TY - JOUR
T1 - Evaluation of Early Response to Preoperative Accelerated Partial Breast Irradiation (PAPBI) by Histopathology, Magnetic Resonance Imaging, and 18F-fluorodexoyglucose Positron Emission Tomography/Computed Tomography (FDG PET/CT)
AU - Bosma, Sophie C. J.
AU - van der Leij, Femke
AU - Elkhuizen, Paula H. M.
AU - Vreeswijk, S.
AU - Loo, Claudette E.
AU - Vogel, Wouter V.
AU - Bartelink, Harry
AU - van de Vijver, Marc J.
N1 - Funding Information: This study was supported by the Dutch Cancer Society-Kankerbestrijding grant NKI 2009-4389 and the Cancer Society in Stockholm, Sweden . Publisher Copyright: © 2021 Elsevier Inc.
PY - 2021/7/15
Y1 - 2021/7/15
N2 - Purpose: This study aimed to find indicators for early response to radiation therapy in breast cancer. These would be of help in tailoring treatment for individual patients. Methods and Materials: We analyzed 66 patients with low-risk breast cancer (≥60 years; cT1-2pN0) treated within the Preoperative Accelerated Partial Breast Irradiation (PAPBI) trial. Patients received radiation therapy (RT; 10 x 4 Gray or 5 x 6 Gray), followed by a wide local excision after 6 weeks. Patients underwent magnetic resonance imaging (MRI) and 18F-fluorodexoyglucose (FDG) positron emission tomography/computed tomography (PET/CT) before RT and 5 weeks after RT, before surgery. We assessed the response to PAPBI using a histopathologic assessment and correlated this with responses on MRI and FDG PET/CT. We calculated the positive predictive values (PPVs) of MRI and PET/CT as the number of true positives (complete response on MRI/normalized at visual evaluation on PET/CT and pathologic complete response) divided by the number of patients with a complete response on MRI/normalized at visual evaluation on PET/CT. Similarly, the negative predictive values (NPVs) of MRI and PET/CT were calculated. Results: The pathologic response was (nearly) complete in 15 (23%) of the 66 patients and partially complete in 28 (42%). The remaining 23 patients (35%) were nonresponders. The PPV of MRI (Response evaluation criteria in solid tumors [RECIST]) was 87.5% and the NPV was 85%. The PPV and NPV of PET/CT were 25% and 92%, respectively. Conclusions: The most accurate method to predict a response and residual disease after preoperative RT in low-risk breast cancer was MRI, using RECIST.
AB - Purpose: This study aimed to find indicators for early response to radiation therapy in breast cancer. These would be of help in tailoring treatment for individual patients. Methods and Materials: We analyzed 66 patients with low-risk breast cancer (≥60 years; cT1-2pN0) treated within the Preoperative Accelerated Partial Breast Irradiation (PAPBI) trial. Patients received radiation therapy (RT; 10 x 4 Gray or 5 x 6 Gray), followed by a wide local excision after 6 weeks. Patients underwent magnetic resonance imaging (MRI) and 18F-fluorodexoyglucose (FDG) positron emission tomography/computed tomography (PET/CT) before RT and 5 weeks after RT, before surgery. We assessed the response to PAPBI using a histopathologic assessment and correlated this with responses on MRI and FDG PET/CT. We calculated the positive predictive values (PPVs) of MRI and PET/CT as the number of true positives (complete response on MRI/normalized at visual evaluation on PET/CT and pathologic complete response) divided by the number of patients with a complete response on MRI/normalized at visual evaluation on PET/CT. Similarly, the negative predictive values (NPVs) of MRI and PET/CT were calculated. Results: The pathologic response was (nearly) complete in 15 (23%) of the 66 patients and partially complete in 28 (42%). The remaining 23 patients (35%) were nonresponders. The PPV of MRI (Response evaluation criteria in solid tumors [RECIST]) was 87.5% and the NPV was 85%. The PPV and NPV of PET/CT were 25% and 92%, respectively. Conclusions: The most accurate method to predict a response and residual disease after preoperative RT in low-risk breast cancer was MRI, using RECIST.
UR - http://www.scopus.com/inward/record.url?scp=85103736550&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.ijrobp.2021.02.033
DO - https://doi.org/10.1016/j.ijrobp.2021.02.033
M3 - Article
C2 - 33647369
SN - 0360-3016
VL - 110
SP - 1151
EP - 1158
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 4
ER -