Out of the woods, but still in the weeds: When cancer therapy becomes part of a chronic condition

Imatinib was introduced on the cover of TIME magazine in 2001 as ‘the magic bullet’ to cure cancer, ushering in a new era of targeted cancer therapeutics that has transformed the modern landscape of cancer treatment. As the first tyrosine kinase inhibitor (TKI) targeting the Bcr-Abl protein, imatinib revolutionised the treatment of chronic myelogenous leukaemia (CML) by improving 10-year survival from 20% to 90%.1 In patients who achieve complete cytogenetic remission on imatinib, overall survival with CML is now comparable to that of population-based controls.2 Due to this metamorphosis from devastating diagnosis to chronic illness, better understanding of non-cancer-related morbidity and mortality is needed in patients with CML on long-term TKI therapy. In this issue of Heart , Leong et al 3 examined the incidence of major adverse cardiovascular events (MACE) and cardiovascular mortality in 4238 patients with CML from Ontario, Canada between 1986 and 2017, as compared with an age-matched and sex-matched control group. Separate analyses were performed for patients diagnosed before and after the introduction of TKIs in 2001. MACE was defined as hospitalisation for myocardial infarction, cerebrovascular disease or peripheral arterial disease using administrative codes, while cardiovascular death was determined by the physician certifying the patient’s death. Among 46 618 patients included in the study, the authors found increased risk of all-cause mortality in the patients with CML that was attenuated post-TKIs, consistent with known improvement in overall survival on TKI therapy. While risks of MACE and cardiovascular mortality were lower in the patients with CML pre-TKIs, there were no differences between the CML and control groups post-TKIs. In fact, the risk of peripheral arterial disease was higher in the patients with CML post-TKIs (HR=1.66 (95% CI 1.15 to …