ESTRO 2024 - Abstract Book

S1222

Clinical - Head & neck

ESTRO 2024

Between June 2014 and July 2020, 57 pts (tonsil: 46 pts, base of tongue: 4 pts, soft palate: 7 pts) were enrolled from 23 institutions. The pts consisted of 36 men and 21 women with the median age of 68 years (range, 41-80). T1/2 pts were 11/46, N0/1 pts were 31/26, and Stage Ⅰ / Ⅱ / Ⅲ pts were 6/25/26. No deviations or violations were observed in the post-treatment individual case review of treatment plan. The 3-year OS for the 57 pts was 93% [80% CI 87%- 96%, 95% CI 82-97%]. The 3-year PFS and loco-regional PFS were 81% [95% CI 68-89%] and 83% [95% CI 70-90%]. The lower limit of the 80% CI of the 3-year OS (87%) was higher than the threshold 3-year OS of 80%; thus the primary endpoint was met. There were four loco-regional recurrences, none from outside the minimally established prophylactic irradiation area. Although no Grade 3-5 late adverse reactions were observed, 24 patients (43%) developed Grade 2 late adverse reactions. Grade 2 xerostomia was noted in 18% (10/56), 11% (6/56), and 6% (3/53) at 1, 2, and 3 years after starting IMRT, respectively. Grade 2 hypothyroidism was observed in 0% (0/56),4% (2/55), and 11% (6/53) until 1, 2, and 3 years, respectively.

Conclusion:

IMRT alone with reduced dose and extent of prophylactic irradiation for early-stage OPC showed excellent 3-year OS and loco-regional PFS with considerably lower toxicity. This method would be a new standard treatment for early stage OPC.

Keywords: radiotherapy alone, oropharyngeal cancer

References:

Garden AS, et al. Final Report of NRG Oncology RTOG 0022: A Phase 1/2 Study of Conformal and Intensity Modulated Radiation for Oropharyngeal Cancer. Int J Radiat Oncol Biol Phys 117: 333-340, 2023.

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Poster Discussion

Depth of Invasion predicting survival with adjuvant radiotherapy in early tongue squamous carcinoma

Sarthak Tandon 1 , Akash Bellige 1 , Sandeep Purohit 1 , Shaifali Mahajan 1 , Gerim Prasai 1 , Sauharda Lohani 1 , Mudit Agarwal 2 , Abhishek Singh 2 , Kondamudi Dheeraj 2 , Apoorva Nayak 1 , Aslam Najeem 1 , Munish Gairola 1 , Parveen Ahlawat 1 1 Rajiv Gandhi Cancer Institute and Research Center, Radiation Oncology, Delhi, India. 2 Rajiv Gandhi Cancer Institute and Research Center, Surgical Oncology, Delhi, India

Purpose/Objective:

Throughout the years, the scientific literature has been abundant with publications emphasizing the significance of depth of invasion (DOI) in the management of oral squamous cancers (OSCC). The predominant focus of these