The Role of Surgery for Asymptomatic Primary Tumors in Unresectable Stage IV Colorectal Cancer

Palliative procedures for advanced obstructive colorectal cancer: a systematic review and meta-analysis

PURPOSE

Advanced obstructive colorectal cancer (AOCC) presents surgical challenges. Consideration must be given to alleviating symptoms and also quality of life and survival time. This study compared prognostic efficacies of palliative self-expanding metal stents (SEMSs) and surgery to provide insights into AOCC treatment.

METHODS

PubMed, Web of Science, MEDLINE, and Cochrane Library were searched for studies that met inclusion criteria. Using a meta-analysis approach, postoperative complications, survival rates, and other prognostic indicators were compared between patients treated with SEMSs and those treated surgically. Network meta-analysis was performed to compare prognoses between SEMS, primary tumor resection (PTR), and stoma/bypass (S/B).

RESULTS

Twenty-one studies were selected (1754 patients). The odds ratio (OR) of SEMS for clinical success compared with surgery was 0.32 (95% confidence interval [CI] 0.15, 0.65). The ORs for early and late complications were 0.34 (95% CI 0.19, 0.59) and 2.30 (95% CI 1.22, 4.36), respectively. The ORs for 30-day mortality and stoma formation were 0.65 (95% CI 0.42, 1.01) and 0.11 (95% CI 0.05, 0.22), respectively. Standardized mean difference in hospital stay was - 2.08 (95% CI - 3.56, 0.59). The hazard ratio for overall survival was 1.24 (95% CI 1.08, 1.42). Network meta-analysis revealed that SEMS had the lowest incidence of early complications and rate of stoma formation and the shortest hospital stay. PTR ranked first in clinical success rate and had the lowest late-complication rate. The S/B group exhibited the lowest 30-day mortality rate.

CONCLUSION

Among palliative treatments for AOCC, SEMSs had lower early complication, stoma formation, and 30-day mortality rates and shorter hospital stays. Surgery had higher clinical success and overall survival rates and lower incidence of late complications. Patient condition/preferences should be considered when selecting AOCC treatment.

Prognosis of patients with unresectable stage IV Colon cancer undergoing primary tumor resection: A multicenter study of minimally symptomatic or asymptomatic primary tumor

AIM

To determine the factors affecting survival of patients with unresectable stage IV colon cancer with Primary tumour resection (PTR) as first treatment compared with those with conventional palliative chemotherapy.

METHODOLOGY

Patient with minimally or asymptomatic stage IV colon cancer at diagnosis were identified from prospectively managed database in included centers from 2015 to 2020. Patient with and without PTR performed were followed up. Primary end point was overall survival. Risk factors affecting survival will be analysis by Kaplan Meier statistics and Cox regression analysis. Secondary outcome will be stoma formation, complication rate and reoperation.

RESULTS

162 patients were included in analysis. 68 patients treated with systemic therapy PTR and 94 patients with tumour in-situ before systemic therapy. Baseline demographics including sex, age, functional status, tumour location, site of metastasis, RAS status were similar except there was slightly more liver metastasis on non-resection group (63.2% vs 79.8%). Cox regression analysis found PTR (HR 0.485, 0.302-0.778, p = 0.003)), bone metastasis (HR 3.163, 1.146-6.918, p = 0.004) commencement (HR 0.579, 0.345-0.971, p = 0.038) and completion of systemic therapy (HR 0.310, 0.178-0.539, p = 0.000) are independent factors predicting survival. The median overall survival after PTR vs tumour in-situ is 28 (IQR: 16-47) vs 12 (IQR:6-31) months (p<0.001).

CONCLUSION

Resection of primary tumour is an independent good prognostic factor in relatively asymptomatic stage IV CA colon patients with unresectable metastasis. Resection should be considered as long as the procedure is straight forward and do not impose significant morbidities with careful patient selection.

Impact of primary tumor resection on the survival of patients with unresectable colon cancer liver metastasis at different colonic subsites: a propensity score matching analysis

OBJECTIVE

To investigate the effect of primary tumor resection (PTR) on the prognosis of patients with unresectable colon cancer liver metastasis (UCCLM) at seven colonic subsites using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

Propensity score matching (PSM) was performed to balance selection bias using all available variables that could be of potential relevance. After matching, the groups were redefined in a 1:1 ratio using the nearest method. Cancer-specific survival (CSS) was compared among the patients of PTR and non-PTR groups. Cox regression models were used to identify the prognostic factors for CSS.

RESULTS

CSS was significantly different between all groups. Cox regression analysis showed that PTR was an independent prognostic factor for all groups. After PSM, PTR significantly prolonged CSS for all groups. Subgroup analysis showed that PTR did not improve the prognosis of N2 stage patients in the cecum, ascending colon, and descending colon groups; T1 + T2 stage patients in the hepatic flexure group; and patients with a tumor size ≤5 cm in the splenic flexure group. Segmental colectomy could prolong CSS of patients in the cecum, ascending colon, transverse colon, splenic flexure, and sigmoid colon groups, while extended colectomy could prolong CSS of patients in the hepatic flexure and descending colon groups.

CONCLUSION

At different colonic subsites, UCCLM patients had different CSS. PTR could improve their prognosis, however, N stage, T stage, and tumor size are important reference indicators. In addition to patients in the hepatic flexure and descending colon groups, we suggested that patients in other groups should choose segmental colectomy.

Asymptomatic Primary Tumor Resection in Metastatic Colorectal Cancer: A Systematic Review and Meta-Analysis

Background

In patients with metastatic colorectal cancer (mCRC) with an asymptomatic primary tumor, there is no consensus on the indication for resection of the primary tumor.

Methods

The PubMed, Embase and the Cochrane Library databases were searched from inception to November 30,2021. A meta-analysis was performed using RevMan (version 5.3.3; The Cochrane Collaboration) on the outcome of mCRC patients with or without resection of the primary tumor in 8 selected studies.

Results

This meta-analysis included 2805 colorectal cancer patients with an asymptomatic primary tumor from 8 selected studies. Primary tumor resection (PTR) patients had longer overall survival (OS: MD =6.76 [3.39, 10.12], I² = 77%, P < 0.0001), compared with non-primary tumor resection (NPTR) patients. In the subgroup, the randomized controlled trials (RCT) PTR group didn’t have longer overall survival (OS: MD =3.79 [-3.49, 11.08], I² = 69%, P= 0.31); the Non-RCT PTR group had longer overall survival (OS: MD =8.42 [3.14, 13.70], I² = 89%, P= 0.002). In the meanwhile, compared with NPTR group, the 2-year overall survival rate, the 3-year overall survival rate, 5-year overall survival rate in the PTR group is higher (OR=2.35 [1.74, 3.18], I² = 0%, P < 0.00001; OR=3.61 [2.35, 5.54], I² = 0%, P < 0.00001; OR=3.02 [1.72, 5.33], I² = 48%, P= 0.0001, respectively).

