Preirradiation evaluation and technical assessment of involved-field radiotherapy using computed tomographic (CT) simulation and neoadjuvant chemotherapy for intracranial germinoma

Current concepts and future strategies in the management of intracranial germinoma

Radiation therapy is the backbone in the management of intracranial germinoma. In localized disease chemotherapy followed by whole brain irradiation is the present standard providing cure rates in excess of 90%. Craniospinal irradiation alone in metastatic disease provides equally excellent outcome. Chemotherapy is able to convert macroscopic to microscopic disease permitting a dose reduction to the tumor site and possibly the ventricular system and is investigated in prospective trials. Chemotherapy alone cannot replace radiotherapy as sole treatment. Whole-ventricular radiotherapy followed by a boost to tumor site without chemotherapy might be feasible. New treatment technologies such as intensity-modulated radiotherapy or proton therapy permit a dose reduction to non-target brain. Data on functional outcome are conflicting and based on small heterogeneous series only mandating prospective investigations.

Bifocal intracranial germinoma: a retrospective analysis of treatment outcomes in 20 patients and review of the literature

PURPOSE

Bifocal germinoma (BFG) is a rare intracranial neoplasm for which the choice of radiation therapy (RT) field is controversial. Some believe that BFG represents disseminated disease requiring craniospinal irradiation (CSI), whereas others believe that BFG represents localized disease and advocate for more limited fields.

METHODS AND MATERIALS

We analyzed 20 BFG patients at our institutions with classic bifocal lesions (pineal gland and suprasellar region). In addition, we identified 60 BFG patients from the literature. The RT fields, use of chemotherapy and extent of disease were recorded and analyzed for each patient.

RESULTS

There were 55 patients with bifocal lesions only (Group I), and 25 with bifocal lesions plus ventricular and/or CSF positive disease (Group II). The 5-year progression-free survival was 95% for Group I and 80% for Group II. In Group I, there were no failures in patients receiving CSI (n = 11), two spinal failures in those treated with more limited RT fields without chemotherapy (n = 17), and one spinal failure with chemotherapy (n = 23). In Group II, there were no failures in patients receiving CSI (n = 11), but four spinal failures were observed in patients receiving more limited RT fields with chemotherapy (n = 13); 1 patient who received whole-brain RT without chemotherapy experienced failure in the spine and brain.

CONCLUSIONS

CSI is associated with excellent PFS in BFG. In Group I BFG patients, omission of spinal irradiation appears to be a reasonable approach, especially when chemotherapy is used. Patients with Group II BFG are best treated with CSI.

Long-term follow-up of 5 patients with intracranial germinoma initially treated by chemotherapy alone

BACKGROUND

High rates of overall- and event-free survival have been reported in patients with intracranial germinoma treated by radiotherapy. We report the long-term results after treatment initially with chemotherapy, but without radiation.

PATIENTS AND METHOD

Five patients with an intracranial germinoma were treated with 2 cycles of etoposide and cisplatin, without radiotherapy. All achieved complete remission; 3 suffered recurrence within 2 years and were again treated with 2 cycles of etoposide and cisplatin followed by radiotherapy.

RESULTS

At long-term follow-up, each of the 5 patients was in complete remission without further recurrence. Each patient with a neurohypophyseal germinoma who presented with endocrinopathy had initially recovered endocrinological function.

CONCLUSION

In a patient with a germinoma chemotherapy, and restriction of radiation to those with recurrence may allow restoration of hypophyseal function damaged by the intracranial germinoma without compromising long term survivial.

Germinoma with synchronous lesions in the pineal and suprasellar regions

BACKGROUND

Germinomas represent the most frequent tumour type in the pineal region and the synchronous involvement of the suprasellar region, frequently termed bifocal disease, is increasingly recognised. The incidence, pathogenesis, histomorphological, radiological, clinical features, and management strategies are discussed.

