Journal Article

Patterns of locoregional failure following post-operative intensity-modulated radiotherapy to oral cavity cancer: quantitative spatial and dosimetric analysis using a deformable image registration workflow

Morrison, William H., Phan, Jack, Rosenthal, David I., Fuller, Clifton D., Mohamed, Abdallah S. R., Gunn, Gary B., El-Gowily, Ahmed G., Belal, Abdelaziz M., Quinlan-Davidson, Sean R., Kamal, Mona, Wong, Andrew J., Skinner, Heath, Frank, Steven J., Garden, Adam S., Beadle, Beth M., Lai, Stephen Y.

2017

Overview

Background We sought to identify spatial/dosimetric patterns of failure for oral cavity cancer patients receiving post-operative IMRT (PO-IMRT). Methods Two hundred eighty-nine OCC patients receiving PO-IMRT were retrospectively reviewed from 2000 to 2012. Diagnostic CT documenting recurrence (rCT) was co-registered with planning CT (pCT) using a validated deformable image registration software. Manually segmented recurrent gross disease (rGTV) was deformed to co-registered pCTs. Mapped rGTVs were compared dosimetrically to planned dose and spatially to planning target volumes using centroid-based approaches. Failures types were classified using combined spatial/dosimetric criteria: A (central high-dose), B (peripheral high-dose), C (central intermediate/low-dose), D (peripheral intermediate/low-dose), and E (extraneous-dose). Results Fifty-four patients with recurrence were analyzed; 26 local recurrence, 19 regional recurrence, and 9 both local and regional recurrence. Median time to recurrence was 4 months (range 0–71). Median rGTVs volume was 3.7 cm 3 (IQR 1.4–10.6). For spatial and dosimetric analysis of the patterns of failure, 30 patients (55.5%) were classified as type A (central high-dose). Non-central high dose failures were distributed as follows: 2 (3.7%) type B, 10 (18.5%) type C, 1 (1.8%) type D, and 9 (16.7%) type E. Non-IMRT failure in the matching low-neck field was seen in two patients. No failures were noted at the IMRT-supraclavicular field match-line. Conclusions Approximately half of patients with local/regional failure had non-central high dose recurrence. Peripheral high dose misses were uncommon reflecting adequate delineation and dose delivery. Future strategies are needed to reduce types C and E failures.

• Publisher: BioMed Central,BioMed Central Ltd,BMC
• Subject: Adult / Aged / Aged, 80 and over / Biomedical and Life Sciences / Biomedicine / Cancer Research / Carcinoma, Squamous Cell - radiotherapy / Care and treatment / CAT scans / Clinical Radiation Oncology / Deformable image registration / Female / Head and Neck Neoplasms - radiotherapy / Health aspects / Humans / Imaging / Male / Middle Aged / Mouth cancer / Mouth Neoplasms - radiotherapy / Neoplasm Recurrence, Local / Oncology / Oral cavity cancer / Patient outcomes / Patterns of failure / Post-operative intensity modulated radiation therapy / Quantitative spatial and dosimetric analysis / Radiology / Radiometry / Radiotherapy / Radiotherapy, Adjuvant - methods / Radiotherapy, Intensity-Modulated - methods / Retrospective Studies / Squamous Cell Carcinoma of Head and Neck / Young Adult