Chemotherapy for Germ Cell Tumors

Cisplatin-based chemotherapy followed by surgery for malignant nonseminomatous germ cell tumor of mediastinum: one institution's experience

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of cisplatin-based chemotherapy followed by surgery for patients with a malignant nonseminomatous germ cell tumor (NSGCT) of the mediastinum.

METHODS

Ten patients with malignant NSGCTs received cisplatin-based induction chemotherapy and then underwent surgery. The clinicopathological characteristics of these 10 patients were examined retrospectively.

RESULTS

A partial response to induction chemotherapy was noted in eight patients and no response in two. The induction chemotherapy was tolerated well by all the patients. Each patient underwent complete surgical resection of the residual tumor following chemotherapy. A yolk sac tumor was detected in one patient and malignant teratoma along with a yolk sac tumor in one patient postoperatively. The overall survival of the 10 patients was 67% at 60 months of follow-up. The survival rate at 60 months was poorer for the patients whose resected specimens exhibited the presence of viable cells than for those whose specimens were free of viable cells.

CONCLUSION

Postchemotherapy surgical resection of the residual tumor plays an integral role in the management of patients with NSGCT. The presence of viable tumor cells in the resected specimens is associated with poor survival.

The challenge of poor-prognosis germ cell tumors

Patients who have a poor prognosis can be identified at presentation by well-defined prognostic factors. Prognostic groups as defined by the International Germ Cell Consensus Classification should be used in the clinic, in clinical trials, and when reporting results. No systemic treatment has been shown to improve outcome compared with four cycles of chemotherapy composed of bleomycin, etoposide, and cisplatin, which remains the standard of care. Surgery to resect residual masses after chemotherapy and in the salvage setting is a vital component of optimal care. The best outcomes occur with treatment at a center with experience and expertise in their management. Further major improvements are likely to require novel systemic therapies rather than modifications of existing approaches.

Management of Primary Malignant Germ Cell Tumor of the Mediastinum

BACKGROUND

Primary mediastinal malignant germ cell tumors (GCTs) are rare and have a worse prognosis than their gonadal counterparts. Although multimodality treatment is a standard therapeutic strategy in mediastinal GCTs, the clinical implications of surgical intervention remain unclear.

METHODS

Forty-eight patients with primary mediastinal malignant GCT who were treated at the National Cancer Center Hospital, Tokyo, from 1962 to 2002 were studied retrospectively with regard to their histology and clinical profile.

RESULTS

Mediastinal GCT occurred predominantly in young males, with a mean age of 28.8 years at the time of diagnosis. There were 46 males (96%) and two females (4%). Histologically, seven patients (15%) were diagnosed as having pure seminoma and 41 (85%) had non-seminomatous GCT. Treatment consisted of surgery alone in nine patients, surgery followed by chemotherapy in two, and chemotherapy followed by surgery in 20. The other 17 patients received chemotherapy and/or radiotherapy without surgery. Of these latter 17 patients, 14 developed progressive disease and three were followed up with a sustained partial response. Among the 31 patients who underwent surgery, complete resection was performed in 27 (87%) and incomplete resection was performed in four (13%). Twelve (41%) patients had elevated serum tumor marker levels preoperatively. Among the 20 patients who received preoperative chemotherapy, viable cells were found in the resected specimen in six (30%). With regard to tumor recurrence in patients with surgical intervention, the preoperative serum tumor marker levels and the presence of viable cells in the resected specimen were significantly associated with recurrence. There was no significant association between surgical curability and recurrence. The 5-year overall survival rate in all 48 patients was 45.5%.

CONCLUSIONS

Surgical intervention for mediastinal GCT may be needed to remove a chemotherapy-refractory tumor or to assess the pathological response to chemotherapy to determine the indications for further chemotherapy.

Platinum-DNA adducts assayed in leukocytes of patients with germ cell tumors measured by atomic absorbance spectrometry and enzyme-linked immunosorbent assay

BACKGROUND

Platinum-DNA adducts can be measured in peripheral blood cells, and high adduct levels have previously been correlated with favorable clinical response to platinum-based therapy in patients with germ cell tumors and ovarian cancer.

METHODS

To evaluate the relationship between platinum-DNA adducts and clinical response to chemotherapy, 36 patients with germ cell tumors treated with cisplatin-based chemotherapy had platinum-DNA adducts assayed in leukocytes by atomic absorption spectrometry (AAS) and cisplatin-DNA enzyme-linked immunosorbent assay (ELISA). Three chemotherapy regimens were involved: cisplatin and etoposide (Regimen A); carboplatin and etoposide (Regimen B); and cyclophosphamide, vinblastine, dactinomycin, bleomycin, and cisplatin [VAB-6] with or without high dose carboplatin plus etoposide plus autologous bone marrow rescue (Regimen C). Blood samples were drawn before and after each cycle of chemotherapy.