CASE REPORT

A 6-year-old girl presented with clinical features of hypothalamic-pituitary axis dysfunction. MRI showed two distinct lesions in the pineal and suprasellar regions. Tumour markers for germ cell tumours from blood and cerebrospinal fluid were within the normal range. The suprasellar lesion was biopsied and the histology revealed a germinoma. She received a radical course of radiotherapy covering the entire craniospinal axis (24 Gy/15#) followed by focal boost to the sites of primary disease (16 Gy/10#). Three months after the completion of treatment, the patient achieved a complete clinical and radiological response, which was maintained during the 13-month follow-up period.

CONCLUSIONS

The optimum management of primary intracranial pineal and suprasellar (bifocal) germinomas still remains controversial. The definition as either localised or disseminated disease has major implications on required treatment and its associated late morbidity. Prospective studies with large cooperative groups worldwide and consensus meetings may reduce uncertainties regarding available management options.

The role of radiotherapy in the treatment of childhood intracranial germinoma: long-term survival and late effects

BACKGROUND

The aim of the present report was to evaluate the role of radiotherapy in the treatment of childhood intracranial germinoma in view of long-term survival and functional outcome.

PROCEDURE

Nine children with histologically verified intracranial germinomas treated in Slovenia between 1983 and 1995 were reviewed. The four boys and five girls were 8.8-16.9 years old (median, 11.3 years). Five tumors were suprasellar, three were in the pineal region, and one patient had bifocal disease. Two patients had disseminated tumor. All patients received radiotherapy: six to the tumor bed, one to the whole brain, and two to the whole central nervous axis (CNA). The doses to the tumor bed ranged from 30 to 46 Gy (median, 44 Gy) and to the CNA were 24 and 34.5 Gy. Five patients received neoadjuvant cyclophosphamide and three patients, all with beta-human chorionic gonadotropin secreting tumors, received neoadjuvant cisplatin-based chemotherapy.

RESULTS

Six patients are alive 12.8-21.8 years (median, 19 years) from diagnosis. The causes of death in three patients were disseminated disease, toxicity of salvage chemotherapy, and secondary etoposide-induced leukemia. All patients with suprasellar tumors presented with overt endocrinopathy. Results of psychological evaluation were subnormal in one out of five patients tested. Estimate of mental deterioration due to therapy ranged from 0% to 30% (median, 15%). Emotional disorder was registered in four patients and psycho-organic syndrome in three.

CONCLUSIONS

Our results on long-term survival and functional outcome confirm the efficacy and relative safety of limited-field and reduced-dose radiotherapy for childhood intracranial germinoma when supplemented with chemotherapy.

Limited-field radiation for bifocal germinoma

PURPOSE

To report the incidence, characteristics, treatment, and outcomes of bifocal germinomas treated with chemotherapy followed by focal radiation.

METHODS AND MATERIALS

This was a retrospective review. Inclusion criteria included radiologic diagnosis of bifocal germinoma involving the pineal and neurohypophyseal region, no evidence of dissemination on spinal MRI, negative results from cerebrospinal fluid cytologic evaluation, and negative tumor markers.

RESULTS

Between 1995 and 2004, 6 patients (5 male, 1 female; median age, 12.8 years) fulfilled the inclusion criteria. All had symptoms of diabetes insipidus at presentation. On MRI, 4 patients had a pineal and suprasellar mass, and 2 had a pineal mass associated with abnormal neurohypophyseal enhancement. All patients received chemotherapy followed by limited-field radiation and achieved complete remission after chemotherapy. The radiation field involved the whole ventricular system (range, 2,400-4,000 cGy) with or without a boost to the primary lesions. All patients remain in complete remission at a median follow-up of 48.1 months (range, 9-73.4 months).

CONCLUSIONS

This experience suggests that bifocal germinoma can be considered a locoregional rather than a metastatic disease. Chemotherapy and focal radiotherapy might be sufficient to provide excellent outcomes. Staging refinement with new diagnostic tools will likely increase the incidence of the entity.

