Colorectal cancer: Ageing, myeloid-derived suppressor cells, and treatment: Report of two cases

Background: Colorectal cancer (CRC) is the third cause of cancer in the world and age is a risk factor for this disease. Treatments such as surgical resection and adjuvant chemotherapy have increased the mean survival and the recurrence-free survival. However, the decrease in the frequency and function of effector T cells in addition to the increase in the frequency of myeloid-derived suppressor cells that have been reported in older individuals could contribute to the impaired efficacy in immunity against cancer. We aimed to evaluate if in old patients with CRC, the pre-treatment immunological status was correlated with patients’ outcome. Methods: Patients with CRC (n = 2) were submitted to curative surgical resection or curative surgical resection plus capecitabine/oxaliplatine. Blood was collected for the evaluation of immunological status prior to the treatment and correlated with patients’ outcome. Results: Approximately 20 months after surgery the patients presented with recurrence-free survival. Patient 2 (66-years-old) with CRC and peritoneal metastases presented higher frequency and absolute cell number of myeloid-derived suppressor cells than patient 1 (58-years-old) with CRC. Patient 2 presented a low frequency of effector memory CD8 T cells in addition to high accumulation of effector memory reexpressing CD45RA (CD4 and CD8 T cells). Conclusion: Immunological status was correlated with the disease complexity and our results suggest that removing/reducing myeloid-derived suppressor cells helps in the control of cancer progression. Immunological status is a useful, low invasive tool to identify the disease complexity and the results can be used in the future development of personal treatment according to the immunological status of the patient.