Prognostic impact of margin status in liver resections for colorectal metastases after bevacizumab

Prognostic implications of margin status in association with systemic treatment in a cohort study of patients with resection of colorectal liver metastases

BACKGROUND

This study investigates the impact of margin status after colorectal liver metastasis (CLM) resection on outcomes of patients after neoadjuvant treatment versus those who underwent upfront resection.

METHODS

An international collaborative database of CLM patients who underwent surgical resection was used. Proportional hazard regression models were created for single and multivariable models to assess the relationship between independent measures and median overall survival (mOS).

RESULTS

R1 was associated with worse OS in the neoadjuvant group (mOS: 51.8 m for R0 vs. 26.0 m for R1; HR: 2.18). In the patients who underwent upfront surgery, R1 was not associated with OS. (mOS: 46.7 m for R0 vs. 42.6 m for R1). When patients with R1 in each group were stratified by adjuvant treatment, there was no significant difference in the neoadjuvant group, while in the upfront surgery group with R1, adjuvant treatment was associated with significant improvement in OS (mOS: 42.6 m for adjuvant vs. 25.0 m for no adjuvant treatment; HR: 0.21).

CONCLUSION

R1 is associated with worse outcomes in the patients who receive neoadjuvant treatment with no significant improvement with the addition of adjuvant therapy, likely representing an aggressive tumor biology. R1 did not impact OS in patients with upfront surgery who received postoperative chemotherapy.

Evolving survival gains in patients with young-onset colorectal cancer and synchronous resectable liver metastases

We aimed to evaluate the practice and the associated outcomes of surgical treatment for young-onset colorectal cancer (YOCRC) patients presenting with synchronous liver metastases. The study cohort was divided into two groups according to surgery date: 131 patients in the early era (EE, 1998-2011) and 179 in the contemporary era (CE, 2012-2020). The CE had a higher rate of node-positive primary tumors, higher carcinoembryonic antigen level, and lower rate of RAS/BRAF mutations. The CE had higher rates of reverse or combined resection, multi-drug prehepatectomy chemotherapy, and two-stage hepatectomy. The median survival was 8.4 years in the CE and 4.3 years in the EE (p = 0.011). On multivariate analysis, hepatectomy in the CE was independently associated with improved overall survival (HR 0.48, p = 0.001). With a combination of perioperative systemic therapy, careful selection of treatment approach, and coordinated resections, durable cure can be achieved in YOCRC patients.

Relationship between hepatic surgical margins of colorectal cancer liver metastases and prognosis: A review

Colorectal cancer (CRC) remains a significant global health concern, as characterized by its high mortality rate ranking second among all the leading causes of death. The liver serves as the primary site of CRC metastasis, and the occurrence of liver metastasis is a significant contributor to mortality among patients diagnosed with CRC. The survival rate of patients with colorectal liver metastasis has significantly increased with the advancement of comprehensive tumor therapy. However, radical surgery remains the key factor. Since there are frequently multiple liver metastases, which are prone to recurrence after surgery, it is crucial to preserve as much liver parenchyma as possible without affecting the prognosis. The issue of surgical margins plays a crucial role in this regard. In this review, we begin by examining the occurrence of positive surgical margins in liver metastases of patients diagnosed with CRC. We aim to define positive margins in hepatic surgery, examine the relationship between margins and prognosis and establish a foundation for future research in this field.

Quantitative analysis of pre-treatment dynamic contrast-enhanced ultrasound for assessing the response of colorectal liver metastases to chemotherapy plus targeted therapy: a dual-institutional study

OBJECTIVES

To investigate the clinical value of pre-treatment quantitative contrast-enhanced ultrasound (CEUS) in assessing the response of colorectal liver metastases (CRLM) to chemotherapy plus targeted therapy.

