Lower-Dose Chemoradiation in Treating Patients With Early-Stage Anal Cancer, the DECREASE Study (NCT04166318)

Check every box below. If you can check all of them, you may meet the study's basic screening requirements (final eligibility is confirmed by the site team).

1. STEP 0 (PRE-REGISTRATION)
2. Patient must be ≥ 18 years of age
3. Patients must be English speaking to participate in the trial. (Please note that this requirement is due to the fact that the quality-of-life studies are mandatory and we currently do not have full translated versions of the questionnaires into other languages)
4. Patient must have histologically proven T1-2N0M0 invasive anal canal or anal margin squamous cell carcinoma with tumors measuring =\< 4 cm. This may include tumors of non-keratinizing histology such as basaloid, transitional cell or cloacogenic histology. Measurable disease is not required
5. Patients who are status/post local excision or excisional biopsy procedure are eligible provided there was tumor involvement of the anal canal and/or anal verge prior to the reaction, if the margins were positive, and/or if the stage is T2N0 based on tumor size before the procedure. This means that patients with T1N0M0 anal margin squamous cell carcinoma who underwent surgical excision with negative margins and no involvement of the anal verge and/or anal canal are not eligible
6. Tumor size must be documented based on physical examination including digital rectal exam and/or anoscopy/proctoscopy within 4 weeks prior to Step 0 pre-registration
7. Patient's human immunodeficiency virus (HIV) status must be known and documented at baseline
8. NOTE: For patients without a history of HIV infection, it is recommended (but not required) that updated HIV testing be performed within one year of study enrollment
9. Patients who are HIV-negative will be registered to Arm R. They must not have lymph nodes that are radiographically-concerning for cancer involvement using computed tomography (CT) and fludeoxyglucose F-18 (FDG) - positron emission tomography (PET)/CT-based criteria
10. NOTE: Patients who are HIV-negative and meet the below criteria may proceed directly to Step 1 Randomization
11. Patients will be considered to be lymph node (LN) positive and thereby not eligible in this study if the lymph nodes meet any of the following criteria:
12. Mesorectal, presacral, internal iliac or obturator LN with:

🔍 Extracted verbatim from the official NIH eligibility criteria. Always confirm with the study coordinator.

📍 All Participating Trial Locations (659 Sites)

• University of Alabama at Birmingham Cancer Center — Birmingham, Alabama
• Anchorage Associates in Radiation Medicine — Anchorage, Alaska
• Anchorage Radiation Therapy Center — Anchorage, Alaska
• Alaska Breast Care and Surgery LLC — Anchorage, Alaska
• Alaska Oncology and Hematology LLC — Anchorage, Alaska
• Alaska Women's Cancer Care — Anchorage, Alaska
• Anchorage Oncology Centre — Anchorage, Alaska
• Katmai Oncology Group — Anchorage, Alaska
• Providence Alaska Medical Center — Anchorage, Alaska
• Fairbanks Memorial Hospital — Fairbanks, Alaska
• Kingman Regional Medical Center — Kingman, Arizona
• Cancer Center at Saint Joseph's — Phoenix, Arizona
• Mercy Hospital Fort Smith — Fort Smith, Arkansas
• CHI Saint Vincent Cancer Center Hot Springs — Hot Springs, Arkansas
• University of Arkansas for Medical Sciences — Little Rock, Arkansas
• Mission Hope Medical Oncology - Arroyo Grande — Arroyo Grande, California
• PCR Oncology — Arroyo Grande, California
• Providence Saint Joseph Medical Center/Disney Family Cancer Center — Burbank, California
• Mercy Cancer Center - Carmichael — Carmichael, California
• Mercy San Juan Medical Center — Carmichael, California
• Mercy Cancer Center - Elk Grove — Elk Grove, California
• UCI Health - Chao Family Comprehensive Cancer Center and Ambulatory Care — Irvine, California
• UC San Diego Moores Cancer Center — La Jolla, California
• Contra Costa Regional Medical Center — Martinez, California
• Mercy Cancer Center — Merced, California

💰 Cost, Insurance & Patient Rights

• 100% Free Items: The investigational treatment and protocol-required procedures are supplied at zero cost by the sponsor.
• Routine Patient Care: Under federal law (ACA § 2709) and many state statutes, routine care costs are covered during participation.
• Voluntary Participation: You may withdraw at any time without affecting your standard medical care.