Nomogram for predicting the risk of locoregional recurrence in patients treated with accelerated partial-breast irradiation

Int J Radiat Oncol Biol Phys. 2015 Feb 1;91(2):312-8. doi: 10.1016/j.ijrobp.2014.09.029. Epub 2014 Nov 11.


Purpose: To develop a nomogram taking into account clinicopathologic features to predict locoregional recurrence (LRR) in patients treated with accelerated partial-breast irradiation (APBI) for early-stage breast cancer.

Methods and materials: A total of 2000 breasts (1990 women) were treated with APBI at William Beaumont Hospital (n=551) or on the American Society of Breast Surgeons MammoSite Registry Trial (n=1449). Techniques included multiplanar interstitial catheters (n=98), balloon-based brachytherapy (n=1689), and 3-dimensional conformal radiation therapy (n=213). Clinicopathologic variables were gathered prospectively. A nomogram was formulated utilizing the Cox proportional hazards regression model to predict for LRR. This was validated by generating a bias-corrected index and cross-validated with a concordance index.

Results: Median follow-up was 5.5 years (range, 0.9-18.3 years). Of the 2000 cases, 435 were excluded because of missing data. Univariate analysis found that age <50 years, pre-/perimenopausal status, close/positive margins, estrogen receptor negativity, and high grade were associated with a higher frequency of LRR. These 5 independent covariates were used to create adjusted estimates, weighting each on a scale of 0-100. The total score is identified on a points scale to obtain the probability of an LRR over the study period. The model demonstrated good concordance for predicting LRR, with a concordance index of 0.641.

Conclusions: The formulation of a practical, easy-to-use nomogram for calculating the risk of LRR in patients undergoing APBI will help guide the appropriate selection of patients for off-protocol utilization of APBI.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Algorithms
  • Brachytherapy / statistics & numerical data*
  • Breast Neoplasms / diagnosis
  • Breast Neoplasms / epidemiology*
  • Breast Neoplasms / radiotherapy*
  • Dose Fractionation, Radiation
  • Female
  • Humans
  • Middle Aged
  • Neoplasm Recurrence, Local / diagnosis
  • Neoplasm Recurrence, Local / epidemiology*
  • Neoplasm Recurrence, Local / prevention & control*
  • Nomograms*
  • Organ Sparing Treatments / methods
  • Organ Sparing Treatments / statistics & numerical data*
  • Outcome Assessment, Health Care / methods
  • Prognosis
  • Reproducibility of Results
  • Risk Assessment / methods
  • Sensitivity and Specificity
  • United States / epidemiology