Immunohistochemistry-Based Consensus Molecular Subtypes as a Prognostic and Predictive Biomarker for Adjuvant Chemotherapy in Patients with Stage II Colorectal Cancer

Background

For stage II colorectal cancer (CRC), the efficacy of adjuvant chemotherapy remains controversial. Consensus molecular subtype (CMS) has been validated to be a prognostic tool for CRCs. In this study, CMS status was investigated as a prognostic biomarker for the efficacy of adjuvant chemotherapy for stage II colorectal cancer.

Materials and Methods

The tissue microarray was retrospectively constructed of 165 nonconsecutive, primary, and sporadic stage II CRCs. CMS status was determined by immunohistochemistry staining of CDX2, HTR2B, FRMD6, and ZEB1, combining with microsatellite instability testing. The prognostic for adjuvant chemotherapy efficacy of CMS status was calculated by Kaplan‐Meier curves and Cox regression analysis. Subgroup analyses were conducted according to tumor location.

Results

Kaplan‐Meier curves indicated that CMS was associated with overall survival (OS) and disease‐free survival for stage II CRCs. Cox regression analysis showed that CMS was an independent risk factor for OS. Among high‐risk clinicopathological factors, patients with CMS2/3 (hazard ratio [HR]: 0.445, 95% confidence interval [CI]: 0.227–0.875), left‐sided tumors (HR: 0.488, 95% CI: 0.247–0.968), or fewer than 12 lymph nodes examined (HR: 0.307, 95% CI: 0.097–0.974) had survival benefit from adjuvant chemotherapy. Subgroup analysis showed that adjuvant chemotherapy only improved OS for patients with left‐sided tumors of CMS2/3 subtype. Regardless of CMS, right‐sided tumors had no benefit from adjuvant chemotherapy.

Conclusion

CMS is a better prognostic factor for adjuvant chemotherapy for stage II CRCs. Together with tumor location, CMS classification will aid in personalized treatment for stage II CRCs.

Implications for Practice

For stage II colorectal cancer (CRC), the efficacy of adjuvant chemotherapy remains controversial, in that its minimal benefit (no more than 5% on average) is considered not worth the toxic effects of the drugs. There are still no effective prognostic and predictive biomarkers. This study showed that consensus molecular subtype (CMS) status is a predictive marker for adjuvant chemotherapy efficacy. Patients with left‐sided tumors of CMS2/3 subtype have survival benefit by receiving adjuvant chemotherapy, which will aid in personalized treatment for stage II CRCs. Moreover, this test of CMS based on immunohistochemistry is cheap, not time consuming, and easily conducted in the laboratories of most hospitals.

Currently, no clinical evidence exists for the ability of consensus molecular subtype status to predict the efficacy of adjuvant chemotherapy for stage II colorectal cancer. This article reports results of a study that adopted an immunohistochemical‐based classifier to validate the feasibility of this approach, assessing the prognostic and predictive accuracy of consensus molecular subtype status as a biomarker for adjuvant chemotherapy compared with traditional clinicopathological high‐risk factors.

Immunological nomograms predicting prognosis and guiding adjuvant chemotherapy in stage II colorectal cancer

BACKGROUND

The type, abundance, and location of tumor-infiltrating lymphocytes (TILs) have been associated with prognosis in colorectal cancer (CRC). This study was conducted to assess the prognostic role of TILs and develop a nomogram for accurate prognostication of stage II CRC.

METHODS

Immunohistochemistry was conducted to assess the densities of intraepithelial and stromal CD3+, CD8+, CD45RO+, and FOXP3+ TILs, and to estimate PD-L1 expression in tumor cells for 168 patients with stage II CRC. The prognostic roles of these features were evaluated using COX regression model, and nomograms were established to stratify patients into low- and high-risk groups and compare the benefit from adjuvant chemotherapy.

RESULTS

In univariate analysis, patients with high intraepithelial or stromal CD3+, CD8+, CD45RO+ and FOXP3+ TILs were associated significantly with better relapse-free survival (RFS) and overall survival (OS), except for stromal CD45RO+ TILs. In multivariate analysis, patients with high intraepithelial CD3+ and stromal FOXP3+ TILs were associated with better RFS (p<0.001 and p=0.032, respectively), while only stromal FOXP3+ TILs was an independent prognostic factor for OS (p=0.031). The nomograms were well calibrated and showed a c-index of 0.751 and 0.757 for RFS and OS, respectively. After stratifying into low- and high-risk groups, the high-risk group exhibited a better OS from adjuvant chemotherapy (3-year OS of 81.9% vs 34.3%, p=0.006).

