Strategy of combined treatment of germ cell tumors

Long-term outcomes in patients with pineal nongerminomatous malignant germ cell tumors treated by radical resection during initial treatment combined with adjuvant therapy

BACKGROUND

For pineal nongerminomatous malignant germ cell tumors (NGMGCTs), we mainly performed radical tumor resection during initial treatment combined with adjuvant therapy.

METHODS

We retrospectively analyzed 17 patients treated for pineal NGMGCTs between 1986 and 2007 at the University of Niigata.

RESULTS

Twelve patients underwent total or subtotal resection of their tumor via the occipital transtentorial approach. Five patients underwent partial resection, and four of them later underwent total resection by salvage surgery. After surgery, eight patients were treated with combined radiochemotherapy including whole-brain irradiation, two received radiation monotherapy, one had chemotherapy with local irradiation, and six were treated with chemotherapy alone. The median follow-up period for surviving patients was 179 months. The 10-year overall survival and progression-free survival rates for the radiochemotherapy group were both 75.0 % (two patients had a recurrence and died); the rates for other adjuvant therapies were 77.8 % (two died) and 22.2 % (seven had a recurrence), respectively. Radiochemotherapy was significantly associated with an increased rate of progression-free survival compared with the other adjuvant therapies (p = 0.0396).

CONCLUSIONS

For pineal NGMGCTs, initial treatment strategies including gross total resection of the tumor before or after whole-brain irradiation and chemotherapy provided good therapeutic outcomes. Obtaining complete remission of the primary tumor, irrespective of the timing of surgical resection (i.e., before or after adjuvant therapies), or complete response by neoadjuvant radiochemotherapy during an initial treatment appears to be essential for improving therapeutic outcomes of intracranial NGMGCTs.

Occurrence of metachronous pure germinomas long after treatment of a mixed germ cell tumor containing yolk sac tumor and germinoma

The authors report a rare case involving the occurrence of metachronous pure germinomas long after treatment of a mixed germ cell tumor (GCT) categorized as having a poor prognosis. A neurohypophysial germinoma occurred 4 years and 6 months after the initial treatment of a mixed pineal GCT containing a yolk sac tumor and a germinoma. Furthermore, intramedullary germinomas occurred 21 years after the initial treatment of the mixed GCT and 15 years after the second treatment of the neurohypophysial germinoma. The neurohypophysial germinoma was not confirmed histopathologically, but the intramedullary germinoma was histopathologically diagnosed as a pure germinoma. Serum α-fetoprotein levels at the second neurohypophysial and third intramedullary occurrences of the germinomas were less than 10 ng/ml. Therefore, no yolk sac components seemed to be contained in the tumors. The second neurohypophysial and third intramedullary germinomas might be recurrences of the germinoma component of the pineal mixed GCT, which consisted of a yolk sac tumor and a germinoma. However, it seems very unlikely that only the germinoma, categorized in the good prognosis group, would be the only one to recur. Hence, it seems plausible that both the second and the third occurrences of pure germinoma were de novo metachronous GCTs arising after the pineal mixed GCT was cured. The authors' case indicates the possibility of multicentric GCTs in the CNS.

Validation of tumor markers in central nervous system germ cell tumors by real-time reverse transcriptase polymerase chain reaction using formalin-fixed paraffin-embedded tissues

The therapeutic protocols for treatment of germinomas and non-germinomatous germ cell tumors (NGGCTs) are completely different, so it is important to distinguish pure germinomas from NGGCTs. As it can be difficult to diagnose by morphology alone, immunohisto-chemistry (IHC) has been widely used as an ancillary test to improve diagnostic accuracy. However, IHC has limitations due to the misinterpretation of results or the aberrant loss of immunoreactivity. However, real-time RT-PCR has certain advantages over IHC, including its quantitative nature. The aim of our study was to evaluate the usefulness of real-time RT-PCR on formalin-fixed paraffin-embedded (FFPE) tissue blocks for the diagnosis of germ cell tumors of the central nervous system. We selected eight markers of germ cell tumors using a literature search, and validated them using real-time RT-PCR. Among them, POU5F1, NANOG and TGFB2 were statistically significant (P=0.05) in multiple comparisons (MANOVA) of three groups (pure germinomas, mature teratomas and malignant germ cell tumors). Two-group (pure germinomas and NGGCTs) discriminant analysis achieved a 70.0% success rate in cross-validation. We concluded that real-time RT-PCR using FFPE tissue has adequate validating power comparable to IHC in the diagnosis of central nervous system germ cell tumors; therefore, when IHC is not available, not conclusive or not informative, RT-PCR is a potential alternative to a repeat biopsy.

[Solid as a rock]

A 42-year-old patient presented with a 7-year history of a slowly enlarging mass in the right submandibular area, which has been growing faster for the last 6 month. Apart from that there were no other symptoms. Physical examination and a magnetic resonance imaging (MRI) scan did not identify the nature of the tumor. A resection of the mass was performed and the surgical specimen was revealed to be a mature teratoma by histology.