METHODS

This study retrospectively enrolled 50 CRLM patients from the Zhongshan Hospital, Fudan University as the training cohort and 14 patients from Shanghai Tenth People's Hospital as the testing cohort. Patients underwent the CEUS examination before receiving chemotherapy (CAPOX, FOLFOX, FOLFIRI, or FOLFOXIRI) plus targeted therapy (Bevacizumab or Cetuximab). The therapy response was determined according to Response Evaluation Criteria in Solid Tumors version 1.1 based on pre-treatment CT and 3-month follow-up CT after therapy. Dynamic analysis was performed by VueBox® software. Time-intensity curves with quantitative perfusion parameters were obtained. In the training cohort, univariable and multivariable logistic regression analyses were used to develop the predictive model of therapy response. The predictive performance of the developed model was validated in the testing cohort.

RESULTS

After the logistic regression analyses, the peak enhancement (PE) (odds ratio = 1.640; 95% confidence intervals [CI] 1.022-2.633) and time to peak (TTP) (odds ratio = 0.495; 95% CI 0.246-0.996) were determined as independent predictive factors. PE and TTP generated from VueBox® were not affected by ultrasound instruments and contrast agent dosage in therapy response evaluation (P > 0.05). The logistic regression model achieved satisfactory prediction performance (area under the curve: 0.923 in the training cohort and 0.854 in the testing cohort).

CONCLUSION

CEUS with dynamic quantitative perfusion analysis, which presents high consistency, has potential practical value in predicting the response of CRLM to chemotherapy plus targeted therapy.

Prognostic impact of R1 resection margin in synchronous and simultaneous colorectal liver metastasis resection: a retrospective cohort study

BACKGROUND

A margin ≥ 1 mm is considered a standard resection margin for colorectal liver metastasis (CRLM). However, microscopic incomplete resection (R1) is not rare since aggressive surgical resection has been attempted in multiple and bilobar CRLM. This study aimed to investigate the prognostic impact of resection margins and perioperative chemotherapy in patients with CRLM.

METHODS

A total of 368 of 371 patients who underwent simultaneous colorectal and liver resection for synchronous CRLM between 2006 and June 2017, excluding three R2 resections, were included in this study. R1 resection was defined as either abutting tumor on the resection line or involved margin in the pathological report. The patients were divided into R0 (n = 304) and R1 (n = 64) groups. The clinicopathological characteristics, overall survival, and intrahepatic recurrence-free survival were compared between the two groups using propensity score matching.

RESULTS

The R1 group had more patients with ≥ 4 liver lesions (27.3 vs. 50.0%, P < 0.001), higher mean tumor burden score (4.4 vs. 5.8%, P = 0.003), and more bilobar disease (38.8 vs. 67.2%, P < 0.001) than the R0 group. Both R0 and R1 groups showed similar long-term outcomes in the total cohort (OS, P = 0.149; RFS, P = 0.414) and after matching (OS, P = 0.097, RFS: P = 0.924). However, the marginal recurrence rate was higher in the R1 group than in the R0 group (26.6 vs. 16.1%, P = 0.048). Furthermore, the resection margin did not have a significant impact on OS and RFS, regardless of preoperative chemotherapy. Poorly differentiated, N-positive stage colorectal cancer, liver lesion number ≥ 4, and size ≥ 5 cm were poor prognostic factors, and adjuvant chemotherapy had a positive impact on survival.

CONCLUSIONS

The R1 group was associated with aggressive tumor characteristics; however, no effect on the OS and intrahepatic RFS with or without preoperative chemotherapy was observed in this study. Tumor biological characteristics, rather than resection margin status, determine long-term prognosis. Therefore, aggressive surgical resection should be considered in patients with CRLM expected to undergo R1 resection in this multidisciplinary approach era.

