High dose chemotherapy--results of American studies

High-dose chemotherapy for male germ cell tumor

Today, 20-30% of male patients with advanced germ cell tumor (GCT) do not have durable, complete remission in spite of cis-platinum (CDDP)-based chemotherapy. High-dose chemotherapy (HDCT) has been tried in CDDP refractory GCT patients. Initially HDCT was performed with autologous bone marrow transplantation in heavily treated patients. However, the clinical outcome was not good and the treatment-related death rate was not ignorable. Therefore, earlier introduction of HDCT with peripheral blood stem cell transplantation was preferable as it renders HDCT more effective and less toxic, and multicycle HDCT is feasible. The durable free rate of recent HDCT for refractory GCT patients is 32-65%. HDCT is also performed as first line chemotherapy for poor prognosis GCT patients. Induction chemotherapy followed by multicycles of HDCT was tried. The durable free rate of recent HDCT as first line chemotherapy is 43-73%. Although previous reports suggest the superiority of HDCT, one recent randomized controlled trial (RCT) failed to show an improvement with one cycle of HDCT followed by three cycles of standard-dose chemotherapy (SDCT) compared with four cycles of SDCT. Ongoing RCT comparing multicycles of HDCT with SDCT for poor prognostic GCT patients will clarify the role of HDCT. Recently, new regimens of HDCT containing paclitaxel have been devised. In this review, the history, current status and future of HDCT for advanced or refractory GCT will be discussed.

Recent advances in management of patients with platinum-refractory testicular germ cell tumors

With the use of cisplatin-based combination chemotherapy, metastatic testicular germ cell tumors can be cured in 70-80% of patients, but patients refractory to cisplatin-based chemotherapy continue to have a very poor prognosis. Various chemotherapeutic agents have been evaluated in intensively pretreated or cisplatin-refractory patients, but as single agents, only orally administered etoposide, paclitaxel, gemcitabine, and, most recently, oxaliplatin have been shown to be active with selected patients achieving complete remissions. This has for the first time lead to clinical evaluation of combination chemotherapy regimens such as gemcitabine-paclitaxel or oxaliplatin-gemcitabine, demonstrating the feasibility of combination therapy in these heavily pretreated patients. High response rates of up to 45% were observed in particular with the latter combination. Salvage surgery remains a very important treatment option for patients with resectable disease. The molecular mechanisms of cisplatin resistance have been intensively studied, and several mechanisms have been discussed such as a decreased intracellular concentration of the drug, increased repair of the drug-induced damage, or an altered apoptotic response to this damage. This increasing knowledge may now allow design of new therapeutic options. Ongoing studies in refractory germ cell tumors are evaluating 3-drug regimens such as gemcitabine-paclitaxel-oxaliplatin but also biologic approaches such as inhibitors of the epidermal growth factor receptor or the vascular endothelial growth factor. This research may eventually allow the development of a noncross-resistant multidrug combination regimen that can be evaluated in an earlier line of therapy.

Paclitaxel-containing high-dose chemotherapy for relapsed or refractory testicular germ cell tumours

High-dose regimes containing etoposide, carboplatin and an oxazaphospharine can salvage 30–40% of patients with relapsed or refractory male germ cell tumours (GCTs). The additional benefit of paclitaxel in such high-dose therapy has not been tested. Between March 1995 and November 2002, 36 male GCT patients were treated with Carbop-EC-T (paclitaxel 75 mg m⁻², etoposide 450 mg m⁻², carboplatin AUC 10 on days −7, −5 and −3 and cyclophosphamide 60 mg kg⁻¹ on days −5 and −3) followed by peripheral blood stem cell infusion (day 0). The 1-year overall survival rate for all patients is 67% (median follow-up 29 months). For the 24 patients with cisplatin-sensitive disease, the 1-year overall and event-free survivals are 88 and 64%, respectively. For those with cisplatin refractory or absolutely refractory disease, the 1-year overall survival is 25%. In all, 12 patients relapsed at a median duration of 5 months, 11 of whom have died. There were also six treatment-related deaths, five associated with pneumonitis. Pulmonary toxicity has been reported with paclitaxel in other high-dose regimes. Since altering our protocol so that paclitaxel is infused over 24 h with steroid prophylaxis, only one of 18 patients (13 testicular GCTs and five other tumour types) has had a treatment-related death. Our results suggest that Carbop-EC-T may enable a greater proportion of patients with relapsed and refractory GCTs to enter long-term remission.

Improved prognosis of patients with intermediate- and poor-risk nonseminomatous germ cell tumours by optimizing combined treatment

OBJECTIVE

To assess whether the optimal use of combined treatment with chemotherapy and appropriately timed surgical intervention by a specialized team might improve the outcome for patients with poor- and intermediate-prognosis (International Germ Cell Consensus Classification, IGCCC) nonseminomatous germ cell tumours (NSGCTs).

PATIENTS AND METHODS

Between 1984 and 1998, 47 patients with intermediate (16) and poor prognosis (31) NSGCT were treated; 43 had a testicular and four a retroperitoneal primary.

RESULTS

Of the 47 patients only seven (15%) had a complete radiological response after primary chemotherapy; 36 (77%) required surgery after chemotherapy (29 para-aortic lymphadenectomy, 13 resection of pulmonary metastases, two each excision of supraclavicular and retrocrural lymph nodes and one resection of brain metastases; 13 required surgery at more than one site). There was no surgical mortality, with postoperative wound pain the commonest morbidity. On pathology, the resected masses were mature teratoma in 13, necrosis in 12 and malignant disease in 11 patients, the resection being complete in 30. There were microscopically positive margins in the other six patients, all but one having viable residual cancer. Of the 47 patients, 18 needed treatment for relapse, with four having surgery for growing mature teratoma, six chemotherapy plus surgery and eight salvage chemotherapy alone. Of 31 patients, 22 (71%) with a poor and 13 of 16 with an intermediate prognosis were alive at a median (range) follow-up of 94 (41-171) months; of all 47, 34 (72%) remain in complete remission. Ten patients died from disease progression. The presence of residual malignant disease at the resection margin was significantly associated with poorer survival (hazard ratio 7.21, P = 0.0016). Prognostic factors, e.g. number of involved sites, IGCCC group and viable tumour in resected masses, were not significant. The 5-year overall and relapse-free survival (95% confidence interval) was 81 (69-93)% and 57 (43-71)%, respectively.

CONCLUSION

The optimal delivery and timing of chemotherapy and surgical resection by a specialist team of oncologists, urological and cardiothoracic surgeons is critical in treating poor-risk NSGCT and might be responsible for improving the outcome of these patients. The detection of residual malignant disease after chemotherapy by positron emission tomography should be investigated to identify those who might benefit from further systemic treatment before complete surgical resection.