Childhood Cancer

Surgery is performed at different times during treatment. Varying amounts of tumor are removed—from a small biopsy to the whole tumor. This section describes several of the most common surgeries used to treat children with brain or spinal cord tumors.

Biopsy

An area that looks abnormal on an MRI scan is not always a tumor, so a biopsy is usually necessary before major surgery or other treatment begins. In some situations, a biopsy is not possible because of tumor location or it is not recommended because of the damage the procedure could cause. For example, biopsies are not often done for pontine gliomas.

A biopsy involves taking a tiny sample of tissue through a small incision. When the pathologist evaluates the tissue removed in a biopsy, she determines whether the lesion is a tumor and, if so, what type of tumor it is.

Jordan was 3 years old when she was diagnosed with an inoperable pilocytic astrocytoma. Since she was not using her right hand, our pediatrician told me to take her to a pediatric neurologist. But, because of insurance, our first visit was to a local neurologist. Now this doctor was used to seeing adults, so when he saw her MRI, he told us to give her a happy 6 months. He referred us on to the pediatric doctors at a children’s hospital 3 hours away. They took a biopsy and told us there were treatments available.

You should have your child’s biopsy done at a pediatric center that uses MRI and/or CT scans to guide the surgeon to the site of the tumor. The scans are used as a roadmap so the neurosurgeon can obtain the biopsy from the center of the tumor (called a stereotactic biopsy). If the biopsy doesn’t obtain adequate tissue, a diagnosis is sometimes not possible. In other cases, the piece of tumor obtained by biopsy is not representative of the whole tumor. Some tumors have areas that are very aggressive (“high grade”); other areas appear “low grade.”

If a stereotactic biopsy does not provide a diagnosis, an open biopsy may be considered. In this case, an operation is done to directly view the tumor and to obtain an adequate sample. MRI and CT guidance can also be used with this approach.

Special tools called endoscopes are used by neurosurgeons to biopsy tumors that are located in the fluid spaces called ventricles. These telescope-like tools contain a camera that allows the surgeon to see the tumor with one channel and to use a separate channel to biopsy the tumor.

Debulking

Surgical debulking is the partial removal (usually 40 to 90 percent) of the tumor. This type of procedure is done for tumors that are deep within the brain, next to large blood vessels, or growing from the brainstem. In these areas, the risk is too great to allow total removal. Instead, the goal of surgery is to relieve any symptoms caused by the tumor, especially increased intracranial pressure. A debulking procedure is often done prior to giving either radiation or chemotherapy, because these treatments are sometimes more effective on smaller tumors.

A debulking procedure may also slow or stop the growth of a slow-growing tumor for a period of time, thus delaying the need for other treatments.

Anthony was just over 2 years old when he was diagnosed with an optic nerve glioma. Radiation was not recommended, because of the risks of serious long-term side effects. We agreed that the pediatric neurosurgeon should debulk as much of the tumor as possible. She removed most of the low-grade tumor that extended into the temporal lobe. Chemotherapy was not needed for several years.

Delaying treatment, if possible, has several advantages. For instance, studies have shown that children who have radiation to the brain at an older age have fewer long-term effects than children who have radiation before age 5. Slowing tumor growth for several years can also allow time for the discovery of newer and more effective methods of treatment.

Surgical resection

My brain tumor is located in the midbrain, and my neurosurgeon told us at diagnosis that it was inoperable. Since it was diagnosed though, I have had numerous surgeries to shrink it. So, even though they say it is inoperable, they can still go in and reduce its size. My neurosurgeon has always said that the medical field is an ongoing research area. What they couldn’t do yesterday, they can do today.

