Diffusion MRI correlation with p16 status and prediction for tumor progression in locally advanced head and neck cancer

Purpose

To investigate p16 effects on diffusion image metrics and associations with tumor progression in patients with locally advanced head and neck cancers.

Methods

Diffusion images pretreatment and after 20 Gy (2wk) of RT were analyzed in patients with cT4/N3 p16+ oropharynx cancer (OPSCC) (N=51) and locoregionally advanced head and neck squamous cell carcinoma (LAHNSCC) (N=28), enrolled onto a prospective adaptive RT trial. Mean ADC values, subvolumes with ADC <1.2 um2/ms (TVLADC), and peak values of low (µL) and high (µH) components of ADC histograms in primary and total nodal gross tumor volumes were analyzed for prediction of freedom from local, distant, or any progression (FFLP, FFDP or FFLRDP) using multivariate Cox proportional-hazards model with clinical factors. P value with false discovery control <0.05 was considered as significant.

Results

With a mean follow up of 36 months, 18 of LAHNSCC patients and 16 of p16+ OPSCC patients had progression. After adjusting for p16, small µL and ADC values, and large TVLADC of primary tumors pre-RT were significantly associated with superior FFLRDP, FFLP and FFDP in the LAHNSCC (p<0.05), but no diffusion metrics were significant in p16+ oropharynx cancers. Post ad hoc analysis of the p16+ OPSCC only showed that large TVLADC of the total nodal burden pre-RT was significantly associated with inferior FFDP (p=0.05).

Conclusion

ADC metrics were associated with different progression patterns in the LAHNSCC and p16+ OPSCC, possibly explained by differences in cancer biology and morphology. A deep understanding of ADC metrics is warranted to establish imaging biomarkers for adaptive RT in HNSCC.

Abstract IA20: Radiotherapy plus cetuximab or cisplatin in human papilloma-virus positive oropharyngeal cancer (NRG 1016): A randomized multicenter noninferiority trial*

Background: Patients with HPV-related oropharynx cancer have high survival when treated with radiotherapy plus cisplatin. Whether replacement of cisplatin with cetuximab can preserve high survival and reduce toxicity is unknown. We performed a randomized trial comparing survival and toxicity in 987 patients enrolled at 182 health care centers in the US and Canada between July 2011 and July 2014.

Methods: Eligibility included histologically confirmed HPV positive carcinoma, clinical stage TI-T2, N2-N3 or T3-T4, N0-N3. Zubrod status 0 or 1. All patients received intensity modulated radiotherapy (IMRT) delivered in 35 fractions to 70 gray over 6 weeks using 6 fractions per week. High-dose cisplatin at 100 mg/m² was given every 3 weeks for 2 cycles in arm A (standard of care) versus arm B loading dose cetuximab plus weekly cetuximab. Patients were stratified by T category, N category, Zubord performance status, and smoking history.

Primary analysis was based on modified intention to treat for all patients meeting eligibility criteria. 849 patients were randomly assigned to radiation plus cetuximab (425) or radiotherapy plus cisplatin (424). Median follow-up is 4.5 years.

Results: Radiotherapy plus cetuximab did not meet the non-inferiority criteria for overall survival. Estimated 5-year overall survival was 78% in the cetuximab group versus 85% in the cisplatin group (p=0.016). Progression-free survival was 67% versus 78% (p=0.0002). Local-regional failure was higher in the cetuximab group, 17% versus 10% (p=0.005). High-grade acute toxicity was similar at 77% for both groups. Late toxicity was also similar.

Conclusions: For HPV-positive oropharyngeal carcinoma, radiotherapy plus cetuximab showed inferior overall survival, progression-free survival, and locoregional control compared with radiation plus cisplatin. This study defines radiation using IMRT plus cisplatin as the standard of care for this population.

*Lancet. Vol 393, p 40-50, January 5, 2019

Citation Format: J.A. Ridge, J. Ringash, M. Yao, D.M. Blakaj, M.A. Razaq, A.D. Colevas, J.J. Beitler, C.U. Jones, N.E. Dunlap, S.A. Seaward, S. Spencer, T.J. Galloway, J.J. Dignam, Q.T. Le, M.L. Gillison, E.M. Sturgis, J. Phan, A.M. Trotti, J. Harris, A. Eisbruch, P.M. Harari, D.J. Adelstein, S.A. Koyfman, B. Burtness. Radiotherapy plus cetuximab or cisplatin in human papilloma-virus positive oropharyngeal cancer (NRG 1016): A randomized multicenter noninferiority trial [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr IA20.

Delineation of the primary tumour Clinical Target Volumes (CTV-P) in laryngeal, hypopharyngeal, oropharyngeal and oral cavity squamous cell carcinoma: AIRO, CACA, DAHANCA, EORTC, GEORCC, GORTEC, HKNPCSG, HNCIG, IAG-KHT, LPRHHT, NCIC CTG, NCRI, NRG Oncology, PHNS, SBRT, SOMERA, SRO, SSHNO, TROG consensus guidelines

PURPOSE

Few studies have reported large inter-observer variations in target volume selection and delineation in patients treated with radiotherapy for head and neck squamous cell carcinoma. Consensus guidelines have been published for the neck nodes (see Grégoire et al., 2003, 2014), but such recommendations are lacking for primary tumour delineation. For the latter, two main schools of thoughts are prevailing, one based on geometric expansion of the Gross Tumour Volume (GTV) as promoted by DAHANCA, and the other one based on anatomical expansion of the GTV using compartmentalization of head and neck anatomy.

METHOD

For each anatomic location within the larynx, hypopharynx, oropharynx and oral cavity, and for each T-stage, the DAHANCA proposal has been comprehensively reviewed and edited to include anatomic knowledge into the geometric Clinical Target Volume (CTV) delineation concept. A first proposal was put forward by the leading authors of this publication (VG and CG) and discussed with opinion leaders in head and neck radiation oncology from Europe, Asia, Australia/New Zealand, North America and South America to reach a worldwide consensus.

RESULTS

This consensus proposes two CTVs for the primary tumour, the so called CTV-P1 and CVT-P2, corresponding to a high and lower tumour burden, and which should be associated with a high and a lower dose prescription, respectively.

CONCLUSION

Implementation of these guidelines in the daily practice of radiation oncology should contribute to reduce treatment variations from clinicians to clinicians, facilitate the conduct of multi-institutional clinical trials, and contribute to improved care of patients with head and neck carcinoma.