Prognostic factors associated with primary cancer in curatively resected stage IV colorectal cancer

Development and validation of a prognostic scoring system for patients with colorectal cancer hepato-pulmonary metastasis: a retrospective study

Background

Hepato-pulmonary metastasis of colorectal cancer (CRC) is a rare disease with poor prognosis. This study aims to establish a highly efficient nomogram model to predict overall survival (OS) and cancer-specific survival (CSS) in patients with colorectal cancer hepato-pulmonary metastasis (CRCHPM).

Methods

We retrospectively analyzed the data of patients with CRCHPM from SEER database and Wuhan Union Hospital Cancer Center (WUHCC). A total of 1250 CRCHPM patients were randomly assigned to the training, internal validation, and external validation cohorts from 2010 to 2016.Univariate and multivariate cox analysis were performed to identify independent clinicopathological predictors of OS and CSS, and a nomogram was constructed to predict OS and CSS in CRCHPM patients.

Results

A nomogram of OS was constructed based on seven independent predictors of age, degree of differentiation, T stage, chemotherapy, number of lsampled lymph nodes, number of positive lymph nodes, and tumor size. Nomogram showed favorable sensitivity in predicting OS at 1, 3 and 5 years, with area under the receiver operating characteristic curve (AUROC) values of 0.802, 0.759 and 0.752 in the training cohort;0.814, 0.769 and 0.716 in the internal validation cohort;0.778, 0.756 and 0.753 in the external validation cohort, respectively. A nomogram of CSS was constructed based on three independent predictors of T stage, chemotherapy, and tumor size. The AUROC values of 1, 3 and 5 years were 0.709,0.588,0.686 in the training cohort; 0.751, 0.648,0.666 in the internal validation cohort;0.781,0.588,0.645 in the external validation cohort, respectively. Calibration curves, Concordance index (C-index), and decision curve analysis (DCA) results revealed that using our model to predict OS and CSS is more efficient than other single clinicopathological characteristics.

Conclusion

A nomogram of OS and CSS based on clinicopathological characteristics can be conveniently used to predict the prognosis of CRCHPM patients.

Has the COVID-19 Pandemic Caused Upshifting in Colorectal Cancer Stage?

Purpose

Coronavirus disease 2019 (COVID-19) has affected many parts of daily life and healthcare, including cancer screening and diagnosis. The purpose of this study was to determine whether there was an upshift in the colorectal cancer stage at diagnosis due to delays related to the COVID-19 outbreak.

Methods

From January to June of each year from 2017 to 2020, a total of 3,229 patients who were first diagnosed with colorectal cancer were retrospectively reviewed. Those enrolled from 2017 to 2019 were classified as the ‘pre-COVID’ group, and those enrolled in 2020 were classified as the ‘COVID’ group. The primary outcome was the rate of stage IV disease at the time of diagnosis.

Results

There was no statistically significant difference in the proportion of stage IV patients between the pre-COVID and COVID groups (P=0.19). The median preoperative carcinoembryonic antigen level in the COVID group was higher than in the pre-COVID group in all stages (all P<0.05). In stage I, II patients who underwent radical surgery, the lymphatic invasion was more presented in COVID patients (P=0.009).

Conclusion

We did not find significant stage upshifting in colorectal cancer during the COVID-19 outbreak. However, there were more initially unresectable stage IV colorectal cancer patients with a low conversion rate to resectable status, and more patients had factors related to poor prognosis. These results may become more apparent over time, so it is vital not to neglect cancer screening to not delay the diagnosis during the COVID-19 epidemic.

Nomogram for predicting overall survival in colorectal cancer with distant metastasis

Background

Colorectal cancer (CRC) is a major cancer burden, and prognosis is determined by many demographic and clinicopathologic factors. The present study aimed to construct a prognostic nomogram for colorectal cancer patients with distant metastasis.

Methods

Colorectal cancer patients with distant metastasis diagnosed between 2010 and 2016 were selected from the Surveillance, Epidemiology, and End Results database. Cox proportional hazards regression was used to identify independent prognostic factors. A nomogram was constructed to predict survival, and validation was performed.