The goal of surgery for most brain and spinal cord tumors is to remove the entire tumor (called maximal safe surgical resection). It is important to understand what this term means. Unlike a tumor in the intestine, where the surgeon can cut a wide margin on either side of the tumor to ensure that no tumor cells are left behind, brain and spinal cord tumors can’t be removed with large margins because there are vital structures throughout the brain and spinal cord. Surgeons usually remove a brain or spinal cord tumor by working from the inside of the tumor out, coring out the cavity. Some tumors are removed and require no more treatment.

ln 2008, I suffered a mild seizure. A CT scan revealed a lesion, and a nervous, bow-tied neurologist added the word “suspicious” to the findings. Oops, time for a second opinion. This led me to a renowned pediatric neurosurgeon who diagnosed a low-grade, benign juvenile pilocytic astrocytoma (JPA) tumor on the frontal left lobe of my brain. The thought of a tumor made my insides shake. While the slow-growing tumor was in a quiet part of the brain and did not pose an immediate threat, if not removed, it would eventually affect my speech and other neurological functions. My surgery was scheduled for the following week. Suddenly reality hit—I was 14, and instead of spring break and boys, I was thinking about mortality.

No matter how hard I tried to be cool, the day of my surgery was probably the most terrifying day of my life. As the anesthesiologist prepared the lV, I held on tightly to my mother’s hand and drifted away with the prayers of my friends and family in my heart. A night in intensive care and one in the pediatric oncology unit followed the surgery. By the third day, I was ready to go home. Less than a week later, the surgical staples were removed and I returned to school and all activities.

It has been almost 3 years since my surgery. From a medical point of view, I am a healthy statistic that will be cited when another person is diagnosed with the same grade JPA. There is an empty cavity where the tumor was removed because brain matter does not regenerate. Reality has taught me to never take anyone or anything for granted. Today I am preparing for college, dealing with my parents’ divorce, working, volunteering and dancing competitively. Although I accept my flaws more graciously now, embracing my strengths and weaknesses is still a work in progress. Mostly, I am grateful just to be me.

Recent studies have indicated that the best chance for long-term survival and cure occurs with total, or near total, removal of the tumor. This may not be possible if the tumor is deep within the brain or near a part of the brain responsible for a vital function (for example, near the area that controls breathing). A maximal surgical resection, however, is now possible in many areas within the brain and spinal cord due to new technology in operating equipment and monitoring. The majority of tumors in the frontal, parietal, temporal, and occipital lobes and the cerebellum can be totally, or almost totally, removed. Similarly, most spinal cord tumors can also have maximal surgical resections.

John Michael was 11 years old at the time of surgery. He has a brain tumor located in the thalamus. We were told that it was inoperable by our local neurosurgeon. Then we found a more experienced pediatric neurosurgeon. He did indeed have surgery to remove about 85 percent of his golf ball-size tumor, and he has no lasting deficits.

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Exactly 3 weeks after being diagnosed with a pilocytic astrocytoma almost the size of an orange in the cerebellum, Christopher went back to school! The tumor was benign and located in the most accessible place possible, so he arrived at school with a full head of hair, no residual effects from surgery, and a bigger smile than he left with 3 weeks before.

It is common for children to undergo more than one surgical procedure during the treatment process. Total, or near total, removal of the tumor is often achieved by operating in more than one stage and/or from different approaches. For example, if an MRI scan after surgery reveals a lump of tumor remaining and the surgeon feels he can remove it safely, a second surgery is performed. Similarly, a deep tumor may be approached surgically from above and then during a separate operation from the side. Tumors that are very slow growing are debulked and the remaining tumor monitored with MRI scans every 3 to 6 months. A second surgery is performed months or years later if the tumor grows.

About 2 weeks following surgery, I had to return to the hospital for a post-op checkup and MRI to check the residual tumor. The MRI showed that the pediatric neurosurgeon removed about 50 percent of the tumor, but he informed us that he could see himself going in from another direction to obtain more of the tumor. We left the office feeling a little peace of mind, because we now knew that the tumor was smaller.

The results from a number of clinical trials support a second-look operation after a phase of treatment (chemotherapy or radiation) if tumor is still visible on the MRI scan. During a second-look surgery, a piece of the remaining tumor is obtained and sent to a pathologist to see if the treatments have injured or killed the tumor cells. Occasionally, on second look, an abnormality thought to be tumor on the MRI scan turns out to be scar tissue. The results of the second-look surgery provide information to the treating physician that helps him plan the next step of treatment. In some cases, children have special imaging studies done (e.g., positron emission tomography [PET] scan or MRI spectroscopy) rather than a second-look surgery to evaluate treatment effect.

