Clinical benefit of surgery for stage IV colorectal cancer with synchronous peritoneal metastasis

Cytoreductive surgery without intra-peritoneal chemotherapy for metachronous colorectal peritoneal metastases

BACKGROUND

Cytoreductive surgery and chemotherapy reportedly improve the prognosis of patients with metachronous peritoneal metastases. However, the types of peritoneal metastases indicated for cytoreductive surgery remains unclear. Therefore, we aimed to clarify the category of cases for which cytoreductive surgery would be effective and report the prognosis associated with cytoreductive surgery for metachronous peritoneal metastases.

METHODS

This study included 52 consecutive patients who underwent cytoreductive surgery for metachronous peritoneal metastases caused by colorectal cancer between January 2005 and December 2018 and fulfilled the selection criteria. The median follow-up period was 54.9 months. Relapse-free survival was calculated as the time from cytoreductive surgery of metachronous peritoneal metastases to recurrence. Overall survival was defined as the time from cytoreductive surgery of metachronous peritoneal metastases to death or the end of the follow-up period.

RESULTS

The 5-year relapse-free survival rate was 30.0% and the 5-year overall survival rate was 72.3%. None of the patients underwent hyperthermic intraperitoneal chemotherapy. The analysis indicated no potential risk factors for 5-year relapse-free survival. However, for 5-year overall survival, the multivariate analysis revealed that time to diagnosis of metachronous peritoneal metastases of < 2 years after primary surgery (hazard ratio = 4.1, 95% confidence interval = 2.0-8.6, p = 0.0002) and number of metachronous peritoneal metastases ≥ 3 (hazard ratio = 9.8, 95% confidence interval = 2.3-42.3, p = 0.002) as independent factors associated with a poor prognosis.

CONCLUSIONS

Long intervals of more than 2 years after primary surgery and 2 or less metachronous peritoneal metastases were good selection criteria for cytoreductive surgery for metachronous peritoneal metastases from colorectal cancer.

Prognosis and predictive factors of conversion surgery for initially unresectable advanced colorectal cancer

PURPOSE

The aim of this study was to report the outcomes of conversion surgery for initially unresectable advanced colorectal cancer and to identify factors that enable successful conversion surgery.

METHODS

We compared the outcomes of patients with colorectal cancer with distant metastases, including extrahepatic metastases, who underwent upfront surgery, neoadjuvant chemotherapy, conversion surgery, and chemotherapy only at our department from 2007 to 2020. In addition, factors influencing the achievement of conversion surgery in patients who were initially unresectable were examined in univariate and multivariate analyses.

RESULTS

Of 342 colorectal cancer patients with distant metastases treated during the study period, 239 were judged to be initially unresectable, and 17 (conversion rate: 7.1%) underwent conversion surgery. The prognosis for the conversion surgery group was better than that of the chemotherapy only group but worse than that of the upfront surgery group. In the conversion surgery group, the recurrence-free survival after resection was significantly shorter than that upfront surgery group and neoadjuvant chemotherapy group, and no patients have been cured. Among patients who were initially unresectable, left-sided primary cancer and normal CA19-9 level were identified as independent factors contributing to the achievement of conversion surgery in a multivariate analysis.

CONCLUSIONS

Although relapse after conversion surgery is common, and no patients have been cured thus far, overall survival was better in comparison to patients who received chemotherapy only. Among unresectable cases, patients with left-sided primary cancer and normal CA19-9 levels are likely to be candidates for conversion surgery.

Conversion therapy with pembrolizumab for a peritoneal metastasis of rectal cancer causing hydronephrosis in a patient with Lynch syndrome

A 44-year-old woman with Lynch syndrome was referred to our hospital for treatment of recurrence of microsatellite instability-high rectal cancer. [18F]Fluorodeoxyglucose (18FDG)-positron emission tomography revealed a peritoneal metastasis with invasion to the small intestine and left ureter. The peritoneal metastasis was diagnosed initially as unresectable because of extensive invasion to the left ureter requiring nephrectomy. Hence, first-line treatment with pembrolizumab was started. After the first course of pembrolizumab, she developed hydronephrosis and a resulting urinary tract infection (UTI). A percutaneous nephrostomy was performed to control the UTI. After six courses of pembrolizumab, 18FDG-positron emission tomography showed that the peritoneal metastasis was smaller with significantly reduced 18FDG uptake, and it was then diagnosed as resectable without nephrectomy. She underwent R0 resection of the peritoneal metastasis with partial resection of the small intestine. Intraoperatively, the peritoneal metastasis showed no invasion of the left ureter, allowing its preservation. The percutaneous nephrostomy was removed postoperatively, and she has not developed any subsequent UTIs. Histopathologically, the tumor showed a pathological complete response to pembrolizumab. To the best of our knowledge, this is the first case of conversion therapy with pembrolizumab for peritoneal metastasis with hydronephrosis.

Impact of resection for ovarian metastases from colorectal cancer and clinicopathologic analysis: A multicenter retrospective study in Japan

Aim

The aim of this study was to clarify the significance of resection of ovarian metastases from colorectal cancer and to identify the clinicopathologic characteristics.

Methods

In this multicenter retrospective study, we evaluated data on ovarian metastases from colorectal cancer obtained from patients at 20 centers in Japan between 2000 and 2014. We examined the impact of resection on the prognosis of patients with ovarian metastases and examined prognostic factors.

Results

The study included 296 patients with ovarian metastasis. The 3-y overall survival rate was 68.6% for solitary ovarian metastases. In all cases of this cohort, the 3-y overall survival rates after curative resection, noncurative resection, and nonresection were 65.9%, 31.8%, and 6.1%, respectively (curative resection vs noncurative resection [P < 0.01] and noncurative resection vs nonresection [P < 0.01]). In the multivariate analysis of prognostic factors, tumor size of ovarian metastasis (P < 0.01), bilateral ovarian metastasis (P = 0.01), peritoneal metastasis (P < 0.01), pulmonary metastasis (P = 0.04), liver metastasis (P < 0.01), and remnant of ovarian metastasis (P < 0.01) were statistically significantly different.

