Macrophages and apoptotic cells in human colorectal tumours

Immune classification of colorectal cancer patients: impressive but how complete?

INTRODUCTION

There is now accumulating evidence to suggest that intratumoral adaptive immune responses predict patient prognosis. The presence of tumor-infiltrating lymphocytes has been correlated with patients' disease-free and overall survival. Recent exciting studies of human colorectal cancers (CRCs) have underlined the significance of including immunological biomarkers as prognostic markers.

AREAS COVERED

This review covers recent literature which suggests that the type, density and location of immune cells within the colorectal tumors represent a better predictor of patient survival than the histopathological methods currently used to stage CRC.

EXPERT OPINION

Remarkably, the quantity, quality and spatial distribution of immune cells within the tumor has a greater prognostic value than the standard tumor staging based on tumor burden, infiltration of draining and regional lymph nodes by tumor cells, and evidence of metastases. In addition, such an immune classification may also have a predictive value. Thus, by increasing the knowledge of the immune events inside the tumors and by better understanding the immune architecture of these tumors as well as the functional programs of their constituents, there will certainly be a more complete idea of how tumors evade from immunosurveillance. This knowledge will help to identify new targets for the development of therapeutic strategies.

Peritumoral inflammatory infiltrate is not a prognostic factor in distal rectal cancer following neoadjuvant chemoradiation therapy

BACKGROUND

Peritumoral inflammatory response has been considered a good prognostic factor for colorectal cancer. However, this has not been evaluated in patients submitted to neoadjuvant therapy for distal rectal cancer. For this reason, we decided to study the effect of the presence of this pathological finding on disease recurrence and survival.

METHODS

The peritumoral inflammatory infiltrate from recovered pathological specimens of patients operated after neoadjuvant therapy for distal rectal cancer was graded (positive or negative). Patients were compared according to the presence of peritumoral inflammatory response.

RESULTS

Of the 168 patients, 63 (37%) patients had a peritumoral inflammatory response. The lack of peritumoral inflammatory response was significantly associated with the presence of mucinous component (13 vs 3%; p = 0.02). Five-year overall survival (91 vs 81%) and disease-free survival (57 vs 48%) were not significantly different between patients with and without peritumoral inflammatory response (p = 0.5 and 0.3, respectively).

CONCLUSIONS

Peritumoral inflammatory response is not a favorable prognostic factor in patients with distal rectal cancer after neoadjuvant chemoradiation therapy. Possibly, the immunosuppressive action of chemoradiation therapy may lead to a loss of function of the immunological response, which may represent a disadvantage of the neoadjuvant approach for the management of distal rectal cancer.

Inflammation and prognosis in colorectal cancer

AIM OF THE STUDY

Previous work has indicated that quantification of inflammatory cell reaction is of prognostic value in colorectal cancer. We evaluated the prognostic significance of inflammatory cell reaction patterns in colorectal cancer and developed a grading method which could be used in the routine assessment of tumours.

METHODS

The intensity of overall inflammatory cell reaction, numbers of neutrophilic and eosinophilic granulocytes, lymphoid cells and macrophages in both the central region and the invasive margin were estimated in 386 colorectal cancer patients. Prognostic significance was analysed by uni- and multivariate analysis.

RESULTS

Our method for classification of inflammatory reaction was reliable. High-grade inflammation at the invasive margin in Dukes' stage A and B cancers (pT1-2N0 and pT3N0, respectively) was associated with better 5-year-survival (87.6%) than low-grade inflammation (47.0%).

CONCLUSIONS

Inflammatory cell response at the invasive border is a relevant prognostic indicator and could be easily incorporated into the routine evaluation of histopathological specimens.

Local and distant recurrences in rectal cancer patients are predicted by the nonspecific immune response; specific immune response has only a systemic effect--a histopathological and immunohistochemical study

BACKGROUND

Invasion and metastasis is a complex process governed by the interaction of genetically altered tumor cells and the immunological and inflammatory host response. Specific T-cells directed against tumor cells and the nonspecific inflammatory reaction due to tissue damage, cooperate against invasive tumor cells in order to prevent recurrences. Data concerning involvement of individual cell types are readily available but little is known about the coordinate interactions between both forms of immune response.

PATIENTS AND METHODS

The presence of inflammatory infiltrate and eosinophils was determined in 1530 patients with rectal adenocarcinoma from a multicenter trial. We selected 160 patients to analyze this inflammatory infiltrate in more detail using immunohistochemistry. The association with the development of local and distant relapses was determined using univariate and multivariate log rank testing.

RESULTS

Patients with an extensive inflammatory infiltrate around the tumor had lower recurrence rates (3.4% versus 6.9%, p = 0.03), showing the importance of host response against tumor cells. In particular, peritumoral mast cells prevent local and distant recurrence (44% versus 15%, p = 0.007 and 86% versus 21%, p < 0.0001, respectively), with improved survival as a consequence. The presence of intratumoral T-cells had independent prognostic value for the occurrence of distant metastases (32% versus 76%, p < 0.0001).

CONCLUSIONS

We showed that next to properties of tumor cells, the amount and type of inflammation is also relevant in the control of rectal cancer. Knowledge of the factors involved may lead to new approaches in the management of rectal cancer.