Iodine‑125 seeds combined with carboplatin in the treatment of retroperitoneal metastatic seminoma: A case report and literature review

Abstract

Testicular seminoma is a relatively rare malignant tumor, with the most common site of recurrence and metastasis being the retroperitoneal lymph nodes. Since seminoma is highly sensitive to radiotherapy and chemotherapy, even if it metastasizes, its cure rate is still >95%. However, the long-term toxicity and side effects of radiotherapy and chemotherapy cannot be ignored. Iodine-125 seeds represent a low-energy radioactive source that kills tumor cells while protecting the surrounding normal tissues, and brachytherapy using iodine-125 seeds has been widely used for the treatment of various malignancies. In addition, carboplatin can be used as an alternative to cisplatin-based combination chemotherapy to reduce the incidence of pulmonary toxicity, neurological damage and renal toxicity. In the present study, a case in which iodine-125 seeds were implanted for the treatment of retroperitoneal metastatic seminoma is reported. The patient was diagnosed with postoperative recurrence of seminoma that metastasized to the retroperitoneal lymph nodes. Since the tumor was large and surrounded blood vessels, surgical intervention and external radiotherapy were not considered. Moreover, considering the potential long-term toxic side effects of standard chemotherapy, a treatment plan for the patient using iodine-125 seed implantation combined with carboplatin (AUC7) therapy was finally formulated. No disease recurrence or toxic reactions occurred during the 3-year follow-up after treatment. The present case therefore demonstrated the antitumor efficacy and reduced toxicity of iodine-125 seeds combined with carboplatin for treating seminoma.

Keywords: case report; iodine-125 seeds; retroperitoneal lymph node metastasis; seminoma.

Figure 1.

Computed tomography scans showing (A) the right hydronephrosis and (B) a retroperitoneal mass of ~6.6×8.7-cm surrounding the (C) abdominal aorta and (D) bilateral iliac vessels extending downward.

Figure 2.

(A) Computed tomography-guided puncture biopsy image. (B) H&E staining of tissue from the retroperitoneal mass; magnification, ×200. The tumor cells were arranged in a sheet, nest and cord shape, and the small fiber trabeculae divided the cell nests, (C) H&E staining of tissue from the retroperitoneal mass; magnification, ×400. Tumor cells with light cytoplasmic staining and clear envelope boundaries are observed. (D) Immunohistochemical analysis of CD117 in the tissue from the retroperitoneal mass; magnification, ×400. Neoplastic plasma cells were positive for CD117. H&E, hematoxylin and eosin.

Figure 3.

During the procedure, GE Revolution HD computed tomography was used for guidance. A 5-mm thickness was selected for spiral scanning, and the (A) lumbar and back approach was used for the puncture path. (B) The puncture needle was inserted step-by-step to ensure that the surrounding organs were not damaged. (C) When the boundary between the tumor and the abdominal aorta (red arrow) appeared unclear during the operation, a real-time enhanced scan was used to guide the puncture, thus avoiding the abdominal aorta. (D) The puncture needle successfully avoided the abdominal aorta and reached the distal end of the tumor.

Figure 4.

(A) Post-operative reexamination scans showing satisfactory iodine-125 seed distribution. (B) The implanted iodine-125 seeds were evenly distributed and did not damage the intestines. (C) The iodine-125 seed arrangement in the tumor on the right side of the abdominal aorta. (D) The iodine-125 seed arrangement in the tumor on the left side of the abdominal aorta.

Figure 5.

Computed tomography reexamination 2 months after surgery showing that (A) the right kidney had returned to a normal shape and (B) the metastases around the abdominal aorta had completely subsided. (C) After the metastasis around the abdominal aorta had subsided, iodine-125 seeds were arranged in a contractile pattern. (D) The metastases around the bilateral iliac vessels were also completely subsided.