Conclusion

The prognosis after curative resection for solitary ovarian metastases was shown to be relatively favorable as Stage IV colorectal cancer. Resection of ovarian metastases, not only curative resection but also noncurative resection, confers a survival benefit. Prognostic factors were large ovarian metastases, bilateral ovarian metastases, the presence of extraovarian metastases, and remnant ovarian metastases.

Clinical Impact of Radical Resection of Synchronous and Metachronous Peritoneal Metastases from Colorectal Cancer

BACKGROUND

According to some case series, patients with colorectal cancer (CRC) who underwent radical resection of synchronous peritoneal metastases (PM) with the primary tumor had better survival than patients who underwent non-surgical treatment. However, little evidence exists regarding the significance of radical resection for metachronous PM.

OBJECTIVE

This study aimed to evaluate the clinical significance of surgical intervention for isolated PM from CRC, with a particular focus on time to PM.

METHODS

A total of 74 consecutive patients with isolated PM from CRC, including 40 and 34 patients with synchronous and metachronous PM, respectively, treated between 2007 and 2018 were retrospectively analyzed. The primary outcome measure was overall survival (OS) from diagnosis, and the OS was compared between radical resection and palliative chemotherapy.

RESULTS

Five-year OS was 39.7% for all patients. Patients with radical resection had significantly better 5-year OS compared with those with palliative chemotherapy (62.8% vs. 11.0%; p < 0.0001). According to time to PM, patients with radical resection had significantly better 5-year OS compared with those with palliative chemotherapy for both synchronous PM (47.6% vs. 0%; p = 0.019) and metachronous PM (77.2% vs. 15.2%; p < 0.0001). Multivariable analysis stratified by time to PM revealed that surgical intervention is a significant favorable prognostic factor only in patients with metachronous PM (hazard ratio 0.117, 95% confidence interval 0.020-0.678; p = 0.017).

CONCLUSIONS

Patients with radical resection of PM had good survival compared with those with chemotherapy alone, especially for metachronous PM. Surgical intervention should be considered for isolated metachronous PM when radical resection is feasible.

A proposed new Japanese classification of synchronous peritoneal metastases from colorectal cancer: A multi-institutional, prospective, observational study conducted by the Japanese Society for Cancer of the Colon and Rectum

Aim

To establish a new Japanese classification of synchronous peritoneal metastases from colorectal cancer.

Methods

This multi-institutional, prospective, observational study enrolled patients who underwent surgery for colorectal cancer with synchronous peritoneal metastases. Overall survival rates were compared according to the various models using objective indicators. Each model was evaluated by Akaike's information criterion (AIC). The region of peritoneal metastases was evaluated by the peritoneal cancer index (PCI).

Results

Between October 2012 and December 2016, 150 patients were enrolled. The AIC of the present Japanese classification was 1020.7. P1 metastasis was defined as confined to two regions. The minimum AIC was obtained with the cutoff number of 10 or less for P2 metastasis and 11 or more for P3 metastasis. As for size, the best discrimination ability between P2 and P3 metastasis was obtained with a cutoff value of 3 cm. The AIC of the proposed classification was 1014.7. The classification was as follows: P0, no peritoneal metastases; P1, metastases localized to adjacent peritoneum (within two regions of PCI); P2, metastases to distant peritoneum, number ≤10 and size ≤3 cm; P3, metastases to distant peritoneum, number ≥11 or size >3 cm; P3a, metastases to distant peritoneum, number ≥11 and size ≤3 cm, or number ≤10 and size >3 cm; P3b, metastases to distant peritoneum, number ≥11 and size >3 cm.

Conclusion

This objective classification could improve the ability to discriminate prognosis in patients with synchronous peritoneal metastases from colorectal cancer.

Effect of adjuvant chemotherapy after curative resection of colorectal cancer peritoneal metastasis

PURPOSE

Several guidelines have recommended surgical resection for localized peritoneal metastases, but the prognosis remains poor. In addition, the efficacy of adjuvant chemotherapy (AC) after curative resection is under debate. The present study compared long-term outcomes between curative and non-curative resection and evaluated the effects of AC after curative resection.

METHODS

Using a multicenter database, we retrospectively reviewed 123 colorectal cancer patients with peritoneal metastases between April 2016 and December 2021. Of these patients, 49 underwent curative resection, and 74 underwent non-curative resection.

RESULTS

The frequency of broad metastases was lower in the curative resection group (8.2%) than in the non-curative resection group (43.2%, p < 0.001). Among all patients, 5-year overall survival rate was higher in the curative resection group (43.0%) than in the non-curative resection group (7.3%, p = 0.004). Among patients who underwent curative resection, 5-year overall survival rate was significantly higher in the AC group (48.2%) than in the non-AC group (38.1%, p = 0.037). Multivariate analysis of all patients revealed pathological N status and non-curative resection as independent predictors of overall survival. In patients who underwent curative resection, advanced age was an independent predictor of relapse-free survival, and AC was an independent predictor of overall survival.

CONCLUSION

This multicenter study of colorectal cancer patients with peritoneal metastases revealed that prognosis was more favorable for curable cases than for non-curable cases. Prognosis was more favorable in the AC group than in the non-AC group after curative resection.

Clinical outcomes of curative surgical resection of peritoneal metastasis in patients with colorectal cancer: A long-term follow-up study

INTRODUCTION

Colorectal cancer with peritoneal metastasis (PM) has been considered a non-curative disease. PM is associated with reduced overall survival (OS) and worse prognosis compared with metastasis at other sites. We aimed to investigate the treatment outcome and recurrence after curative resection of colorectal PM during a long-term follow-up.

METHODS

Patients who were diagnosed with colorectal PM and underwent surgery between December 2001 and December 2019 were included (n = 309). Curative resection was defined as PM resection without residual disease after surgery (complete macroscopic resection).

