Role of adjuvant radiotherapy for localized extrahepatic bile duct cancer

American Radium Society (ARS) Appropriate Use Criteria (AUC) for Extrahepatic Cholangiocarcinoma

Although uncommon, extrahepatic cholangiocarcinoma (EHCC) is a deadly malignancy, and the treatment approaches remain controversial. While surgery remains the only cure, few patients are candidates for resection up front, and there are high rates of both local and distant failure following resection. Herein, we systematically review the available evidence regarding treatment approaches for patients with EHCC, including surgery, radiation, and chemotherapy. The evidence regarding treatment outcomes was assessed using the Population, Intervention, Comparator, Outcome, and Study design (PICOS) framework. A summary of recommendations based on the available literature is outlined for specific clinical scenarios encountered by providers in the clinic to guide the management of these patients.

Neoadjuvant and Adjuvant Therapy in Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer and causes major economic and health burdens throughout the world. Although the incidence of ICC is relatively low, an upward trend has been seen over the past few decades. Owing to the lack of specific manifestations and tools for early diagnosis, most ICC patients have relatively advanced disease at diagnosis. Thus, neoadjuvant therapy is necessary to evaluate tumor biology and downstage these patients so that appropriate candidates can be selected for radical liver resection. However, even after radical resection, the recurrence rate is relatively high and is a main cause leading to death after surgery, which makes adjuvant therapy necessary. Because of its low incidence, studies in both neoadjuvant and adjuvant settings of ICC are lagging compared with other types of malignancy. While standard neoadjuvant and adjuvant regimens are not available in the current guidelines due to a lack of high-level evidence, some progress has been achieved in recent years. In this review, the available literature on advances in neoadjuvant and adjuvant strategies in ICC are evaluated, and possible challenges and opportunities for clinical and translational investigations in the near future are discussed.

Adjuvant Radiotherapy for Extrahepatic Cholangiocarcinoma: A Quality Assessment-Based Meta-Analysis

INTRODUCTION

The benefits of adjuvant radiotherapy (ART) for extrahepatic cholangiocarcinoma are uncertain largely because existing publications lack clear comparisons between ART and non-ART arms.

METHODS

PubMed, Medline, Embase, and the Cochrane library were systematically searched until December 2020. The primary endpoint was overall survival (OS). Sensitivity analysis was performed for studies with reliable comparability (i.e., no favorable prognosticators in the ART arm that could skew the data).

RESULTS

Twenty-three studies involving 1,731 patients with extrahepatic cholangiocarcinoma were reviewed. The overall median of all median prescribed doses was 50.4 Gy; brachytherapy or an intraoperative boost of 10-21 Gy was applied in 5 studies. The pooled 1-, 3-, and 5-year OS rates in the non-ART and ART arms were 69.2% versus 81.0%, p = 0.035; 34.3% versus 44.7%, p = 0.025; 25.6% versus 31.7%, p = 0.115, respectively. The corresponding pooled locoregional recurrence rates were 52.1% versus 34.9% (p = 0.014). The pooled rate of grade ≥3 gastrointestinal complications was 9.8%. Sensitivity analysis performed on 14 eligible studies showed that the ART arms had a lower pooled R0 rate (36.8% vs. 63.2%, p = 0.02) and a higher rate of positive lymph nodes (47.4% vs. 34.9%, p = 0.08). The pooled 1-, 3-, and 5-year OS rates in the non-ART versus ART arms of the selected studies were 78.2% versus 84.9%, p = 0.143; 38.5% versus 49.2%, p = 0.026; and 27.8% versus 34.5%, p = 0.11, respectively.

CONCLUSIONS

ART was shown to improve OS in all studies and in those selected for their reliable comparability.

Role of adjuvant (chemo)radiotherapy for resected extrahepatic cholangiocarcinoma: a meta-analysis

BACKGROUND

Adjuvant (chemo)radiotherapy (A(C)RT) may be an important supplement to surgery for extrahepatic cholangiocarcinoma (EHCC). However, whether all patients would achieve benefits from A(C)RT and which adjuvant regimen, adjuvant radiotherapy (ART) or adjuvant chemoradiotherapy (ACRT), would be preferred, are still undetermined. The low incidence of EHCC makes it difficult to carry out randomized controlled trials (RCTs); therefore, almost all clinical studies on radiotherapy are retrospective. We have conducted a meta-analysis of these retrospective studies.

