Combining molecular markers with the TNM staging system to improve prognostication in stage II and III colon cancer: are we ready yet?

Prothrombin time (PT) and CEA as prognostic predictive biomarkers for postoperative recurrence after curative resection in patients with stage I-III colorectal cancer: a retrospective cohort study

There are no ideal biomarkers including the TNM stage that can accurately predict the recurrence of colorectal cancer (CRC) and the benefit of chemotherapy for stage II patients. Here, 451 CRC patients were divided into three groups according to preoperative levels of prothrombin time (PT) and CEA to analyze the value of these indexes in predicting postoperative recurrence in different TNM stages. Preoperatively elevated levels of PT and CEA were significantly associated with a high 5-year cumulative recurrence rate (CRR) and short recurrence-free survival (RFS). According to PT and CEA levels, the 5-year CRR and RFS differed significantly among the High-risk (PT ≥ 12.65 s and CEA ≥ 10.175 ng/ml), Middle-risk (PT ≥ 12.65 s or CEA ≥ 10.175 ng/ml), and Low-risk (PT < 12.65 s and CEA < 10.175 ng/ml) groups (p < 0.001). In the same TNM stage, the 5-year CRR of the High-risk group was significantly higher and the RFS was markedly shorter than those in the Low-risk and even those in stage III (p < 0.001). In the subgroup of early stage (stage I and II), the 5-year CRR of the High-risk group was significantly higher and the RFS was significantly shorter than those in stage IIIA and IIIB (p < 0.001), which is similar to IIIC. In conclusion, preoperatively elevated levels of serum PT and CEA were reliable predictors of postoperative high-risk recurrence in CRC and combined with TNM stage precisely identify postoperative recurrence CRC patients in stage I-III and the benefit of adjuvant chemotherapy for patients with stage II CRC.

Prognostic and Predictive Cross-Roads of Microsatellite Instability and Immune Response to Colon Cancer

Understanding molecular features of colon cancer has shed light on its pathogenesis and progression. Over time, some of these features acquired clinical dignity and were incorporated in decision making. Namely, microsatellite instability (MSI) due to mismatch repair of defects, which primarily was adopted for the diagnosis of Lynch syndrome, became recognized as the biomarker of a different disease type, showing a less aggressive behavior. MSI tumors harbor high amounts of tumor infiltrating lymphocytes (TILs) due to their peculiar load in neoantigens. However, microsatellite stable colon cancer may also show high amounts of TILs, and this feature is as well associated with better outcomes. High TIL loads are in general associated with a favorable prognosis, especially in stage II colon cancer, and therein identifies a patient subset with the lowest probability of relapse. With respect to post-surgical adjuvant treatment, particularly in stage III, TILs predictive ability seems to weaken along with the progression of the disease, being less evident in high risk patients. Moving from cohort studies to the analysis of a series from clinical trials contributed to increase the robustness of TILs as a biomarker. The employment of high TIL densities as an indicator of good prognosis in early-stage colon cancers is strongly advisable, while in late-stage colon cancers the employment as an indicator of good responsiveness to post-surgical therapy requires refinement. It remains to be clarified whether TILs could help in identifying those patients with node-positive cancers to whom adjuvant treatment could be spared, at least in low-risk groups as defined by the TNM staging system.

The Impact of KRAS Mutation on the Presentation and Prognosis of Non-Metastatic Colon Cancer: an Analysis from the National Cancer Database

INTRODUCTION

Approximately 40% of colorectal cancers have a KRAS mutation. The prognostic significance of KRAS mutations in patients with non-metastatic colon cancer has not been well elucidated. The National Cancer Database (NCDB) was used to analyze factors associated with KRAS mutation as well as its impact on the presentation and survival of patients with stages I-III colon cancer.

METHODS

The NCDB was queried to identify patients diagnosed with stages I-III adenocarcinoma of the colon from 2004 to 2015.

RESULTS

A total of 19,877 patients with known KRAS status were identified: mutation rates were 33% in stage I, 35% in stage II, and 38% in stage III patients (p < 0.01). On multivariable analysis, black race and right-sided location were independently associated with KRAS-mutated cancers (all p < 0.01). On univariate analysis for overall survival (OS), KRAS mutation was not significantly associated with a worse 5-year OS for stages I and II patients (p = 0.60 and 0.88, respectively). However, stage III KRAS-mutated colon cancers had a lower OS as compared with KRAS wild type cancers both on univariate and multivariable analysis. Right-sided colon cancers were independently associated with a worse prognosis compared with left-sided lesions (p < 0.01).

CONCLUSIONS

KRAS-mutated colon cancers were more frequently observed in black patients, right-sided locations, and higher-stage tumors. These mutations had a negative prognostic impact for stage III patients, suggesting that the incorporation of genotypic data into colon cancer staging may help to guide systemic therapy and prognostication of colon cancer patients.

Evolving notions on immune response in colorectal cancer and their implications for biomarker development

INTRODUCTION

Colorectal cancer (CRC) still represents the third most commonly diagnosed type of cancer in men and women worldwide. CRC is acknowledged as a heterogeneous disease that develops through a multi-step sequence of events driven by clonal selections; this observation is sustained by the fact that histologically similar tumors may have completely different outcomes, including a varied response to therapy.

METHODS

In "early" and "intermediate" stage of CRC (stages II and III, respectively) there is a compelling need for new biomarkers fit to assess the metastatic potential of their disease, selecting patients with aggressive disease that might benefit from adjuvant and targeted therapies. Therefore, we review the actual notions on immune response in colorectal cancer and their implications for biomarker development.