RESULTS

Of 309 patients, 208 (67.8%) had PM as an initially metastatic disease. Curative (R0/1) resection was achieved in 155 (50.2%) patients, while non-curative operation (R2 resection or palliative operation including colostomy) was performed in 154 (49.8%) patients. Compared with patients who underwent non-curative operation, those with curative resection more often had a single PM on preoperative imaging (34.2% vs. 20.8%, p = 0.011) and postoperative results (59.4% vs. 22.7%, p < 0.001) and less often had concurrent metastasis (distant lymph node, liver, or lung) at the time of surgery (p < 0.001). During a median follow-up of 90.4 months, 80.6% (125/155) patients had recurrence in the curative resection group; the peritoneum was the most common site (56.0%). The median OS was 47.7 months (95% CI, 39.2-56.2) in the curative resection group and 24.8 months (95% CI, 20.8-28.9) in the non-curative resection group, respectively (p < 0.001). In particular, twenty-six patients without recurrence showed long-term survival after curative resection (median OS, 87.1 months; range, 40.1-127.5).

CONCLUSION

Surgical resection can be considered for selected patients with colorectal PM because a significant number of them could seize the cure changes during their treatment continuum.

A 77-Year-Old Man with a Pulse Granuloma of the Descending Colon Identified by Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) Imaging 19 Months Following Surgical Resection for Rectal Carcinoma

Patient: Male, 77-year-old

Final Diagnosis: Pulse granuloma

Symptoms: None

Medication:—

Clinical Procedure: —

Specialty: Gastroenterology and Hepatology • Oncology

Development and Validation of a Prognostic Nomogram for Colorectal Cancer Patients With Synchronous Peritoneal Metastasis

Purpose

Synchronous peritoneal metastasis (S-PM) is considered a poor prognostic factor for colorectal cancer (CRC) and there is no nomogram to predict the survival of these patients. In this study, we aimed to use a multicenter data to identify the factors associated with S-PM of CRC to construct a nomogram for predicting the overall survival (OS) of these patients.

Methods

CRC patients with S-PM from two medical centers were enrolled between September 2007 and June 2017. Multivariate analysis was used to identify independent factors associated with OS for the nomogram to predict the 1-, 2-, and 3-year OS rates in the development group. The concordance index (C-index), calibration plot, relative operating characteristic (ROC) curve with area under the curve (AUC) were calculated to evaluate the performance of the nomogram in both the development and an external validation group.

Results

277 CRC patients with S-PM in the development group and 68 patients in the validation group were eligible for this study. In multivariate analysis of development group, age, carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen 125 (CA125), cytoreductive surgery (CRS), hyperthermic intraperitoneal chemotherapy (HIPEC), and chemotherapy were independent variables for OS, based on which the nomogram was built. The C-index of the nomogram in the development and validation group was 0.701 (95% Cl, 0.666–0.736) and 0.716 (95% Cl, 0.622–0.810); demonstrating good discriminative ability. The calibration plots showed satisfactory consistency between actual observation and nomogram-predicted OS probabilities in the development and external validation group. The nomogram showed good predictive accuracy for 1-, 2-, and 3-year OS rates in both groups with AUC >0.70. An online dynamic webserver was also developed for increasing the ease of the nomogram.

Conclusions

We developed and validated a predictive nomogram with good discriminative and high accuracy to predict the OS in CRC patients with S-PM.

Impact of R0 resection for synchronous peritoneal metastasis from colorectal cancer: A propensity score-matched analysis of a multi-institutional database

AIM

To investigate the usefulness of resection for synchronous peritoneal metastasis from colorectal cancer.

METHODS

The patients who underwent surgery for stage IV colorectal cancer at 16 hospitals between 1991 and 2007 were enrolled in this study. The overall survival rates of patients with synchronous peritoneal metastasis from colorectal cancer with and without R0 resection were compared using a propensity score-matched analysis.

RESULTS

Among the 3965 patients with stage IV colorectal cancer, 1169 had synchronous peritoneal metastasis (28.5%). No patients received hyperthermic intraperitoneal chemotherapy (HIPEC) in this study. Among the 1169 patients, 783 had enough clinicopathologic information and went through further analysis. Out of 783 patients, 204 underwent R0 resection. A multivariate analysis revealed that severity of peritoneal metastasis according to the Japanese classification (P < .0001) and distant metastases (P < .0001) were independently associated with non-R0 resection. In a propensity score-matched analysis, 118 patients who underwent R0 resection were matched with 118 patients who did not undergo R0 resection. There was no significant difference in each parameter between patients with and without R0 resection. After matching, the overall survival in patients with R0 resection was better than that without R0 resection (median survival time: 28.8 months and 15.6 months, P < .0001).

CONCLUSION

The overall survival of patients with R0 resection for synchronous peritoneal metastasis from colorectal cancer was better than that without R0 resection even without HIPEC.

Investigation of the Japanese Classification of Peritoneal Metastasis from Colorectal Cancer Referring to the Correlation with PCI

Objectives:

In Japan, there are three grades of peritoneal metastasis from colorectal cancer. The grade depends on the extent and number of lesions (P classification). The P classification is useful for its simplicity but lacks objectivity. On the other hand, the peritoneal cancer index (PCI) objectively indicates the peritoneal metastasis grade. However, the evaluation process is complicated clinically. In this study, we compared these two methods and investigated how to improve the P classification's objectivity by referring to PCI.

Methods:

We investigated 150 cases of synchronous peritoneal metastasis from colorectal cancer. We inspected the correlation between the P classification and the PCI and pointed out the problems which prevented objective evaluation when using the P classification. We also estimated new criteria for extent and number in the P classification.

Results:

We found the ideal definition for the best alignment between the P classification and the PCI was:

・P1 is metastases confined to one peritoneal region,

・P2 is 19 or fewer peritoneal metastases in two or more regions, and

・P3 is 20 or more metastases in two or more regions.

This revision improved the P classification's objectivity and correlated with the PCI.

Conclusions:

Grading using the P classification was both imprecise and subjective. We propose a new standard value of extent and number in the P classification based on the PCI. This improvement would provide an objective, simple method of grading for peritoneal metastasis from colorectal cancer.

Treatment Outcome of Resection of Disseminated Peritoneal Metastases from Colorectal Cancer

AIM

To show the treatment outcomes of disseminated nodule resection for peritoneal metastasis of colorectal cancer and describe the details of cured cases.

PATIENTS AND METHODS

From January 2001 to December 2016, patients who underwent disseminated nodule resection of colorectal adenocarcinoma with no macroscopic residual tumor in our institution were retrospectively analyzed for clinicopathological factors associated with prognosis.