Results

A total of 7099 stage IV colorectal cancer patients were enrolled in the construction cohort. The median overall survival was 20.0 (95% CI 19.3–20.7) months. Age at diagnosis, marital status, race, primary tumour site, tumour grade, CEA level, T stage, N stage, presence of bone, brain, liver and lung metastasis, surgery for primary site and performance of chemotherapy were independent prognostic factors. The nomogram was constructed and the calibration curve showed satisfactory agreement. The C-index was 0.742 (95% CI 0.726–0.758). In the validation cohort (7098 patients), the nomogram showed satisfactory discrimination and calibration with a C-index of 0.746 (95% CI 0.730–0.762).

Conclusion

A series of factors associated with the survival of CRC patients with distant metastasis were found. Based on the identified factors, a nomogram was generated to predict the survival of stage IV colorectal cancer patients. The predictive model showed satisfactory discrimination and calibration, which can provide a reference for survival estimation and individualized treatment decisions.

High Serum CA19-9 Concentration Predicts Poor Prognosis in Elderly Patients with Stage IV Colorectal Cancer

BACKGROUND/AIM

The optimal treatment strategy for elderly patients with stage IV colorectal cancer (CRC) remains controversial due to limited research data. The purpose of this study was to evaluate treatment results and to clarify the prognostic factors, especially poor prognosis factors, in elderly patients with stage IV CRC.

METHODS

We retrospectively reviewed the data of 82 elderly patients (aged ≥75 years) with stage IV CRC who underwent surgical treatment at our hospital between April 2001 and March 2017. Factors that affected prognosis and the ability to undergo treatment were analyzed via multivariate analysis.

RESULTS

The median overall survival (OS) in the patients with high pretreatment serum carbohydrate antigen 19-9 (CA19-9) concentration (> 370 U/mL) was significantly worse than in those with lower serum CA19-9 concentration (0-370 U/mL) (8.5 vs. 19.2 months, p = 0.0059). In univariate analysis, age (≥80 years) (p = 0.014), performance status of 1-3 (p = 0.028), and high pretreatment serum CA19-9 concentration (p = 0.014) were significant prognostic factors for poor OS. By contrast, resection of the primary tumor (p = 0.024), chemotherapy (p < 0.0001), and resection of distant metastasis (p = 0.0005) were significant prognostic factors for favorable OS. Multivariate analysis showed that a high pretreatment serum CA19-9 concentration was an independent prognostic factor for poor OS (p = 0.01). Meanwhile, resection of the primary tumor (p = 0.033), chemotherapy (p < 0.0001), and resection of distant metastasis (p = 0.0008) were prognostic factors for favorable OS.

CONCLUSIONS

A high pretreatment serum CA19-9 concentration (> 370 U/mL) was a reliable predictive factor for poor prognosis, and aggressive treatments should be performed carefully in these patients. Moreover, various treatments, including surgery and chemotherapy, might improve OS in elderly patients with stage IV CRC.

Outcomes of stage IV patients with colorectal cancer treated in a single institution: What is the key to the long-term survival?

OBJECTIVES

The purpose of this study is to summarize our short- and long-term treatment results for stage IV colorectal cancer (CRC) and to clarify the factors predicting the favorable long-term survival.

METHODS

Between January 2008 and December 2015, 149 consecutive patients with stage IV CRC underwent initial treatment at Nagoya University Hospital. Their clinical and pathological characteristics, the treatment methods used, and the outcomes were retrospectively analyzed.

RESULTS

The median observation period was 23 months. All of the primary and metastatic lesions were technically resectable in 74 patients; however, the remaining 75 were judged as initially unresectable. R0/1 resection during the treatment course was achieved in 74 patients (50%). For the cohort as a whole, the 5-year overall survival (OS) rate was 35%. The 5-year OS rate in the R0/1 resection group was 57%, which was significantly better than that of the non-R0/1 resection group (6%, p < 0.001). In the R0/1 resection group, perioperative chemotherapy significantly improved the outcome (5-year OS; 62% vs. 0%, p = 0.03). In the non-R0/1 resection group, primary tumor resection was associated with a significantly higher favorable prognosis (3-year OS; 20.4% vs. 0%, p = 0.026). Moreover, the additional use of molecular targeted drugs significantly improved the survival. In multivariate analysis, the differentiated histologic type, R0/1 resection, and parallel use of molecular targeted drugs remained independent factors of a favorable outcome.

