NCCN Guidelines for Patients® | Diffuse Large B-cell Lymphoma

31 NCCN Guidelines for Patients ® : Diffuse Large B-cell Lymphoma, 2017 3 Overview of cancer treatments Radiation therapy Radiation therapy Radiation therapy uses high-energy x-rays to treat DLBCL. The x-rays damage DNA in cancer cells. This either kills the cancer cells or stops new cancer cells from being made. Radiation therapy may be received after drug regimens to treat stages I and II. It is used less often to treat stages III and IV. A radiation oncologist will oversee your radiation treatment. A radiation oncologist is a doctor who’s an expert in treating cancer with radiation. He or she will tailor treatment to you. Involved-site radiation therapy ISRT ( i nvolved- s ite r adiation t herapy) is sometimes used to treat DLBCL. It can treat lymph nodes in which the cancer first started. It may also treat cancer near to these nodes. It is given with a method called EBRT ( e xternal b eam r adiation t herapy). A large machine makes high- energy x-rays used for treatment. This machine is called a LINAC ( lin ear ac celerator). See Figure 10 . Planning and setup sessions A planning session is needed to map out your treatment. The planning process is called simulation. It involves obtaining a scan of your body in the position that is needed for treatment. The scan is only used for treatment planning. A CT scan with contrast is used. PET/CT and MRI ( m agnetic r esonance i maging) often enhance treatment planning for ISRT. For tumors near the breastbone, 4D-CT ( four - d imensional c omputed t omography) or fluoroscopy can account for tumor movement from breathing. If your breathing causes large movements, motion control methods during the scans may be used. After simulation, your radiation team will further plan your treatment. Plans are made by viewing your scans on the treatment planning computer. Your radiation oncologist will work closely with a dosimetrist. They will plan the best dose, number and shape of radiation beams, and number of treatments. Your plan will be designed to treat the cancer while sparing normal tissue. Once your treatment plan is made, a setup session is needed. This session is sometimes called “port film” day or dress rehearsal. The setup session occurs in the treatment room. Figure 10 External beam radiation therapy Radiation therapy is often delivered from a large machine called a linear accelerator. The rays pass through skin and travel to the tumor. Healthy tissue is protected using modern types of treatment.