RESULTS

Forty-one cases were included in this study. The 3-year relapse-free survival was 12.5%, and the 5-year overall survival was 38.4%. In a multivariate analysis, lack of post-operative adjuvant chemotherapy and pre-operative carbohydrate antigen 19-9 over 100 IU/l were extracted as independent factors associated with short relapse-free survival, respectively. Among 41 cases, 32 were followed-up 5 years after surgery and five (15.6%) survived without relapse and were regarded as 'cured'.

CONCLUSION

More than a few cases of colorectal peritoneal metastasis, which is thought to be difficult to cure, were cured by resection of disseminated nodules without resorting to highly invasive treatment.

Prognostic Impact of Curative Resection for Peritoneal Recurrence of Colorectal Cancer

BACKGROUND

Peritoneal recurrence (PR) of colorectal cancer is a poor prognostic factor but may be treatable by curative resection. We investigated the efficacy of this treatment and identified risk factors for postoperative recurrence.

METHODS

The subjects were patients who underwent radical surgery for colorectal cancer between January 2006 and March 2014. Those with PR were retrospectively reviewed. Prognostic factors for overall survival (OS) and risk factors for postoperative recurrence were identified.

RESULTS

Among 2256 patients, 66 had PR (2.9%). Surgical resection of PR was performed in 41 patients. Curative resection was achieved macroscopically in 38 cases without diffuse metastases in the peritoneum distant from the primary tumor and with a peritoneal cancer index < 10. In multivariate analysis, curative resection was a significant prognostic factor [hazard ratio (HR) 0.198] for better 5-year OS compared with cases without curative resection (68.7% vs. 6.3%, P < 0.001). In 28 cases with concurrent metastasis, curative resection significantly improved 5-year OS compared with no curative resection (78.7% vs. 0%, P = 0.008). In the 38 patients with curative resection, the 3-year recurrence-free survival rate was 21.4%. In multivariate analysis, concurrent metastasis was a significant risk factor [HR 3.394] for postoperative recurrence, and cases with concurrent metastasis more frequently had recurrence within 2 years after curative resection.

CONCLUSIONS

Curative resection improved the prognosis in patients with limited and resectable PR of colorectal cancer with or without concurrent metastasis. However, recurrence after curative resection was common and concurrent metastasis was a risk factor for this recurrence.

Comparison of four lymph node staging systems for predicting prognosis for stage IV rectum cancer

Background

With recommendation of surgical management in primary site, both the positive and negative lymph nodes (LNs) retrieved have been emphasized to predict prognosis in stage IV rectum cancer. Therefore, we attempt to compare the prognostic performance of American Joint Committee on Cancer (AJCC) N-stage relative to lymph node ratio (LNR), log odds of metastatic lymph nodes (LODDS), and N-score in stage IV rectal cancer.

Methods

Total 5,090 patients taken surgical resection of primary site in rectum cancer with distant metastasis were extracted from Surveillance, Epidemiology, and End Results Program (SEER) database. Harrell's C statistic (C-index) and Akaike's Information Criterion (AIC) were used to evaluate the discriminative ability of the different LN staging systems.

Results

Of the 3,243 patients without radiotherapy, 82.46% (n=2,675) had been found with lymph nodes metastasis with median number of 16 lymph nodes collected (IQR: 11-22). Modeled as categorical cutoff variables for further clinical usage, when number of LNs was between 12 and 25 (C-index: 0.5997, AIC: 1,698.015), 8^th AJCC N-stage outperformed other three schemas with increasing C-index and less AIC value. Assessed as continuous values, the LODDS shown as the best schemas with greatest discriminatory power (C-index: 0.5971, AIC: 3,680.017), generally. On the other hand, in the cohorts of other 1274 patients taken radiation, the median number of lymph nodes retrieved was 13 (IQR: 9-18). LODDS still remained remarkable performance as continuous (C-index: 0.5912; AIC: 1,058.765) and categorical variables (C-index: 0.5700; AIC: 1,061.703), while N-staging outperformed with less than 25 lymph nodes retrieved (LNs <12 C-index: 0.5678, AIC: 481.94; 12< LNs <25 C-index: 0.5933, AIC: 390.395).

Conclusions

When assessed as categorical variables, N-stage performed superiorly with adequate lymph nodes examined, whether the patients have got radiotherapy prior to surgery or not. LODDS showed, when assessed as a continuous variable, good discriminative ability and goodness of fit in predicting survival for stage IV rectum cancer patients regardless of radiation therapy status.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2019 for the treatment of colorectal cancer

The number of deaths from colorectal cancer in Japan continues to increase. Colorectal cancer deaths exceeded 50,000 in 2016. In the 2019 edition, revision of all aspects of treatments was performed, with corrections and additions made based on knowledge acquired since the 2016 version (drug therapy) and the 2014 version (other treatments). The Japanese Society for Cancer of the Colon and Rectum guidelines 2019 for the treatment of colorectal cancer (JSCCR guidelines 2019) have been prepared to show standard treatment strategies for colorectal cancer, to eliminate disparities among institutions in terms of treatment, to eliminate unnecessary treatment and insufficient treatment and to deepen mutual understanding between healthcare professionals and patients by making these guidelines available to the general public. These guidelines have been prepared by consensuses reached by the JSCCR Guideline Committee, based on a careful review of the evidence retrieved by literature searches and in view of the medical health insurance system and actual clinical practice settings in Japan. Therefore, these guidelines can be used as a tool for treating colorectal cancer in actual clinical practice settings. More specifically, they can be used as a guide to obtaining informed consent from patients and choosing the method of treatment for each patient. Controversial issues were selected as clinical questions, and recommendations were made. Each recommendation is accompanied by a classification of the evidence and a classification of recommendation categories based on the consensus reached by the Guideline Committee members. Here, we present the English version of the JSCCR guidelines 2019.

An increase in the peripheral lymphocyte-to-monocyte ratio after primary site resection is associated with a prolonged survival in unresectable colorectal carcinoma

PURPOSE

The prognostic benefits of primary tumor resection in patients with unresectable distant metastatic colorectal cancer remain unclear. A high pre-treatment lymphocyte-to-monocyte ratio (LMR) was previously shown to be associated with a better prognosis. We assessed whether or not primary tumor resection was associated with an improved survival if the peripheral lymphocyte-to-monocyte ratio increased after primary site resection.