Conclusions

Our results from studies demonstrate that the resection of primary tumor is a prognostic factor for survival in mCRC patients. However, 2 RCTs showed the resection of primary tumor was not related with a significant survival benefit in subgroup. Therefore, a larger RCT in the era of modern chemotherapy and liver resection techniques would be helpful.

Pretreatment inflammatory markers predicting treatment outcomes in colorectal cancer

We aimed to review whether pretreatment inflammatory markers reflect the short- and long-term outcomes of patients with colon cancer, rectal cancer, colon and rectal cancers, and metastatic colorectal cancer (CRC). We found that pretreatment complete blood count and blood chemistry tests reflect short-term and long-term oncological outcomes in patients with CRC. Specifically, in patients with colon cancer, hypoalbuminemia was associated with worse postoperative morbidity, mortality, and inferior survival. In patients with rectal cancer, elevated neutrophil-lymphocyte ratio (NLR) and thrombocytosis were associated with postoperative complications, poor overall survival (OS), and disease-free survival (DFS). A high C-reactive protein/albumin ratio (CAR) was associated with poor OS and DFS. In patients with metastatic CRC, increased NLR and platelet-lymphocyte ratio (PLR) were associated with poor OS, DFS, and progression-free survival (PFS). In addition, high CAR and a low albumin/globulin ratio on blood chemistry tests were associated with poor OS and PFS. Although universal cut-off values were not available, various types of pretreatment laboratory markers could be utilized as adjuncts to predict prognosis in patients with CRC.

Stenting as a bridge to surgery for obstructed stage IV colorectal cancers - long-term outcomes of a 10-year study

INTRODUCTION

Successful stenting of an obstructing colorectal tumor can avert upfront emergency surgery in malnourished obstructed patients with metastatic disease and poor physiological condition. This study aims to evaluate the outcomes of stenting followed by primary colorectal tumor resection among patients with obstructed stage IV colorectal cancer at presentation, over a 10-year period.

METHODS

From 2007 to 2016, a cohort comprising 25 consecutive patients were retrospectively reviewed from a prospectively collected database. The durability of palliation of bowel obstruction, oncological outcomes and factors influencing overall survival were analyzed.

RESULTS

No re-interventions were required for bowel obstruction during the study period. The overall perioperative morbidity rate was 16%, with no postoperative 90-day mortality. Laparoscopic resection rate was 52% and stoma formation rate was 8%. The median overall survival was 24 months for the entire cohort, and the 1-, 3- and 5-year survival rates were 80%, 35% and 23.33% respectively. More than one site of distant metastases, peritoneal involvement, and elevated carcinoembryonic antigen levels were significantly associated with poorer survival outcomes. Patients with peritoneal-only metastasis had worse outcomes, with a median survival of 7 months and no patients surviving beyond 18 months.

CONCLUSION

Stenting followed by resection of the primary obstructing colorectal cancer provides durable palliation among patients with stage IV disease, with low perioperative morbidity and stoma formation rates. Superior survival was observed among patients with single-site, non-peritoneal distant metastases.

Surgery on primary tumor shows survival benefit in selected stage IV colon cancer patients: A real-world study based on SEER database

Objectives: Most patients with stage IV colon cancer did not have the opportunity for curative surgery, only selected patients could benefit from surgery. This study aimed to determine whether surgery on the primary tumor (SPT) should be performed in patients with stage IV colon cancer and how to select patients for SPT.

Methods: This study included 48,933 patients with stage IV colon cancer who were identified in the Surveillance, Epidemiology and End Results (SEER) database between 1998 and 2015. Propensity score matching (PSM) analysis was adopted to balance baseline differences between SPT and non-surgery groups. Kaplan-Meier (K-M) curves were utilized to compare the overall survival (OS). Prognostic nomograms were generated to predict survival based on pre- and post-operative risk factors. Patients were divided into low, middle, and high mortality risk subsets for OS by X-tile analyses based on scores derived from above nomograms.

Results: Patients with SPT had a significantly longer OS than those without surgery, regardless of the metastatic sites and diagnostic years. Nomograms, according to the pre- and post-operative risk factors, showed moderate discrimination (all C-indexes above 0.7). Based on X-tile analyses, low mortality risk subset (post-operative score ≤ 22.3, preoperative score ≤ 9.7) recommended for SPT, and high mortality risk was not.

Conclusions: SPT led to prolonged survival in stage IV colon cancer. Our nomograms would help to select suitable patients for SPT.

The systemic immune-inflammation index is an independent predictor of survival for metastatic colorectal cancer and its association with the lymphocytic response to the tumor

BACKGROUND

Systemic inflammation and immune dysfunction has been proved to be significantly associated with cancer progression and metastasis in many cancer types, including colorectal cancer. We examined the prognostic significance of the systemic immune-inflammation index (SII) in patients with metastatic colorectal cancer (mCRC) and the relationship between the lymphocytic response to the tumor and this index.

METHODS

This retrospective study evaluated 240 consecutive patients with newly diagnosed stage IV mCRC who underwent surgical resection. The SII values were calculated based on preoperative laboratory data regarding platelet, neutrophil, and lymphocyte counts. Tumor-infiltrating lymphocytes were evaluated using the surgical specimens. The overall survival and their 95% confidence interval (95% CI) were estimated by regression analyses and the Kaplan-Meier method.

RESULTS

After a mean follow-up of 26.7 (1.1-92.4) months, 146 patients (60.8%) died. In the univariate analysis, a high SII was significantly associated with poor overall survival (P = 0.009). The multivariable analysis also confirmed that a high SII was independently associated with poor overall survival (hazard ratio: 1.462, 95% confidence interval 1.049-2.038, P = 0.025). The SII value was significantly correlated with the TILs value at the tumor's center (P = 0.04), but not at the invasive margin (P = 0.39). When we evaluated overall survival for groupings of the tumor-infiltrating lymphocytes and SII values, we identified three distinct prognostic groups. The group with low tumor-infiltrating lymphocyte values and high SII values had the worst prognosis.

CONCLUSIONS

A high SII value independently predicts poor clinical outcomes among patients with mCRC. In addition, combining the lymphocytic response to the tumor and SII could further enhance prognostication for mCRC.

Identification of factors predictive of postoperative morbidity and short-term mortality in older patients after colorectal carcinoma resection: A single-center retrospective study

OBJECTIVES

The aim of this study is to investigate the effect of age on patient outcome after colorectal carcinoma (CRC) resection in patients over 65 years of age.

