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Treatment for pineal germinomas

Treatment for pineal germinomas

Question

Dear OncoLink "Ask The Experts,"
My 8-year-old daughter has been diagnosed with a germinoma. The primary germinoma was in the pineal region and 80% was resected by surgery. There also is another very small tumor located very near where the first was. We are now entering chemo treatment using carboplatinum and etoposide for a total of 3 treatment rounds. Then radiation will be used. I am aware that germ cell tumors in the pineal region are rare, but even more rare in female patients. Any info regarding treatments used or where to obtain more studies done in these cases would be greatly appreciated. 

Answer

Amit Maity, MD, PhD, Assistant Professor of Radiation Oncology at the Hospital of the University of Pennsylvania, responds:

The treatment for pineal germinomas is extremely controversial, perhaps more that for any other pediatric brain tumor. The reason for this is that there is more than one treatment that is highly effective. Historically the treatment has been craniospinal radiation (radiation directed to treat the entire contents within the skull along with the spinal region) to fairly high doses without chemotherapy. In fact, I just reviewed the CHOP/HUP experience using this approach. Out of 39 patients with intracranial germinomas (not all had pineal tumors but at least half did), not a single one has relapsed. Other centers have had similar results with craniospinal radiation. Therefore, we know that this treatment is highly effective.

However, in an eight year-old girl, treating the entire brain and entire spine with radiation to the doses that have been used historically has some serious potential complications including growth retardation, endocrine deficits, cognitive problems and possible infertility. An alternate approach is to use chemotherapy, which is known to be very effective for germ cell tumors in other sites. A study reported many years ago showed that chemotherapy alone for intracranial germinomas leads to a very high relapse rate. Therefore, chemotherapy alone is not generally accepted as being appropriate treatment for these tumors. Most experts would certainly advocate radiation in addition to chemotherapy. However, if it is combined with chemotherapy, the radiation volumes and doses should be able to be decreased compared to the historical standard. What volume needs to be irradiated depends a lot on what the staging work-up showed. If thorough imaging was done and showed no dissemination into the spinal canal and cytology was negative, then the spine does not have to be irradiated. However, controversy still remains as to what volume should be treated. One camp would argue that in the absence of evidence of dissemination outside the pineal region, that only this localized volume needs to be irradiated. However, others would treat the entire ventricular system because these tumors often spread in this manner. Some might even want to treat the whole brain initially before boosting the pineal region. The fact that in your daughter's case there is a second tumor near the first might argue for larger radiation fields. The dose is also controversial. If radiation only was used, most radiation oncologists would favor going to 45-50 Gy to the original tumor. However, most studies using chemotherapy and radiation together have gone to lower dose, somewhere around 40 Gy.

As you can see, there is no single way to treat these tumors that is universally accepted. Not knowing the details of this case and not having reviewed the imaging studies myself, I can not make any specific recommendations. I would advise that you consult more than one radiation oncologist, including one that treats lots of pediatric cases at a major academic center.