METHODS

The survival in 64 and 59 patients with and without primary tumor resection, respectively, was retrospectively compared. After resection, the survival in 39 patients with a postoperatively increased LMR (LMR-increase) and 25 patients with a decreased LMR (LMR-decrease) was compared.

RESULTS

Primary tumor resection prolonged the median survival more frequently in cases of non-differentiated adenocarcinoma, obstructive symptoms, high serum albumin levels, and no lymph-node metastasis than in others. Cox regression showed that the potential independent prognostic variable was non-resection of the primary lesion. After resection, the median survival in the LMR-increase vs. LMR-decrease groups was significantly different (27.3 vs. 20.8 months). There were no marked differences in patient background characteristics between the groups, except for in the number of pre-operative peripheral blood lymphocytes. The resected specimens showed significantly lower CD8⁺:CD163⁺ invading leukocyte ratios in the LMR-increase group than in the LMR-decrease group.

CONCLUSIONS

Primary tumor resection in patients with unresectable metastatic colorectal cancer may be associated with an improved survival, especially when the LMR is increased after primary tumor resection.

Factors affecting R0 resection of colorectal cancer with synchronous peritoneal metastases: a multicenter prospective observational study by the Japanese Society for Cancer of the Colon and Rectum

BACKGROUND

In Japan, R0 resection has been recommended for colorectal cancer patients with peritoneal metastases confined to the adjacent peritoneum and those with a few metastases to the distant peritoneum. R0 resection for M1c disease has drawn attention in Western countries and is currently considered an acceptable therapeutic option in the US National Comprehensive Cancer Network guidelines. However, clinical factors that affect the choice of R0 resection are unknown.

METHODS

This multicenter, prospective, observational study was conducted by the Japanese Society for Cancer of the Colon and Rectum. Colorectal cancer patients with synchronous peritoneal metastases were enrolled at 28 institutions in Japan from October 2012 to December 2016. To determine factors affecting R0 resection and R1 resection with intended R0 resection, stepwise logistic regression analyses were performed on clinical factors including age, sex, performance status (PS), body mass index, peritoneal cancer index (PCI) score, presence of ascites, presence of distant metastases, and primary tumor site.

RESULTS

R0/R1 resection was performed in 36 (31/5; 25%) of 146 patients. No distant metastases [odds ratio (OR) 52.9; 95% confidence interval (CI) 13.3-210.1; p < 0.0001], low PCI score (1-6) (OR 20.0; 95% CI 4.8-83.4; p < 0.0001), and high PS (0) (OR 2.40; 95% CI 0.66-8.68; p = 0.18) were independent factors affecting R0/R1 resection. PCI score and PS were also independent factors affecting R0/R1 resection in M1c patients without non-peritoneal distant metastases (n = 59).

CONCLUSION

Distant metastases, PCI score, and PS are three factors which affect R0 resection for M1c disease.

Outcome of Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy in Colorectal Cancer

Colorectal cancer (CRC) is stated as the third most frequent cancer in people around the world. In patients, its recurrence occurs most commonly in the peritoneum, accounting for 25% to 35% of all recurrences, making it the second most common site for CRC. Although new and more effective chemotherapeutic agents and combinations were developed, the results of systemic chemotherapy showed only a limited impact on survival, which is disappointing. It is known that cytoreductive surgery (CRS) in combination with hyperthermic intraperitoneal chemotherapy (HIPEC) lead to survival improvement in comparison to the sole treatment consisting in intravenous chemotherapy. This combined procedure showed encouraging results in terms of overall survival, lower complication rates and better patient outcomes in many reported findings. The objective of this article was to review published data for evaluating the outcome of CRS and HIPEC versus standard of care.

Prognostic predictions based on pathological findings of peritoneal dissemination in patients with stage IV colorectal cancer without residual disease (R0 status)

PURPOSE

This study aimed to clarify the prognosis of patients after resection of stage IV colorectal cancer and synchronous peritoneal metastasis (no residual disease: R0 status) based on histopathologic findings.

METHODS

The subjects of this study were 26 patients who underwent radical resection of synchronous peritoneal metastases of stage IV colorectal cancer. Only patients with one synchronous peritoneal metastasis were included in this study. The peritoneal lesions were initially classified into two categories based on the presence or absence of adenocarcinoma on their surface: RM-negative or RM-positive. The lesions were subsequently classified as being of massive or diffuse type and of small (< 6 mm) or large (≥ 6 mm) type according to the maximum metastatic tumor dimension.

RESULTS

Multivariate analysis revealed that massive type metastatic tumors were associated with a better disease-free survival (DFS; p = 0.047) and overall survival (OS; p = 0.033), than diffuse type tumors.

CONCLUSION

A detailed stratification of pathological findings could contribute remarkably to prognostic predictions for patients with synchronous peritoneal metastases.

Predictive factors of synchronous colorectal peritoneal metastases: Development of a nomogram and study of its utilities using decision curve analysis

BACKGROUND

The objective of this study was to summarize the clinicopathological and molecular features of synchronous colorectal peritoneal metastases (CPM). We then combined clinical and pathological variables associated with synchronous CPM into a nomogram and confirmed its utilities using decision curve analysis.

MATERIALS AND METHODS

Synchronous metastatic colorectal cancer (mCRC) patients who received primary tumor resection and underwent KRAS, NRAS, and BRAF gene mutation detection at our center from January 2014 to September 2015 were included in this retrospective study. An analysis was performed to investigate the clinicopathological and molecular features for independent risk factors of synchronous CPM and to subsequently develop a nomogram for synchronous CPM based on multivariate logistic regression. Model performance was quantified in terms of calibration and discrimination. We studied the utility of the nomogram using decision curve analysis.

RESULTS

In total, 226 patients were diagnosed with synchronous mCRC, of whom 50 patients (22.1%) presented with CPM. After uni- and multivariate analysis, a nomogram was built based on tumor site, histological type, age, and T4 status. The model had good discrimination with an area under the curve (AUC) at 0.777 (95% CI 0.703-0.850) and adequate calibration. By decision curve analysis, the model was shown to be relevant between thresholds of 0.10 and 0.66.

