Efficacy of chimeric antigen receptor T-cell therapy in testicular relapse of pediatric acute lymphoblastic leukemia: a multicenter retrospective study.

[INTRODUCTION] Testicular relapse constitutes one of the most frequent extramedullary recurrences in pediatric acute lymphoblastic leukemia (ALL), yet its clinical management remains incompletely characterized.

[METHODS] This study assessed treatment outcomes and long-term survival in children with testicular relapse following initial therapy under the CCCG-ALL-2015 study (ChiCTR-IPR-14005706, http://www.chictr.org.cn). In total, 66 patients from 13 medical centers were retrospectively analyzed. Clinical characteristics and survival outcomes were compared across salvage treatment modalities.

[RESULTS] The median interval from initial diagnosis to testicular relapse was 37 months. Among 59 patients who received post-relapse therapy, the 2-year overall survival (OS) rate was 86.1% after a median follow-up of 33 months. Patients treated with chimeric antigen receptor T-cell (CAR-T) therapy showed a 2-year OS of 90.7%, compared to 81.7% in those managed with conventional regimens, such as chemotherapy, orchiectomy, or hematopoietic stem-cell transplantation (P > 0.05). Among 37 children with isolated testicular relapse, 18 underwent CAR-T therapy and 10 underwent orchiectomy, achieving 2-year OS rates of 92.3% and 100%, respectively (P > 0.05).

[DISCUSSION] Testicular relapse typically emerged approximately 3 years after initial diagnosis. CAR-T therapy proved to be both safe and effective, providing survival comparable to conventional regimens and offering potential advantages in preserving life quality among long-term survivors.