Is Proton Therapy a “Pro” for Breast Cancer? A Comparison of Proton vs. Non-proton Radiotherapy Using the National Cancer Database

Abstract

Background: Limited data exists demonstrating the clinical benefit of proton radiotherapy (PRT) in breast cancer. Using the National Cancer Database, we evaluated predictors associated with PRT use for patients with breast cancer. An exploratory analysis also investigates the impact of PRT on overall survival (OS).Methods: Patients with non-metastatic breast cancer treated with adjuvant radiotherapy from 2004 to 2014 were identified. Patients were stratified based on receipt of PRT or non-PRT (i.e., photons ± electrons). A logistic regression model was used to determine predictors for PRT utilization. For OS, Multivariable analysis (MVA) was performed using Cox proportional hazard model.Results: A total of 724,492 patients were identified: 871 received PRT and 723,621 received non-PRT. 58.3% of the PRT patients were group stage 0–1. Median follow-up time was 62.2 months. On multivariate logistic analysis, the following factors were found to be significant for receipt of PRT (all p < 0.05): academic facility (odds ratio [OR] = 2.50), South (OR = 2.01) and West location (OR = 12.43), left-sided (OR = 1.21), ER-positive (OR = 1.59), and mastectomy (OR = 1.47); pT2-T4 disease predicted for decrease use (OR = 0.79). PRT was not associated with OS on MVA for all patients: Hazard Ratio: 0.85, p = 0.168. PRT remained not significant on MVA after stratifying for subsets likely associated with higher heart radiation doses, including: left-sided (p = 0.140), inner-quadrant (p = 0.173), mastectomy (p = 0.095), node positivity (p = 0.680), N2-N3 disease (p = 0.880), and lymph node irradiation (LNI) (p = 0.767).Conclusions: Receipt of PRT was associated with left-sided, ER+ tumors, mastectomy, South and West location, and academic facilities, but not higher group stages or LNI. PRT was not associated with OS, including in subsets likely at risk for higher heart doses. Further studies are required to determine non-OS benefits of PRT. In the interim, given the high cost of protons, only well-selected patients should receive PRT unless enrolled on a clinical trial.

Acute toxicities after proton beam therapy following breast‐conserving surgery for breast cancer: Multi‐institutional prospective PCG registry analysis

“…Although PBT offers several dosimetric advantages compared to photons, 4,6‐8,14 higher rates of RD have been observed with PBT for breast cancer. DeCesaris et al reported higher rates of grade ≥2 RD with PBT compared to photons (69.2% vs 29.8%; P = .002) 10 .…”

“…PBT offers unique dosimetric advantages, such as improved target and internal mammary nodal (IMN) coverage, 4,5 decreased lung dose, 6,7 and decreased heart dose 6,7 . However, PBT has some disadvantages including decreased patient access, 8 increased cost, 9 and higher rates of acute radiation dermatitis (RD) 10 . We report a prospectively evaluated multi‐institutional cohort of patients who received adjuvant whole‐breast PBT after BCS for breast cancer.…”

Is there any benefit to particles over photon radiotherapy?

“…The overall survival (OS) in breast cancer patients was assessed using the US National Cancer Database between 2004 and 2014. The OS of patients that received proton therapy was not statistically significantly longer than those that received photon therapy [Hazard ratio (HR) 0.85 (95% Confidence interval (CI) 0.68-1.07)] [7].…”

Does the addition of chemotherapy to neoadjuvant radiotherapy impact survival in high‐risk extremity/trunk soft‐tissue sarcoma?

“…[15][16][17] The data files are compliant with the US Health Insurance Portability and Accountability Act and completely de-identified. [15][16][17] The data files are compliant with the US Health Insurance Portability and Accountability Act and completely de-identified.…”

“…The NCDB is a hospital-based, national registry maintained jointly by the American College of Surgeons and the American Cancer Society and includes data from more than 1500 accredited facilities in the United States. [15][16][17] The data files are compliant with the US Health Insurance Portability and Accountability Act and completely de-identified. Therefore, institutional review board review was not required.…”