Grant to reduce side effects of radiotherapy for larynx and pharynx cancer 1.3 million euros for research into promising care

Radiation oncologist Sven van den Bosch of the Radboud university medical center receives a grant of 1.3 million euros from the Dutch National Health Care Institute. The research project focuses on the sentinel lymph node procedure in patients with larynx or pharynx cancer that will be treated with radiotherapy. Sentinel lymph node biopsy is a diagnostic procedure that has very high accuracy to determine whether the disease has spread to lymph nodes in the neck. When the sentinel lymph nodes are free of metastases, elective irradiation of cervical lymph nodes is futile, whereas it is now standard of care in the majority of patients. When omitting elective neck irradiation, permanent long-term radiation side effects will be reduced enormously and quality of life after treatment will be significantly improved.

Despite modern multimodal diagnostic imaging (e.g. ultrasound, CT- and MRI-scan), cervical lymph node metastases are missed in approximately one-third of patients with larynx or pharynx cancer because these metastases are too small to be detected. It is for this reason that elective neck irradiation if performed in the majority of patients that receive definitive radiotherapy for larynx or pharynx cancer. The aim is to eradicate metastases that stay under the diagnostic detection level (i.e. occult or microscopic metastases). However, most toxicity and permanent long-term radiation side effects are caused by elective neck irradiation because the irradiated tissue volume is much larger than what is necessary to treat only the primary tumor. These side effects, and in particular dysphagia and xerostomia, are notoriously known to negatively and permanently affect quality of life after treatment.

PRIMO study

Radiation oncologist Sven van den Bosch of the Radboudumc is now receiving 1.3 million euros from the Dutch National Health Care Institute (research program ‘Potentially Promising Care’). ‘With the Radboud Center of Expertise in Head and Neck Oncology and in collaboration with a large number of the Dutch Head and Neck Oncology Centers, we will compare the safety and efficacy of personalized elective neck irradiation guided by the results of sentinel lymph node biopsy versus standard elective neck irradiation in the multicenter randomized controlled non-inferiority trial: the PRIMO study’, Van den Bosch says. ‘The sentinel lymph node procedure is based on the premise that metastases orderly progress with the lymphatic flow from the primary tumor to the sentinel lymph node before spreading to subsequent draining lymph nodes, and the pathologic status of the sentinel lymph node accurately reflects the histology of subsequent lymph nodes. In this procedure, a radioactive tracer is injected around the primary tumor and progresses with the lymphatic flow to the sentinel lymph node. The sentinel lymph nodes can be visualized by SPECT/CT and will be surgically removed for histopathological examination.

In the PRIMO study, elective neck irradiation is omitted when the sentinel lymph node is free of metastases. In this case, only the primary tumor is irradiated. This approach is expected to prevent futile elective neck irradiation in approximately 70% of the patients with a clinically negative neck. The irradiated volume will be approximately 80% smaller in these patients. Van den Bosch: ‘With personalized elective neck irradiation guided by sentinel lymph node biopsy, permanent long-term radiation side effects can be reduced substantially in the majority of patients, and quality of life after treatment will be much better.’

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