Radiotherapy of localised intracranial germinoma: time to sever historical ties?

The optimum management of localised intracranial germinoma remains controversial. Cure rates for this rare CNS tumour, which arises mainly in adolescents, exceed 90% at 10 years, and limitation of treatment-related late morbidity is therefore essential. Craniospinal radiotherapy plus boost is perceived to be the gold-standard treatment, but there have been suggestions that reduced-volume radiotherapy could be adequate for cure. We reviewed publications since 1988 to compare patterns of disease relapse and cure rates after craniospinal radiotherapy, reduced-volume irradiation alone (i.e., whole-brain or whole-ventricular irradiation followed by a boost), and focal or localised irradiation alone. The recurrence rate after whole-brain or whole-ventricular radiotherapy plus boost was 7.6% compared with 3.8% after craniospinal radiotherapy, with no predilection for isolated spinal relapses (2.9% vs 1.2%). We challenge the consensus that craniospinal radiotherapy is the best treatment for localised germinomas and conclude that reduced-volume radiotherapy plus boost should replace craniospinal radiotherapy when a radiotherapy-only approach is used.

Combined chemotherapy and radiotherapy for intracranial germinomas in adultpatients: a single-institution study

We report on our experience in the treatment of intracranial germinomas (18 pure germinomas and two germinomas with syncytiotrophoblastic giant cells) according to a strategy of radiotherapy doses and fields reduction after a neoadjuvant chemotherapy (Cisplatin-vinblastine and bleomycin combination). Radiation therapy was delivered after the completion of the third and last course of chemotherapy. For the solitary germinoma the target volume was the gross tumour volume. In the five multifocal germinoma patients the whole ventricle volume was irradiated. For the single disseminated germinoma patient we treated the whole central nervous system. The cumulative doses were 30 Gy for the pure germinomas. For the STGCs, a cumulative dose of 35 Gy was used. The median follow-up was 55 months (range 12-120). 18 patients were alive without recurrence of disease. In the two patients with STGCs the death took place 16 and 35 months after diagnosis.

Impact of margin for target volume in low-dose involved field radiotherapy after induction chemotherapy for intracranial germinoma

PURPOSE

We previously published a report stating that germinomas with elevated serum beta human chorionic gonadotropin (HCG-beta) had a poor relapse rate, but these findings have not been supported by a multi-institutional trial. The margin for initial gross tumor volume (GTV) before surgery and chemotherapy of the same materials was investigated by retrospective review.

METHODS AND MATERIAL

The 27 patients reported on in the previous paper were analyzed. The two-dimensional margin from the initial GTV to 90% of the prescribed dose of 24 Gy was 2.0 cm for a solitary lesion in the protocol. This margin was measured retrospectively without knowledge of the serum HCG-beta level. The whole ventricle field was used for patients with multifocal disease and whole central nervous system field was used for disseminated disease, respectively.

RESULTS

Six relapses were seen in 18 patients with solitary tumors, and were treated with the minimum margin of 1.5 cm or less to the initial GTV. Five of the 6 had initially elevated serum HCG-beta at the median of 7.4 mIU/mL, ranging from 0.7-233 mIU/mL. No relapses were seen in the 9 patients who were treated with whole ventricle or whole central nervous system field.

CONCLUSIONS

An inadequate margin and elevated serum HCG-beta were equally determined to be candidates that caused the poor local control. The whole ventricle is recommended as the smallest target volume for germinoma with or without elevated HCG-beta after induction chemotherapy.