Label-free multiphoton microscopy enables histopathological assessment of colorectal liver metastases and supports automated classification of neoplastic tissue

As the state of resection margins is an important prognostic factor after extirpation of colorectal liver metastases, surgeons aim to obtain negative margins, sometimes elaborated by resections of the positive resection plane after intraoperative frozen sections. However, this is time consuming and results sometimes remain unclear during surgery. Label-free multimodal multiphoton microscopy (MPM) is an optical technique that retrieves morpho-chemical information avoiding all staining and that can potentially be performed in real-time. Here, we investigated colorectal liver metastases and hepatic tissue using a combination of three endogenous nonlinear signals, namely: coherent anti-Stokes Raman scattering (CARS) to visualize lipids, two-photon excited fluorescence (TPEF) to visualize cellular patterns, and second harmonic generation (SHG) to visualize collagen fibers. We acquired and analyzed over forty thousand MPM images of metastatic and normal liver tissue of 106 patients. The morphological information with biochemical specificity produced by MPM allowed discriminating normal liver from metastatic tissue and discerning the tumor borders on cryosections as well as formalin-fixed bulk tissue. Furthermore, automated tissue type classification with a correct rate close to 95% was possible using a simple approach based on discriminant analysis of texture parameters. Therefore, MPM has the potential to increase the precision of resection margins in hepatic surgery of metastases without prolonging surgical intervention.

Prospective Non-Randomized Study of Intraoperative Assessment of Surgical Resection Margin of Colo-Rectal Liver Metastases

Introduction: More than 50% of patients with colorectal cancer (CRC) develop liver metastases during the natural course of disease. Surgical resection is currently the most potentially curative method in the treatment of colorectal liver metastases (CRLM). The goal of surgery is to achieve a negative resection margin (RM) of at least 1 mm, which provides the best prognosis for patients. The RM can be assessed by the pathologist of the resected liver specimen (RLS) and by the surgeon intraoperatively. The aim of this research paper is to determine the degree of agreement on intraoperative assessment of the RM by the surgeon and histopathological RM assessment by the pathologist.

Material and methods: This prospective non-randomized double-blind study was approved by the Ethics Committee of the Oncology Institute of Vojvodina and registered on ClinicalTrials.gov #NCT04634526. The study was conducted at the Oncology Institute of Vojvodina, Sremska Kamenica, Serbia. An experienced hepatobiliary surgeon assessed RM for every specimen intra-operatively, immediately after CRLM resection. Resected CRLM lesions were analyzed by two experienced pathologists. These data were compared with pathological RM assessment as a “gold standard”. RM of 1 mm or more was rated as negative RM (RM-). Disease-free survival (DFS) and recurrence rate was calculated by RM status defined by surgeon and by pathologist.

Results: From 01 January 2015 to 31 August 2019, 98 patients were enrolled in the study. There were 219 RLS with 245 CRLM. The surgeon registered positive RM (RM+) of <1mm in 41 (18.7%) RLS. Taking the result of the histopathological assessment (HPA) as the “gold standard”, it was determined that RM was true positive in 32 (14.6%) cases. False positive RM was found in 9 (4.1%) cases. False negative RM was found in 20 (9.1%) cases. True negative RM was found in 158 (72.2%) cases. Sensitivity of surgical assessment (SA) of RM+ was 61.5% (32/52). Specificity of SA of RM+ was 94.6% (158/167). The positive predictive value (PPV) was 78.0% (32/41), while the negative predictive value (NPV) was 88.8% (158/178). The overall accuracy of the RM+ SA was 86.8% (190/219). There was no statistically significant difference in the assessment of RM+ per RLS by surgeon and pathologists (p=0.061), but it was significant when analyses per patients was performed (p=0.017). Recurrence rate for RM+ patients was 48.1% (13/27, p=0.05) for SA and 35.0% (14/40, p=0.17) for HPA. Three year DFS for RM- and RM+ was 66.5% and 27.9% (p=0.04), respectively, by SA, and 64.8% and 42.1% (p=0.106), respectively, by HPA.

Conclusion: Intraoperative assessment of RM- by surgeon of RLS is clinically meaningful. There is not a statistically significant difference in the assessment of RM+ by surgeon and pathologists per RLS, but it was statically significant on a per patient basis. RM determined by surgeon has better prognostic impact on recurrence rate and 1- and 3-year DFS than standard histopathological assessment.

