Response to first-line treatment and histology are associated with achieving complete remission after the first salvage high-dose chemotherapy in relapsing germ cell tumor patients

Pediatric Extracranial Germ Cell Tumors: Review of Clinics and Perspectives in Application of Autologous Stem Cell Transplantation

Pediatric extracranial germ cell tumors (GCTs) are rare, accounting for approximately 3.5% of childhood cancers. Since the introduction of platinum-based chemotherapy, the survival rate of patients has improved to more than 80%. However, poor-risk subtypes of pediatric extracranial GCTs do not respond well to chemotherapy, leading to refractory or relapsed (R/R) diseases. For example, long-term survival rates of mediastinal GCTs or choriocarcinoma are less than 50%. According to reports in recent years for adult patients with R/R GCTs, the use of high-dose chemotherapy (HDCT) combined with autologous stem cell transplantation (ASCT) has clinical advantages; however, HDCT combined with ASCT has rarely been reported in pediatric GCTs. The R/R and poor-risk groups of pediatric GCTs could benefit from HDCT and ASCT.

High-dose chemotherapy for relapsed germ cell tumours: outcomes in low-volume specialized centres

OBJECTIVE

To report treatment patterns and survival outcomes of patients with relapsed and refractory metastatic germ cell tumours (GCTs) treated with high-dose chemotherapy (HDCT) and autologous stem-cell transplantation in low-volume specialized centres within the widely dispersed populations of Australia and New Zealand between 1999 and 2019.

PATIENTS AND METHODS

We conducted a retrospective analysis of 111 patients across 13 institutions. Patients were identified from the Australasian Bone Marrow Transplant Recipient Registry. We reviewed treatment regimens, survival outcomes, deliverability and toxicities. Primary endpoints included overall (OS) and progression-free survival (PFS). Cox proportional hazards models were used to test the association of survival outcomes with patient and treatment factors.

RESULTS

The median (range) age was 30 (14-68) years and GCT histology was non-seminomatous in 84% of patients. International Prognostic Factors Study Group (IPFSG) prognostic risk category was very low/low, intermediate, high and very high in 18%, 36%, 25% and 21% of patients, respectively. Salvage conventional-dose chemotherapy (CDCT) was administered prior to HDCT in 59% of patients. Regimens included paclitaxel, ifosfamide, carboplatin and etoposide (50%), carboplatin and etoposide (CE; 28%), carboplatin, etoposide and ifosfamide (CEI; 6%), carboplatin, etoposide and cyclophosphamide (CEC; 5%), CEC-paclitaxel (6%) and other (5%). With a median follow-up of 4.4 years, the 1-, 2- and 5-year PFS rates were 62%, 57% and 52%, respectively, and OS rates were 73%, 65% and 61%, respectively. There were five treatment-related deaths. Progression on treatment occurred in 17%. In a univariable analysis, worse International Germ Cell Cancer Collaborative Group (IGCCCG) and IPFSG prognostic groups were associated with inferior survival outcomes. An association of inferior survival was not found with the number of high-dose cycles received nor when HDCT was delivered after salvage CDCT.

CONCLUSION

This large dual-national registry-based study reinforces the efficacy and deliverability of HDCT for relapsed and refractory metastatic GCT in low-volume specialized centres in Australia and New Zealand, with survival outcomes comparable to those found in international practice.

Prophylactic corticosteroid use prevents engraftment syndrome in patients after autologous stem cell transplantation

Engraftment syndrome (ES) following autologous stem cell transplantation (ASCT) at the time of neutrophil recovery may comprise fever, rash, pulmonary edema, or diarrhea. Usually, ES is easily manageable using corticosteroids but may prolong hospitalization. In two consecutive cohorts of subsequent patients with myeloma, lymphomas, and testicular/germ cell cancer, we assessed the benefit of corticosteroid use to prevent incidence and severity of ES following ASCT. Whereas Cohort A (82 patients) received no prophylactic corticosteroids, corticosteroids (4 mg dexamethasone oral daily) were started in Cohort B (60 patients) at day +9 until day +13 following ASCT. Steroid prophylaxis significantly reduced the incidence of ES (6/60; 10% vs. 33/82; 40%; p < 0.001). Hospitalization duration was longer in patients with ES than in patients without ES within both cohorts (in Cohort A: p = 0.007; and B: p = 0.011), but did not differ significantly between cohorts A and B. Finally, in Cohort A, there was a trend to an inferior 2-year overall survival rate in patients without ES compared to patients with ES (p = 0.067), but definite conclusions are not yet allowed. Our results suggest that corticosteroid prophylaxis from days +9 to +13 following ASCT significantly reduces the risk of ES and shortens hospitalization duration.