Intraoperative monitoring

Our 10-month-old daughter was diagnosed with medulloblastoma. Her first surgery took about 9 hours to remove the baseball-sized tumor. The pathology showed that it was malignant. She had chemotherapy that she tolerated very well. The first MRI after chemo showed a shadow where the tumor had been. So, they did a second-look surgery, which thankfully, only showed scarring. That surgery didn’t take as long as the first since they had nothing to remove. After a week in the hospital, we went home. Kristin is now 13 years old, with no late effects from treatment. She is mentally and physically on par with her friends—whom she spends a lot of time talking with on the phone and computer!

Intraoperative monitoring involves watching the electrical nerve impulses as they travel from an area of the brain to another part of the body, such as the arms, legs, or face and eyes. Electrodes are placed on the scalp and on the extremities (similar to an electroencephalogram [EEG]) to monitor the brain’s electrical impulses. By using this technology during an operation, the surgeon can determine the location of a tumor in relation to important body functions. This technology helps the surgeon remove the tumor while preserving as much function as possible. Intraoperative monitoring is most often used for tumors in the frontal and parietal lobes adjacent to the motor strip or the brainstem. Intraoperative monitoring is also vital for surgery in the spinal cord, because the monitoring allows the surgeon to remove the tumor while observing the nerve activity from the brain down the spinal cord and out to the arms and legs.

Another type of monitoring uses electrodes to locate seizure activity in the brain. This type of EEG involves placing a grid or strip of electrodes on the surface of the brain after a tumor has been removed. It monitors the tumor cavity and surrounding brain to determine whether seizure-generating tissue is still present. If the place where the seizure starts is not in a vital area, then that seizure-generating tissue is also removed to try to reduce or eliminate the seizures. If the tumor is near the speech center, this procedure is done while the child is awake. By having the child awake, the surgeon can converse with him during the tumor removal, ensuring that the speech center remains uninjured. The child has to be mature enough to cooperate, and this is usually not possible until at least early teen years.

Computer-guided surgery

An attempt to awaken my son Michael during his first awake craniotomy for a mixed tumor of JPA [juvenile pilocytic astrocytoma] and PNET [primitive neuroectodermal tumor] failed. He was only 12, but more importantly, I think the person who was talking with him was cold and aloof, as was his surgeon. As he came out of the anesthetic, he tried to move his head while in the cage, was very confused, and they ended up just putting him back to sleep.

The second surgery was a whole different story. Now he was 15, and we used a major neurosurgery center. Both the pediatric neurosurgeon and his assistant took the time to really talk to Michael, get to know him well, and goof around with him (making him feel comfortable with them). When they woke him up, they chatted to him about gymnastics (his first love), his best friend Alex, his desire to be third in his class (to escape having to make a speech at graduation), and so on. The awake surgery was a super success—the surgeon was able to go deeper, get all of the tumor, and yet know that Michael’s speech would remain intact.

Until recently, neurosurgeons had only an MRI picture to refer to during surgery. Now it is possible to use the MRI along with a computer in the operating room to help the surgeon localize and remove the tumor. An MRI is performed prior to the surgery. The information from the MRI is transmitted to a computer in the operating room, which serves as a navigational system. The surgeon then uses a pointer aimed at various reference points on the child’s head and the computer generates a three-dimensional picture of the brain and tumor location. This technology allows removal of the tumor through a much smaller incision.

My son had a late effect from radiation called a cavernous angioma. It is an abnormal collection of blood vessels that is not a problem unless it gets big and/or it starts to bleed. Six years after my son’s initial treatment, this was diagnosed on a follow-up MRI and 3 months later it had grown quite large and had some signs of having bled, so our local vascular neurosurgeon felt that surgery was necessary. Unfortunately, the location of the angioma was quite poor, deep in the frontal lobe on his dominant side, so very near the speech center. My son was 12 at the time, and I really wanted to find a pediatric vascular neurosurgeon, someone who would think that my son’s brain looked quite large, rather than an adult neurosurgeon who might think it a bit on the small side from his experience.