Does KRAS mutation status impact the risk of local recurrence after R1 vascular resection for colorectal liver metastasis? An observational cohort study

INTRODUCTION

R0 margin is the standard in the surgical treatment of colorectal liver metastases (CLM). Recently R1 surgery, at least that enabling CLM vessel-detachment (R1vasc), seems comparable to R0. As a possible background of that biologic factors could play some role. Among them, KRAS has been investigated in the present study.

METHODS

Patients who underwent curative surgery for CLM between 2008 and 2016 were identified. R0, R1vasc and parenchymal R1 (R1par; tumor exposure once dissected from the parenchyma) resections with known KRAS status were analyzed.

RESULTS

Of 1000 resection areas in 340 patients, 654 (65%) R0, 98 (10%) R1vasc and 248 (25%) R1par. In mutated KRAS (mKRAS), local recurrence (LR) was similar between R0 and R1vasc (per-patient 4,8% vs. 2%, p = 0.628; per-area 2,1% vs. 1,9%, p = 0.940), while higher in R1par (per-patient 25,4% and per-area 19,5%; p < 0.001 for both). In wild-type KRAS (wtKRAS), R0 had less LR compared to R1vasc (per-patient 7,6% vs 14,6%, p = 0.335; per-area 3,1% vs 13,3%, p = 0.012) and R1par (per-patient 18,3%, p = 0.060; per-area 9,9%, p = 0.013). KRAS did not impact LR in R0 (per-patient 7,6% vs. 4,8%, p = 0.491; per-area 3,1% vs. 2,1%, p = 0.555), while wtKRAS R1par had less LR compared to mKRAS R1par (per-patient 18,3% vs 25,4%, p = 0.404; per-area 9,9% vs 19,5%, p = 0.048). Inversely, LR was increased in wtKRAS R1vasc compared to mKRAS R1vasc (per-patient 14,6% vs 2%, p = 0.043; per-area 13,3% vs 1,9%, p = 0.046).

CONCLUSION

KRAS status does not impact LR risk in R0 resection. Inversely, R1vasc vs R1par LR risk is reduced in mKRAS, and increased in wtKRAS. If confirmed these results are of note.

Response to preoperative chemotherapy: impact of change in total burden score and mutational tumor status on prognosis of patients undergoing resection for colorectal liver metastases

BACKGROUND

Progression of colorectal liver metastasis (CRLM) on preoperative chemotherapy has been associated with a worse prognosis compared with patients who have responsive disease. Defining response can be challenging as traditional criteria largely assess only tumor size.

METHODS

Patients who underwent hepatectomy between 2010 and 2017 were identified using a multi-centric database. This study aimed to define the impact of preoperative chemotherapy response relative to initial tumor burden score (TBS) and determine impact of clinico-pathological variables on overall survival (OS).

RESULTS

Among 784 patients who received preoperative chemotherapy, the regimen was oxaliplatin- (66%) or irinotecan-based (34%). Among patients with a TBS<6 at diagnosis, genetic status was the most important prognostic variable. Patients with a TBS<6, 5-year OS was 55%, 35%, and 0% for patients with KRAS/NRAS/BRAF wild-type, KRAS/NRAS, and BRAF mutations, respectively. Among patients who presented with CRLM with a TBS≥6, only Δ-TBS was prognostically important and patients with a Δ-TBS ≥ -10% had a 5-year OS of 27% compared with 49% for patients with a Δ-TBS < -10%.

CONCLUSIONS

Prognostic stratification of patients with CRLM receiving preoperative chemotherapy should be multi-faceted and include consideration of initial tumor burden, change in tumor burden due to chemotherapy, and tumor genetic status.

Sub-millimeter surgical margin is acceptable in patients with good tumor biology after liver resection for colorectal liver metastases

BACKGROUND

The definition of R1 resection in colorectal cancer liver metastases (CRLM) remains debatable. This retrospective study was conducted to clarify the impact of R1 margin on patient survival after liver resection for CRLM, taking into consideration tumor biology, including RAS status and chemotherapy response.

METHODS

We retrospectively analysed the clinical and survival data of 214 CRLM patients with initially resectable liver metastases who underwent liver resection after receiving neoadjuvant chemotherapy between January 2006 and December 2016.