Radiotherapy-induced thyroid disorders

Despite their specific functional consequences, radiotherapy-induced thyroid abnormalities remain under-estimated and underreported. These sequelae may include primary or central hypothyroidism, thyroiditis, Graves' disease, euthyroid Graves' ophthalmopathy, benign adenomas, multinodular goitre and radiation-induced thyroid carcinoma. Primary hypothyroidism, the most common radiation-induced thyroid dysfunction, affects 20-30% of patients administered following curative radiotherapy to the neck region, with approximately half of the events occurring within the first 5 years after therapy. The relative risk of radiation-induced cancer (mainly well-differentiated tumours) is 15-53-fold higher than in non-irradiated population. The aetiology of radiation-induced thyroid injury includes vascular damage, parenchymal cell damage and auto-immune reactions. Total radiotherapy dose, irradiated volume of the thyroid gland, and the extent of prior thyroid resection are among the most important factors associated with the risk of hypothyroidism. The contribution of other treatment modalities (chemotherapy, endocrine therapy) as well as patient- and tumour-related factors is less clear. Reduction in radiation dose to the thyroid gland and hypothalamic/pituitary complex should be attempted whenever possible. New radiotherapy techniques, such as stereotactic radiosurgery, three-dimensional conformal irradiation, intensity modulated radiotherapy and proton therapy allow generally better dose distribution with lower dose to the non-target organs. The diagnostic approach to thyroid radiation injury includes baseline thyroid function assays in all patients undergoing thyroid or parasellar irradiation. Recommended follow-up procedures include at least annual evaluation with a history for symptoms of thyroid dysfunction, clinical examination, and measurement of thyroid hormones and thyrotropin. Management of overt hypothyroidism is based on hormone replacement therapy. Thyroid hormone therapy is also recommended in cases of subclinical hypothyroidism. Treatment of other radiation-induced thyroid disorders (thyroiditis, Graves' disease, thyroid cancer) is similar to that employed in spontaneously occurring conditions. Further improvements in radiotherapy techniques and progress in endocrine diagnostics and therapy may allow better prevention and management of radiation-related thyroid injury.

Long-term results of radiotherapy for intracranial germinoma: a multi-institutional retrospective review of 126 patients

PURPOSE

Optimal management of radiotherapy (RT) for intracranial germinoma remains controversial. This study was conducted to evaluate the long-term results of RT in patients with these tumors.

METHODS AND MATERIALS

The study group consisted of 126 patients with intracranial germinoma (50 patients with pathologically verified germinoma and 76 clinically diagnosed with germinoma by clinical and neuroradiologic signs) who were treated by RT alone between 1980 and 2001. The median age at diagnosis was 17 years (range, 2-47), and various radiation doses and treatment fields were used. Serum human chorionic gonadotropin (hCG) levels were elevated in 18 patients. The median follow-up of the 114 surviving patients was 122 months (range, 13-263).

RESULTS

The 10-year actuarial overall survival and cause-specific survival rate for all patients was 90% and 95%, respectively. The 10-year actuarial cause-specific survival rate for patients with and without elevated hCG levels was 94%. Relapses were noted in 10 patients, 7 of whom died of the disease. No in-field relapses at primary sites were observed in 72 patients treated with total doses of 40-50 Gy. The incidence of spinal relapses was 4% (2 of 56) for patients treated with spinal irradiation and 3% (2 of 70) for those without spinal irradiation. After a median 10-year follow-up, 54 (92%) of 59 patients with tumors not involving the neurohypophyseal region and 42 (76%) of 55 patients with tumors involving the neurohypophyseal region had Karnofsky performance status scores of 90-100%. With regard to school education and occupation, 54 (92%) of 59 patients with tumors not involving the neurohypophyseal region and 39 (71%) of 55 patients with tumors involving the neurohypophyseal region were attending school or undertaking occupations. Hormonal replacement therapy was required in 50 (44%) of 114 surviving patients before RT; only 4 patients (4%), all with neurohypophyseal tumors, required hormonal replacement therapy after RT. Clinically evident severe neurocognitive dysfunctions were documented in 10 patients before RT, and no patients treated with total doses of <55 Gy developed apparent neurocognitive dysfunctions or other complications after RT.

