Most patients with obstructive jaundice caused by malignant tumors lose the opportunity for surgical treatment. Biliary stent implantation and reopening of the occluded bile duct is the main treatment method at present. Tumor progression and stent intimal hyperplasia are the main reasons for the recurrence or deterioration of jaundice in patients[13–14]. Therefore, how to control tumor growth and delay the hyperplasia of the bile duct intima is the key to preventing stent blockage and prolonging the survival time of patients. Previous clinical studies have used biliary stents combined with external radiotherapy, biliary stents combined with arterial intubation chemoembolization and the installation of radiotherapy devices for biliary radiotherapy and other methods. Due to the poor basic condition of the patient, the sensitivity of surrounding organs to radiotherapy, the limitation of the primary tumor type and the cumbersome surgical operation, etc., it cannot be widely used in clinical applications. SEMS combined with 125I seed implantation and intracavitary irradiation has been used to treat malignant biliary obstruction[18–19], and certain clinical effects have been achieved.
125I seeds are a kind of low-dose-rate microradiation that release γ-rays. Because of their short range of radiation, low penetration, and maximum killing of tumors without damaging the surrounding normal tissues, 125I seeds are widely used in radiotherapy. They have been applied to the clinical treatment of prostate cancer, rectal cancer, nasopharyngeal cancer, liver cancer and other malignant tumors[20–21] and have achieved good results. Based on the advantages of 125I seeds, we explored the difference in clinical efficacy between SEMS combined with 125I seeds and SEMS alone in the treatment of MBO. In this study, first, 125I seeds were placed in the carrier device and fixed on the bile duct wall through the support of a biliary stent, which effectively solved the difficulty of direct puncture and implantation of 125I seeds for the treatment of malignant tumors growing along the bile duct. Compared with simple biliary stent implantation, a biliary stent combined with 125I seed implantation will not cause obstruction of bile drainage and will ensure the patency of the biliary tract. The continuous radiation can effectively inhibit and kill tumor cells and reduce the proliferation of biliary intima. This treatment has an obvious curative effect in delaying the recurrence of obstructive jaundice. In this study, the bilirubin level was significantly improved at 1 week and 1 month after biliary stent implantation in each group (P <0.001). The two methods had good short-term curative effects in the treatment of MBO, and the effect on jaundice was obvious, but the difference between the two groups was not statistically significant (P>0.05). Even though the two groups had no significant difference in short-term jaundice reduction, the recurrence time of jaundice in the combined group was significantly longer than that in the control group (9.01 mo. vs. 6.79 mo., P<0.001). This result is comparable to previous results[22–23]. This study also found that the incidence of jaundice recurrence started to differ between groups 5 months after biliary stent implantation. The main reason was that the combination method effectively killed or inhibited the tumor cells in the bile duct wall and then inhibited the intimal hyperplasia around the biliary stent and thereby delayed the recurrence of obstructive jaundice. In addition to delaying the recurrence of jaundice, a biliary stent combined with brachytherapy can also prolong the survival time of patients. Although Isayama et al. reported that the cumulative survival rate of a biliary stent combined with internal radiotherapy was no different from that of R1 resection, the median survival time of the stent combined with internal radiotherapy group was significantly longer than that of the stent-only group. The results of this article also show that the median survival time of the combined group was significantly longer than that of the control group (12.08 mo. vs. 9.10 mo., P<0.001).
In addition, existing studies have shown that the incidence of early complications of percutaneous biliary stent implantation is 5.7–28%, the mortality rate related to surgery is 0–4%, and the mortality rate 1 month after surgery is 9–15%. %, most of the complications can be resolved by conservative medical treatment, and the occurrence of death one month after surgery is generally related to some of the original underlying diseases of the patient. The results of this article show that the early complication rates of the two groups of patients were 18.92% and 11.11%, both of which improved after conservative medical treatment, and the surgery-related mortality rate was 0%. Previous studies have shown that biliary drainage brings a risk of biliary tract infection and puncture tumor implantation and metastasis, so percutaneous biliary drainage and stent implantation should be done with cautious. Our study did not observe the occurrence of tumor implantation or metastasis in the puncture tract, which was due to the improvements of interventional treatment technology and equipment in recent years. Therefore, percutaneous biliary stent combined with 125I seed implantation is a relatively safe and feasible palliative treatment.
In conclusion, percutaneous liver puncture biliary stent placement combined with 125I seed implantation is safe, effective and feasible for patients with unresectable Bismuth type I or II malignant biliary obstruction. This treatment scheme can extend the patency time of the stent as well as the survival time of patients. The limitations of this study are that it was retrospective, and the sample size was small. Therefore, prospective multicenter and larger randomized controlled studies are needed to further confirm our results.