CONCLUSIONS

The present study suggested that aggressive curative resection with perioperative chemotherapy might improve survival and that primary tumor resection might improve the outcome in the non-R0/1 group.

High preoperative serum CA 19-9 levels can predict poor oncologic outcomes in colorectal cancer patients on propensity score analysis

Purpose

The purpose of this study is to evaluate the prognostic value of preoperative serum CA 19-9 levels in colorectal cancer patients.

Methods

Between 2008 and 2011, 4,794 consecutive patients who underwent curative resection for colorectal cancer were analyzed. These patients were classified into 2 groups according to preoperative CA 19-9 (high CA 19-9: ≥37 ng/mL, n = 440; normal CA 19-9: <37 ng/mL, n = 4,354). We used 1:20 propensity score matching to adjust for potential baseline confounders between groups.

Results

After matching, 424 patients (10.5%) among 4,021 patients with colorectal cancer showed a high pre-CA 19-9 level (≥37 ng/mL). There were no significant differences between these 2 groups in age, sex, preoperative CEA level, or T, N, and M stage after matching. Of the 424 patients with high pre-CA 19-9, 141 (33.3%) exhibited cancer recurrence more frequently than patients with normal preoperative CA 19-9 (18.5%). Patients with an elevated preoperative CA 19-9 level showed significantly poorer survival than those with normal levels. The 5-year overall survival rate was 79.7% in the high preoperative CA 19-9 group and 91.9% in the normal preoperative CA 19-9 group (P < 0.001). The 5-year disease-free survival rate was 70.2% in the high preoperative CA 19-9 group and 82.7% in the normal preoperative CA 19-9 group (P < 0.001).

Conclusion

Patients with an elevated preoperative CA 19-9 level in colorectal cancer have a significantly poorer prognosis than those with normal levels of CA 19-9. We therefore suggest preoperative CA 19-9 level can be used as an additional prognostic indicator of poor outcomes in colorectal cancer.

The impacts of surgery of the primary cancer and radiotherapy on the survival of patients with metastatic rectal cancer

The role of surgery of the primary cancer and radiation in metastatic colorectal cancer (mCRC) is still controversial currently, and evidence implied that colon cancer (CC) and rectal cancer (RC) should be treated with difference. Hence we focused on metastatic rectal cancer (mRC) solely to compare the cancer cause-specific survival (CSS) of patients receiving varied treatments of the primary cancer: no treatment, surgery only, radiation only, and surgery plus radiation, based on the records of the Surveillance, Epidemiology, and End Results (SEER) database. A total of 8669 patients were included. Results demonstrated that the 2-year CSS was 28.1% for no treatment group, 30.7% for only radiation group, 50.2% for only surgery group, and 66.5% for surgery plus radiation group, reaching statistical difference (P < 0.001). Furthermore, the CSSs of mRC patients in the surgery group were similar regardless of resection ranges (P = 0.44). Besides, we analyzed the prognostic factors for mRC and found carcinoembryonic antigen (CEA) level, metastasis (M) stage, Tumor (T) stage, tumor size, differentiate grade, age and marital status should be taken into consideration when estimating the prognosis. Particularly, patients with normal CEA level or M1a stage showed a significant survival advantage. Overall, present study suggested that surgery of the primary cancer and radiation might help to improve the survival of mRC patients, especially when both treatments were conducted. Our results may assist clinicians to make better treatment strategy for patients with mRC.

Synchronous hepatic metastasis and metachronous Krukenberg tumor from advanced colon cancer. A case report with an unexpected disease-free survival

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The prognosis of a colon cancer with hepatic and ovarian metastasis is very poor.

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A colon cancer patient with hepatic and ovarian metastases can heal.

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In the literature we have never found a similar case.

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An appropriate surgical approach, a tailored chemotherapy and an intensive follow-up are essential.

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The degree to which HIPEC may have had an impact is still unknown.

Background

In the international literature we have never found a long survival in patients treated for a colon cancer with synchronous hepatic metastases and for a metachronous Krukenberg tumor.

