by Nalee Kim, Won Park, Won Kyung Cho, Hae Young Kim, Doo Ho
Choi, Seok Jin Nam, Seok Won Kim, Jeong Eon Lee, Jonghan Yu, Byung Joo Chae, Se
Kyung Lee, Jai Min Ryu, Goo-Hyun Mun, Jai-Kyong Pyon, Byung-Joon Jeon
The Breast: Published: September 23, 2022
Aim
Both skin-sparing mastectomy (SSM) and nipple-sparing
mastectomy (NSM) have been widely adopted. Although postmastectomy radiation
therapy (PMRT) can improve clinical outcomes, it can worsen cosmesis following
reconstruction. Therefore, identifying risk factors of ipsilateral breast tumor
recurrence (IBTR) could help de-escalate PMRT after NSM/SSM in patients with
pT1-2 disease.
Methods
We retrospectively reviewed patients treated with SSM
(N = 400) and NSM (N = 156) in patients with pT1-2N0-1
disease between 2009 and 2016. Seventy-four patients received PMRT with
50–50.4 Gy in 25–28 fractions. The Cox proportional hazards model was used
to analyze the prognostic factors of IBTR.
Results
With a median follow-up of 66.2 months, 17 IBTR events were
observed, with 5-year IBTR-free rate of 97.2%. Although only one IBTR was
observed after PMRT, there was no statistical difference in the 5-year
IBTR-free rate (PMRT vs. no PMRT, 98.6% vs. 97.0%, p = 0.360).
Multivariable analyses demonstrated that age ≤45 years and lymphovascular
invasion (LVI) were adverse features of IBTR. The low-risk group (0 risk factor)
showed a better 5-year IBTR-free rate than the high-risk group (≥1 risk factor)
(100.0% vs. 95.8%, p = 0.003). In the high-risk group, PMRT slightly
improved 5-year IBTR-free rate compared with no PMRT (98.6% vs. 95.2%,
p = 0.166). In addition, PMRT increased 5-year cumulative incidence
of reconstruction failure (10.0% vs. 2.8%, p = 0.001).
Conclusion
We identified risk factors (age and LVI) related to IBTR
following upfront SSM/NSM with pT1-2 disease. As a hypothesis-generating study,
de-escalation of PMRT by omitting chest wall irradiation in selective patients
could improve reconstruction-related complications without compromising
oncologic outcomes.
