Progress in Radiotherapy for Cholangiocarcinoma

Abstract

Cholangiocarcinoma (CCA) originates from the epithelium of the bile duct and is highly malignant with a poor prognosis. Radical resection is the only treatment option to completely cure primary CCA. Due to the insidious onset of CCA, most patients are already in an advanced stage at the time of the initial diagnosis and may lose the chance of radical surgery. Radiotherapy is an important method of local treatment, which plays a crucial role in preoperative neoadjuvant therapy, postoperative adjuvant therapy, and palliative treatment of locally advanced lesions. However, there is still no unified and clear recommendation on the timing, delineating the range of target area, and the radiotherapy dose for CCA. This article reviews recent clinical studies on CCA, including the timing of radiotherapy, delineation of the target area, and dose of radiotherapy. Further, we summarize large fraction radiotherapy (stereotactic body radiotherapy [SBRT]; proton therapy) in CCA and the development of immunotherapy and the use of targeted drugs combined with radiotherapy.

Keywords: cholangiocarcinoma; indications for radiotherapy; radiotherapy dose; radiotherapy mode; target area delineation.

Figure 1

Principles of radiation in different cholangiocarcinoma stages. ECCA, extrahepatic cholangiocarcinoma; ICCA, intrahepatic cholangiocarcinoma; R0, no cancer at resection margins; R1, microscopic residual cancer; R2, macroscopic residual cancer; SBRT, stereotactic body radiation therapy. The boxes with solid lines indicate Category I or II recommendations and the boxes with dotted lines indicate Category III recommendations.

Figure 2

Lymph node delineation in cholangiocarcinoma. The left figure shows the range of LNS with high risk in ICCA, the red dotted line represents the delineation range of LNS for left ICCA, and the blue line represents corresponding LNS for right ICCA; The right figure represents the corresponding the range of LNS with high risk for ECCA, the red dotted line represents the corresponding LNS area for pCCA, and the blue line represents the corresponding lymph node drainage area of dCCA. ECCA, extrahepatic cholangiocarcinoma; ICCA, intrahepatic cholangiocarcinoma; pCCA, perihilar cholangiocarcinoma; dCCA, distal cholangiocarcinoma; LNS, lymph node stations.