This is a rare thing in children, so I did some investigation. I asked my local neurosurgeon for a name for a second opinion. I also asked other parents in my brain tumor support group, and I did a literature search to see who had published an article on this complication. There was one name that came up more often than others, and I contacted him by email. He was very responsive and kind to me immediately. When we met with him, he told us what we wanted to hear, that he could perform this surgery without any danger of our son losing his ability to talk. He told us to be prepared for a week in the hospital, but my son was up talking immediately, and he was walking within 6 hours of surgery. He ate a breakfast burrito 8 hours after surgery and we were discharged less than 24 hours after surgery. He had just a small bandage, otherwise you would not know that he had undergone a major operation.

Preoperative MRI scans that use a technology called diffusion tractography generate a picture that shows the child’s vital motor or visual pathways, which helps the surgeon plan her route to the tumor. MRI scans are also used with the guidance system to minimize the risk of injury during the surgery.

Surgeons are also working with MRI companies to develop MRI scanners for the operating room. An intraoperative MRI scanner allows the surgeon to obtain an MRI scan during the surgery to show him how much tumor is left. This technology has faced some challenges in development and is only available in a small number of pediatric centers.

Another new method to help neurosurgeons safely remove tumors is intraoperative ultrasonography, which uses ultrasound probes to guide the surgical approach. Ultrasonography is also used to examine the ventricles during surgery to look for collections of cerebrospinal fluid (CSF) or cysts.

Surgical treatment of hydrocephalus

Hydrocephalus is the buildup of fluid in the brain caused when a tumor blocks the normal flow of CSF. The surgeon can insert a tube (called a drain or ventriculostomy) prior to or during the tumor removal surgery to remove excess CSF. The tube shunts fluid from the brain to a collection bag outside the body. The drain is usually removed a few days after surgery.

We were fortunate to be located near one of the most experienced pediatric neurosurgeons in California. They put Megan, who was just 20 months old, in the hospital for 2 days on Decadron® to reduce brain swelling before doing surgery. The tumor, an anaplastic ependymoma, was huge, and they did a gross total resection. They told us ahead of time that she might have language retrieval/word-finding issues and loss of mobility on the right side, but that didn’t happen. She did have an external drain after surgery, and they said she might need a permanent shunt because of the tumor’s size, but the temporary drain worked well and came out without any fluid buildup, so they didn’t need to do that.

Occasionally, part of the tumor remains or blood from the surgery scars the normal sites of CSF reabsorption and the hydrocephalus persists after surgery. In this case, a shunt surgery is performed. The shunt functions as a drain inside the body. The tube diverts the excess fluid from the brain into another space in the body—abdomen, chest, or a large vein in the heart. The fluid is then absorbed by the body. If your child has persistent hydrocephalus, an excellent resource is the Hydrocephalus Association (www.hydroassoc.org).

Tori had a regular ventriculostomy that had a tube that drained out to a bag at the bedside. The reason that they do this is that she had impressive hydrocephalus and they wanted to decrease the pressure during the surgery to resect the medulloblastoma. There was great hope that she might not even need a shunt. They tried for 10 days (intermittently clamping the tube) but once they clamped the bag to see if her body could handle the fluid, it started to drain out her incision site. Even if it is only a teaspoon a day that the body cannot handle, the child must have a shunt as it will build up. This was one of the hardest things for me; I really did not want a shunt. It meant to me that she would be a medical device kid her entire life. We could never leave this experience behind. Funny thing—our shunt has been blissfully easy so far. Not a problem at all.

