The effect of induction chemotherapy on tumor volume and organ-at-risk doses in patients with locally advanced oropharyngeal cancer

Patricia Doornaert*, Max Dahele, Wilko F. A. R. Verbakel, Omar Bohoudi, Ben J. Slotman, Johannes A. Langendijk

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)

Abstract

Background and purpose: To retrospectively report changes in gross tumor volume (GTV) and organ-at-risk (OAR) doses after induction chemotherapy (IC) in oropharyngeal cancer using different contouring strategies.

Materials and methods: GTV and OARs were delineated on pre- and post-IC planning CT. Two post-IC GTV contours were made: (I) a 'consensus set' using published guidelines (GTV(consensus)). and (2) 'visible set', delineating only visible post-IC GTV (GTV(visible)). Pre-IC interactively optimized volumetric modulated arc therapy plans were generated. The pre-IC planning constraints served as the starting point for both post-IC plans. Results reflect pooled data from all 10 patients.

Results: Mean reduction in volume post-IC was 24% and 47% for consensus and visible primary tumor and 57% and 60% for consensus and visible nodes. Compared to pre-IC plans, average mean OAR dose for post-IC GTV(consensus) plans was significantly lower for CL parotid. For GTV(visible) plans both parotids, upper/lower larynx, inferior pharyngeal constrictor and cricopharyngeal muscles were significantly lower. However reductions compared with post-IC GTV(consensus) plans were modest (1.6/1.5/1.2/3.7/5.9/2.6 Gy, respectively).

Conclusion: IC in patients with oropharyngeal carcinoma results in substantial reductions in GTVs. If post-IC GTVs are used, which is contrary to current consensus, statistically significant but relatively small OAR dose reductions are observed. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)269-274
Number of pages6
JournalRadiotherapy and Oncology
Volume109
Issue number2
DOIs
Publication statusPublished - Nov-2013

Keywords

  • Induction chemotherapy
  • Oropharynx cancer
  • Organ-at-risk dose
  • Volumetric change
  • INTENSITY-MODULATED RADIOTHERAPY
  • SQUAMOUS-CELL CARCINOMA
  • NECK-CANCER
  • ADVANCED HEAD
  • CONCURRENT CHEMORADIOTHERAPY
  • SEQUENTIAL CHEMORADIOTHERAPY
  • DELINEATION
  • FLUOROURACIL
  • CISPLATIN
  • DOCETAXEL

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