RESULTS

R1 resection significantly impacted patients' overall survival (OS) and disease-free survival (DFS) in the overall patient cohort (5-year OS: 53.2% for R0 vs 38.2% for R1, P = 0.001; 5-year DFS: 26.5% for R0 vs 10.5% for R1, P = 0.002). In the RAS wild-type subgroup and respond to chemotherapy (RC) subgroup, R1 reached a similar OS to those who underwent R0 resection (RAS wild-type, P = 0.223; RC, P = 0.088). For the RAS mutated subgroup and no response to chemotherapy (NRC) subgroup, OS was significantly worse underwent R1 resection (RAS mutant, P = 0.002; NRC, P = 0.022). When considering tumor biology combining RAS and chemotherapy response status, R1 resection was only acceptable in patients with both RAS wild-type and RC (5-year OS: 66.4% for R0 vs 65.2% for R1, p = 0.884), but was significantly worse in those with either RAS mutation or NRC.

CONCLUSIONS

Tumor biology plays an important role in deciding the appropriate resection margin in patients with CRLM undergoing radical surgery. R1 resection margin is only acceptable in RAS wild-type patients who respond to chemotherapy.

Higher Tumor Burden Neutralizes Negative Margin Status in Hepatectomy for Colorectal Cancer Liver Metastasis

OBJECTIVE

The aim of this study was to examine if the prognostic significance of margin status in hepatectomy for colorectal cancer liver metastasis (CRLM) varies for different levels of tumor burden because hepatectomy indications for CRLM have been recently expanded to include patients with a higher tumor burden in whom achieving an R0 resection is difficult.

METHODS

Clinicopathological variables in an exploration cohort of 290 patients receiving hepatectomy in Japan for CRLM were investigated. R0 resection was defined as a margin width > 0 mm. Tumor burden was assessed using the recently introduced Tumor Burden Score (TBS), which was calculated as TBS² = (maximum tumor diameter in cm)² + (number of lesions)². The principal findings were validated using a cohort from the United States.

RESULTS

R1 resection rates significantly increased as TBS increased: 4/86 (4.7%) in patients with TBS < 3, 29/171 (17.0%) in patients with TBS ≥ 3 and < 9, and 9/33 (27.3%) in patients with TBS ≥ 9 (p < 0.001). R0 resection was significantly superior to R1 resection in patients with TBS ≥ 5; however, this was not the case for TBS ≥ 6, as confirmed by both univariate and multivariate analyses. Furthermore, prehepatectomy chemotherapy was associated with significantly improved survival for patients with TBS ≥ 8. Analysis of the validation cohort yielded similar results.

CONCLUSIONS

R0 resection appeared to have a positive impact on prognosis among patients with low tumor burden; however, this was not the case for patients with high tumor burden. As such, systemic treatment, in addition to surgery, may be central to achieving satisfactory outcomes in the latter patient population.

Current status of surgical treatment of colorectal liver metastases

Liver metastasis (LM) is one of the major causes of death in patients with colorectal cancer (CRC). Approximately 60% of CRC patients develop LM during the course of their illness. About 85% of these patients have unresectable disease at the time of presentation. Surgical resection is currently the only curative treatment for patients with colorectal LM (CRLM). In recent years, with the help of modern multimodality therapy including systemic chemotherapy, radiation therapy, and surgery, the outcomes of CRLM treatment have significantly improved. This article summarizes the current status of surgical treatment of CRLM including evaluation of resectability, treatment for resectable LM, conversion therapy and liver transplantation for unresectable cases, liver resection for recurrent CRLM and elderly patients, and surgery for concomitant hepatic and extra-hepatic metastatic disease (EHMD). We believe that with the help of modern multimodality therapy, an aggressive oncosurgical approach should be implemented as it has the possibility of achieving a cure, even when EHMD is present in patients with CRLM.

