BACKGROUND: A large variety of factors can affect colorectal cancer (CRC) survival, including type 2 diabetes mellitus (T2DM) and paraneoplastic thrombocytosis. Although several common factors play a role in their development and platelets are damaged in both diseases, the combined relationship of the three conditions was never investigated previously.

METHODS: A prospective, real-life observational cohort study was conducted with the inclusion of 108 CRC patients and 166 voluntary non-CRC subjects. Plasma interleukin-6 and thrombopoietin levels were measured.

RESULTS: Study participants were divided into cohorts based on the presence of T2DM. Platelet count ( < 0.0500) and interleukin-6 ( < 0.0100) level were significantly higher in the CRC groups. Thrombopoietin level was higher in the T2DM, CRC, and groups ( < 0.0500). Analysis of parameter changes over time and survival models revealed that neither platelet count, interleukin-6, nor thrombopoietin levels were affected by T2DM. Death of patients was associated with higher baseline platelet count ( = 0.0042) and interleukin-6 level ( < 0.0001).

CONCLUSION: Although the independent, disease-worsening effect of paraneoplastic thrombocytosis and T2DM is known, the coexistence of the two did not further impair the survival of CRC patients, suggesting that T2DM has no significant effect over paraneoplastic thrombocytosis.