METHODS

This study included patients aged 65 years and older who underwent CRC resection between 2003 and 2013 at a single-center institution. Patients were divided into two groups: Group A (65-74 years old) and Group B (≥75 years old).

RESULTS

Multivariable logistic analysis of 415 patients revealed serum albumin levels on the third postoperative day (POD) (Odds Ratio (OR), 0.44; 95% CI, 0.21-0.94; P = 0.03) and C-reactive protein (CRP) levels (OR, 1.05; 95% CI, 1.00-1.01; P = 0.04) in patients with colon cancer as predictive factors for morbidity. In addition, the multivariable logistic analysis revealed serum albumin levels (OR, 0.27; 95% CI, 0.08-0.87; P = 0.03) in patients with rectal cancer as predictive factors for morbidity. The multivariate Cox Proportional Hazards Model identified re-intervention for colon cancer (Hazard Ratio (HR), 4.57; 95% CI, 1.36-15.4 P = 0.01) and for rectal cancer (HR, 11.8; 95% CI, 1.08-129 P = 0.04) as a predictive factor for 30-day mortality. Serum albumin level on the third POD was predictive of 30-day mortality (HR, 0.30; 95% CI, 0.13-0.71; P = 0.01) and of 1-year mortality (HR, 0.34; 95% CI, 0.17-0.66; P < 0.01) in patients with colon cancer.

CONCLUSION

Age is not predictive of postoperative morbidity and mortality in patients with CRC. Serum albumin levels on the third POD can predict morbidity and mortality for colon and rectal carcinoma in older patients undergoing colorectal resections.

The American Society of Anesthesiologists score influences on postoperative complications and total hospital charges after laparoscopic colorectal cancer surgery

The aim of this study was to investigate the influence of American Society of Anesthesiologists (ASA) scores on postoperative complication rates and total hospital charges following laparoscopic surgery for colorectal cancer.All patients (n = 664) underwent laparoscopic colorectal cancer surgery. A group of patients with an ASA score of 1 or 2 (n = 575) and a group of patients with an ASA score of 3 (n = 89) were compared.The mean age was higher in the group of patients with an ASA score of 3 than in the group of patients with an ASA score of 1 or 2 (70 vs 67 years). The rate of ICU admission (27% vs 15%) was higher in the ASA score 3 group. The mean hospital stay (14 vs 12 days) was longer in the ASA score 3 group. Postoperative 30-day complications (38% vs 27%), 30-day mortality (2% vs 0%), and a Clavien-Dindo classification of ≥3 (21% vs 11%) occurred more frequently in the ASA score 3 group. Mean total hospital charges were significantly higher in the ASA score 3 group (13,906 vs 11,575 USD). Independent risk factors that affected postoperative complications were older age [≥80 years, hazard ratio (HR) = 2.8], an ASA score of 3 (HR = 1.6), and the presence of a primary rectal tumor (HR = 1.6). Postoperative complication rates were 21.9%, 28.5%, and 38.2% in the ASA score 1, 2, and 3 groups, respectively. Total hospital charges were 14,376 USD and 10,877 USD in the groups with and without postoperative complications, respectively. Mean total hospital charges were 10,769 USD, 11,756 USD, and 13,906 USD in the ASA score 1, 2, and 3 groups, respectively.Preoperative ASA scores may be a predictor of postoperative complications and hospital costs when planning laparoscopic surgery for colorectal cancer.

Tumor-infiltrating lymphocyte as a prognostic biomarker in stage IV colorectal cancer should take into account the metastatic status and operation modality

BACKGROUND

Although tumor-infiltrating lymphocytes (TILs) have been understood for years as a favorable prognostic factor for colorectal cancers (CRCs) after complete surgical resection, its prognostic role in metastatic CRC (mCRC) remains poorly defined, and it is largely unknown how this prognostic benefit relates to the metastatic status and operation modality.

MATERIALS AND METHODS

After reviewing 2215 consecutive cases of surgically resected CRC, 332 patients newly diagnosed with stage IV CRC and treated at the Sun Yat-Sen University Cancer Center between 2009 and 2014 were included. H&E-stained (HES) slides from surgical specimens were evaluated for the extent of TILs. The primary end point was overall survival (OS). Cox proportional hazards regression was conducted to determine the prognostic significance of TILs. All statistical tests were 2-sided.

RESULTS

HES slides from primary tumor samples were evaluable for 302 of the 332 included cases. Among the 302 patients, 105 patients (34.8%) were classified as high TIL, the remaining 197 (65.2%) were defined as low TIL. In the univariate analysis, TILs were significantly associated with better OS (P=0.015). Multivariable analysis confirmed that high TIL strongly predicted better survival (hazard ratio =0.62, 95% CI: 0.44-0.89, P=0.008), independent of other patients' clinicopathological characteristics. Stratified analysis revealed a prognostic benefit of high TIL for patients in the subgroup with non-oligometastatic disease (P=0.002), ≥2 metastatic organs (P=0.006), and non-metastasectomy (P=0.005). By contrast, oligometastatic disease, 1 metastatic organ, or metastasectomy fully abrogated the prognostic effect of TIL.

CONCLUSION

Our findings indicate that the level of TILs can be used to predict the outcome for patients with mCRC; however, the operation modality and the metastatic status of patients should also be taken into account.

Comparison of the Short-Term Outcomes of Laparoscopic and Open Resections for Colorectal Cancer in Patients with a History of Prior Median Laparotomy

This study aimed to investigate the short-term outcomes of laparoscopic resection in comparison with those of open resection for colorectal cancer in patients with a history of prior median laparotomy (PML). Eighty-seven consecutive patients (87/1121, 7.8 %) with a history of PML who underwent major colorectal cancer resection were enrolled (laparoscopy, n = 40; open, n = 47). The conversion rate to open surgery was 25 % (n = 10). The laparoscopy group had a higher proportion of female patients (57.5 vs. 36.2 %), a lower rate of American Society of Anesthesiologists (ASA) score for physical status of ≥3 (7.5 vs. 25.5 %), and a lower pT4 tumor rate (15 vs. 38.3 %) than the open resection group. Regarding the reasons for PML, radical hysterectomy with extended lymphadenectomy for gynecologic cancer was more common (32.5 vs. 4.3 %), but gastrointestinal surgeries, such as gastrectomy and colectomy, were less frequent in the laparoscopy group. Regarding intraoperative outcomes, the laparoscopy group showed a similar operative time (197 vs. 204 min), intraoperative enterotomy rate (2.5 vs. 2.1 %), and bowel resection rate (2.5 vs. 2.1 %) with the open resection group. Regarding postoperative outcomes, the laparoscopy group showed a lower complication rate (20 vs. 40.4 %), significantly reduced time to soft diet (5 vs. 7 days), and shorter hospital stay (12 vs. 18 days). Despite the high rate of open conversion, favorable short-term outcomes were observed in the laparoscopic group. Laparoscopy may be chosen as the primary approach in selected patients with a history of non-gastrointestinal PML (prior abdominal surgery for gynecological cancer).