The impact of R1 resection for colorectal liver metastases on local recurrence and overall survival in the era of modern chemotherapy: An analysis of 1,428 resection areas

BACKGROUND

It is still unclear whether a positive surgical margin after resection of colorectal liver metastases remains a poor prognostic factor in the era of modern perioperative chemotherapy. The aim of this study was to evaluate whether preoperative chemotherapy has an impact on reducing local recurrence after R1 resection, and the impact of local recurrence on overall survival.

METHODS

Between 2000 and 2014, a total of 421 patients underwent resection for colorectal liver metastases at our unit after preoperative chemotherapy. The overall number of analyzed resection areas was 1,428.

RESULTS

The local recurrence rate was 12.8%, significantly higher after R1 resection than after R0 (24.5% vs 8.7%; P < .001). These results were also confirmed in patients with response to preoperative chemotherapy (23.1% after R1 vs 11.2% after R0; P < .001). At multivariate analysis, R1 resection was the only independent risk factor for local recurrence (P < .001). At the analysis of the 1,428 resection areas, local recurrence significantly decreased according to the increase of the surgical margin width (from 19.1% in 0 mm margin to 2.4% in ≥10 mm). At multivariable logistic regression analysis for overall survival, the presence of local recurrence showed a significant negative impact on 5-year overall survival (P < .001).

CONCLUSION

Surgical margin recurrence after modern preoperative chemotherapy for colorectal liver metastases was still significantly higher after R1 resection than it was after R0 resection. Local recurrence showed a negative prognostic impact on overall survival. R0 resection should be recommended whenever technically achievable, as well as in patients treated by modern preoperative chemotherapy.

The Prognostic Value of Varying Definitions of Positive Resection Margin in Patients with Colorectal Cancer Liver Metastases

BACKGROUND

Varying definitions of resection margin clearance are currently employed among patients with colorectal cancer liver metastases (CRLM). Specifically, a microscopically positive margin (R1) has alternatively been equated with an involved margin (margin width = 0 mm) or a margin width < 1 mm. Consequently, patients with a margin width of 0-1 mm (sub-mm) are inconsistently classified in either the R0 or R1 categories, thus obscuring the prognostic implications of sub-mm margins.

METHODS

Six hundred thirty-three patients who underwent resection of CRLM were identified. Both R1 definitions were alternatively employed and multivariable analysis was used to determine the predictive power of each definition, as well as the prognostic implications of a sub-mm margin.

RESULTS

Five hundred thirty-nine (85.2%) patients had a margin width ≥ 1 mm, 42 had a sub-mm margin width, and 52 had an involved margin (0 mm). A margin width ≥ 1 mm was associated with improved survival vs. a sub-mm margin (65 vs. 36 months; P = 0.03) or an involved margin (65 vs. 33 months; P < 0.001). No significant difference in survival was detected between patients with involved vs. sub-mm margins (P = 0.31). A sub-mm margin and an involved margin were both independent predictors of worse OS (HR 1.66, 1.04-2.67; P = 0.04, and HR 2.14, 1.46-3.16; P < 0.001, respectively) in multivariable analysis. Importantly, after combining the two definitions, patients with either an involved margin or a sub-mm margin were associated with worse OS in multivariable analysis (HR 1.94, 1.41-2.65; P < 0.001).

CONCLUSIONS

Patients with involved or sub-mm margins demonstrated a similar inferior OS vs. patients with a margin width > 1 mm. Consequently, a uniform definition of R1 as a margin width < 1 mm should perhaps be employed by future studies.

Local Option: The Rational Use of Local Therapy in Patients at High Risk to Die of Metastatic Progression

On occasion, clinicians may be motivated to offer local therapy (eg, surgery, radiation, ablation) to patients with advanced cancer in the hope of prolonging survival (as opposed to palliating a symptom). An appropriately informed discussion of risks and benefits should push clinicians to reflect on the rationale for use of local therapy in a patient who is far more likely to die as a result of systemic progression. Ultimately, the justification for local therapy in advanced cancer must be based on several assumptions of what a patient’s cancer will and will not do. The following is an attempt to provide the framework for patients and their care teams to collectively consider the assumptions surrounding the use of local therapy and the potential consequences of being wrong.