Inclusion Criteria:  Histologically confirmed biopsy proven invasive SCCA (any T, any N) deemed a candidate to undergo standard of care definitive chemoradiation at MD Anderson Cancer Center (MDACC) with curative intent Age > 18 years at time of study entry Ability to provide written informed consent  Exclusion Criteria:  Patients unwilling to participate in a PET/CT at baseline and at 3 months post completion of definitive chemoradiation Patients with an active second primary malignancy requiring chemotherapy or radiation treatment Stage IV SCCA