Presentation of case

A 46-year old woman for an advanced colon cancer with a synchronous hepatic metastases was subjected to a left hemicolectomy and a resection of liver segment V (R0 resection; T4N2bM1; stage IVa according AJCC 2010). After one year a CT of the abdomen revealed an expansive formation of the left ovary. The patient was subjected to a bilateral ovariectomy, hysterectomy and hiperthermic intraperitoneal chemotherapy (HIPEC). The patient, after several cycles of adjuvant chemotherapy, is disease-free 13 years after surgery.

Discussion

To our knowledge, in the literature there do not appear to be cases of such disease-free survival. The survival of patient despite the prognostic indexes is discussed. The authors discus the importance of an adequate surgical treatment especially for liver metastases simultaneously treated to colon cancer. The authors also focus on chemotherapy (FOLFOX and then FOLFIRI) performed in a pre-biological era. Furthermore, the degree to which the HIPEC may have had an impact is still unknown, although it seems to be the gold standard for the treatment of the microscopic peritoneal neoplastic remnant.

Conclusion

The authors emphasize that the long term survival in colon cancer with hepatic and ovarian metastases is possible as long as it has an adequate surgical approach, a tailored chemotherapy and an intensive follow-up. Most likely new prognostic markers will have to be identified.

Prognostic impact of carcinoembryonic antigen and carbohydrate antigen 19-9 in stage IV colorectal cancer patients after R0 resection

BACKGROUND

Although preoperative carcinoembryonic antigen (pre-CEA) and carbohydrate antigen 19-9 (pre-CA 19-9) are reportedly prognostic indicators for colorectal cancer (CRC), the prognostic roles of postoperative CEA (post-CEA) and CA 19-9 (post-CA 19-9) shortly after surgery have not been clarified in patients with curatively resected stage IV CRC. The aim of this study was to evaluate the predictive abilities of post-CEA and post-CA 19-9.

METHODS

A total of 129 consecutive patients who had stage IV CRC and underwent R0 resection were retrospectively analyzed. Pre-CEA and post-CEA and CA 19-9 levels were measured within 1 mo before and 3 mo after surgery, respectively. Relapse-free survival (RFS) and overall survival were estimated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazards model.

RESULTS

Pre-CEA was elevated (≥5.0 ng/mL) in 73.6% of the patients and remained elevated after surgery in 32.7% of the patients. Elevated post-CA 19-9 (≥50 U/mL) was observed in 9.5% of the patients. Neither elevated pre-CEA nor elevated pre-CA 19-9 was significantly associated with RFS but both elevated post-CEA and elevated post-CA 19-9 were associated with markedly reduced RFS (P = 0.0002 and P = 0.0004, respectively). When considered in combination, post-CEA and post-CA 19-9 significantly stratified RFS and was an independent predictive factor for recurrence (P = 0.0035), as was lymphatic invasion (P = 0.0015). Post-CA 19-9 was the only evident independent predictive factor for overall survival (P = 0.0336).

CONCLUSIONS

In patients with stage IV CRC who underwent curative resection, the combination of post-CEA and post-CA 19-9 at 3 mo after surgery was a potent prognostic indicator for recurrence.

Prognostic Significance of Preoperative Serum Carbohydrate Antigen 19-9 in Patients With Stage IV Colorectal Cancer

INTRODUCTION

Carbohydrate antigen (CA) 19-9 is a widely used tumor marker in colorectal cancer (CRC). However, its prognostic impact in patients with stage IV CRC who have undergone curative resection is not clear. We evaluated the prognostic power of preoperative serum CA 19-9 in these patients.

PATIENTS AND METHODS

We performed a retrospective review of 173 patients with stage IV CRC who had undergone curative resection at our institution. Patients were categorized into normal and high CA 19-9 groups, and relapse-free survival and overall survival were compared using Kaplan-Meier curves. Multivariate analyses were performed using a Cox proportional hazard model.

