Background: The aim of this study was to determine the chemosensitivity of pregnancy-associated breast cancer (PABC) in the neoadjuvant setting by comparing the observed pathological complete response (pCR) rate with the rate predicted by a validated nomogram.
Methods: Data from 48 PABC patients who received neoadjuvant chemotherapy (NACT) were collected. To predict the response rate to chemotherapy, we used well-calibrated logistic regression-based nomograms to calculate individual probability of pCR.
Results: Observed rates of pCR were concordant with predictions in the whole sample and in the analyzed subgroups. For the whole sample, the area under the receiver-operated curve (AUC) was 0.77 (95% CI 0.66-0.87). The calibration of predicted and observed probabilities was excellent. In the subgroup analyses (NACT initiated during pregnancy or postpartum, NACT with only anthracycline or both anthracycline and taxanes), discriminations assessed by AUC were significantly above 0.5, except for patients treated with anthracycline only. The interpretation was limited by a lack of power.
Conclusion: Through the use of nomograms, our study demonstrates that PABC is as chemosensitive as non-PABC and suggests that taxanes should be part of the NACT regimen for PABC. Further studies are warranted to increase the power of the presented data.