Postoperative chemotherapy is associated with prognosis of stage IV colorectal cancer treated with preoperative chemotherapy/chemoradiotherapy and curative resection

Oxidative Stress Induced by Chemotherapy: Evaluation of Glutathione and Its Related Antioxidant Enzyme Dynamics in Patients with Colorectal Cancer

One of the mechanisms of chemotherapy is to increase the oxidative stress of cancer cells, leading to their apoptosis. Glutathione (GSH) and its related antioxidant enzymes might be stimulated to cope with increased oxidative stress during chemotherapy. Here, we studied the fluctuation in oxidative stress and GSH-related antioxidant capacities before tumor resection, after tumor resection, and after resection either with or without chemotherapy in patients with colorectal cancer (CRC). This was a cross-sectional and follow-up design. We followed patients before having tumor resection (pre-resection), one month after tumor resection (post-resection), and after the first scheduled chemotherapy (post-chemo). If patients were required to receive chemotherapy after tumor resection, they were assigned to the chemotherapy group. Eligible patients were scheduled to undergo six to twelve cycles of chemotherapy at 2-week intervals and received single, double, or triple chemotherapeutic drugs as required. Those patients who did not require chemotherapy were assigned to the non-chemotherapy group. Indicators of oxidative stress and GSH-related antioxidant capacities were determined at the above three time points. We found in 48 patients of the chemotherapy group and in 43 patients of the non-chemotherapy group different fluctuations in levels of oxidative stress indicators and GSH-related antioxidant capacities starting from pre-resection, post-resection through the post-chemo period. Both groups showed significantly or slightly increased levels of advanced oxidation protein products (AOPP), GSH, and its related enzymes in tumor tissues compared to adjacent normal tissues. Patients in the chemotherapy group had significantly lower plasma levels of GSH and glutathione disulfide (GSSG), but had significantly higher plasma glutathione peroxidase and glutathione reductase activities than patients in the non-chemotherapy group post-chemo. Plasma levels of malondialdehyde and AOPP were positively or negatively associated with GSH and GSSG levels post-chemo after adjustment for age, sex, and histological grading in patients receiving chemotherapy. These significant associations were, however, not seen in patients without chemotherapy. Patients with CRC may require higher GSH demands to cope with a greater oxidative stress resulting from chemotherapy.

Nomograms for predicting overall survival in colorectal cancer patients with metastasis to the liver, lung, bone, and brain

BACKGROUND

The aim of this study was to identify the heterogeneous and homogeneous prognostic factors associated with distant metastasis to the liver, lung, bone, and brain in colorectal cancer (CRC) patients and then construct nomograms to predict the prognosis.

METHODS

CRC patients registered in the surveillance, epidemiology, and end results database between 2010 and 2017 were included. A Cox regression model was used to analyse homogeneous and heterogeneous prognostic factors, and Kaplan‒Meier analysis was performed to estimate overall survival (OS). Predictive nomograms were constructed, and their performance was evaluated with C-indexes, calibration curves and the area under the receiver operating characteristic (ROC) curve (AUC).

RESULTS

A total of 37,641 patients with distant metastasis to the liver, lung, bone, and brain were included. The median survival times of patients with liver metastasis, lung metastasis, bone metastasis, and brain metastasis were 12.00 months (95% CI 11.73-12.27 months), 10.00 months (95% CI 9.60-10.41 months), 5.00 months (95% CI 4.52-5.48 months), and 3.00 months (95% CI 2.28-3.72 months), respectively. An older age, higher N stage, elevated carcinoembryonic antigen level, no surgery at the primary site and no/unknown treatment with chemotherapy were identified as homogeneous prognostic factors for the four types of metastases. The calibration curves, C-indexes and AUCs exhibited good performance for predicting the OS of patients with distant metastases to the liver, lung, bone, and brain.

CONCLUSIONS

CRC patients with distant metastasis to the liver, lung, bone, and brain exhibited homogeneous and heterogeneous prognostic factors, all of which were associated with shorter survival. The nomograms showed good accuracy and may be used as tools for clinicians to predict the prognosis of CRC patients with distant metastasis.

Nomogram of conditional survival probability of long-term Survival for Metastatic Colorectal Cancer: A Real-World Data Retrospective Cohort Study from SEER database

BACKGROUND

Many patients with metastatic colorectal cancer (mCRC) have better prognosis than the prediction at diagnosis. Compared with invariable traditional Kaplan Meier assessment, conditional survival (CS) assessment has become a more accurate and informative assessment method to predict survival time.