CONCLUSION

Synchronous CPM is more likely to happen to patients with age ≤60, right-sided primary lesions, signet ring cell cancer or T4 stage. This is the first nomogram to predict synchronous CPM. To ensure generalizability, this model needs to be externally validated.

Long-Term Outcomes After R0 Resection of Synchronous Peritoneal Metastasis from Colorectal Cancer Without Cytoreductive Surgery or Hyperthermic Intraperitoneal Chemotherapy

BACKGROUND

The National Comprehensive Cancer Network (NCCN) guidelines for colon cancer recently added the following footnote regarding the therapeutic strategy for peritoneal metastases: "If R0 resection can be achieved, surgical resection of isolated peritoneal disease may be considered at experienced centers." This study investigated the efficacy of R0 resection of peritoneal metastasis from colorectal cancer without cytoreductive surgery or hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

This retrospective cohort study was conducted at a single-institution tertiary care cancer center. Among 496 consecutive M1c colorectal cancer patients, R0 resection was achieved for 94 patients (19%). The subjects were 78 consecutive patients with colorectal cancer and simultaneous peritoneal metastasis but no other distant metastases who underwent R0 resection at the National Cancer Center Hospital from 1971 to 2016 (16% of all M1c patients). Overall survival (OS) was investigated, and clinicopathologic variables were analyzed for prognostic significance.

RESULTS

No perioperative mortality was noted. The 3-year OS rate was 45%, and the 5-year OS rate was 28.7%. The median survival time was 33.4 months. Notably, 17 patients survived for more than 5 years, and 9 of these patients did not receive any chemotherapy. Multivariate analysis showed cancer location in the colon and harvesting of 12 or more lymph nodes to be independent factors associated with a better prognosis.

CONCLUSIONS

From the perspective of long-term outcomes and no perioperative mortality, R0 resection of peritoneal metastasis from colorectal cancer, without complete peritonectomy or HIPEC, appeared to be an acceptable therapeutic option for some patients with peritoneal metastasis.

Clinical Analysis of Primary Colorectal Signet-Ring Cell Carcinoma

The objective of the study was to investigate the clinicopathological features of primary colorectal signet-ring cell carcinoma. We retrospectively analyzed the clinical and survival data of 37 patients with primary colorectal signet-ring cell carcinoma. The mean survival time of patients in stage II, III, and IV were estimated using Student t test and the cumulative survival rates were estimated according to the method of Kaplan-Meier. The significance of the differences in survival rates were calculated using the log rank test. The incidence of primary colorectal signet-ring cell carcinoma was 1.40%, the median age of 37 patients was 50 years, the male to female ratio was 1.47:1, and 21 patients (56.8%) received a radical resection. Most patients 33 (89.2%) had an advanced tumor stage at the time of diagnosis (17 patients 45.9% stage III and 16 patients 43.2% stage IV), 34 (94.5%) patients showed a tumor depth of >T3, lymph node involvement occurred in 26 patients (70.3%), patients had a high incidence of peritoneal metastasis (16 patients 43.2% at presentation, 30 patients 81.1% at presentation and recurrence) and a low incidence of liver metastases (1 patients 2.7% at presentation, 5 patients 13.5% at presentation and recurrence). The 5-year survival rate after the initial surgery was 10.8%, the mean survival time of 37 patients was 27.1 ± 3.3 months, the mean survival time of patients in stage II, III, and IV were 47.0 ± 12.8 months, 37.1 ± 3.9 months, and 10.5 ± 1.4 months, respectively (P < .000). Colorectal signet-ring cell carcinoma is a rare neoplasm with a predominance in men. Its characteristic features were the advanced stage at the time of diagnosis, a high incidence of peritoneal metastases, a low incidence of liver metastasis, and a poor prognosis.

Clinicopathological Parameters in Patient Selection for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Colorectal Cancer Metastases: A Meta-analysis

OBJECTIVE

To improve patient selection for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) by evaluating various preoperatively assessable clinicopathological parameters as markers for survival after CRS and HIPEC.

SUMMARY BACKGROUND DATA

Peritoneal metastases (PMs) originating from colorectal cancer are treated with CRS and HIPEC. Despite increasing survival, high morbidity and mortality warrant selection of patients with optimal benefit from this treatment. Many studies report a number of variables to be associated with survival after CRS and HIPEC, but no definitive analysis has been made to validate various markers.

METHODS

In concordance with PRISMA guidelines, we performed a literature search encompassing 4110 articles to select 50 articles that reported the influence of 1 or more clinicopathological variables on overall survival after CRS and HIPEC. In absence of RCTs, 25 cohort studies could be used to perform a meta-analysis on 10 prognostic variables.

RESULTS

We determined that concurrent liver metastasis, lymph node metastasis, Eastern Cooperative Oncology Group score, tumor differentiation, and signet ring cell histology are all negative prognostic variables on overall survival after CRS and HIPEC. Conversely, sex and location of primary could not be validated as prognostic markers. More research is required to make definitive conclusions about neoadjuvant chemotherapy, onset of PMs, and mucinous histology.

CONCLUSIONS

Current clinical practice, which selects patients based on extraperitoneal metastasis, lymph node stage, performance status, and tumor histology, is validated by our pooled analysis. Our data merit further research into neoadjuvant chemotherapy in the setting of CRS and HIPEC for PMs.

Multidisciplinary Treatment for Colorectal Peritoneal Metastases: Review of the Literature

Peritoneum is one of the common sites of metastasis in advanced stage colorectal cancer patients. Colorectal cancer patients with peritoneal metastases (PM) are traditionally believed to have poor prognosis, which indicates it is of no value to adopt surgical treatment. With the advancement of surgical techniques, hyperthermic intraperitoneal chemotherapy (HIPEC), and multidisciplinary treatment in recent years, the cognition and treatment strategies of colorectal peritoneal metastases (CPM) have changed dramatically. In terms of prognosis, CPM under the palliative systemic treatment shows an inferior outcome compared with nonperitoneal metastasis. Nevertheless, some CPM patients amenable to the complete peritoneal cytoreductive surgery (CRS) combined with HIPEC may achieve long-term survival. The prognostic factors of CPM comprise peritoneal carcinomatosis index (PCI), completeness of cytoreduction score (CC score), the presence of extraperitoneal metastasis (liver, etc.), Peritoneal Surface Disease Severity Score (PSDSS), Japanese peritoneal staging, and so forth. Taken together, literature data suggest that a multimodality approach combining complete peritoneal CRS plus HIPEC, systemic chemotherapy, and targeted therapy may be the best treatment option for PM from colorectal cancer.