CONCLUSION

RT was a curative treatment for intracranial germinoma, and elevated serum hCG levels did not affect the prognosis of patients treated by RT alone. A total dose of 40-50 Gy to adequate treatment fields was effective in preventing intracranial relapse, and the incidence of spinal relapses was too low to warrant routine spinal irradiation. Karnofsky performance status scores, educational achievement, and the ability to work were generally good, particularly in patients with tumors that did not involve the neurohypophyseal region. Because most complications, such as hormonal deficiency and neurocognitive dysfunction, were documented before RT and newly diagnosed complications after RT were infrequent, the treatment toxicity faced by germinoma patients appears to be less than anticipated.

Radiation therapy for intracranial germ cell tumors

PURPOSE

To review the combined experiences of University of California, San Francisco, and Stanford University Medical Center in the treatment of intracranial germ cell tumors (GCT) and to assess the impact of craniospinal radiation (CSI) on patterns of relapse, progression-free survival (PFS), and overall survival (OS).

PATIENTS AND METHODS

Ninety-three patients received radiation for newly diagnosed intracranial GCTs, including 49 germinomas, 16 nongerminomatous GCTs (NGGCT), and 28 with no biopsy. Median follow-up for surviving patients was 4.5 years (range 0.25-34). Tests for variables correlating with OS and PFS were conducted using Cox proportional hazards model.

RESULTS

Five-year PFS and OS rates were 60% +/- 15% and 68% +/- 14% for patients with NGGCT and 88% +/- 5% and 93% +/- 4% for those with germinoma. Of 6 patients with localized NGGCT who did not receive CSI, 1 experienced an isolated spinal recurrence but was salvaged. Of 41 patients with localized germinoma, 6 who received CSI and 35 who did not, no isolated spinal cord relapses occurred. Twenty-one patients with localized germinoma received neither CSI nor whole brain radiation. Of these, none of 18 with ventricular radiation relapsed. One of 3 patients with primary tumor radiation relapsed intracranially but had only received 11 Gy at initial treatment. On multivariate analysis, germinoma histology but not CSI correlated with improved PFS and OS.

CONCLUSION

CSI is not indicated in the treatment of localized germinomas. For patients with localized germinomas treated with radiation alone, we recommend ventricular irradiation followed by primary tumor boost to a total of 45-50 Gy.

Induction chemotherapy followed by low-dose involved-field radiotherapy for intracranial germ cell tumors

PURPOSE

To investigate the efficacy of chemotherapy followed by low-dose involved-field radiotherapy for the treatment of intracranial germ cell tumors (GCTs).

PATIENTS AND METHODS

Thirty-three patients with GCTs, including 16 pure germinomas, 11 human chorionic gonadotropin-beta (HCG-beta)-secreting germinomas, three mixed GCTs composed of immature teratomas plus germinomas (IMT/G), and three highly malignant mixed GCTs, were treated. Etoposide and cisplatin (EP) were used for the treatment of solitary pure germinomas, and ifosfamide, cisplatin, and etoposide (ICE) were used for the treatment of other GCTs. The dose schedule was 24 Gy for germinomas and 40 to 54 Gy for other GCTs. An involved-field set-up was used except for highly malignant GCTs, in which craniospinal irradiation was used. The median follow-up was 58 months (range, 18 to 102 months).

RESULTS

Disease-related, overall, and relapse-free survival rates at 5 years were 100%, 93%, and 69% for all patients, 100%, 100%, and 86% for patients with pure germinomas, and 100%, 75%, and 44% for patients with HCG-beta-secreting germinomas, respectively. All six patients with nongerminomatous GCTs were alive at the last follow-up. All eight relapses (one pure germinoma, five HCG-beta-secreting germinomas, and two IMT/G), except one in a course of salvage treatment, were salvaged and free of disease at the last follow-up. No decline was observed in the full-scale, verbal, or performance intelligence quotient at 12 to 51 months after the treatment in 11 patients.

CONCLUSION

Our results support an excellent prognosis after EP and ICE regimens followed by radiotherapy. Dose and volume can be reduced to 24 Gy in 12 fractions and involve a field set-up after EP chemotherapy for the treatment of pure germinomas.