Like the plumbing in your house, shunts can block and back up. This blockage is called a shunt obstruction or shunt malfunction. Buildup of proteins or debris from surgery that circulates in the CSF can prevent the fluid from draining properly through the shunt. Symptoms of a shunt problem are the same as the symptoms of hydrocephalus (headaches, vomiting, double vision). When this happens, the surgeon replaces the entire shunt or repairs the part of the shunt that is obstructed. Rarely, shunts fracture or become disconnected. Surgical repair is also the treatment for this problem.

An infection in the shunt can also cause a blockage. In this situation, intravenous antibiotics are given to treat the infection. The bottom end of the shunt is brought outside the body and connected to a drainage bag while the infection is treated. Daily cultures of the fluid are sent to the laboratory to confirm that the antibiotics are working. Once three negative cultures have been obtained, the entire shunt system is removed and a new clean one is surgically inserted.

I was 16 when I had my first surgery, when a VP shunt was placed for a large amount of fluid buildup. Then I had a second surgery to remove part of the tumor. About a month later, I started having severe headaches again. This time I could not raise my head up without becoming ill. I was rushed back to the emergency room, and another MRI was done. My neurosurgeon explained that the MRI was showing fluids back in the head again. He said that this was unusual, since I did have the shunt, and the shunt appeared to be working when he completed the last surgery. He performed some tests to see if he could figure out why the fluids were building up in the head. The next day, he told us that he wanted to go back in to check the shunt. He went in and discovered that my shunt had shut down due to a buildup of scar tissue around a valve on the shunt. He replaced the valve so that the shunt began working again. My stay in the hospital this time was about 7 days.

Hydrocephalus caused by a tumor that blocks the flow of CSF is sometimes treated with a procedure called an anterior third ventriculostomy (also called an endoscopic bypass or an endoscopic third ventriculostomy [ETV]). The surgeon uses an endoscope (a long tube with a camera at the end) to make an opening in the floor of the third ventricle. This new opening is a detour for the fluid around the obstruction caused by the tumor. The opening creates a pathway from inside the brain’s fluid spaces to the outside circulation. Here the fluid can be absorbed normally by the subarachnoid space without the need of a shunt tube.

Palliation

Although Molly (14 months old) had no outward symptoms of hydrocephalus, the main concern at diagnosis was surgery to relieve the pressure on her brain from the pineoblastoma. We were given the option of either a shunt, or something called a third ventriculostomy. This would create a hardware-free channel for the extra cerebrospinal fluid to leave her brain. This sounded like the best option for Molly, so surgery was scheduled for the next afternoon. Surgery went very well, and she was released the following afternoon. Molly is now 3 years old, she is followed regularly, but she hasn’t had any more problems with pressure in the brain.

Palliation is a type of health care that focuses on relieving or preventing suffering. Surgery is sometimes used to improve the quality of life of terminally ill children. Some tumors that do not respond to radiation or chemotherapy grow and cause painful pressure. Surgeons can remove parts of the tumor that are causing the pain. The insertion of a shunt or an ETV also may be considered to temporarily improve the quality of life in a child who develops hydrocephalus because of tumor growth.

Vascular access

Surgery was the only thing that made Laura feel better. She wanted to have the tumor operated on each time it came back. Before the last operation, she spoke to the surgeon and asked him to take it out one more time so that she could enjoy her summer.

Children with brain or spinal cord tumors have to endure many months or years of treatment. To avoid the pain of repeated needle sticks, many children receive a surgically implanted catheter. Direct access to a blood vessel allows the administration of chemotherapy, antibiotics, blood products, and hyperalimentation (IV nutrition) and avoids the pain of repeated needle sticks for the child. For more information, see Chapter 9, Venous Catheters.

Enteral access

Adequate nutrition plays an important role in children’s overall well-being and prognosis. Children who are unable to eat or drink a liquid diet sometimes need enteral access, a method that delivers nutrients directly to the gastrointestinal tract. Enteral access can be accomplished in several ways, including the insertion of a nasogastric tube (a tube passed down the nose to the stomach) or the surgical installation of a gastrostomy tube (a tube placed through the abdominal wall into the stomach). For more information, see Chapter 20, Nutrition.