Retrospective Study of Cardiac Toxicity of Hypofractionated Radiotherapy in Left Sided Breast Cancer

Background and aim: Postoperative adjuvant breast radiotherapy is considered
one of the main steps in management of breast cancer. Fortunately, there has
been a marked revolution in breast radiation therapy techniques and nowadays
efficiently sparing the heart without affecting either local control or overall
survival is possible .But still at the present time some controversies as regards
most effective fractionation schedule with least side effects and comparable to
conventional fractionation .The purpose of this study is to assess the impact of
high dose per fraction used in hypofractionation schedules (40Gy/15, 39Gy/13
or 42.5Gy/16) on the heart in left sided breast cancer patients and its
relationship with the clinical outcome.
Patients and methods: A retrospective study, enrolled a total of 175 women
with non-metastatic left sided breast cancer in South Egypt Cancer Institute
(SECI) from 2015-2020.All patients full filling eligibility criteria including
patients with age 18-75 years old with left sided pathologically confirmed breast
cancer and received 3D hypo fractionation radiotherapy after surgery, their
medical reports were evaluated and their medical data were debriefed. They
were followed to assess frequency of cardiac affection by echocardiography
focusing on left ventricular ejection fraction at starting planned treatment
protocol and re-evaluated 3 years after radiotherapy course.
Results: 175 patients were accrued in this study, mean age was 53.30±9.46
years, and ninety-two (52.6%) women were pre/perimenopausal. Patients with
T2 disease were the most common, also positive node were noticed in one
hundred forty nine patients (84.9%). Ninety eight (56%) patients had stage-III
disease, One hundred forty three (81.7%) of patients underwent modified radical
mastectomy (MRM). Estimated patients received hypo fractionated 3D
radiotherapy dose schedules (3900/13, 4005/15 and 4240/16) were (4%),
(34.9%) and (61.1%), respectively. Overall survival in studied patients based on
development of LV dysfunction was 5.2 years and DFS was 3.4years with no
significant difference between both groups as regard survival who are affected
with cardiac toxicity of any grade and those without cardiac toxicity.
Conclusion: Cardiac toxicities is uncommon in women who received adjuvant
breast irradiation with hypo-fractionated radiotherapy. Patients with advanced
tumor stage, neoadjuvant chemotherapy and/or received trastuzumab are more
vulnerable to develop LV dysfunction.