Survival and Prognostic Factors for Metachronous Peritoneal Metastasis in Patients with Colon Cancer

BACKGROUND

The clinical course of metachronous peritoneal metastasis of colorectal origin is poorly understood. In this retrospective study, we aimed to elucidate survival and prognostic factors for metachronous peritoneal metastasis.

METHODS

Patients with metachronous peritoneal metastasis after curative resection for stage I-III colon cancer were retrospectively reviewed, and the incidence and prognosis of metachronous peritoneal metastasis were investigated. Prognostic factors were identified by univariate and multivariate analyses.

RESULTS

Among 1582 surgically resected stage I-III colon cancer patients, 65 developed metachronous peritoneal metastasis. The 5-year cumulative incidence rate was 4.5%, and the median survival after diagnosis of peritoneal metastasis was 29.6 months. None of the patients underwent peritonectomy or intraperitoneal chemotherapy. Independent prognostic factors included right colon cancer [hazard ratio (HR) 2.69, 95% confidence interval (CI) 1.26-5.64; p = 0.011], time to metachronous peritoneal metastasis of <1 year (HR 2.02, 95% CI 1.04-3.87; p = 0.040), Peritoneal Cancer Index (PCI) >10 (HR 3.68, 95% CI 1.37-8.99; p = 0.012), concurrent metastases (HR 4.09, 95% CI 2.02-8.23; p < 0.001), and peritoneal nodule resection (HR 0.31, 95% CI 0.13-0.65; p = 0.002).

CONCLUSIONS

A proportion of colon cancer patients with metachronous peritoneal metastasis may benefit from combined peritoneal nodule resection and systemic chemotherapy. Right colon cancer, early peritoneal metastasis, a high PCI, and concurrent metastases negatively affected prognosis in patients with metachronous peritoneal metastasis.

Palliative surgery for colorectal cancer with peritoneal metastasis: a propensity-score matching analysis

PURPOSE

Peritoneal metastasis (PM) in patients with colorectal cancer (CRC) is associated with poor prognosis. We conducted this study to assess whether palliative resection (PR) of the primary tumor improved the overall survival (OS) of patients with PM-CRC.

METHODS

We analyzed retrospectively, data collected prospectively from patients with CRC. PM was categorized into three subgroups according to the Japanese classification of PM. A propensity-score model was used to compare the outcomes of patients who underwent PR (PR group) and those who did not [non-resection (NR) group].

RESULTS

Among 1909 patients with metastatic CRC, 309 (16 %) had only peritoneal metastases and 255 of these patients who underwent palliative surgery (R2) were the subjects of our analysis: 161 in the PR group and 94 in the NR group. Median OS was significantly longer in the PR group than in the NR group (23 vs. 11 months, P < 0.001). Patients in the PR group had less extensive PM and a higher rate of receiving palliative chemotherapy than those in the NR group (P < 0.001). In a Cox multivariate analysis of 69 propensity-score matched pairs, PR resulted in significantly longer OS than NR (hazard ratio 0.496, 95 % confidence interval 0.268-0.919, P = 0.025).

CONCLUSIONS

Our results show that PR resulted in better OS than NR for patients with PM-CRC, when their overall condition permitted a more aggressive approach.

Therapeutic options for peritoneal metastasis arising from colorectal cancer

Peritoneal metastasis is a common sign of advanced tumor stage, tumor progression or tumor recurrence in patients with colorectal cancer. Due to the improvement of systemic chemotherapy, the development of targeted therapy and the introduction of additive treatment options such as cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), the therapeutic approach to peritoneal metastatic colorectal cancer (pmCRC) has changed over recent decades, and patient survival has improved. Moreover, in contrast to palliative systemic chemotherapy or best supportive care, the inclusion of CRS and HIPEC as inherent components of a multidisciplinary treatment regimen provides a therapeutic approach with curative intent. Although CRS and HIPEC are increasingly accepted as the standard of care for selected patients and have become part of numerous national and international guidelines, the individual role, optimal timing and ideal sequence of the different systemic, local and surgical treatment options remains a matter of debate. Ongoing and future randomized controlled clinical trials may help clarify the impact of the different components, allow for further improvement of patient selection and support the standardization of oncologic treatment regimens for pmCRC. The addition of further therapeutic options such as neoadjuvant intraperitoneal chemotherapy or pressurized intraperitoneal aerosol chemotherapy, should be investigated to optimize therapeutic regimens and further improve the oncological outcome.

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.

Factors affecting recurrence and prognosis after R0 resection for colorectal cancer with peritoneal metastasis

BACKGROUND

Peritoneal metastases (PM) are a well-known poor prognostic factor. The aim of this study was to investigate the factors affecting recurrence and prognosis after R0 resection for colorectal cancer with synchronous peritoneal metastases.

METHODS

We conducted a multi-institutional retrospective analysis of 72 patients without distant metastases who underwent R0 surgery between 1991 and 2007 for colorectal cancer with PM localized to the adjacent peritoneum. Clinicopathological variables were analyzed for their significance to recurrence and prognosis.

RESULTS

Recurrence was found in 51 patients (70.8%) after R0 surgery. In logistic regression analyses, lymph node metastasis was shown to be an independent factor affecting recurrence. Non-intensive or no postoperative chemotherapy and eight or fewer dissected lymph nodes were identified as independent poor prognostic factors using the Cox proportional hazards model. Among patients who received postoperative chemotherapy, prognosis was significantly better in those who received intensive adjuvant chemotherapy using camptothecin-11 or oxaliplatin after R0 surgery than in those who received non-intensive chemotherapy. Among 47 patients whose recurrence date was known, 33 patients (70.2%) experienced recurrence within 18 months after R0 surgery for peritoneal metastases, and hematogenous recurrence was observed significantly more often than peritoneal recurrence.

