Imaging characteristics and treatment of recurrent germinoma.

Objective: An MRI protocol for germinoma surveillance after complete remission has not been established. Moreover, the standard treatment for recurrent or refractory germinoma has not been determined. In this study, the authors explored the imaging characteristics of recurrent germinoma and discuss their institution's experience with multidisciplinary treatment of this malignancy.

Methods: The medical records of 16 patients (14 male, 2 female) with recurrent germinoma and 62 patients (52 male, 10 female) without recurrence who were treated at the authors' institution between 1989 and 2023 were retrospectively examined. Data including diagnostic imaging, tumor markers, treatment at diagnosis and recurrence, and overall survival were collected from patients' medical records and statistically analyzed.

Results: No patients with recurrence received craniospinal irradiation (CSI) as an initial therapy, and local irradiation was a significant risk factor of recurrence (p = 0.0072). The period between the start of first-line treatment and confirmation of the first recurrence ranged from 4.2 to 272 months (median 66.8 months). Among the recurrences, 13 tumors occurred outside the radiation field, including 6 cases of spinal cord/canal recurrence. One-third of patients did not exhibit elevated tumor marker levels in the serum. Fourteen patients had contrast-enhanced recurrent lesions. In the 2 patients with non-contrast-enhanced lesions, recurrence was detected by high signal intensity on diffusion-weighted imaging (DWI) and elevated tumor marker levels in CSF. Fifteen patients received chemotherapy for the first recurrence, and 14 received radiation therapy, with 9 receiving CSI. The patients who received CSI survived without further recurrence during the study period. However, the median progression-free survival and overall survival after the first recurrence among patients who did not undergo CSI were 12.2 and 37.4 months, respectively, which were shorter than those for patients treated with CSI (both p < 0.01, log-rank test).

Conclusions: Spinal MRI for surveillance in patients with recurrent germinoma, especially for those who do not receive CSI, is recommended. DWI might be useful for detecting recurrent germinoma. Aggressive treatment at the time of recurrence is crucial, and even if remission is achieved with chemotherapy, CSI for consolidation is important to prevent further recurrence.