2130 - Adaptive Radiotherapy Using PRECISE ART in Head and Neck Cancer: Impact on Toxicity and Clinical Outcomes

02:30pm - 04:00pm PT

Hall F

Screen: 2

POSTER

Presenter(s)

Rishabh Kumar, MD - Amrita Institute of Medical Sciences, New Delhi, Delhi

R. Kumar¹, B. Vishwanathan¹, R. Kamal¹, and D. Thaper²; ¹Amrita Institute of Medical Sciences and Research Centre, Faridabad, India, ²Institute of Liver and Bilary Sciences, New Delhi, Punjab, India

Purpose/Objective(s): Adaptive radiotherapy (ART) optimizes tumor coverage while minimizing normal tissue toxicity in head and neck cancer patients. This study evaluates whether ART using PRECISE ART reduces treatment-related toxicities and improves clinical outcomes. We hypothesized that ART would enhance target conformity, improve organ-at-risk (OAR) sparing, and minimize interruptions without compromising oncologic efficacy.

Materials/Methods: This retrospective analysis included 88 patients enrolled in a prospective cancer registry undergoing curative-intent radiation. Patients were treated using 3-D CRT and IMRT system/treatment delivery system, with ART triggered when body hotspots exceeded 107% for 2cc, OAR constraints were violated, or CTV was underdosed. Plan adaptation was performed using MVCT with PRECISE ART. 63 patients underwent ART, and radiation dose parameters to key OARs were analyzed. Clinical outcomes, toxicity profiles (CTC v5), and oncologic responses were assessed. The median overall survival (OS) and progression-free survival (PFS) were calculated.

Results: Among 88 patients, 54 underwent surgery followed by adjuvant RT/CTRT, and 34 received definitive RT/CTRT. All underwent adaptive planning using PRECISE ART. Plan adaptation was performed using MVCT in 63 patients. The mean radiation doses to OARs were: constrictor muscles (42 Gy), spinal cord max (32 Gy), parotid glands (28 Gy), oral cavity (41 Gy), lips (28 Gy), and larynx (38 Gy).

Three patients experienced treatment interruptions. The mean fractionation duration was 42 days. NG tube placement was required in 8% of patients. Pre-treatment PAS scores were 1 in all patients except three, who had scores of 4, 5, and 3, respectively. The average weight loss was 5.2% of body weight. Post-radiation aspiration/penetration was observed in 10 patients on video FESS.

Among the definitive RT/CTRT group (n=34), 23 patients achieved complete response (CR), five had partial response (PR), and four experienced progressive disease (PD). In the adjuvant RT/CTRT group (n=54), 10 patients had disease progression. The median follow up was 8.4 months, 6 months PFS was 82%. The mean package time for surgery and adjuvant therapy was 11 weeks and 4 days. 11 deaths were reported in total. Two patients died during treatment (one aspiration pneumonia, one hematemesis). One patient died of aspiration post-treatment, while eight died due to disease progression. Most common pattern of failure was distant.

Conclusion: Adaptive radiotherapy using PRECISE ART demonstrated effective treatment adaptation with improved OAR sparing and minimal toxicity. ART reduced treatment interruptions and maintained tumor control despite anatomical changes. Low incidence of severe toxicity, including dysphagia and aspiration-related complications, supports ART’s role in functional preservation. Further prospective trials are needed to confirm ART’s impact on long-term survival and quality of life outcomes in head and neck cancer patients.