METHODS

We conducted a meta-analysis of current retrospective studies using PubMed, Embase, and ClinicalTrials databases. All studies published in English that were related to A(C)RT and which analyzed overall survival (OS), disease-free survival (DFS), or locoregional recurrence-free survival (LRFS) were included. Estimated hazard ratios (HRs) were calculated for OS, DFS, and LRFS.

RESULTS

Data from eight studies including 685 patients were included. Our analysis showed that A(C)RT significantly improved OS (HR 0.69, 95% confidence interval (CI) 0.48-0.97, P=0.03), DFS (HR 0.60, 95% CI 0.47-0.76, P<0.0001), and LRFS (HR 0.27, 95% CI 0.17-0.41, P<0.00001) of EHCC overall. In subgroups, patients with microscopically positive resection margin (R1) could achieve a benefit from A(C)RT (HR 0.44, 95% CI 0.27-0.72, P=0.001). No statistically OS difference was observed in negative resection margin (R0) subgroup (HR 0.98, 95% CI 0.30-3.19, P=0.98).Significant OS benefit was found in patients who received concurrent ACRT (HR 0.40, 95% CI 0.26-0.62, P<0.0001), while the result of ART without chemotherapy showed no significant benefit (HR 1.14, 95% CI 0.29-4.50, P=0.85). In the distal cholangiocarcinoma subgroup, no significant difference was seen when ACRT and ART were included (HR 0.61, 95% CI 0.14-2.72, P=0.52), but a significant difference was seen when analyzing the concurrent ACRT only (HR 0.29, 95% CI 0.13-0.64, P=0.002).

CONCLUSIONS

A(C)RT may improve OS, DFS, and LRFS in EHCC patients, especially in those with R1 resection margins. ACRT may be superior to ART especially in distal patients.

The Significance of Adjuvant Therapy for Extrahepatic Cholangiocarcinoma After Surgery

Extrahepatic cholangiocarcinoma (EHCC) is a rare malignant tumor, and current treatment methods are also relatively limited. Radical surgery is the only potentially curative method for the long survival time. However, despite undergoing radical resection, prognosis remained poor due to the high recurrence rate and distant metastasis. Therefore, adjuvant chemotherapy and radiotherapy should be offered to patients who have undergone surgery. Unfortunately, the low incidence of this disease has resulted in a lack of high-level evidence to confirm the importance of adjuvant chemotherapy or radiotherapy. At present, it is still controversial whether adjuvant therapy can prolong the survival of patients after operation, especially patients with negative margins or lymph nodes. Furthermore, standard regimens of adjuvant have not been identified. This review summarizes the currently available evidence of the effect of adjuvant therapy in the management of EHCC. Ultimately, we concluded that adjuvant therapy may improve survival in high-risk (positive margin or lymph node or advanced stage) patients and adjuvant concurrent chemoradiotherapy followed by chemotherapy may be the optimum selection for them. This needs to be verified by randomized prospective clinical trials.

Radiation therapy for extrahepatic bile duct cancer: Current evidences and future perspectives

Extrahepatic bile duct cancer (EBDC) is a rare malignancy that involves neoplastic changes extending from both hepatic ducts to the common bile duct. The treatment of choice is surgical resection, but the predominant pattern of initial treatment failure is locoregional recurrence. Accordingly, adjuvant radiotherapy has been administered after surgical resection based on these rationales. At this time, there is minimal evidence supporting adjuvant radiotherapy, because there have been no phase III trials evaluating its benefit. Relatively small retrospective studies have tried to compare outcomes associated with EBDC treated with or without radiotherapy. We aimed to review studies investigating adjuvant radiotherapy for resected EBDC. Because less than one-third of EBDC cases are amenable to curative resection at diagnosis, other locoregional treatment modalities need to be considered, including radiotherapy. The next aim of this review was to summarize reports of definitive radiotherapy for unresectable EBDC. Patients with advanced EBDC often experience biliary obstruction, which can lead to jaundice and progress to death. Biliary stent insertion is an important palliative procedure, but stents are prone to occlusion after subsequent ingrowth of the EBDC. Radiotherapy can be effective for maintaining the patency of inserted stents. We also reviewed the benefit of palliative radiotherapy combined with the biliary stent insertion. Lastly, we discuss the existing gaps in the evidence supporting radiotherapy in the management of EBDC.