Personalized Elective Neck Irradiation Guided by Sentinel Lymph Node Biopsy in Larynx and Pharynx Cancer. The PRIMO Study.

Rationale \| Elective neck irradiation is performed in head and neck cancer patients treated with definitive (chemo)radiotherapy. The aim is to eradicate nodal metastases that are not detectable by pretreatment imaging techniques. It is conceivable that personalized neck irradiation can be performed guided by the results of sentinel lymph node biopsy. It is expected that elective neck irradiation can be omitted to one or both sides of the neck in 9 out of 10 patients with a clinically negative neck (cN0). For patients with clinically positive ipsilateral nodes (cN1-2b), it is expected that elective irradiation of the contralateral neck can be omitted in 7 out of 10 patients. This will enable better sparing of normal tissues from radiation and result in less permanent long-term radiation side effects with better quality of life. Methods/design \| This is a multicenter randomized controlled trial aiming to compare safety and efficacy of treatment with sentinel lymph node biopsy guided neck irradiation versus standard bilateral elective neck irradiation in 242 patients with cN0-N2b squamous cell carcinoma of the oropharynx, larynx or hypopharynx for whom bilateral elective neck irradiation is indicated. Patients randomized to the experimental-arm will undergo sentinel lymph node biopsy. Based on the histopathologic status of the sentinel lymph nodes, patients will receive no elective neck irradiation (if no nodal metastases found at both sides of the neck), unilateral neck irradiation only (if no nodal metastases found at contralateral side of the neck only) or bilateral neck irradiation (if nodal metastases found at both sides of the neck). Patients randomized to the control arm will not undergo sentinel lymph node biopsy but will receive standard bilateral elective neck irradiation. The primary safety endpoint is the number of patients with recurrence in regional lymph nodes within 2 years after treatment. The primary efficacy endpoint is patient reported xerostomia-related quality of life at 6 months after treatment. Discussion \| If this trial demonstrates that the experimental treatment is non-inferior to the standard treatment in terms of regional recurrence and is superior in terms of xerostomia-related quality of life, this will become the new standard of care.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

* Adult patients (≥18 years) with newly diagnosed cT1-4N0-2bM0 squamous cell carcinoma of the oropharynx (HPV-), larynx or hypopharynx, or cT1-4N0-1M0 oropharynx (HPV+) (AJCC TNM 8)
* Histopathological diagnosis of squamous cell carcinoma.
* Adequate staging of the neck including CT or MRI, and 18F-FDG-PET demonstrating no contralateral lymph node metastases.
* Recommendation for curative intent external beam (chemo)radiotherapy made by a multidisciplinary head and neck oncology team (in case of chemoradiotherapy, only patients receiving concomitant platinum-based regimen are eligible).
* Bilateral ENI is indicated according to Dutch consensus guidelines (LPHHRT) (see Appendix 13.1).
* Procedures for SLNB (i.e. tumor accessible for tracer injection, imaging and surgery under general anesthesia) are deemed feasible by the head and neck surgeon.

Exclusion Criteria:

* Recurrent disease or previous anticancer treatment to the head and neck area (e.g. radical attempt or tumor reductive surgery, neck dissection, neo-adjuvant chemotherapy or radiotherapy) except for endoscopic glottic laser micro surgery.
* Well lateralized oropharyngeal cancers and early stage laryngeal cancers requiring no or unilateral ENI according to Dutch consensus guidelines (LPHHRT)
* Patients receiving concomitant non-platinum-based systemic agents (e.g. cetuximab).
* Patients that qualify for proton therapy and want to be treated accordingly.
* Compromised airway or tracheostomy.
* Any active invasive malignancy within the last 3 years except for early stage basal/squamous cell carcinoma of the skin and incidental finding of stage T1N0M0 prostate cancer.
* Any somatic, psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol or follow-up schedule.

• BACKGROUNDvan den Bosch S, Takes RP, de Ridder M, de Bree R, Al-Mamgani A, Schreuder WH, Hoebers FJP, van Weert S, Elbers JBW, Hardillo JA, Meijer TWH, Plaat BEC, de Jong MA, Jansen JC, Wellenstein DJ, van den Broek GB, Vogel WV, Arens AIJ, Kaanders JHAM. Personalized neck irradiation guided by sentinel lymph node biopsy in patients with squamous cell carcinoma of the oropharynx, larynx or hypopharynx with a clinically negative neck: (Chemo)radiotherapy to the PRIMary tumor only. Protocol of the PRIMO study. Clin Transl Radiat Oncol. 2023 Oct 26;44:100696. doi: 10.1016/j.ctro.2023.100696. eCollection 2024 Jan. PMID 37965060
• BACKGROUNDvan den Bosch S, Czerwinski M, Govers T, Takes RP, de Bree R, Al-Mamgani A, Hannink G, Kaanders JHAM. Diagnostic test accuracy of sentinel lymph node biopsy in squamous cell carcinoma of the oropharynx, larynx, and hypopharynx: A systematic review and meta-analysis. Head Neck. 2022 Nov;44(11):2621-2632. doi: 10.1002/hed.27175. Epub 2022 Sep 1. PMID 36047597