Primary tumor resection in stage IV unresectable colorectal cancer: what has changed?

Most current guidelines do not recommend primary tumor resection in stage IV unresectable colorectal cancer. Rapid chemotherapy development over the last decade has substantially changed the decision making. However, results of recently published trials and meta-analyses suggest that primary tumor resection may in fact be beneficial, principally in terms of prolonged survival. Additional factors, such as use of minimally invasive approach or protocols of enhanced recovery after surgery, affect clinical outcomes as well, but are often neglected when discussing the state of the art in this area. There are still no randomized studies determining the legitimacy of upfront surgery in asymptomatic patients. Also, quality of life also plays an important role in choosing appropriate treatment. Having said that, there is no data that would prove whether primary tumor resection has an advantage on that issue. With all the uncertainty, currently decision making in unresectable stage IV colorectal cancer is primarily up to clinicians' knowledge, common sense and patients' preferences.

The impact of delayed commencement of adjuvant chemotherapy (eight or more weeks) on survival in stage II and III colon cancer: a national population-based cohort study

BACKGROUND

To examine the impact of chemotherapy delay on survival in patients with stage II or III colon cancer and the factors associated with the delay (≥8 weeks) of adjuvant chemotherapy.

METHODS

Patients undergoing curative resection and adjuvant chemotherapy in a national population-based cohort were included.

RESULTS

Among 5355 patients, 154 (2.9%) received chemotherapy more than 8 weeks after surgery. Based on a multivariate analysis, the risk factors associated with chemotherapy delay ≥8 weeks were older age [65 to 74 years (hazard ratio [HR]=1.48) and ≥75 years (HR=1.69), p=0.0354], medical aid status in the health security system (HR=1.76, p=0.0345), and emergency surgery (HR=2.43, p=0.0002). Using an 8-week cutoff, the 3-year overall survival rate was 89.62% and 80.98% in the <8 weeks and ≥8 weeks groups, respectively (p=0.008). Independent prognostic factors for inferior overall survival included chemotherapy delay ≥8 weeks (HR=1.49, p=0.0365), older age [65 to 74 years (HR=1.94) and ≥75 years (HR=3.41), p<0.0001], TNM stage III (HR=2.46, p<0.0001), emergency surgery (HR=1.89, p<0.0001), American Society of Anesthesiologists score of 3 or higher (HR=1.50, p<0.0001), and higher transfusion amounts (HR=1.09, p=0.0392).

CONCLUSIONS

This study shows that delayed commencement of adjuvant chemotherapy, defined as ≥ 8 weeks, is associated with inferior overall survival in colon cancer patients with stage II or III disease. The delay to initiation of adjuvant chemotherapy is influenced by several multidimensional factors, including patient factors (older age), insurance status (medical aid), and treatment-related factors (emergency surgery).

The influence of local therapy on the survival of patients with metastatic rectal cancer: a population-based, propensity-matched study

PURPOSE

This study was aimed to determine the effect of the local tumor therapy on patients' prognosis in the management of metastatic rectal cancer.

METHODS

Patients diagnosed with metastatic rectal cancer from 2004 to 2013 were selected from the SEER (Surveillance, Epidemiology, and End Results) database. Overall survival and cancer-specific survival were compared between the local treatment group and the nonlocal treatment group using Kaplan-Meier methods. Uni- and multivariate analyses were further performed to confirm or deny the results. The statistical approach of propensity score matching was conducted to avoid potential confounding factors.

RESULTS

Of 6867 patients included in this analysis, 3971 (57.8%) received local therapy to the primary tumor and 2896 (42.2%) did not receive. Both univariable and multivariable analysis showed local therapy continued to be associated with an improvement in OS (HR 0.532; 95% CI 0.503-0.563, p < 0.001 and HR 0.532; 95% CI 0.498-0.568, p < 0.001, respectively) and CSS (HR 0.527; 95% CI 0.497-0.559, p < 0.001 and HR 0.521; 95% CI 0.487-0.557, p < 0.001, respectively) in the unmatched cohorts. Further analysis showed patients underwent local tumor destruction or surgical resection had a better overall survival compared with those who did not undergo (p < 0.001). In the matched population, patients receiving local therapy had a better OS (HR 0.427; 95% CI 0.428-0.519, p < 0.001) and CSS (HR 0.462; 95% CI 0.418-0.511, p < 0.001) compared with those who did not receive.

CONCLUSIONS

Local therapy to the primary tumor may be associated with a better survival in patients with metastatic rectal cancer.

A Novel Derivation Predicting Survival After Primary Tumor Resection in Stage IV Colorectal Cancer: Validation of a Prognostic Scoring Model and an Online Calculator to Provide Individualized Survival Estimation

BACKGROUND

A prognostic scoring model has been devised previously to predict survival following primary tumor resection in patients with metastatic colorectal cancer and unresectable metastases. This has yet to be validated.

OBJECTIVE

The main objectives of this study are to validate the proposed prognostic scoring model and create an interactive online calculator to estimate an individual's survival after primary tumor resection.

DESIGN

Clinical data and survival outcomes of patients were extracted from a prospectively maintained database. Patients were categorized into good, moderate, or poor survivor groups based on the previously proposed scoring algorithm. Discrimination was assessed and recalibration was performed, with the recalibrated model implemented as an interactive Web application to provide individualized survival probability.

SETTINGS

This study was conducted at a tertiary referral center.

PATIENTS

The study included 324 consecutive patients with metastatic colorectal carcinoma and unresectable metastases who underwent primary tumor resection between January 2008 and December 2013.

MAIN OUTCOME MEASURES

The primary outcome measured was overall survival.

RESULTS

Three hundred twenty-four patients were included in the study. Median survival in the good, moderate, and poor prognostic groups was 56.8, 25.7, and 19.9 months (log rank test, p = 0.003). The κ statistic was 0.638 and RD was 0.101. Significant differences in survival were found between the moderate and good prognostic groups (HR, 2.79; 95% CI, 1.51-5.15; p = 0.001) and between poor and good prognostic groups (HR, 4.12; 95% CI, 1.98-8.55; p < 0.001). The model was implemented as an interactive online calculator to provide individualized survival estimation after primary tumor resection (http://bit.ly/Stage4PrognosticScore).

