Takotsubo cardiomyopathy (TCM) represents an acute systolic left ventricular dysfunction typically triggered by severe psychological or physical stress. Oncological patients due to emotional distress of the diagnosis, proinflammatory and prothrombotic nature of cancer and also physical stress often following complex anticancer therapies are at high-risk of TCM. Moreover, there are also few reports of TCM associated with oncological treatment, mostly chemotherapy. Recent data from large registries indicate a surprisingly high incidence of malignancy in TCM, significant differences in clinical characteristics and unfavorable short- and long-term clinical outcomes in this specific group of patients. Therefore, we present two case reports of TCM that occurred during active anticancer therapy. Both women were admitted with suspicion of acute coronary syndrome. The first patient underwent mastectomy two years before due to hormone receptor-positive breast cancer and on admission she was during adjuvant hormonotherapy with tamoxifen. The admission of the second patient was preceded by fifteen fractions of adjuvant external beam radiotherapy due to intermediate-risk endometrial cancer after radical hysterectomy. Based on coronary angiography type I of acute coronary syndrome was excluded. Both patients negated stressful situations in the period immediately before the symptoms onset. Within hospital course baseline apical ballooning observed in both cases fully recovered and enabled subsequent completion of oncological treatment in accordance with adopted treatment protocols without recurrence of TCM. To our knowledge, presented cases are the first reports showing direct relationship between TCM and adjuvant hormonotherapy with tamoxifen or pelvic radiotherapy.