Triapine With Chemotherapy and Radiation Therapy in Treating Patients With IB2-IVA Cervical or Vaginal Cancer

Inclusion Criteria: * Patient has a new, untreated histologic diagnosis of stage IB2 (\> 5 cm), II, IIIB, IIIC or IVA squamous, adenocarcinoma, or adenosquamous carcinoma of the uterine cervix or stage II-IVA squamous, adenocarcinoma, or adenosquamous carcinoma of the vagina not amenable to curative surgical resection alone; the presence or absence of lymph node metastasis will be based on pre-therapy 18F-FDG PET/CT; the patient must be able to tolerate imaging requirements of an 18F-FDG PET/CT scan * Age \>= 18 years old * Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2 * Life expectancy greater than 6 months * Absolute neutrophil count (ANC) \>= 1.5 x 10\^9/L * Platelets \>= 100 x 10\^9/L * Hemoglobin (Hgb) \>= 10.0 g/dL (blood transfusions to reach this amount are allowed) * Serum creatinine =\< 1.5 mg/dL to receive weekly cisplatin * If serum creatinine is between 1.5 and 1.9 mg/dL, patients are eligible for cisplatin if the estimated creatinine clearance (CCr) is \> 30 ml/min (for the purpose of estimating the CCr, the formula of Cockcroft and Gault for females should be used) * Total serum bilirubin =\< 1.5 x upper limit of normal (ULN) (in patients with known Gilbert syndrome, a total bilirubin =\< 3.0 x ULN, with direct bilirubin =\< 1.5 x ULN) * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =\< 2.5 x ULN * Able to take oral medication * Not pregnant and not breastfeeding; the effects of triapine on the develo…