LIMITATIONS

Selection bias and single-center data preclude the generalizability of the proposed model. Information regarding the severity or likelihood of developing symptoms from the primary tumor were also not accounted for in the prognostic scoring model proposed.

CONCLUSIONS

The prognostic scoring model provides good prognostic stratification of survival after primary tumor resection and may be a useful tool to predict survival after primary tumor resection. See Video Abstract at http://links.lww.com/DCR/A330.

Centralization of Liver Cancer Surgery and Impact on Multidisciplinary Teams Working on Stage IV Colorectal Cancer

Surgical resection is the most effective treatment approach for colorectal liver metastases but only a minority of patients is suitable for upfront surgery. The treatment strategies of stage IV colorectal cancer have shifted towards a continuum of care in which medical and surgical treatment combinations are tailored to the clinical setting of the individual patient. The optimization of treatment through appropriate decision-making and multimodal therapy for stage IV colorectal cancer require a joint multidisciplinary meeting in a centralized liver cancer unit.

Primary tumor location as a predictor of the benefit of palliative resection for colorectal cancer with unresectable metastasis

Background

It is still under debate that whether stage IV colorectal cancer patients with unresectable metastasis can benefit from primary tumor resection, especially for asymptomatic colorectal cancer patients. Retrospective studies have shown controversial results concerning the benefit from surgery. This retrospective study aims to evaluate whether the site of primary tumor is a predictor of palliative resection in asymptomatic stage IV colorectal cancer patients.

Methods

One hundred ninety-four patients with unresectable metastatic colorectal cancer were selected from Sun Yat-sen University Cancer Center Database in the period between January 2007 and December 2013. All information was carefully reviewed and collected, including the treatment, age, sex, carcinoembryonic antigen, site of tumor, histology, cancer antigen 199, number of liver metastases, and largest diameter of liver metastasis. The univariate and multivariate analyses were used to detect the relationship between primary tumor resection and overall survival of unresectable stage IV colorectal cancer patients.

Results

One hundred twenty-five received palliative resection, and 69 received only chemotherapy. Multivariate analysis indicated that primary tumor site was one of the independent factors (RR 0.569, P = 0.007) that influenced overall survival. For left-side colon cancer patients, primary tumor resection prolonged the median overall survival time for 8 months (palliative resection vs. no palliative resection: 22 vs. 14 months, P = 0.009); however, for right-side colon cancer patients, palliative resection showed no benefit (12 vs. 10 months, P = 0.910).

Conclusions

This study showed that left-side colon cancer patients might benefit from the primary tumor resection in terms of overall survival. This result should be further explored in a prospective study.

Lymph node status as a prognostic factor after palliative resection of primary tumor for patients with metastatic colorectal cancer

Lymph node (LN) status is one of the most important predictors for M0 colorectal cancer patients. However, its clinical impact on stage IV colorectal cancer remains unclear. The study aimed to explore the prognostic value of LN status after palliative resection of primary tumor for patients with metastatic colorectal cancer (mCRC). We combined analyses of mCRC patients in Surveillance, Epidemiology and End Results (SEER) database and Fudan University Shanghai Cancer Center (FUSCC).A total of 17,553 patients with mCRC were identified in SEER database. X-tile program was adopted to identify 2 and 10 as optimal cutoff values for negative lymph node (NLN) count to divide patients into 3 subgroups of high, middle and low risk of cancer related death. N stage and NLN count were verified as independent prognostic factors in multivariate analyses of patients in whole cohort and in subgroup analyses of each N stage (P<0.05). Validation of FUSCC cohort of patients demonstrated that metastatic tumor burden (P = 0.042), NLN count (P = 0.039) and sequential chemotherapy (P = 0.040) were significant predictors of poorer CSS. Specifically, the prognosis of patients at stage N0 was significantly more favorable than that of patients at stage N2 (P = 0.038). In conclusion, primary tumor LN status was a strong predictor of CSS after palliative resection of metastatic colorectal cancer. Advanced N stage and small number of NLN were correlated with high risk of cancer related death after palliative resection of primary tumor.

Comparative effectiveness of chemotherapy vs resection of the primary tumour as the initial treatment in older patients with Stage IV colorectal cancer

AIM

The objectives were to determine trends in the use of chemotherapy as the initial treatment and to evaluate the comparative effectiveness of initial chemotherapy vs resection of the primary tumour on survival (intention-to-treat analysis) in Stage IV colorectal cancer (CRC).

METHOD

This cohort study used 2000-2011 data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database, including patients ≥ 66 years of age presenting with Stage IV CRC. Cox proportional hazards models and instrumental variable analysis were used to compare the effectiveness of chemotherapy as the initial treatment with resection of the primary tumour as the initial treatment, with 2-year survival as the end point.

RESULTS

The use of chemotherapy as the first treatment increased over time, from 26.8% in 2001 to 46.9% in 2009 (P < 0.0001). The traditional Cox model showed that chemotherapy as the initial treatment was associated with a higher risk of mortality [hazard ratio (HR) = 1.35; 95% CI: 1.27-1.44]. When accounting for known and unknown confounders in an instrumental variable analysis, chemotherapy as the initial treatment suggested benefit on 2-year survival (HR = 0.68; 95% CI: 0.44-1.04); however, the association did not reach statistical significance. The study findings were similar in six subgroup analyses.

CONCLUSION

The use of chemotherapy as the initial therapy for CRC increased substantially from 2001 to 2009. Instrumental variable analysis found that, compared with resection, chemotherapy as the initial treatment offers similar or better 2-year survival in patients with Stage IV CRC. Given the morbidity and mortality associated with colorectal resection in elderly patients, chemotherapy provides an option to patients who are not good candidates for resection.

Meta-analysis of outcomes of patients with stage IV colorectal cancer managed with chemotherapy/radiochemotherapy with and without primary tumor resection

Background

Colorectal cancer is the third leading cause of death worldwide. Currently, novel chemotherapeutic agents are first-line therapy for unresectable stage IV colorectal cancer, while benefits of noncurative primary tumor resection in advanced disease remain debatable.

Objective

This meta-analysis evaluated outcomes of patients with unresectable stage IV colorectal cancer receiving systemic chemotherapy with or without primary tumor resection.

Materials and methods

A database search of PubMed and Cochrane Library databases identified 167 studies that were screened for relevance. After 119 were excluded, 48 were assessed for eligibility and 26 were included for meta-analysis, including 24 retrospective studies, one prospective study, and one randomized, controlled trial. Extracted data included patient demographics (age, sex), clinical data (tumor stage, metastasis), targeted therapy agents, and surgical data (with/without tumor resection). Patients’ overall and progression-free survival was compared between groups with/without primary tumor resection.

