected CRLM.

METHODS

All patients who underwent resection of CRLM with curative intent between January 2011 and December 2016 and had a KRAS type recorded were included in the study. Overall survival (OS), as well as death-censored overall (RFS) and liver-specific (LS-RFS) recurrence-free survival between KRAS types and the margin status within KRAS subgroups were compared using Cox regression models.

RESULTS

Data were available for N = 500 patients (30.4% mt-KRAS). mt-KRAS status was independently associated with significantly shorter OS. Within the wt-KRAS subgroup, smaller margins were found to be associated with significantly shorter death-censored LS-RFS (p < 0.001), with HRs of 1.93 (p = 0.005) for 1-4 mm margins and 2.83 (p < 0.001) for <1 mm margins, relative to those with clear margins. No such association was observed in the mt-KRAS subgroup (p = 0.721).

CONCLUSION

The resection margin status is of greater importance in patients with wt-KRAS. Such information could be useful in the operative planning, especially for those with multiple metastatic deposits, and also in the post-operative counselling and surveillance based on the margin and KRAS status.

Colorectal cancer liver metastases within the central and peripheral segments: Parenchymal sparing surgery adaptation

Background

The debate over the surgical strategy optimization in colorectal cancer patients with liver metastases (mCRC) has been ongoing in the last 20 years. However, parenchyma sparing surgery (PPS) in cases of hard to reach liver cites (HTRLC) remain to be controversial.

Methods

A prospective analysis of 185 mCRC patients performed who were devided in two groups depending by predominant liver cite localization. Peripherally localized metastases (PLM) (n = 107) (S2, S3, S6, S7, Spiegel lobe and subcapsular area 1-2 cm below the liver surface). Group 2 included those with metastases localized in HTRLC (n = 78) - metastatic lesions of the "right venous core", portal and caval hilum, paracaval part of S1, "deep" parenchyma cites of S5, S8 and S4.

Results

In 26 (33,3%) and 32 (29,9%) patients of HTRLC and PLM, respectively, performed one liver re-resection (0,62). In HTRLC group 2 and more re-resection were performed in 7 (8,9%) cases while in PLM in 11 (10,3%), p = 0,76. Postoperative major morbidity was 24,4%, 21,8% (p = 0,15) and mortality 8,9%, 4,6% for HTRLC and PLM groups, respectively. R1v principles were implemented in 24 (30,7%) cases with centrally located metastases and in only 6 cases (5.6%) with peripheral localized metastases (p = 0,001). Cumulative 3-year disease-free survival (DSF) for PLM and HTRLC groups was 63% and 41% (p = 0,008). DFS for R1v (n = 24) and R0 (54) cochorts in HTRLC group was 33% and 43%, respeсtively (p = 0,44).

Conclusions

Principles of the PPS tactic provides an adequate removal of metastatic lesions in hard to reach liver cites allowing to maintain organ functions and increases the feasibility of the repeated liver resections in case of the initial disease progression.

Histopathological growth patterns and positive margins after resection of colorectal liver metastases

BACKGROUND

Histopathological growth patterns (HGPs) of colorectal liver metastases (CRLM) may be an expression of biological tumour behaviour impacting the risk of positive resection margins. The current study aimed to investigate whether the non-desmoplastic growth pattern (non-dHGP) is associated with a higher risk of positive resection margins after resection of CRLM.

METHODS

All patients treated surgically for CRLM between January 2000 and March 2015 at the Erasmus MC Cancer Institute and between January 2000 and December 2012 at the Memorial Sloan Kettering Cancer Center were considered for inclusion.

RESULTS

Of all patients (n = 1302) included for analysis, 13% (n = 170) had positive resection margins. Factors independently associated with positive resection margins were the non-dHGP (odds ratio (OR): 1.79, 95% confidence interval (CI): 1.11-2.87, p = 0.016) and a greater number of CRLM (OR: 1.15, 95% CI: 1.08-1.23 p < 0.001). Both positive resection margins (HR: 1.41, 95% CI: 1.13-1.76, p = 0.002) and non-dHGP (HR: 1.57, 95% CI: 1.26-1.95, p < 0.001) were independently associated with worse overall survival.

CONCLUSION

Patients with non-dHGP are at higher risk of positive resection margins. Despite this association, both positive resection margins and non-dHGP are independent prognostic indicators of worse overall survival.