MATERIALS AND METHODS

Patients with mCRC between 2010 and 2015 were extracted from Surveillance, Epidemiology and End Results linked database. CS analysis was applied to depict exact survival for patients who have survived for specific year and standardized difference (d) was used to evaluate the differences between subgroups in CS analysis. Based on variables selected by Lasso analysis, nomograms for each year after diagnosis were fitted to estimate 3-year survival of stage IV CRC, respectively.

RESULTS

Of 9732 patients, overall actuarial survival (OS) decreased from 24% at 4-year to 16% at 6-year, while corresponding 3-year CS (CS3) increased from 33% at 1-year to 48% at 3-year. Overall, CS3 was higher than corresponding actuarial survival. All clinicopathological characteristics were associated with actuarial survival (p < 0.05). However, in CS3 analysis, survival difference caused by gender, race and tumor size gradually disappeared over time (|d|>0.1→ |d|<0.1). Furthermore, survival difference caused by histological type, brain metastasis and chemotherapy reversed over time (d > 0→d<0 or d<0→d>0). Based on lasso analysis, nomograms for 1st, 2nd and 3rd year after diagnosis were conducted respectively. The AUC of nomogram for 1st year was 0.705, for 2nd year was 0.675, and for 3rd year was 0.648.

CONCLUSION

Patients with mCRC demonstrated a substantial increase in CS over time. Risk factors collected at diagnosis may change gradually. Nomograms constructed by survival time can predict more accurate survival for patients with mCRC. Conditional survival assessments provide important quantitative information about the probability of survival and are therefore of great value to patients and health care professionals.

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.

Downregulation of Ascl2 promotes cell apoptosis by enhancing autophagy in colorectal cancer cells

Background

Colorectal cancer (CRC) is the third most common cancer, according to recently published literature. While the incidence and the mortality of CRC has decreased due to effective cancer screening measures, there has been an increase in the number of young patients diagnosed with colon cancer due to unclear reasons. As a target molecule of the Wnt signaling pathway, Ascl2 is an important marker of CRC stem cells and plays an important role in maintaining the nature of colon cancer stem/precursor cells. However, the role of Ascl2 in autophagy in CRC cells is rarely elucidated.

Methods

In this study, we found that Ascl2 was increased in CRC compared with adjacent tissue. Downregulation of Ascl2 in CRC cells could suppress proliferation and invasion, and induce apoptosis, of CRC cells. Moreover, we found that autophagy-relative protein LC3 increased after Ascl2 knockdown. Furthermore, we treated CRC cells with autophagy inhibitors 3-MA (3-Methyladenine) and CQ (Chloroquine).

Results

The results showed that autophagy inhibitors could prevent apoptosis, which was induced by Ascl2 knockdown. Finally, we confirmed that the downregulation of Ascl2 in CRC cells could alleviate the pathological process in vivo by xenograft experiment.

Conclusions

Our findings indicated that si-Ascl2 (small/short interfering) exerted a tumor suppression function in CRC by inducing autophagic cell death, and suggest that Ascl2 targeted therapy represents a novel strategy for CRC treatment.

Change in skeletal muscle index and its prognostic significance in patients who underwent successful conversion therapy for initially unresectable colorectal cancer: observational study

BACKGROUND

Systemic therapy can cause loss of skeletal muscle mass in colorectal cancer (CRC) patients in the neoadjuvant and palliative settings. However, it is unknown how the body composition is changed by chemotherapy rendering unresectable CRC to resectable disease or how it affects the prognosis. This study aimed at elucidating the effects of systemic therapy on skeletal muscles and survival in stage IV CRC patients who underwent conversion therapy.

METHODS

We reviewed 98 stage IV CRC patients who received systemic therapy in our hospital. According to the treatment setting, patients were divided into the conversion, neoadjuvant chemotherapy (NAC), and palliation groups. The cross-sectional area of skeletal muscles at the third lumbar level and changes in the skeletal muscle index (SMI), defined as the area divided by height squared, during systemic therapy were compared among patient groups. The effects of these parameters on prognosis were analyzed in the conversion group.

RESULTS

The mean SMI increased by 9.4% during systemic therapy in the conversion group (n = 38), whereas it decreased by 5.9% in the NAC group (n = 18) and 3.7% in the palliation group (n = 42, p < 0.0001). Moreover, patients with increased SMI during systemic therapy had a better overall survival (OS) than those whose SMI decreased in the conversion group (p = 0.025). The increase in SMI was an independent predictor of favorable OS on multivariate analysis (hazard ratio 0.25).

CONCLUSIONS

Stage IV CRC patients who underwent conversion to resection often had an increased SMI. On the other hand, a decrease in the SMI during systemic therapy was a negative prognostic factor in such patients.