Results

The 26 studies included 43,903 patients with colorectal cancer, with 29,639 receiving chemotherapy/radiotherapy plus primary tumor resection, and 14,264 managed medically with chemotherapy/chemoradiotherapy alone without primary tumor resection. Patients receiving primary tumor resection plus chemotherapy/radiotherapy had longer overall survival (hazard ratio [HR 0.59], 95% confidence interval [CI] 0.51–0.68; P<0.001), with significant differences in overall survival between patients with and without primary tumor resection (HR 0.58, 95% CI 0.49–0.68; P<0.001). Longer overall survival was also found among patients receiving primary tumor resection who were treated with bevacizumab/cetuximab targeted therapy agents (HR 0.63, 95% CI 0.46–0.86; P=0.003). Patients from three studies who received primary tumor resection had longer progression-free survival (HR 0.73, 95% CI 0.58–0.91; P=0.005). Results are limited by retrospective data, inconsistent complications data, and publication bias.

Conclusion

Study results support primary tumor resection in stage IV colorectal cancer, but significant biases in studies suggest that randomized trials are warranted to confirm findings.

Oncometabolite D-2-Hydroxyglurate Directly Induces Epithelial-Mesenchymal Transition and is Associated with Distant Metastasis in Colorectal Cancer

Deranged metabolism is a hallmark of cancer, playing a significant role in driving the disease process. One such example is the induction of carcinogenesis by the oncometabolite D-2 hydroxyglutarate (D-2HG), which is produced by the mutated enzyme isocitrate dehydrogenase (IDH) occurring in subsets of leukaemias and brain tumours. The oncogenic property of D-2HG appears to stem from its ability to interfere with the activities of α-ketoglutarate-dependent dioxygenases, including the Jumonji family histone demethylases. Here, we find in colorectal cancer cells that even in the absence of IDH mutation, the levels of D-2HG and its enantiomer L-2HG were elevated through glutamine anaplerosis. D-2HG, but not L-2HG, increased the trimethylation of histone H3 lysine 4 of the promoter region of ZEB1, a master regulator of epithelial-mesenchymal transition (EMT), and increased the expression of the ZEB1 gene to directly induce EMT in colorectal cancer cells. EMT promotes the ability of cancer cells to invade the local tissue and enter into the bloodstream, leading to distant organ metastasis. D-2HG levels were elevated in colorectal cancer specimens, particularly in those associated with distant metastasis, supporting the observations in vitro and implicating the contribution of D-2HG in metastasis, the major cause of death in this disease.

A Pretargeted Approach for the Multimodal PET/NIRF Imaging of Colorectal Cancer

The complementary nature of positron emission tomography (PET) and near-infrared fluorescence (NIRF) imaging makes the development of strategies for the multimodal PET/NIRF imaging of cancer a very enticing prospect. Indeed, in the context of colorectal cancer, a single multimodal PET/NIRF imaging agent could be used to stage the disease, identify candidates for surgical intervention, and facilitate the image-guided resection of the disease. While antibodies have proven to be highly effective vectors for the delivery of radioisotopes and fluorophores to malignant tissues, the use of radioimmunoconjugates labeled with long-lived nuclides such as ⁸⁹Zr poses two important clinical complications: high radiation doses to the patient and the need for significant lag time between imaging and surgery. In vivo pretargeting strategies that decouple the targeting vector from the radioactivity at the time of injection have the potential to circumvent these issues by facilitating the use of positron-emitting radioisotopes with far shorter half-lives. Here, we report the synthesis, characterization, and in vivo validation of a pretargeted strategy for the multimodal PET and NIRF imaging of colorectal carcinoma. This approach is based on the rapid and bioorthogonal ligation between a trans-cyclooctene- and fluorophore-bearing immunoconjugate of the huA33 antibody (huA33-Dye800-TCO) and a ⁶⁴Cu-labeled tetrazine radioligand (⁶⁴Cu-Tz-SarAr). In vivo imaging experiments in mice bearing A33 antigen-expressing SW1222 colorectal cancer xenografts clearly demonstrate that this approach enables the non-invasive visualization of tumors and the image-guided resection of malignant tissue, all at only a fraction of the radiation dose created by a directly labeled radioimmunoconjugate. Additional in vivo experiments in peritoneal and patient-derived xenograft models of colorectal carcinoma reinforce the efficacy of this methodology and underscore its potential as an innovative and useful clinical tool.

Factors associated with postoperative complications and 1-year mortality after surgery for colorectal cancer in octogenarians and nonagenarians

Purpose

To identify the factors affecting 30-day postoperative complications and 1-year mortality after surgery for colorectal cancer in octogenarians and nonagenarians.

Methods

Between 2005 and 2014, a total of 204 consecutive patients aged ≥80 years who underwent major colorectal surgery were included.

Results

One hundred patients were male (49%) and 52 patients had American Society of Anesthesiologists (ASA) score ≥3 (25%). Combined surgery was performed in 32 patients (16%). Postoperative complications within 30 days after surgery occurred in 54 patients (26%) and 30-day mortality occurred in five patients (2%). Independent risk factors affecting 30-day postoperative complications were older age (≥90 years, hazard ratio [HR] with 95% confidence interval [CI] =4.95 [1.69−14.47], P=0.004), an ASA score ≥3 (HR with 95% CI =4.19 [1.8−9.74], P=0.001), performance of combined surgery (HR with 95% CI =3.1 [1.13−8.46], P=0.028), lower hemoglobin level (<10 g/dL, HR with 95% CI =7.56 [3.07−18.63], P<0.001), and lower albumin level (<3.4 g/dL, HR with 95% CI =3.72 [1.43−9.69], P=0.007). An ASA score ≥3 (HR with 95% CI =2.72 [1.15−6.46], P=0.023), tumor-node-metastasis (TNM) stage IV (HR with 95% CI =3.47 [1.44−8.39], P=0.006), and occurrence of postoperative complications (HR with 95% CI =4.42 [1.39−14.09], P=0.012) were significant prognostic factors for 1-year mortality.

Conclusion

Patient-related factors (older age, higher ASA score, presence of anemia, and lower serum albumin) and procedure-related factors (performance of combined surgical procedure) increased postoperative complications. Avoidance of 30-day postoperative complications may decrease 1-year mortality.

Long-term outcomes of palliation for unresectable colorectal cancer obstruction in patients with good performance status: endoscopic stent versus surgery

BACKGROUND

In patients with unresectable colorectal cancer (CRC) obstruction, choosing whether to perform self-expandable metal stent (SEMS) or palliative surgery is challenging, especially in those with good performance status. We aimed to compare the long-term outcomes of SEMS with those of palliative surgery in patients with unresectable CRC obstruction.