CONCLUSIONS

Harvesting of more than eight lymph nodes and administration of intense adjuvant chemotherapy after R0 surgery are recommended for greater prediction accuracy and improved prognosis. Intensive follow-up should be performed within 18 months after R0 surgery for colorectal cancer with synchronous peritoneal metastases.

Outcome following incomplete surgical cytoreduction combined with intraperitoneal chemotherapy for colorectal peritoneal metastases

Cytoreductive surgery combined with intraperitoneal chemotherapy can improve survival in appropriately selected patients with colorectal peritoneal metastases. Outcomes are best in those patients in whom a complete cytoreduction can be achieved. Unresectable disease is however encountered in approximately one-quarter of patients at laparotomy. The merits, or otherwise, of proceeding with an incomplete cytoreduction in this setting are unclear. We performed a review of published outcomes following incomplete cytoreduction for colorectal peritoneal metastases. Using the electronic databases, PubMed and MEDLINE, a systematic search of available literature published during the period January 1997 to September 2014 was conducted. Following application of exclusion criteria, 19 papers were identified and included in this review. These comprised fifteen case series, 3 case control studies and one randomised control trial. In the nineteen studies included in this review, 2790 patients underwent cytoreductive surgery with or without intraperitoneal chemotherapy for peritoneal metastases of colorectal origin. Of these, 1732 (62%) underwent a complete cytoreduction while 986 (35%) patients underwent an incomplete cytoreduction. Median survival in the complete cytoreduction group ranged from 11 to 62 mo while survival in the latter group ranged from 2.4 to 32 mo. Of the 986 patients with an incomplete cytoreduction, 331 patients received intraperitoneal chemotherapy and survival in this cohort ranged from 4.5 to 32 mo. An incomplete cytoreduction, with or without intraperitoneal chemotherapy, does not appear to confer a survival benefit. The limited available data points to a palliative benefit in a subset of patients. In the absence of high quality data, the decision as to whether or not to proceed with surgery should be made on an individual patient basis.

Prognoses and treatment strategies for synchronous peritoneal dissemination of colorectal carcinoma

PURPOSE

We devised a simple dichotomous classification system and showed sufficient reproducibility to indicate treatment strategies for peritoneal metastasis of colorectal cancer.

METHODS

We included 67 patients with peritoneal metastasis of colorectal cancer and classified them according to the largest lesion size, number of lesions and number of regional peritoneal metastases. The oncological data were recorded and compared.

RESULTS

According to the univariate analyses, the prognoses were significantly better in patients with ≤3 disseminated lesions than in those with ≥4, and in patients with disseminated lesions in only one region than in those with ≥2 lesions. A multivariate analysis showed that primary tumor resection and the presence of peritoneal metastases in only one region were favorable factors for the patient survival. Patients with disseminated lesions in only one region (localized group) and those with nonlocalized lesions had three-year survival rates of 45.6 and 12.2 %, respectively. Finally, primary tumor resection improved the prognoses in both the localized and nonlocalized groups.

CONCLUSIONS

Colorectal cancer patients were categorized into localized and nonlocalized groups according to the number of regions with peritoneal metastasis, and significant prognostic associations were demonstrated. Subsequent analyses of the oncological data suggested that primary tumor resection contributes to an improved prognosis in all patients with synchronous peritoneal metastases.

Impact of adjuvant chemotherapy in patients with curatively resected stage IV colorectal cancer

The aim of this study was to investigate the impact of adjuvant chemotherapy on survival of patients who had curative resection for stage IV colorectal cancer.The efficacy of adjuvant chemotherapy after curative resection for stage IV colorectal cancer remains unclear.The database of 3695 patients with stage IV colorectal cancer between 1991 and 2007 collected from 16 member hospitals of the Japanese Society for Cancer of the Colon and Rectum was used for this investigation. The survivals of patients with and without adjuvant chemotherapy after curative resection for stage IV colorectal cancer were evaluated using a propensity score matching method.The data of 689 patients who underwent curative resection for both primary and synchronous metastatic tumors were extracted from the database and used for analysis in this study. The 5-year overall survival rates of the patients with and without adjuvant chemotherapy were 41.8% and 33.9%, respectively. A Cox proportional hazards model showed that adjuvant chemotherapy (P = 0.0042), regional lymph node metastasis (P < 0.0001), and peritoneal metastasis (P = 0.0006) were independent factors for overall survival. In the propensity score-matched cohort, patients with adjuvant chemotherapy had better overall survival than those without (P = 0.026).The present study demonstrated that adjuvant chemotherapy improved overall survival after curative resection for stage IV colorectal cancer. The efficacy of each chemotherapeutic regimen in the adjuvant setting for stage IV colorectal cancer should be clarified in the future.

Oncological benefit of primary tumor resection with high tie lymph node dissection in unresectable colorectal cancer with synchronous peritoneal metastasis: a propensity score analysis of data from a multi-institute database

BACKGROUND

Peritoneal metastasis is recognized as a predictor of poor prognosis in patients with colorectal cancer, and whether surgical intervention for peritoneal metastasis has any clinical benefit has remained controversial. The purposes of this study were to identify prognostic factors in cases of unresectable colorectal cancer with synchronous peritoneal metastasis and to clarify the impacts of primary tumor resection with high tie lymph node dissection.

METHODS

A multi-institutional retrospective analysis was conducted of 579 patients who underwent resection of the primary tumor for unresectable colorectal cancer with peritoneal metastasis between 1991 and 2007. For these 579 patients, clinicopathological variables were analyzed for prognostic significance using Cox proportional hazards model and propensity score analysis to mitigate the selection bias.

RESULTS

Multivariate analysis revealed hematogenous metastasis (p < 0.001), histology of the tumor (p = 0.006), postoperative chemotherapy (p < 0.001), and lymph node dissection (p = 0.001) as independent prognostic factors. In the propensity-matched cohort, patients treated with high tie lymph node dissection showed a significantly better overall survival than those with low tie lymph node dissection (median overall survival 13.0 vs. 11.5 months; p = 0.041).

CONCLUSIONS

It is suggested that primary tumor resection with high tie lymph node dissection favorably affects survival, even in unresectable colorectal cancer with peritoneal metastasis.