Cancer is a disease in which cells divide uncontrollably. These fast-growing cancer cells can form masses of tissue called tumors.

What are solid tumors?

Solid tumors are masses of tissue. Tumors that are cancerous are called malignant. These tumors can grow back even after they are removed.

Tumors that are not cancerous are called benign tumors. When a benign tumor is removed, it usually doesn't grow back.

Doctors refer to solid tumors to exclude blood cancers such leukemia and lymphoma.

We care for children with all types of solid tumor cancers. Conditions we treat include:

• Neuroblastomas
• Bone sarcomas, like Ewing’s sarcoma and osteogenic sarcoma
• Soft tissue sarcomas, like rhabdomyosarcoma
• Kidney tumors, like Wilms’ tumor
• Germ cell tumors of the ovary or testicle
• Brain and spinal cord tumors
• Hepatoblastoma (liver tumor)
• Other rare childhood cancers
• Cancer predisposition syndromes (such as Li-Fraumeni syndrome)

Symptoms

Cancer in children can be difficult to recognize early. Symptoms can be similar to those of more common childhood illnesses and injuries or there might be no symptoms at all. Childhood cancer is also rare, so symptoms are most likely linked to something that is not cancer.

Still, there are symptoms to watch for and discuss with your child's doctor, especially if the symptoms continue for a while. These include:

• Pain that doesn’t get better with treatment
• Enlarged abdomen or pain in the abdomen
• Unusual lumps or swelling
• Inability to bear weight or walk, without a known injury (for example, a toddler who stops walking)
• Back pain, joint pain or swelling unrelated to an injury
• Fever lasting longer than five days (without other symptoms like runny nose, cough or vomiting)
• Blood in urine
• Pain or swelling in arms or legs unrelated to an injury
• Bruises in the upper and lower eyelids (“raccoon eyes”) unrelated to an injury
• Early onset of puberty
• Rapid, unintended weight loss (more than 10% over several months)

What cancer stages mean in pediatrics

A tumor’s stage is a way to measure how much cancer is inside the body. Staging is based on the tumor’s size, location and whether it has spread.

We know from research that in children, cancer can quickly move into other parts of the body. We think about cancer staging for children differently than we do for adults.

Cancer in children is sorted into two stages:

• Localized: The solid tumor (cancer) is only in the tissue or organ where it started.
• Metastatic: The cancer has spread to other parts of the body.

We treat all children with cancer as if it’s metastatic. That’s because we know that in children, a localized tumor can quickly become metastatic. Treating all our patients this way gives us the best chance for success.

Your child’s doctor can help you understand the stage of your child’s cancer.

Long-term effects of cancer

Children who’ve been treated for cancer need follow-up care and monitoring, most likely for the rest of their lives. That’s because chemotherapy, radiation therapy and other cancer treatments can cause long-term side effects as children become adults.

Childhood cancer survivors also may experience social and emotional issues related to cancer. OHSU has a Life After Cancer program to support kids, teens and young adults. We can answer your questions and help your child manage many of these issues.

How is cancer in children different than in adults?

Children get different cancers, and their bodies respond to treatment differently.

About half of all children with cancer have leukemia or brain tumors. Adults are most often diagnosed with breast cancer, lung cancer, prostate cancer and skin cancer.

Cancer in children often grows faster than adult cancers and can get worse more quickly. Some cancer treatments for adults aren’t safe for children’s growing bodies.

But many childhood cancers are easier to cure. Children can often tolerate higher doses of chemotherapy, for instance, with fewer side effects.

Who gets childhood cancer?

Cancer is much rarer in children than it is in adults. Each year in the U.S., about 9,900 children younger than 15 are diagnosed with cancer, compared with about 2 million adults.

The most common cancers in children and young teens are leukemia, brain tumors, and lymphoma. Among older teens, sarcomas of soft tissue and bone are also common.

More than 80% of kids and young teens with cancer today will be cancer-free survivors in five years. For the most common form of childhood cancer (acute lymphoblastic leukemia, or ALL), that number is more than 92%. The five-year survival rate is the standard way of measuring cancer outcomes.

What causes childhood cancer?

In most cases, scientists don't know the cause. Some adult cancers can be linked to lifestyle — such as smoking, sun exposure or diet. But in kids, it is extremely unlikely that you or your child could have done anything to prevent cancer.

Tumor molecular testing

Your child’s doctor might talk to you about opting in to molecular testing. Molecular testing lets us study a tumor’s genes to identify changes in proteins or other molecules that could be signs of cancer. It is not the same as testing your child’s genetics.

In most cases, your child will need a biopsy to diagnose their cancer. A biopsy is a procedure to remove a sample of your child’s tumor. If you opt in to molecular testing, we perform a second biopsy at the same appointment. Because treatment kills cancer cells, we can only do molecular testing before treatment starts.

This research could help us create better treatment for kids with cancer. Talk to your child’s doctor if you have questions about participating in this research.