RESULTS

The preoperative serum CA 19-9 level was elevated in 80 patients (46%). The 3-year relapse-free survival of the high CA 19-9 group was significantly worse than that of the normal CA 19-9 group (18% vs. 28%, respectively; P = .026). The 3-year overall survival of the high CA 19-9 group was significantly lower than that of the normal CA 19-9 group (75% vs. 82%; P = .047). Multivariate analyses indicated that elevated preoperative serum CA 19-9 level was an independent prognostic factor for poor relapse-free survival and overall survival, with a hazard ratio of 1.46 (95% confidence interval, 1.03-2.06; P = .035) and 1.90 (95% confidence interval, 1.10-3.29; P = .023), respectively.

CONCLUSION

The preoperative serum CA 19-9 level is a good predictive marker of tumor recurrence and prognosis in patients with stage IV CRC who have undergone curative resection.

A clinical prognostic scoring system for resectable gastric cancer to predict survival and benefit from paclitaxel- or oxaliplatin-based adjuvant chemotherapy

Background

Gastrectomy with D2 lymphadenectomy is a standard procedure of curative resection for gastric cancer (GC). The aim of this study was to develop a simple and reliable prognostic scoring system for GC treated with D2 gastrectomy combined with adjuvant chemotherapy.

Methods

A prognostic scoring system was established based on clinical and laboratory data from 579 patients with localized GC without distant metastasis treated with D2 gastrectomy and adjuvant chemotherapy.

Results

From the multivariate model for overall survival (OS), five factors were selected for the scoring system: ≥50% metastatic lymph node rate, positive lymphovascular invasion, pathologic TNM Stage II or III, ≥5 ng/mL preoperative carcinoembryonic antigen level, and <110 g/L preoperative hemoglobin. Two models were derived using different methods. Model A identified low- and high-risk patients for OS (P<0.001), while Model B differentiated low-, intermediate-, and high-risk patients for OS (P<0.001). Stage III patients in the low-risk group had higher survival probabilities than Stage II patients. Both Model A (area under the curve [AUC]: 0.74, 95% confidence interval [CI]: 0.69–0.78) and Model B (AUC: 0.79, 95% CI: 0.72–0.83) were better predictors compared with the pathologic TNM classification (AUC: 0.62, 95% CI: 0.59–0.71, P<0.001). Adjuvant paclitaxel- or oxaliplatin-based or triple chemotherapy showed significantly better outcomes in patients classified as high risk, but not in those with low and intermediate risk.

Conclusion

A clinical three-tier prognostic risk scoring system was established to predict OS of GC treated with D2 gastrectomy and adjuvant chemotherapy. The potential advantage of this scoring system is that it can identify high-risk patients in Stage II or III who may benefit from paclitaxel- or oxaliplatin-based regimens. Prospective studies are needed to confirm these results before they are applied clinically.

Synchronous Resectable Metastatic Colorectal Cancer: Lymph Node Involvement Predicts Poor Outcome

To evaluate the value of lymph node status of primary tumors in predicting the prognosis of synchronous resectable metastatic colorectal cancer (mCRC).The characteristics of resectable mCRC are substantially different from other cancers, and the prognostic factors of resectable mCRC are still controversial.The data of 2007 patients with mCRC who received resection of the primary tumors and metastatic lesions synchronously were reviewed from the Surveillance, Epidemiology and End-Result database. The Kaplan-Meier method was used to evaluate the capacity of different prognostic factors. Univariate and multivariate logistic regression models were used to evaluate the relationship between the lymph node status and other factors. The mRNA profiles of primary resectable mCRC tumors were obtained by microarray at our center.The median survival times were 50, 36, 32, 27, and 19 months in the N0-stage, N1a-stage, N1b-stage, N2a-stage, and N2b-stage subgroups according to the 7th American Joint Committee on Cancer (AJCC) Tumor Lymph Node Metastasis (TNM) N-classification (P = 0.000), and 40, 29, 22, and 15 months in patients with metastatic lymph node ratio (LNR) <0.25, 0.25-0.49, 0.5-0.74, and ≥0.75 subgroups (P = 0.000). In the COX model, the 7th AJCC TNM N-stage and LNR were independent prognostic factors. The mRNA profile was not associated with lymph node involvement.Both the N-stage according to the 7th AJCC TNM staging system and LNR had the capacity to subclassify synchronous resectable mCRC with different prognoses. The lymph node might be integrated into the AJCC staging system as a diagnose-delay prognostic factor for stage IV disease.

