Abstract and Introduction
Abstract
Background Most of the current research in gastrointestinal oncology is focused on biology of cancer itself, but there is growing interest in the patient's immune system response and its relation with cancer cells.
Aim To review the impact of the antitumoural immune response on epidemiology, prognosis and treatment of colorectal cancer.
Methods Search of the literature published in English using the PubMed database.
Results The role of the immune system in the antitumoural immunosurveillance is clearly supported by the increased incidence of colorectal cancer and adenomatous polyps in immunosuppressed patients. Moreover, the degree of infiltration of the tumours by the immune cells has been shown to be a strong prognostic factor of both disease recurrence and survival. The immune system plays an important role in the chemotherapy-induced cell death. New therapeutic strategies targeting the antitumoural immunity are being currently investigated with promising results.
Conclusion Better knowledge of antitumoural immune system can have a major impact on patients' management in daily clinical practice. Colorectal cancer screening is an important issue in immunosuppressed patients, and recommendations should be refined for selected high-risk patients. The use of an immune score to guide the therapeutic strategies in the adjuvant setting should be supported. Further and larger clinical trials are necessary to accelerate the development of innovative immune therapies.
Introduction
Colorectal cancer (CRC) is the third most commonly diagnosed cancer with around 1 million new cases and more than 500 000 deaths every year in the world. Despite recent progress, many advances are needed to improve the prognosis. This could be achieved by a better understanding of cancer epidemiology and risk factors, by the identification of new prognostic and predictive factors that would allow selecting patients for intensified therapies and by the development of new therapeutic agents. Many recent research studies focused on tumour cells and tumoural mutation such as KRAS, BRAF or PTEN mutations. But there is growing evidence that the immune response to the tumour may play an important role in oncogenesis and in the prognosis and the response to treatments.
The aim of this review is to address clinically relevant issues concerning the role of the immune system and its potential applications in the screening and the management of CRC. In particular, the following questions will be addressed: Is there a clinically relevant increased risk of CRC in a population with long-term impaired immunity? Are the intensity and the characteristics of the immune response prognostic factors in CRC? What is the impact of the immune response on the efficacy of standard chemotherapy and can we develop accordingly immune therapies?