Testing Shorter Duration Radiation Therapy Versus the Usual Radiation Therapy in Patients Receiving the Usual Chemotherapy Treatment for Bladder Cancer, ARCHER Study

Inclusion Criteria: * Histologically proven, cT2-T3,N0M0 urothelial carcinoma of the bladder prior to randomization. * Note: Patients with mixed urothelial carcinoma will be eligible for the trial, but the presence of small cell carcinoma will make a patient ineligible * Must undergo a transurethral resection of bladder tumor (TURBT) prior to randomization. Patients may have either completely or partially resected tumors as long as the treating urologist attempted maximal resection * Must undergo radiological staging prior to randomization. Imaging of chest, abdomen, and pelvis must be performed using CT or MRI (with or without contrast is acceptable). Patients must not have evidence of T4 or node positive disease. Fluorodeoxyglucose (FDG) PET imaging is acceptable for radiological staging * If any lymph nodes ≥ 1.0 cm in shortest cross-sectional diameter are noted on imaging (CT / MRI of abdomen and pelvis), then the patient must have had a biopsy of the enlarged lymph node showing no tumor involvement prior to randomization * No diffuse carcinoma in situ (CIS) based on cystoscopy and biopsy * No definitive clinical or radiologic evidence of metastatic disease * Must not have had urothelial carcinoma or histological variant at any site outside of the urinary bladder within 24 months prior to registration except Ta/T1/Carcinoma in situ (CIS) of the upper urinary tract including renal pelvis and ureter if the patient had undergone complete nephroureterectomy * Age ≥ 18 * Zubrod performance status of ≤ 2 * Not pregnant and not nursing * Negative urine or serum pregnancy test (in persons of childbearing potential) within 14 days prior to registration. Childbearing potential is defined as any person who has experienced menarche and who has not undergone surgical sterilization (hysterectomy or bilateral oophorectomy) or who is not postmenopausal * Absolute neutrophil count (ANC) ≥ 1,500 cells/mm\^3 * Platelets ≥ 100,000 cells/mm\^3 * Hemoglobin ≥ 8.0 g/dl (Note: The use of transfusion or other intervention to achieve hemoglobin \[Hgb\]) ≥ 8.0 g/dl is acceptable) * Creatinine clearance (CrCL) of ≥ 30 mL/min by the Cockcroft-Gault formula * Total bilirubin ≤ 2 x institutional upper limit of normal (ULN) * Aspartate aminotransferase (AST)(serum glutamic oxaloacetic transaminase \[SGOT\]) and alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase \[SGPT\]) ≤ 3 x institutional ULN * All adverse events associated with any prior therapy must have resolved to Common Terminology Criteria for Adverse Events (CTCAE) grade ≤ 3 prior to randomization * For patients who have completed ≥3 cycles of neoadjuvant chemotherapy prior to randomization, this eligibility window from diagnosis (TURBT Path) to enrollment is extended to 240 days before randomization. It remains a 180 day window for all others * Must not have had prior pelvic radiation * New York Heart Association Functional Classification II or better (NYHA Functional Classification III/IV are not eligible) (Note: Patients with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification.) * No active infection requiring IV antibiotics * Patients with hydronephrosis are eligible if they have unilateral hydronephrosis and kidney function meet criteria specified