This study determines whether a positron emission tomography (PET)/computed tomography (CT) 4-point scoring system may predict overall survival for anal squamous cell cancer patients. A 4-point scoring system involving imaging scans may help to predict how patients with anal squamous cell cancer respond to chemoradiation therapy.

PRIMARY OBJECTIVE:

I. To determine whether a PET/CT scoring system in invasive biopsy proven anal squamous cell carcinoma (SCCA) to be treated with chemoradiation with curative intent (any T any N) predicts for overall survival (OS).

SECONDARY OBJECTIVES:

I. To determine whether a PET/CT scoring system in invasive biopsy proven SCCA to be treated with definitive chemoradiation with curative intent predicts for progression free survival (PFS).

II. To determine and validate inter-reader reliability. III. To calculate C-index to evaluate the prognostic capacity of PET/CT scores for survival.

IV. To determine the association between pre-treatment PET/CT scores after treatment and OS.

EXPLORATORY OBJECTIVE:

I. To correlate level of standardized uptake value (SUV) pre and post therapy and its correlation with overall survival.

OUTLINE:

Patients undergo PET/CT at baseline and at 3 months post therapy completion. Patients' medical records are received. Patients are followed up for 5 years.

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

Patients with invasive SCCA