RESULTS

One hundred ninety-two blood samples were assayed by AAS and 137 by ELISA: DNA adducts measured by AAS and ELISA increased immediately after treatment and decreased during the intervening time before the next treatment. DNA adducts were measurable by both methods 4-8 weeks after the last cycle of therapy. The peak and mean adduct levels measured in samples drawn immediately after Cycles 1 and 2 and after all cycles were analyzed in terms of their relationship to clinical response. In contrast to numerous prior studies, a positive correlation was not observed between DNA adduct formation as determined by either AAS or ELISA and favorable clinical responses.

CONCLUSIONS

This study demonstrated that peak and mean platinum-DNA adduct levels were influenced by the dose and schedule of the platinum analogue. For example, treatment with VAB-6 with or without high dose carboplatin and etoposide (Regimen C) resulted in significantly higher adduct levels when measured by AAS compared with Regimen A or B. Inconsistencies between studies regarding observed correlations of DNA adducts and treatment outcome may be attributable to differences in platinum analogue, dose, schedule, and timing of sample procurement. These factors must be considered in future studies.

Suramin for germ cell tumors. In vitro growth inhibition and results of a phase II trial

BACKGROUND

Several studies have indicated a role for specific growth factors in the differentiation or deregulated growth of germ cell cancers. One proposed mechanism of antitumor activity for suramin is the inhibition of these tumor-derived growth factors.

METHODS

Based on these data, the effects of suramin were studied on the growth of a monolayer culture of two human teratocarcinoma cell lines, NT2/D1 and N2102ep. These represented one cell line that was sensitive (NT2/D1) and one that was resistant (N2102ep) to the differentiation agent retinoic acid. These studies were followed by a Phase II trial of suramin in patients with germ cell tumors. Patients were treated with a continuous infusion of suramin. Dosing was determined by a nomogram based on weekly serum concentrations.

RESULTS

Suramin inhibited the growth of both cell types in a dose-dependent fashion at a concentration attainable in patient plasma. This provided the rationale for a clinical trial of suramin in patients with cisplatin-refractory germ cell tumors. Fourteen patients were treated, and no complete or partial responses were observed. One patient achieved a prolonged decline in serum alpha-fetoprotein level without change in the size of a bidimensionally measurable retroperitoneal mass for more than 11 months.

CONCLUSIONS

Despite the results of the in vitro studies, a Phase II trial failed to demonstrate significant antitumor activity for suramin in patients with cisplatin-refractory germ cell tumors. Although the dosing of suramin by the nomogram was not associated with neurotoxicity, the time needed to achieve therapeutic levels was lengthy, and the levels, once achieved, were of short duration. Thus, an alternative means of administration, i.e., by intermittent bolus administration, is being investigated in trials for patients with prostatic carcinoma. The lack of definitive efficacy for suramin in this trial has led the authors to consider other agents in Phase II trials for cisplatin-refractory germ cell tumor.

Extragonadal and poor risk nonseminomatous germ cell tumors. Survival and prognostic features

One hundred forty-nine patients with poor risk nonseminomatous germ cell tumors (NSGCT) treated between 1975 and 1988 were studied. Patients were considered poor risk if they had an extragonadal primary site or testicular NSGCT with low predicted probability of achieving a complete response (CR). Primary sites were the testis (99 patients), retroperitoneum (18 patients), and mediastinum (32 patients). Patients with mediastinal NSGCT had lower human chorionic gonadotropin (HCG) (P less than 0.0001) and lactate dehydrogenase (LDH) levels (P less than 0.0001), and more frequent yolk sac elements (P = 0.002). CR rates were 38% for mediastinal, 61% for retroperitoneal, and 38% for testicular primary sites. Mediastinal NSGCT patients more frequently required resection of residual malignancy to attain a CR (6 of 12). Mediastinal NSGCT had the worst event-free survival (P = 0.02). Cox regression analysis identified brain or liver metastases as the most important predictor of event-free survival in poor risk patients. Retroperitoneal NSGCT often have a poor outcome due to advanced presentation, but the likelihood of a CR to therapy can be predicted using criteria applicable to testicular primary tumors. Therefore, not all retroperitoneal NSGCT are poor risk, and retroperitoneal tumors are probably of occult testicular origin. Mediastinal NSGCT have distinct clinical and pathologic features, do not respond as well to chemotherapy, relapse more frequently, and have the worst survival. The likelihood of a CR cannot be predicted using criteria developed for primary testicular tumors, suggesting that mediastinal primary NSGCT is a distinct clinical entity.