CONCLUSION

These results may help improve the prognostication of stage II CRC and identify a high-risk subset of patients who appeared to benefit from adjuvant chemotherapy.

A novel prognostic prediction model for recurrence in patients with stage II colon cancer after curative resection

The present study aimed to clarify the risk factors for recurrence of stage II colon cancer in patients and to determine possible treatment options for postoperative adjuvant chemotherapy. A prediction model for recurrence in patients with stage II colon cancer after curative surgical resection was developed. The present study retrospectively investigated 436 patients who underwent curative resection for stage II colon cancer at Osaka International Cancer Institute and Yao Municipal Hospital between 2004 and 2012. Several clinicopathological factors were examined and the Cox regression model was used to develop a prediction model for recurrence. The prediction model was validated in an independent group of 213 patients who underwent surgery at Osaka University Hospital between 2001 and 2012. Univariate analysis revealed that preoperative serum carcinoembryonic antigen level, preoperative obstruction, tumor invasion, lymphatic invasion and venous invasion were significantly correlated with disease-free survival. Using these variables, a classification and regression tree was constructed as a prediction model. The prediction models were validated by external datasets in an independent patient group. The concordance indices for DFS after current surgical resection were 0.675 in the learning set and 0.552 in the validation set. To conclude, a novel, reliable and personalized prognostic model was developed to predict recurrence in patients with stage II colon cancer, which may help clinicians to determine and perform adjuvant chemotherapy.

Smaller tumor size is associated with poor survival in stage II colon cancer: An analysis of 7,719 patients in the SEER database

BACKGROUND

We hypothesized that in patients with colon cancer showing heavy intestinal wall invasion without lymph node metastasis (stage II), small tumor size would correlate with more aggressive tumor behaviors and thus poorer cancer-specific survival (CSS).

METHODS

We analyzed Caucasian patients with stage II colon cancer based on data from the US Surveillance, Epidemiology, and End Results (SEER) database. Survival was analyzed using the Kaplan-Meier method, and the log-rank test was used to identify differences. Risk factors were analyzed using the Cox proportional hazard model.

RESULTS

A total of 7719 stage II colon cancer patients from the SEER database were included in the analysis. The cutoff value (5.0 cm) was determined using the X-tile program. The Kaplan-Meier analysis showed that tumors <5.0 cm had a poorer CSS compared to tumors ≥5.0 cm (p = 0.006). Multivariate analysis indicated that tumor size is an independent prognostic factor for stage II patients, and compared to tumors <5.0 cm, tumors ≥5.0 cm were more likely to result in a better CSS (HR 0.775, 95% CI 0.691-0.870, p < 0.001). Tumor size was also analyzed as a continuous variable in the multivariate analysis, and the CSS decreased with decreasing tumor size (HR 0.958, 95% CI 0.936-0.981, p < 0.001). Subgroup analyses suggested that tumor size is also an independent prognostic factor for stage IIA (p = 0.002) and IIC (p < 0.001) patients.

CONCLUSIONS

Smaller tumor size is associated with poor CSS in the stage II colon cancer and particularly in the stage IIA and IIC subgroups.

Colorectal Cancer Patient Characteristics, Treatment and Survival in Oman--a Single Center Study

BACKGROUND

Colorectal cancer is the most common gastrointestinal cancer in Oman with an increasing incidence. We here report the presenting features, treatment outcomes and survival in a University hospital in Oman and compare our data with regional and international studies.

MATERIALS AND METHODS

Medical records of patients with colorectal cancer were reviewed retrospectively between June 2000 and December 2013 and were followed until June 2014.

RESULTS

A total of 162 patients were diagnosed with colorectal cancer. The majority were males (58.6%), with a median age of 56 years. Rectum was involved in 29.6% of patients, followed by ascending and sigmoid colon. The majority of patients had stage III (42.6%) and stage IV (32.7%) disease at presentation. K-Ras status was checked for 79 patients, and 41 (51.9%) featured the wild type. Median relapse free survival was 22 months. Median overall survival for all patients was 43 months. Observed 5 year overall survival (OS) for stages I, II and III was 100%, 60% and 60% respectively. On Log rank univariate analysis, age, BMI, diabetes, hypertension, metformin use, stage, clinical nodal status for rectal cancer, pathological T and nodal status, site of metastasis, surgical intervention, chemotherapy, radiotherapy, chemotherapy regimen, no of cycles of chemotherapy, response, RFS, site of recurrence and administration of 2nd line chemotherapy were significant factors affecting OS. On Cox regression multivariate analysis none of the factors independently affected the OS.

CONCLUSIONS

The majority of patients present with advanced disease and at young age. The survival rates are comparable to the published regional and international literature.