TITLE:
Role of Radiotherapy-Induced Malignancies in Patients with Both Breast and Lung Cancer Diagnoses
AUTHORS:
Eric Khang Nguyen, Garth Andrew Nicholas, Xinni Song
KEYWORDS:
Breast, Lung, Cancer, Radiotherapy-Induced, Ipsilateral
JOURNAL NAME:
Advances in Breast Cancer Research,
Vol.7 No.3,
July
19,
2018
ABSTRACT: Background:Breast
and lung cancer are two of the most commonly diagnosed cancers in North
America. While patients are living longer with advances in treatment and
supportive care, some patients are being diagnosed with a second malignancy.
The primary objective in this study was to assess the correlation between the
development of an ipsilateral lung cancer or breast cancer, and prior radiation
therapy. In addition, we sought to report the survival outcomes of patients in
these clinical scenarios. Methods: We conducted a single
institution (the Ottawa Hospital Cancer Centre) retrospective review of patients
with the diagnoses of both breast and lung cancer treated between 1995 and 2013. Patients were
included if they received radiation for a breast primary, and subsequently
developed an ipsilateral lung primary, or vice-versa. Data included patient demographics,
lifestyle factors, tumor location and subtype, cancer stages, treatment
modalities, and survival outcomes. Results: Of 252 patients included
in the study, 217 patients developed a breast primary first, with 35 patients
developing a lung primary first. Median disease-free survival from the second
primary diagnosis was 36 months in breast primary first patients, and 59 months
in the lung primary first cohort. There was no significant correlation between the
laterality of radiation treatment and side of second primary based on Fisher’s
exact test. Conclusions: Our data reveal no association between
side of radiation treatment and subsequent cancer development. The benefits of
radiotherapy outweigh the risk of radiation-induced primaries. Longer term
studies with matched patient cohorts are required to further assess treatment
and lifestyle factors that may contribute towards the development of second
malignancies.