Adaptive Planning in Intensity-Modulated Radiation Therapy for Head and Neck Cancers: Single-Institution Experience and Clinical Implications

Journal Article · Fri Jul 01 04:00:00 EDT 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.03.014· OSTI ID:21587585

Ahn, Peter H; Chen, Chin-Cheng ^[1]; Ahn, Andrew I ^[2]; Hong, Linda; Scripes, Paola G; Jin, Shen; Lee, Chen-Chiao; Miller, Ekeni; Kalnicki, Shalom ^[1]

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1. Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine of Yeshiva University, Bronx, New York (United States)
2. Albert Einstein College of Medicine of Yeshiva University, Bronx, New York (United States)

Purpose: Anatomic changes and positional variability during intensity-modulated radiation therapy (IMRT) for head and neck cancer can lead to clinically significant dosimetric changes. We report our single-institution experience using an adaptive protocol and correlate these changes with anatomic and positional changes during treatment. Methods and Materials: Twenty-three sequential head and neck IMRT patients underwent serial computed tomography (CT) scans during their radiation course. After undergoing the planning CT scan, patients underwent planned rescans at 11, 22, and 33 fractions; a total of 89 scans with 129 unique CT plan combinations were thus analyzed. Positional variability and anatomic changes during treatment were correlated with changes in dosimetric parameters to target and avoidance structures between planning CT and subsequent scans. Results: A total of 15/23 patients (65%) benefited from adaptive planning, either due to inadequate dose to gross disease or to increased dose to organs at risk. Significant differences in primary and nodal targets (planning target volume, gross tumor volume, and clinical tumor volume), parotid, and spinal cord dosimetric parameters were noted throughout the treatment. Correlations were established between these dosimetric changes and weight loss, fraction number, multiple skin separations, and change in position of the skull, mandible, and cervical spine. Conclusions: Variations in patient positioning and anatomy changes during IMRT for head and neck cancer can affect dosimetric parameters and have wide-ranging clinical implications. The interplay between random positional variability and gradual anatomic changes requires careful clinical monitoring and frequent use of CT- based image-guided radiation therapy, which should determine variations necessitating new plans.

• OSTI ID: 21587585
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 80; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BODY
CAT SCANNING
CENTRAL NERVOUS SYSTEM
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DISEASES
DOSES
DOSIMETRY
HAZARDS
HEAD
JAW
MEDICINE
NECK
NEOPLASMS
NERVOUS SYSTEM
NUCLEAR MEDICINE
ORGANS
RADIATION DOSES
RADIOLOGY
RADIOTHERAPY
SKELETON
SKIN
SKULL
SPINAL CORD
THERAPY
TOMOGRAPHY
VERTEBRAE