Radiation Therapy for Pineal Tumor

When someone is diagnosed with a pineal tumor, it can be a scary and confusing time. The pineal gland is a small, pea-sized part of the brain that helps control our sleep patterns.

Tumors in this area are rare, and they can be either non-cancerous (benign) or cancerous (malignant). As part of a comprehensive treatment plan, your care team may recommend radiation therapy.

In this article, we'll touch on the different forms radiotherapy can take, the risks and benefits, who is most likely to benefit, as well as the clinical outlook for this cutting-edge treatment. 

Radiation therapy is a common treatment for pineal tumors, especially when there is concern for recurrence or if a tumor is in a difficult to surgically resect area. This type of treatment uses high-energy rays to kill cancer cells or stop them from growing.

The precision of this treatment allows for the preservation of surrounding healthy brain tissue. Germinomas are generally the most radiosensitive pineal tumors and often show an excellent response to radiation therapy.

They can frequently be controlled or cured with radiation alone or in combination with chemotherapy. Non-germinomatous germ cell tumors are typically more aggressive than germinomas but may still respond to radiation, especially when this is combined with chemotherapy.

However, pineocytomas, pineal parenchymal tumors, and pineoblastomas may not respond well to radiation therapy. Although these tumors are different in their disease course, they often require surgery for complete removal of the tumor.

In cases where surgery is not possible, or when these tumors recur, radiotherapy may be the best option.

Several types of radiation therapy can be used for the treatment of pineal tumors, each with its own advantages and specific applications. Here are some of the most common radiation therapy modalities:

This is the most common form of radiation therapy for pineal tumors, and it includes intensity-modulated radiation therapy (IMRT). This allows for the beams of radiation to be delivered at different intensities, reducing damage to surrounding healthy tissue. EBRT often requires multiple short sessions spread out over the course of several weeks. 

Despite its name, SRS is a non-surgical procedure that delivers a high dose of radiation to a precise target in a single or a few sessions. Consequently, this type of radiation is often used for smaller tumors in the pineal region. Each session may only last 30 minutes or less.

This type of therapy uses protons rather than X-rays. Protons can be controlled to stop at the tumor site, reducing the dose to surrounding normal tissues and potentially decreasing side effects. Similar to EBRT, each proton therapy session may only last a few minutes but requires multiple sessions for complete treatment.

Similar to SRS, FSRT delivers radiation in smaller doses over several sessions. However, each session may be slightly longer than SRS. This fractionation can allow healthy tissue more time to repair, potentially reducing side effects.

This radiotherapy is less commonly used when treating pineal region tumors. When there is concern that the pineal tumor has spread to other regions of the brain, WBRT may be used to treat multiple locations at once. However, with the wider area treatment, there is also concern for more widespread side effects. WBRT sessions are often short and occur daily over multiple weeks.

Doctors will use special calculations to figure out the right dose based on a patients’ tumor type, its location, and what type of radiation therapy is selected.

Planning radiotherapy for pineal tumors is a detailed process tailored to each patient. First, imaging tests like MRI or CT scans map the tumor’s precise location, guiding the radiation approach.

A radiation oncologist collaborates with other specialists to select the optimal therapy type, such as external beam or proton therapy. Detailed calculations determine the safest, most effective dose, minimizing exposure to healthy tissue.

During simulation sessions, patients are fitted with a custom mask or positioning devices to ensure accuracy. The team discusses potential side effects, schedules, and goals, preparing patients for a treatment plan designed for maximum precision and safety.

Like any treatment, radiation therapy can have side effects, and this can be different for each patient. Some of the most common side effects are:

• Fatigue: This is common during radiotherapy due to the body’s natural response to the radiation or stress of undergoing treatment.
• Headaches: Radiation may irritate brain structures surrounding the pineal region, resulting in headaches.
• Hair loss: Also known as alopecia, this side effect is common, as radiation may damage hair follicles on the head. This is usually temporary, and hair often grows back following treatment.

There can also be more serious side effects like changes in memory, trouble with thinking, or growth problems in children. Doctors work very carefully to plan the treatment to reduce these risks as much as possible.

Radiation therapy can be very successful, especially for certain types of tumors like germinomas. However, for non-germinomatous and parenchymal tumors, success rates vary with radiation alone, and additional treatment modalities, such as surgery or chemotherapy, may be needed.

The overall success of radiation therapy for pineal tumors also depends on factors such as the precise staging of the tumor, the presence of metastatic disease, and the patient's overall health. Long-term control of the tumor and survival rates are important measures of success, and these are often discussed with patients during treatment planning.

The best candidates for radiation therapy are usually those with tumors that are sensitive to radiation or those who can't have surgery because of the tumor's location or other health issues. Doctors also consider the patient's overall health, age, and the type of tumor when deciding if radiation therapy is the right choice.

• Radiation therapy is a viable treatment for pineal tumors, particularly effective for germinomas, which are highly responsive to this modality.
• There are multiple radiation therapy techniques available, each with specific benefits, which your doctor will take into consideration when suggesting a treatment plan.
• While radiation therapy can be effective, it also carries the risk of side effects, which can range from mild to more severe. The treatment plan is carefully designed to minimize these risks as much as possible.
• The patient's overall health, age, and specific tumor type are also considered when determining the suitability of radiation therapy.

• American Brain Tumor Association (ABTA)
• National Brain Tumor Society (NBTS)
• National Cancer Institute (NCI)
• Cancer Research UK