by Naoum, George E.; Ho, Alice Y.; Shui, Amy; Salama, Laura;
Goldberg, Saveli; Arafat, Waleed; Winograd, Jonathan; Colwell, Amy; Smith,
Barbara L.; Taghian, Alphonse G.
Plastic and Reconstructive Surgery: January 2022
- Volume 149 - Issue 1 - p 1e-12e
Background:
The purpose of this study was to create a nomogram using
machine learning models predicting risk of breast reconstruction complications
with or without postmastectomy radiation therapy.
Methods:
Between 1997 and 2017, 1617 breast cancer patients undergoing
mastectomy and breast reconstruction were analyzed. Those with autologous,
tissue expander/implant, and single-stage direct-to-implant reconstruction were
included. Postmastectomy radiation therapy was delivered either with
three-dimensional conformal photon or proton therapy. Complication endpoints
were defined based on surgical reintervention operative notes as
infection/necrosis requiring débridement. For implant-based patients,
complications were defined as capsular contracture requiring capsulotomy and
implant failure. For each complication endpoint, least absolute shrinkage and
selection operator–penalized regression was used to select the subset of
predictors associated with the smallest prediction error from 10-fold
cross-validation. Nomograms were built using the least absolute shrinkage and
selection operator–selected predictors, and internal validation using
cross-validation was performed.
Results:
Median follow-up was 6.6 years. Among 1617 patients, 23
percent underwent autologous reconstruction, 39 percent underwent
direct-to-implant reconstruction, and 37 percent underwent tissue
expander/implant reconstruction. Among 759 patients who received postmastectomy
radiation therapy, 8.3 percent received proton-therapy to the chest wall and
nodes and 43 percent received chest wall boost. Internal validation for each
model showed an area under the receiver operating characteristic curve of 73
percent for infection, 75 percent for capsular contracture, 76 percent for
absolute implant failure, and 68 percent for overall implant failure.
Periareolar incisions and complete implant muscle coverage were found to be
important predictors for infection and capsular contracture, respectively. In a
multivariable analysis, we found that protons compared to no postmastectomy
radiation therapy significantly increased capsular contracture risk (OR,
15.3; p < 0.001). This was higher than the effect of photons with
electron boost versus no postmastectomy radiation therapy (OR, 2.5; p =
0.01).
Conclusion:
Using machine learning, these nomograms provided prediction
of postmastectomy breast reconstruction complications with and without
radiation therapy.
CLINICAL QUESTION/LEVEL OF EVIDENCE:
Risk, III.
