Radiation Therapy and Fluorouracil With or Without Combination Chemotherapy Followed by Surgery in Treating Patients With Stage II or Stage III Rectal Cancer

This study is looking for adults aged 18 or over who have been diagnosed with stage 2 or stage 3 rectal cancer. Your cancer must be within 12 cm of the opening of your bottom (anus) and doctors need to confirm the exact stage using special scans like an Endorectal Ultrasound (ERUS) or MRI.

There are certain health conditions that mean you wouldn't be able to join. For example, if your cancer has spread to other parts of your body, or if you've had similar cancer in the same area before. You also couldn't join if you have certain heart conditions, uncontrolled seizures, or other serious brain or nerve problems. You also cannot be allergic to any of the chemotherapy drugs used in the study.

If you have a history of inflammatory bowel disease, a specific inherited condition called Familial Adenomatous Polyposis, or if you've had radiation treatment to your pelvis before, you wouldn't be able to participate. Your doctor will carefully review all your health information to understand if this study might be a good fit for you.

If you decide to take part, you would first have a combination of radiation therapy and chemotherapy. You'd receive radiation therapy once a day, five days a week, for five weeks. Alongside this, you'd have the chemotherapy drug fluorouracil given into a vein continuously for about six weeks. After finishing these initial treatments, there would be a pause of at least four weeks.

Depending on which study group you are assigned to, you might then receive additional chemotherapy (called modified FOLFOX-6) before your surgery. This would involve a combination of different drugs given into a vein over a couple of days, repeated every two weeks for either two or four cycles. After these treatments, you would then have your standard surgery to remove the cancer. Throughout the study, you'll have regular hospital visits for assessments, blood tests, and scans to monitor your health and how the treatment is working. The total time you'd be involved in the active treatment and surgery part of the study would vary depending on your assigned group, but it typically involves several weeks of treatment before surgery.