METHODS

This retrospective study comprised 114 patients with unresectable CRC obstruction who underwent SEMS placement (n = 73) or palliative surgery (n = 41). The main outcome measurements were success rate, adverse events, patency, and survival duration.

RESULTS

Early clinical success rates did not differ between SEMS and surgery. However, the rate of late adverse events was significantly higher in the SEMS group (27.4 vs. 9.8 %; P = .005). Patency duration was shorter after SEMS than after surgery (163 vs. 349 days; P < .001), even after additional intervention (202 vs. 349 days; P < .001). The median survival was significantly shorter after SEMS than after surgery (209 vs. 349 days; P = .005). Survival differed between treatments in patients with Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 (P = .016) but not in those with ECOG 2 or 3 (P = .487), and this was confirmed by multivariate analysis, which showed that surgery was a significant favorable predictor of survival for patients with ECOG 0 or 1 (hazard ratio .442; 95 % confidence interval .234-.835; P = .016).

CONCLUSIONS

Surgery may be preferable to SEMS for the palliation of unresectable CRC obstruction in patients with good performance status, especially ECOG 0 or 1.

A scoring model for predicting survival following primary tumour resection in stage IV colorectal cancer patients with unresectable metastasis

BACKGROUND

Stage IV colorectal cancer patients with unresectable metastasis who undergo elective primary tumour resection experience heterogeneous post-operative survival. We aimed to develop a scoring model for predicting post-operative survival using pre-operative variables to identify patients who are least likely to experience extended survival following the procedure.

METHODS

Survival data were collected from stage IV colorectal cancer patients who had undergone elective primary tumour resection between January 1999 and December 2007. Coefficients of significant covariates from the multivariate Cox regression model were used to compute individual survival scores to classify patients into three prognostic groups. A survival function was derived for each group via Kaplan-Meier estimation. Internal validation was performed.

RESULTS

Advanced age (hazard ratio, HR 1.43 (1.16-1.78)); poorly differentiated tumour (HR 2.72 (1.49-5.04)); metastasis to liver (HR 1.76 (1.33-2.33)), lung (HR 1.37 (1.10-1.71)) and bone (HR 2.08 ((1.16-3.71)); carcinomatosis (HR 1.68 (1.30-2.16)); hypoalbuminaemia (HR 1.30 (1.04-1.61) and elevated carcinoembryonic antigen levels (HR 1.89 (1.49-2.39)) significantly shorten post-operative survival. The scoring model separated patients into three prognostic groups with distinct median survival lengths of 4.8, 12.4 and 18.6 months (p < 0.0001). Internal validation revealed a concordance probability estimate of 0.65 and a time-dependent area under receiver operating curve of 0.75 at 6 months. Temporal split-sample validation implied good local generalizability to future patient populations (p < 0.0001).

CONCLUSION

Predicting survival following elective primary tumour resection using pre-operative variables has been demonstrated with the scoring model developed. Model-based survival prognostication can support clinical decisions on elective primary tumour resection eligibility.

Differences in clinical features between laparoscopy and open resection for primary tumor in patients with stage IV colorectal cancer

PURPOSE

To identify differences in clinical features between laparoscopy and open resection for primary tumor in patients with stage IV colorectal cancer. We also evaluated short-term and oncologic outcomes after laparoscopy and open surgery.

METHODS

A total of 100 consecutive stage IV patients undergoing open (n=61) or laparoscopic (n=39) major resection were analyzed. There were four cases (10%) of conversion to laparotomy in the laparoscopy group.

RESULTS

Pathological T4 tumors (56% vs 26%), primary colon cancers (74% vs 51%), and larger tumor diameter (6 vs 5 cm) were more commonly managed with open surgery. Right colectomy was more common in the open surgery group (39%) and low anterior resection was more common in the laparoscopy group (39%, P=0.002). Hepatic metastases in segments II, III, IVb, V, and VI were more frequently resected with laparoscopy (100%) than with open surgery (56%), although the difference was not statistically significant. In colon and rectal cancers, mean operative time and 30-day complication rates of laparoscopy and open surgery did not differ. In both cancers, mean time to soft diet and length of hospital stay were shorter in the laparoscopy group. Mean time from surgery to chemotherapy commencement was significantly shorter with laparoscopy than with open surgery. In colon and rectal cancers, 2-year cancer-specific and progression-free survival rates were similar between the laparoscopy and open surgery groups.

CONCLUSION

Based on our findings, laparoscopy can be selected as an initial approach in patients with a primary tumor without adjacent organ invasion and patients without primary tumor-related symptoms. In selected stage IV patients, tumor factors such as primary rectal tumor, peritoneal carcinomatosis, or liver metastasis may not be absolute contraindications for a laparoscopic approach.

Factors Affecting Use and Delay (≥8 Weeks) of Adjuvant Chemotherapy after Colorectal Cancer Surgery and the Impact of Chemotherapy-Use and Delay on Oncologic Outcomes

Purpose

To evaluate factors affecting the use and delay ≥8 weeks of adjuvant chemotherapy and the impact of chemotherapy use and delay on survival.

Methods

Between 2005 and 2012, consecutive patients with stage II and III colorectal cancer who were treated with major curative resection were enrolled.

Results

Among 750 patients with stage II (n = 318) and III (n = 432) disease, 153 (20.4%) did not receive chemotherapy. Among 597 patients with adjuvant chemotherapy, 31 (5.2%) began chemotherapy 8 weeks or more after surgery. Factors associated with not receiving chemotherapy were: age ≥80 years (hazard ratio [HR] = 5.2), American Society of Anesthesiologists score ≥3 (HR = 1.9), underlying cerebrovascular disease (HR = 1.7), stage II disease (HR = 2.0), presence of postoperative complications (HR = 2.2), or intensive care unit admission (HR = 2.4). Factors associated with chemotherapy delay ≥8 weeks were: male sex (HR = 4.2), rectal primary cancer (HR = 5.4), or presence of postoperative complications (HR = 2.5). Independent prognostic factors for overall survival included TNM III stage (HR = 2.04) and chemotherapy delay ≥8 weeks (HR = 0.39) or <8 weeks (HR = 0.22). Independent prognostic factors for recurrence-free survival were TNM III stage (HR = 2.26) and chemotherapy delay <8 weeks (HR = 0.35).

Conclusions

Postoperative complications were associated with both lack of and delayed chemotherapy. Timely initiation of chemotherapy, defined as <8 weeks, was a favorable prognostic factor for overall and recurrence-free survival. To increase the proportion of patients receiving chemotherapy and timely initiation of chemotherapy, surgical complications should be minimized after curative resection.

