From the social security disability site under the Do You Qualify for benefits section:

Is your condition found in the list of disabling conditions?

For each of the major body systems, we maintain a list of medical conditions that are so severe they automatically mean that you are disabled. If your condition is not on the list, we have to decide if it is of equal severity to a medical condition that is on the list. If it is, we will find that you are disabled. If it is not, we then go to Step 4.

See the link below:

http://ssa.gov/disability/professionals/bluebook/listing-impairments.htm

This is the link to the specific head and neck cancers:

http://ssa.gov/disability/professionals/bluebook/13.00-NeoplasticDiseases-Malignant-Adult.htm#13.02

Here is an excerpt for heand and neck cancers:

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13.02 Soft tissue tumors of the head and neck (except salivary glands

SCC Stage IV, BOT, T2N2bM0
Cisplatin/5FU x 3, 40 days radiation
Diagnosis 07/21/03 tx completed 10/08/03
Post Radiation Lower Motor Neuron Syndrome 3/08.
Cervical Spinal Stenosis 01/11
Cervical Myelitis 09/12
Thoracic Paraplegia 10/12
Dysautonomia 11/12
Hospice care 09/12-01/13.
COPD 01/14
Intermittent CHF 6/15
Feeding tube NPO 03/16
VFI 12/2016
ORN 12/2017
Cardiac Event 06/2018
Bilateral VFI 01/2021
Thoracotomy Bilobectomy 01/2022
Bilateral VFI 05/2022
Total Laryngectomy 01/2023