Background: Colorectal cancer (CRC) is the second most common cancer in women and the third in men in Poland. The role of chemotherapy (CTX) depends on the stage of CRC: adjuvant CTX is a standard treatment in stage III and should also be considered in stage II with risk factors.

Aim: The aim of the paper was to assess the cardiovascular consequences of CTX in CRC enrolled to the ONCOECHO multicentre study (2012–2014). To identify potential cardiotoxicity, we focused on myocardial function, heart rhythm and conduction disorders, and adverse cardiovascular events.

Methods: Twenty-five CRC patients (12 women, mean age 61.3 [35–76] years), all receiving six-month adjuvant CTX were included. Thirteen patients received 5-fluorouracil (5FU)-based CTX, and 12 patients received a capecitabine-based scheme. Subjects were assessed at baseline and followed-up three, six, and 12 months after the onset of treatment. In this analysis we focused on conduction abnormalities, systolic and diastolic function of the left ventricle (LV), and cardiovascular events.

Results: In 12-month follow-up a decrease of selected tissue Doppler parameters (e.g. S’IVS, S’lat, and E’sept) was observed, and it was significant. LV structural parameters and ejection fraction (EF) remained unaffected. Changes in myocardial performance were not influenced by CTX regimen or treatment with beta-blockers or angiotensin-converting enzyme inhibitors. CTX did not affect LV structural parameters, EF, or conduction system, nor was it associated with cardiovascular events during the 12-month follow-up.

Conclusions: CTX in CRC patients does not affect LV structural parameters and EF. It may, however, trigger subtle changes in myocardial performance detectable by tissue Doppler echocardiography after 12 months. Moreover, it causes a transient increase of QT, which resolves after CTX cessation.