Radiologic response of chemotherapy alone versus radiation and chemotherapy in the treatment of locally-advanced or advanced thymic epithelial tumors.
Robert F Chu, Amira Hussien, Q Kay Li, Jiangxia Wang, Cole Friedes, Adam Ferro, Russell K Hales, Richard Battafarano, David S Ettinger, Khinh Ranh Voong
Author Information
Robert F Chu: The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Amira Hussien: Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA.
Q Kay Li: Department of Pathology, Johns Hopkins University, Baltimore, Maryland, USA.
Jiangxia Wang: Department of Biostatistics, Johns Hopkins University, Baltimore, Maryland, USA.
Cole Friedes: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland, USA. ORCID
Adam Ferro: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland, USA.
Russell K Hales: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland, USA.
Richard Battafarano: Department of Surgery, Division of Thoracic Surgery, Johns Hopkins University, Baltimore, Maryland, USA.
David S Ettinger: Department of Oncology, Johns Hopkins University, Baltimore, Maryland, USA.
Khinh Ranh Voong: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland, USA.
BACKGROUND: Here, we investigated radiological responses following chemotherapy alone as compared to both radiation/chemotherapy (chemoRT) in patients with thymic epithelial tumors (TETs) who did not receive upfront surgery. METHODS: TETs treated at a tertiary academic cancer center between January 2007 and July 2018 were identified. Patients received chemotherapy or chemoRT as initial therapy and pre- and post-treatment scans were available. Student's t-test, Wilcoxon rank-sum tests, and Cox proportional hazards method were used to compare clinical details and survival between groups. The primary outcome was change in tumor size, which was compared between groups using linear mixed-effects regression models, adjusting for baseline tumor size, age, and histology. RESULTS: A total of 24 of 114 patients with TETs identified met the inclusion criteria. The majority of patients had 67% thymoma (67%, n = 16) and AJCC8 III-IVA disease (58%, n = 14). Median age was 58.5 years (range: 33-76), median initial tumor volume was 187.1 cc (range: 28.7-653.6) and diameter was 8.5 cm (range: 4.5-14.3). Half of the patients received upfront chemotherapy (n = 12: 83% cisplatin/adriamycin/cyclophosphamide) or chemoRT (n = 12: 58% carboplatin/paclitaxel; median RT dose: 63 Gy [range: 60-70 Gy]). At a median imaging follow-up of 15 months (range: 0-86): ChemoRT was associated with increased average radiological response compared to chemotherapy alone (volume: -47.0 cc more, P < 0.001; diameter: -0.8 cm more, P = 0.03). In eight patients who received chemotherapy, 33% saw further tumor shrinkage (median volume: -42.3%, P = 0.03; diameter: -3.0%, P = 0.049) with additional radiation/chemoradiation. Median survival increased for patients ultimately receiving surgery versus those who did not (46 month, range: 16-127 vs. 14 month, range: 6-82; P < 0.01). CONCLUSIONS: ChemoRT produced a greater radiologic response compared to chemotherapy alone in patients with TETs not suitable for upfront resection. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: We found that chemoRT was associated with a greater radiologic response compared to patients who received chemotherapy alone. WHAT THIS STUDY ADDS: What this study adds: In patients with TET not amenable to upfront resection, chemoRT may be a feasible strategy for cytoreduction.