Is Chemoradiotherapy Beneficial for Stage IV Rectal Cancer?

PURPOSE

The aim of this study was to investigate the oncologic impact of preoperative or postoperative chemoradiotherapy on stage IV rectal cancer.

METHODS

A total of 140 consecutive patients with locally advanced mid-to-lower rectal cancer and resectable stage IV disease were prospectively enrolled. In total, 69 patients received chemoradiotherapy (26 preoperatively and 43 postoperatively); in contrast, 71 did not. Survival curves were constructed using the Kaplan-Meier method, and a multivariate analysis was performed to identify independent prognostic factors.

RESULTS

According to the multivariate analysis, radiation therapy was not an independent factor associated with either survival or recurrence. The overall survival curves revealed that patients who underwent radiotherapy tended to have a better survival compared with patients who did not undergo radiotherapy; however, this trend was not statistically significant (p = 0.057). The disease-free, local recurrence-free, and distant metastasis-free survival curves did not differ significantly between the two groups. The local recurrence-free survival rates for patients who underwent preoperative radiotherapy were significantly higher than those for patients who underwent postoperative radiotherapy (p = 0.042).

CONCLUSION

Preoperative radiotherapy, rather than postoperative radiotherapy, may improve local control of stage IV rectal cancer. However, chemoradiotherapy did not improve the survival of patients with stage IV rectal cancer in this study.

Log odds of positive lymph nodes as a prognostic indicator in stage IV colorectal cancer patients undergoing curative resection

BACKGROUND

Recent studies have proposed the use of log odds of positive lymph nodes (LODDS) as a prognostic indicator in colorectal cancer (CRC) patients without distant synchronous metastasis. In the present study, we aimed to evaluate the prognostic impact of the LODDS in Stage IV CRC patients who have undergone curative resection.

METHODS

We performed a retrospective review of 117 Stage IV CRC patients who underwent curative resection at our institute from 1998 to 2011. Patients were categorized into 3 groups (LODDS1-3) according to the ratio of their LODDS. The relationship between the LODDS and disease-free survival (DFS) and overall survival (OS) rates were assessed.

RESULTS

DFS was not significantly different between patients in each LODDS group. The association between the LODDS classification and OS was statistically significant (P = 0.021). Multivariate analysis indicated that LODDS classification was an independent prognostic factor for OS, with a hazard ratio of 2.95 for LODDS2 (95% confidence interval [CI]: 1.18-8.35; P = 0.021), and 2.98 for LODDS3 (95% CI: 1.20-8.37; P = 0.017).

CONCLUSIONS

The LODDS is a good prognostic indicator in Stage IV CRC patients who have undergone curative resection.

Nomograms for predicting the prognosis of stage IV colorectal cancer after curative resection: a multicenter retrospective study

PURPOSE

Although stage IV colorectal cancer (CRC) encompasses a wide variety of clinical conditions with diverse prognoses, no statistical model for predicting the postoperative prognosis of stage IV CRC has been established. Thus, we here aimed to construct a predictive model for disease-free survival (DFS) and overall survival (OS) after curative surgery for stage IV CRC using nomograms.

METHODS

The study included 1133 stage IV CRC patients who underwent curative surgical resection in 19 institutions. Patients were divided into derivation (n = 586) and validation (n = 547) groups. Nomograms to predict the 1- and 3-year DFS rates and the 3- and 5-year OS rates were constructed using the derivation set. Calibration plots were constructed, and concordance indices (c-indices) were calculated. The predictive utility of the nomogram was validated in the validation set.

RESULTS

The postoperative carcinoembryonic antigen (CEA) level, depth of tumor invasion (T factor), lymph node metastasis (N factor), and number of metastatic organs were adopted as variables for the DFS-predicting nomogram, whereas the postoperative CEA level, T factor, N factor, and peritoneal dissemination were adopted for the nomogram to predict OS. The nomograms showed moderate calibration, with c-indices of 0.629 and 0.640 in the derivation set and 0.604 and 0.637 in the validation set for DFS and OS, respectively.

CONCLUSIONS

The nomograms developed were capable of estimating the probability of DFS and OS on the basis of only 4 variables, and may represent useful tools for postoperative surveillance of stage IV CRC patients in routine practice.

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.