Intracranial germinoma: radiation therapy with tumor volume-based dose selection

PURPOSE

To prospectively investigate whether intracranial germinomas, except large ones, can be cured with radiation doses lower than 50 Gy and to determine 10-year follow-up results.

MATERIALS AND METHODS

Between 1985 and 1995, 38 patients with intracranial germinoma diagnosed histologically or with established criteria were enrolled. Total radiation doses to the primary tumor site were 36 Gy after total removal, 40 Gy for tumors less than 2.5 cm in diameter, 45 Gy for those 2.5-4.0 cm, and 50 Gy for those greater than 4.0 cm, with 1.6-1.8-Gy daily fractions. Patients underwent irradiation of the primary tumor site or cerebrospinal axis (20-24 Gy), depending on findings at diagnosis. No chemotherapy was allowed.

RESULTS

All patients completed radiation therapy. Thirty-five patients were treated according to protocol, and three with relatively slow tumor regression or presence of a cyst received additional radiation (5-7 Gy, 50-52 Gy total). Ten-year overall and relapse-free survival rates were 91% and 95%, respectively. Two patients developed meningeal dissemination, but none had local failure. Treatment complications included chordoma in one patient and internal carotid artery occlusion in another. No treatment-related decline of performance status was observed in the other patients.

CONCLUSION

All tumor volume-based radiation doses were effective, without risk of local failure. Intracranial germinoma 4 cm or less in diameter can be cured with doses of 40-45 Gy. Investigation of further dose reduction seems worthwhile. Radiation therapy alone with these doses should be compared with ongoing chemotherapeutic protocols plus low-dose (24-30-Gy) irradiation in future studies.

The treatment of cranial germ cell tumours

Germ cell tumours of the central nervous system (CNS) include many subtypes whose response to treatment varies, even though the symptoms and radiological appearances are similar. Five-year survival rates are 96% for germinomas, 100% for mature teratomas, 67% for immature teratomas and 69% for immature teratomas mixed with germinomas; for beta-HCG secreting germinomas the rate is only 38%. Patients with choriocarcinoma, embryonal carcinoma, or yolk sac tumour have the lowest survival rates; patients with germinoma or mature teratoma have longer survival rates. Although a wider resection is associated with a higher rate of survival for patients with non-germinomatous germ cell (NGGC) tumours, to date an aggressive surgical approach has been advocated only for pineal region tumours, but not for hypothalamic/neurohypophyseal tumours. Beside the delayed injury induced by radiotherapy, the late injury induced by chemotherapy is becoming increasingly evident. Cisplatin is considered an indispensable drug, but it may cause renal damage, ototoxicity, peripheral neuropathy and sterility, while etoposide is associated with an excess frequency of second neoplasms. Taking into account all of the published literature, the following therapeutic options are suggested: in pure germinoma tumours (GT) radiotherapy alone will usually ensure adequate control of the disease, and the long-term sequelae may be limited by reducing the dose delivered, as was proposed for germ cell testicular tumours, to 30 Gy to limited fields plus 25-30 Gy to the spinal axis if there is disseminated disease. In cases of recurrence, which should be uncommon, patients may be rescued with both radiotherapy and chemotherapy. In NGGC tumours, the prognosis is more unfavourable and there is often dissemination to the spine at diagnosis; however, the tumour's high chemosensitivity suggests neoadjuvant treatment chemotherapy with cisplatin and etoposide for three cycles followed by consolidation radiotherapy with 40 Gy to the limited fields plus 30 Gy to the spinal axis if disseminated. In our opinion, a higher dose of radiotherapy in cases in which chemotherapy does not achieve a radiological complete remission is not advisable, because very often the residual radiological abnormality does not represent biologically active tumour but differentiated forms such as mature teratoma. The challenge for 2000 is to both cure these patients, and avoid the late and permanent sequelae of radiation and/or chemotherapy that may subsequently impair quality of life.