CT-guided 125I brachytherapy combined with chemotherapy for the treatment of unresectable or locally advanced pancreatic carcinoma

Abstract

Purpose: We aimed to explore the feasibility and clinical effectiveness of percutaneous CT-guided iodine-125 (¹²⁵I) brachytherapy combined with chemotherapy for the treatment of patients with unresectable or locally advanced pancreatic carcinoma (PC).

Methods: We retrospectively reviewed 66 patients with Stage III and IV PC who had received chemotherapy. A total of 35 (53%) patients receiving 125I brachytherapy and chemotherapy (gemcitabine + cisplatin, GP) were classified as Group A, and 31 (47%) patients who received GP chemotherapy alone were categorized as Group B. The evaluated indications were local control rate (LCR), local progression-free survival (LPFS), overall survival (OS), treatment-related complications, and the degree of symptom relief. Kaplan-Meier curves, log-rank test and Cox regression models were generated and used for further analysis to identify predictors of outcomes.

Results: The median follow-up time was 6.00±0.84 months. The 1-, 3-, 6-, 12- and 18-month LCRs for Group A were 100% (35/35), 89.3% (25/28), 71.4% (15/21), 37.5% (3/8) and 33.3% (1/3), respectively; and those for Group B were 87.1% (27/31), 69.6% (16/23), 41.2% (7/17), 14.3% (1/7) and 0% (0/3), respectively. The LCR differed at 1-, 3- and 6-months (P = 0.032; P = 0.009; P = 0.030; respectively). The median LPFS was 7.00±0.30 months and 5.00±0.75 months for Groups A and B (P = 0.023), respectively; however, the median OS of the groups were not significantly different (8.00±0.77 months vs. 6.00±1.04 months. P = 0.917). No life-threatening complications occurred during or after the procedures. Patients in Group A experienced better pain control and relief of abdominal distension than those in Group B.

Conclusion: CT-guided 125I brachytherapy is a feasible, safe, and valuable treatment for patients with unresectable PC.

Figure 1. a–e

A 67-year-old male pancreatic carcinoma (PC) patient with high-grade adenocarcinoma confirmed by histopathology. Axial fat-suppressed T2-weighted image (a) shows an elliptical shaped lesion in the pancreatic tail with slightly higher signal intensity. On axial fat-suppressed T1-weighted image (b), the lesion is hypointense. In the arterial phase (c), the lesion is slightly enhanced and its signal intensity is lower than the normal intensity of the pancreas. In the equilibrium phase (d), the lesion is clear with delayed enhancement compared with the arterial phase, which is a typical imaging characteristic of PC. On the PET-CT image (e), the lesion shows high metabolic activity. There was a small hypermetabolic nodule in liver Segment V/VI, indicating a metastatic lesion. This patient was classified with unresectable PC Stage VI.

Figure 2. a–e

Treatment planning system verification. Image (a) shows a tumor in the pancreatic tail. Purple lines represent the tumor’s contour; the red area received 90% of the prescribed dose. Preoperative dose volume histogram (DVH) (b) determined the prescribed dose as 120 Gy with target = tumor. A total of 90% of the tumor area (D90 = 124.1 Gy) received 124.1 Gy, and 91.7% of the tumor area received 100% of the prescribed dose (V₁₀₀ = 91.7%). Postoperative CT image (c) shows two rows of seeds in the pancreatic tail. Image (d) shows postoperative distribution of implanted seeds. Postoperative DVH (e) determined D₉₀ = 125.2 Gy, V₁₀₀ = 92%. The distribution of the postoperative dose was coincident with the preoperative dose.

Figure 3

Local progression-free survival (LPFS) in Groups A and B. There was statistical difference between the two groups with the median LPFS 7.00±0.30 months vs. 5.00±0.75 months, respectively (p = 0.023).

Figure 4. a–d

Patient follow-up after ¹²⁵I treatment. Images (a, b) were acquired one month after ¹²⁵I seed implantation. On axial fat-suppressed T1-weighted image (a), the lesion shows heterogeneous hypointensity. In the equilibrium phases (b), the lesion shows heterogeneous enhancement. However, the degree and extent of enhancement is lower and smaller than those in the preoperative images, indicating a therapeutic response. Images (c, d) were acquired three months after seed implantation. On axial fat-suppressed T1-weighted image (c), the lesion shows heterogeneous hypointensity. In the equilibrium phases (d), the lesion is still hypointense without enhancement compared with the surrounding tissues and preoperative images, indicating no tumor residual.

Figure 5

Overall survival (OS) in Groups A and B. There was no statistical difference between the two groups with the median OS determined as 8.00±0.77 months vs. 6.00±1.04 months, respectively (p = 0.917).

Figure 6

Forest plot of subgroup analysis for local progression-free survival.