The role of palliative resection for asymptomatic primary tumor in patients with unresectable stage IV colorectal cancer

BACKGROUND

The prognostic role of surgical resection of primary tumors is not well established in patients with asymptomatic unresectable stage IV colorectal cancer.

OBJECTIVE

The aims of this study were to reveal the prognostic role of surgical resection of primary tumors and to define prognostic factors affecting long-term oncological outcomes in patients with asymptomatic unresectable synchronous metastases.

DESIGN

This study was a retrospective analysis of prospectively collected data.

PATIENTS

Between 2000 and 2008, a total of 416 patients with asymptomatic unresectable stage IV colorectal cancer were analyzed with propensity score matching.

MAIN OUTCOME MEASURES

Prematching baseline characteristics were compared by bivariate analysis, and 113 pairs were selected after 1:1 matching with propensity scores estimated from logistic regression. The primary end point was overall survival.

RESULTS

Among 416 patients, 218 (52.4%) underwent palliative resection of the primary tumor. Before propensity score matching, palliative resection resulted in a better survival rate than nonresection in univariate analysis (p < 0.001), but not in multivariate analysis (p = 0.08). After matching, the 5-year overall survival rate was significantly lower for patients with peritoneal metastasis and clinical M1b stage tumors in univariate analysis (p = 0.004 and p = 0.02). However, neither peritoneal metastasis nor clinical M1b stage showed any prognostic significance in multivariate analysis. The overall 5-year survival rate of the postmatching group was 4.9% and 3.5% in the palliative resection and nonresection groups. Consequently, palliative resection was not associated with a significant increase in survival compared with nonresection (p = 0.27). A subgroup analysis performed according to the site of metastasis also did not show any significant survival benefit of palliative resection after matching.

LIMITATIONS

Selection bias and potential confounders were limitations of this study.

CONCLUSIONS

Resection of the primary tumor in patients with asymptomatic unresectable stage IV colorectal cancer was not associated with an improvement in overall survival after propensity score matching.

Risk factors for the requirement of surgical or endoscopic interventions during chemotherapy in patients with uncomplicated colorectal cancer and unresectable synchronous metastases

BACKGROUND AND OBJECTIVES

The purpose of this study was to determine the risk factors for requirement of surgical or endoscopic interventions for complications caused by the primary tumor during chemotherapy in patients with unresectable metastatic colorectal cancer.

METHODS

A total of 259 patients were diagnosed with uncomplicated colorectal cancer with unresectable metastatic disease and underwent chemotherapy as an initial treatment. Among them, 57 (22.0%) patients underwent palliative interventions because of complications caused by the primary tumor during chemotherapy, including bypass surgery or diverting enterostomy for 22 patients, insertion of colonic stent for 22, and resection of primary tumor for 13.

RESULTS

Multivariate analysis revealed that rectal lesion (RR, 2.132; 95% CI, 1.080-4.210; P = 0.029) and tumor size larger than 5 cm (RR = 3.644, 95% CI = 1.923-6.902; P < 0.001) were significant risk factors for requirement of palliative intervention. Patients who had none of the risk factors showed better overall survival than those who had one or more (P = 0.021).

CONCLUSIONS

Tumor location in rectum and tumor size larger than 5 cm were significant risk factors for the requirement of surgical or endoscopic interventions during chemotherapy for complications caused by the primary tumor in patients with unresectable metastatic colorectal cancer.

Association between palliative resection of the primary tumor and overall survival in a population-based cohort of metastatic colorectal cancer patients

BACKGROUND

The impact of palliative resection of the primary tumor on outcomes in patients with metastatic colorectal cancer (mCRC) remains unclear. The primary objective of this study was to evaluate the association between palliative resection and overall survival (OS) in a population-based cohort of mCRC.

METHODS

Patients diagnosed with mCRC between 2006 and 2008 and treated at the BC Cancer Agency were reviewed. Survival analysis was conducted using Kaplan-Meier methods. Cox proportional hazards regression models were fitted to evaluate the relationship between palliative resection and OS while controlling for potential confounders, such as age, gender, Eastern Cooperative Oncology Group status, carcinoembryonic antigen level, primary tumor location, metastatic site and number, and receipt of systemic therapy. To adjust for the heterogeneity and selection bias between the group that underwent palliative resection and the group that did not, a propensity score-matched analysis was also performed.

RESULTS

A total of 517 patients were included. Among these cases, 378 (73 %) patients underwent palliative resection of their primary tumor, and 139 (27 %) patients did not. A total of 327 patients (63 %) were treated with palliative chemotherapy. Palliative resection was associated with a longer median OS (17.9 vs. 7.9 months) and more favorable unadjusted and adjusted hazard ratios (HRs) for death (HR 0.46, 95 % CI 0.37-0.56, p < 0.0001 and HR 0.56, 95 % CI 0.40-0.78, p = 0.0007, respectively) when compared with no resection. In a propensity score-matched analysis, prognosis was also more favorable in the resected group (p = 0.0017).

CONCLUSIONS

In this cohort of mCRC patients, palliative resection of the primary tumor was associated with improved OS.

A meta-analysis to determine the effect of primary tumor resection for stage IV colorectal cancer with unresectable metastases on patient survival

BACKGROUND

Approximately 20 % of patients diagnosed with colorectal cancer will have distant metastases at first presentation (stage IV disease). The effect of removing the primary tumor on survival for patients with stage IV disease with unresectable metastases remains unclear. To address this a meta-analysis of all studies comparing primary tumor resection with chemotherapy alone in cases of stage IV colorectal cancer with unresectable metastases was performed.

METHODS

A comprehensive search for published studies examining the effect of primary tumor resection in the setting of colorectal cancer with unresectable metastases was performed. Each study was reviewed and data extracted. Random-effects methods were used to combine data.

RESULTS

There were 21 studies including a total of 44,226 patients that met the inclusion criteria. Resection of the primary tumor in patients with unresectable metastases compared with chemotherapy alone was associated with a lower mortality risk (OR 0.28; 95 % CI 0.165-0.474; P < 0.001), translating into a difference in mean survival of 6.4 months in favor of resection (95 % CI 5.025-7.858, P < 0.001). Patients who underwent resection of the primary tumor were more likely to have liver metastasis only (OR 1.551; 95 % CI 1.247-1.929; P < 0.001), were less likely to have ≥2 metastasis (OR 0.653; 95 % CI 0.508-0.839; P = 0.001), and were less likely to have rectal cancer (OR 0.495; 95 % CI 0.390-0.629; P < 0.001). There was significant cross-study heterogeneity.

CONCLUSIONS

Resection of the primary tumor may confer a survival advantage in stage IV colorectal cancer with unresectable metastases but significant selection bias exists in current studies. Randomized controlled trials are essential to validate these findings.