Figure 5.

Treatment schemes for IMRT and CRT.

In the era of photon treatment, the role of RT/CRT as adjunct to surgery has evolved over decades with changes in the timing (preoperative versus postoperative), length (short versus long course), and delivery (3D-CRT versus IMRT). Many treatment paradigms have been tested using 3D-CRT technique. In this figure, different encircling modes of curves represent different treatment schemes, and there are many therapeutic schemes in theory. However, few comparative prospective studies of IMRT exist now. One cannot accurately assess whether the treatment paradigms in the era of IMRT are superior to those in the era of 3D-CRT. Besides photon treatment, particle RT has gained great attention recently, such as carbon ion and proton. In order to provide precision medicine to patients with rectal cancer, the radiobiological response model should be investigated in more depth.

3D-CRT, three-dimensional chemoradiotherapy; IMRT, intensity-modulated radiotherapy; RT, radiotherapy.