Phenotype-based Model for Managing Chronic Post-treatment Pain Among Head and Neck Cancer Survivors: a Pilot Study

Treatment given based on the clinical phenotype

Participants with myofascial pain disorder will initially receive muscle relaxants, such as tizanidine (up to 8 mg per day), cyclobenzaprine (up to 30 mg per day), or amitriptyline (up to 25 mg per day). When the reported pain intensity is 7 or more out of 10, these participants will additionally undergo masticatory or cervical trigger point injections.

Participants identified with orofacial bone pain disorder who report a pain intensity of less than 7 out of a possible 10 on the Numeric Verbal Rating Scale (NVRS) will receive non-opioid analgesics, including acetaminophen and non-steroidal anti-inflammatory medications. In cases where the pain intensity is 7 or more, participants will be offered targeted nerve blocks. These blocks will be performed along the sensory nerves supplying the affected region to provide localized pain relief.

Participants classified with neuralgia will be treated with pregabalin (up to 600 mg per day) or carbamazepine (up to 1200 mg per day). Nerve blocks will be considered for those experiencing pain of 7 or more out of 10. In summary, participants with persistent pain disorder, burning disorder, or neuralgia phenotypes who present with pain intensity scores of 7 or higher will be given nerve blocks around the sensory nerves corresponding to the region of pain.

Participants with burning pain will receive pregabalin (up to 600 mg per day), carbamazepine (up to 1200 mg per day), or clonazepam (up to 2 mg per day), and if their pain intensity meets or exceeds 7 out of 10, nerve blocks will similarly be provided to target the sensory pathways involved.

Those diagnosed with persistent pain disorder will be treated with either amitriptyline (up to 25 mg per day) or pregabalin (up to 600 mg per day). Participants in this group who report pain intensity of 7 or more will also be offered nerve blocks administered at sites corresponding to the involved sensory distribution.

A phenotype-based pain management model will provide significant pain relief to participants at one month, defined as at least a 75 percent decrease from average baseline pain

Discontinuation of assigned phenotype-based therapy due to adverse events by four weeks is 10 percent or less.