Nodal CTV selection according to primary tumour location and pT stage for biliary tract cancer

Abstract

Introduction/Purpose To assist radiation oncologists in determining the elective nodal CTV for biliary tract cancer, we aimed to provide the rules for selection of the CTV for each subsite of biliary tract with respect to the pT stage, based on the analysis of the incidence and location of metastatic lymph nodes. Methods Systematic review and meta‐analysis was performed to determine the rate of pathological nodal involvement of each individual lymph node station (LNS) as a function of the primary tumour pT stage (pT1‐2 vs. pT3‐4) separately for right intrahepatic cholangiocarcinoma (rIHC), left/hilar intrahepatic cholangiocarcinoma l/hIHC), proximal extrahepatic cholangiocarcinoma (pEHC), middle extrahepatic cholangiocarcinoma (mEHC), distal extrahepatic cholangiocarcinoma (dEHC) and gall bladder cancer (GBC). A 5% or higher risk of involvement was assumed to justify inclusion of the LNS in the CTV. Results Coeliac LNS, which is usually included in the CTV in clinical practice, has a low risk of involvement and can presumably be omitted for pT1‐2 GBC, for dEHC irrespective of pT stage and for mEHC. Para‐aortic and superior mesenteric artery (SMA) LNS that are usually omitted have a high risk of involvement. Para‐aortic LNS should be considered for inclusion for all the subsites except for pT1‐2 dEHC, and SMA LNS for all the subsites except for pT1‐2 dEHC, pT1‐2 GBC and pEHC. Left gastric artery, lesser curvature and paracardial LNS should be considered for inclusion for l/hIHC. Conclusion This systematic review provides an evidence‐based strategy for nodal CTV selection in biliary tract cancer according to primary tumour location and pT stage.

Patterns of locoregional recurrences and suggestion of the clinical target volume in resected perihilar extrahepatic cholangiocarcinoma

“…They compared the risk of lymph node involvement/recurrence and its frequency of inclusion in the CTV, demonstrated the discrepancy between them, and suggested the need for consensus guidelines. They conducted another systematic review and meta-analysis of pathologic data and provided the risk of involvement of each nodal station, and suggested nodal CTV specific to the primary tumor site and tumor stage [19] . They identified the following lymph node areas with ≥5% risk of involvement: CHA, hepatoduodenal ligament, CA, posterior pancreaticoduodenal, para-aortic, and left gastric lymph node stations, and suggested that they should be included in the nodal CTV.…”

“…Previous studies did not include the left perigastric space as a high-risk area for PEHC [18] , [22] . On the contrary, Socha et al recommended the inclusion of the left gastric lymph nodes in the CTV for PEHC [19] . Additionally, they reported different patterns of lymph node involvement between the right and left intrahepatic cholangiocarcinoma and suggested that left gastric lymph nodes should be included for left intrahepatic cholangiocarcinoma.…”

Postoperative recurrent patterns of gallbladder cancer: possible implications for adjuvant therapy

“…J Socha et al performed systematic review and metaanalysis of lymph node metastases in biliary tumors of different T stages [33]. It is suggested that the adjuvant radiotherapy target volume of T3-4 GBC should include No.8, No.9, No.12, No.13, No.14, No.16 lymph node groups.…”

The clinical target volume delineation of para aortic lymph node region for adjuvant radiotherapy based on the regularity of lymph node metastasis in biliary tract cancer

“…And a review article by Socha et al [8] assessed the risk of lymph node involvement based on histopathological surgical data and the areas of inclusion in the target volume of adjuvant radiotherapy in BTC and found that the para aortic region was a high-risk and a potential missing area for any tumor sites of biliary tract. Because of the high rate of retroperitoneal lymph node metastasis and rare surgical dissection of lymph nodes in this region [9][10][11] , adjuvant radiotherapy is preferred to eliminate potential microscopic diseases within a clinical irradiation eld. However, there is still a lack of an accurate and reproducible para-aortic CTV delineating recommendations for adjuvant radiotherapy of biliary malignant tumors.…”