RESULTS

The recognition of the key role of immune cells in human cancer progression has recently drawn attention on the tumor immune microenvironment, as a source of new indicators of tumor outcome and response to therapy. Thus, beside consolidated histopathological biomarkers, immune endpoints are now emerging as potential biomarkers.

CONCLUSIONS

The introduction of immune signatures and cellular and molecular components of the immune system as biomarkers is particularly important considering the increasing use of immune-based cancer therapies as therapeutic strategies for cancer patients.

Lymphocytic Infiltration as a Prognostic Factor in Patients With Colon Cancer

Host-defense mechanisms may have an important role in predicting the outcome of colorectal cancer patients. We designed our study to evaluate the possible prognostic significance of the presence of lymphocytic infiltration (LI) and subgroups of lymphocytes (CD3 and CD20) in the primary tumors. We randomly selected 195 patients operated for colorectal carcinoma from a larger cohort of 1527 patients with colorectal cancer. Histological slides were blindly reevaluated for the presence of LI that was graded 0 to 3. Immunohistochemical phenotyping of the lymphocytes was performed only for tumors with LI score 3 and included antibodies CD3 and CD20. CD3 and CD20 immunostaining were graded in the same manner as LI. The mean duration of follow-up was 63.8 months. The distribution of patients with colorectal cancer according to LI scores was as follows: score 0, 20/195 (10.2%); score 1, 61/195 (31.3%); score 2, 78/195 (40%); and score 3, 36/195 (18.5%). There was no correlation between any clinicopathological pattern and LI. Score 3 staining for CD3 was more common than for CD20 (64.7% vs 8.8%, P < .0001). Prominent lymphocytic infiltration (score 3) was associated with better disease-free survival (P = .062). Recurrence was diagnosed among 2/22 (9.1%) patients with prominent CD3 staining versus 62/171 (36.2%) of all other patient groups (P = .054) and they correspondingly had better disease-free survival (P = .018). It seems we can identify a group of patients with colorectal cancer who have an excellent prognosis according to a single immunological test unrelated to other known prognostic factors.

Molecular alterations and biomarkers in colorectal cancer

The promise of precision medicine is now a clinical reality. Advances in our understanding of the molecular genetics of colorectal cancer (CRC) are leading to the development of a variety of biomarkers that are being used as early detection markers, prognostic markers, and markers for predicting treatment responses. This is no more evident than in the recent advances in testing CRCs for specific molecular alterations in order to guide treatment with the monoclonal antibody therapies cetuximab and panitumumab, which target the epidermal growth factor receptor. In this review, we update a prior review published in 2010 and describe our current understanding of the molecular pathogenesis of CRC and how these alterations relate to emerging biomarkers for early detection and risk stratification (diagnostic markers), prognosis (prognostic markers), and the prediction of treatment responses (predictive markers).

Prognostic impact of deficient DNA mismatch repair in patients with stage III colon cancer from a randomized trial of FOLFOX-based adjuvant chemotherapy

PURPOSE

The association of deficient DNA mismatch repair (dMMR) with prognosis in patients with colon cancer treated with adjuvant fluorouracil, leucovorin, and oxaliplatin (FOLFOX) chemotherapy remains unknown.

PATIENTS AND METHODS

Resected, stage III colon carcinomas from patients (N = 2,686) randomly assigned to FOLFOX ± cetuximab (North Central Cancer Treatment Group N0147 trial) were analyzed for mismatch repair (MMR) protein expression and mutations in BRAF(V600E) (exon 15) and KRAS (codons 12 and 13). Association of biomarkers with disease-free survival (DFS) was determined using Cox models. A validation cohort (Cancer and Leukemia Group B 88903 trial) was used.

RESULTS

dMMR was detected in 314 (12%) of 2,580 tumors, of which 49.3% and 10.6% had BRAF(V600E) or KRAS mutations, respectively. MMR status was not prognostic overall (adjusted hazard ratio [HR], 0.82; 95% CI, 0.64 to 1.07; P = .14), yet significant interactions were found between MMR and primary tumor site (P(interaction) = .009) and lymph node category (N1 v N2; P(interaction) = .014). Favorable DFS was observed for dMMR versus proficient MMR proximal tumors (HR, 0.71; 95% CI, 0.53 to 0.94; P = .018) but not dMMR distal tumors (HR, 1.71; 95% CI, 0.99 to 2.95; P = .056), adjusting for mutations and covariates. Any survival benefit of dMMR was lost in N2 tumors. Mutations in BRAF(V600E) (HR, 1.37; 95% CI, 1.08 to 1.70; P = .009) or KRAS (HR, 1.44; 95% CI, 1.21 to 1.70; P < .001) were independently associated with worse DFS. The observed MMR by tumor site interaction was validated in an independent cohort of stage III colon cancers (P(interaction) = .037).

CONCLUSION

The prognostic impact of MMR depended on tumor site, and this interaction was validated in an independent cohort. Among dMMR cancers, proximal tumors had favorable outcome, whereas distal or N2 tumors had poor outcome. BRAF or KRAS mutations were independently associated with adverse outcome.

What is the optimal means of staging colon cancer?

Although staging for colon cancer has become more complex over time, it is not clear that this complexity has improved prognostic assessment. Even with revisions in the 7th edition of the AJCC staging system, a clear rank order of prognosis from substage to substage has not been established. Improved staging models will need to be developed, and attempts at further identifying those high-risk patients within each stage may be clinically useful. Through improved quality measures with lymph node yield, advances in colon cancer staging accuracy have been made over the last decade. Determining how to incorporate ultrastaging and molecular techniques will be the challenge for future staging models.