Treatment Paradigm Flashcards
What is the most important prognostic factor in germ cell tumors?
Histology is the most important prognostic factor in germ cell tumors.
What is the prognosis of pure germinomas vs. NGGCTs?
The prognosis is better for germinomas (5-yr PFS >90% vs. 40%–70%, respectively).
Describe 2 Tx paradigms for localized pure germinomas.
Tx paradigms for localized germinoma:
- Definitive RT
or
- Neoadj chemo → lower-dose RT
Describe the definitive RT technique for localized germinoma.
Whole ventricular radiation therapy (WVRT) to 21–24 Gy, boost to primary tumor to 40–45 Gy
For which pineal tumor type is Sg generally not done?
Sg is generally not done for germinomas, since they are radiosensitive tumors and Sg can lead to morbidity. However, extent of resection is important for NGGCT.
What is the RT technique for disseminated germinoma?
CSI to 24 Gy, gross Dz boost to 45 Gy
Describe the RT technique with neoadj chemo for localized germinoma.
Reduced RT doses: CR to chemo: WVRT to 18 Gy; boost to 30 Gy in 1.5 Gy/day in pts who achieve a CR on chemo on current COG protocol. PR/stable Dz to chemo, WVRT to 24 Gy +12 Gy boost
In germinoma protocols, what does “occult multifocal germinoma” refer to? What is the boost volume?
Pineal-region tumor and DI. Boost volume is the enhancing tumor (pineal region), infundibular region, and the 3rd ventricle after WVRT.
Describe 2 Tx paradigms for NGGCT.
NGGCT Tx paradigms:
Induction platinum-based chemo 4–6 cycles → CSI RT 30–36 Gy (lower dose for CR) → boost primary to 50.4–54 Gy; Sg for residual or recurrent Dz
Max surgical resection → adj platinum-based chemo; restage; if no neuroaxial involvement, consolidate with IFRT; if +neuroaxial Dz, CSI to 30–36 Gy, boost to 50.4 Gy
When is chemo indicated in the Tx of NGGCTs?
Chemo is always indicated for NGGCTs (influences survival).
What is the Tx paradigm for pineoblastoma?
Pineoblastoma Tx paradigm: treat as high-risk MB (CSI 36 Gy + local boost to 54 Gy)
What is the Tx paradigm for pineocytoma?
Pineocytoma Tx paradigm: treat like a low-grade glioma (GTR → observation; STR → consideration of adj RT or observation with Tx at the time of progression [50–54 Gy])
What chemo agent should be avoided with brain RT? Why?
6-mercaptopurine. It is associated with high rates of secondary HGGs.
What is the long-term rate of RT-induced 2nd CNS malignancies? What type is most common?
5%–10%; usually glioblastoma multiforme
What is the treatment paradigm for intracranial pure germinoma?
Whole ventricle radiation therapy to 24 Gy followed by a boost to the primary site to 40 to 45 Gy OR induction chemotherapy followed by whole ventricle radiation therapy to 24 Gy followed by response-directed boost of 30 to 36 Gy.
Buckner, JC, Peethambaram, PP, Smithson, WA, et al. Phase II trial of primary chemotherapy followed by reduced-dose radiation for CNS germ cell tumors. J Clin Oncol. 1999;17(3):933-940.
