OncoLog

 

From OncoLog, February 2012, Vol. 57, No. 2

Pediatric and Adult Cancer Patients Face Different Issues in Care, Survivorship

By Don Norwood

The challenges faced by children and adults with cancer can differ markedly, even when they have the same type of cancer.

Adults and children often are affected by different types of cancer, which is expected considering that some cancers in adults are linked with long-term exposure to carcinogens. However, in cancers common to both adults and children—which include hematological malignancies, sarcomas, and brain tumors—adults’ and children’s tolerance of and response to treatment, likelihood of remission, and survival rates and durations can be very different.

Same cancer, different disease

“Pediatric malignancies generally are more responsive to chemotherapy than are malignancies in adults because of differences in the biology of the cancer,” said Anna Franklin, M.D., an assistant professor in the Division of Pediatrics at The University of Texas MD Anderson Cancer Center. “In addition, children generally tolerate chemotherapy better than adults because children are less likely to have other health issues like heart disease, kidney disease, lung disease, or diabetes.”

A vivid example of this difference in treatment response occurs in patients with pre–B-cell acute lymphoblastic leukemia. “Treatment of this disease in children has become quite successful because oncologists have developed intensive, repeated chemotherapy regimens that these patients can tolerate,” said Dean Lee, M.D., Ph.D., also an assistant professor in the Division of Pediatrics at MD Anderson. These same regimens have proven to be too toxic for adults, however. According to Dr. Franklin, the 5-year survival rate for children with this cancer is as high as 90%, whereas the 5-year survival rate for adults with the disease is only about 40%.

Some treatment advances, such as those in bone marrow transplantation, benefit both children and adults. Dr. Lee’s current research includes the development of adoptive immune therapy within the context of stem cell transplantation. Hematological malignancies are common in children, and the advances made possible by clinical research in bone marrow and stem cell transplantation for adults have also greatly improved the quality of life of children who receive these transplants.

“Pediatric malignancies generally are more responsive to chemotherapy than are malignancies in adults because of differences in the biology of the cancer.”
— Dr. Anna Franklin

Successful cancer treatment brings challenges of its own. The high longterm survival rate of pediatric cancer patients and their longer life expectancy mean that their treatments—especially chemotherapy and radiation therapy—can cause problems later in life, sometimes decades after therapy has ceased. These problems—which include second cancers, kidney disease, cognitive disorders, sterility, and heart and lung dysfunction—may be exacerbated in children because their bodies are still developing.

The development of the brain, in particular, seems to be affected by cancer treatment. Dr. Lee said, “The ‘chemo brain’ that adults describe when they’re getting chemotherapy, which makes them really forgetful and causes problems, isn’t always temporary in children.” He said people treated with chemotherapy as children have more problems finding jobs and are less likely to get married compared with the general population.

Parent power

“Parents are worried about what will happen to their child 5 or 10 years after cancer treatment,” Dr. Lee said. “That’s completely reasonable because, to help focus their energy on the positive, parents may assume their child will be a survivor and focus on the child’s life after treatment.” But occasionally those concerns lead to conflict between parents and physicians about whether to stop therapy prematurely. Unless a patient completes the entire course of treatment as it was done in a clinical trial, physicians cannot accurately predict the chances of the treatment’s success.

Dr. Lee said these uncertainties can make it difficult for physicians to guide parents who are worried about treatment-related toxicities. “If there weren’t risks of long-term complications from treatment, these decisions would be much easier,” he said. Dr. Lee added that conflicts about treatment between parents and physicians, although potentially serious, are rare because parents and physicians share the goal of successfully treating the child’s cancer.

Dr. Franklin said the support that pediatric patients receive from their parents is crucial and often can make a major difference in the success of cancer treatment. “Parents of pediatric patients will bring them in when they are not feeling well and ensure they take their medicines as prescribed,” she said. Adult patients, on the other hand, sometimes lack dedicated, full-time caregivers who ensure they make it to appointments, and adult patients may skip doses of medicines that have harsh side effects.

“Adherence to prescribed medical therapy plays an ever-increasing role in cancer treatment,” said Dr. Franklin. “When chemotherapy is given intravenously at the hospital, we know they received the medicine. But many targeted therapies used today are pills taken at home, so the responsibility to take the pills lies with the patient. Discussing what the medicine is for, how it should be taken, and its potential side effects can help increase adherence for both adult and pediatric patients.”

Parents help pediatric patients deal with factors like navigating traffic and paying expensive parking fees for office visits, which seem minor to those who do not have to deal with them but can be barriers to treatment. “The drive of parents to do everything they can to save their child is highly motivating, more so probably than the drive for self-preservation,” Dr. Lee said.

Clinical trials

To address the differences in cancer treatment between young adults and children, pediatric and adult oncologists are collaborating more in taking a fresh look at treatment regimens. For example, Dr. Lee said that in the past, a 17-year-old patient with Hodgkin lymphoma would see a pediatric oncologist, whereas an 18-year-old patient with the disease would see an oncologist for adults, often resulting in different courses of treatment. Now, he said, the treatments two such patients receive are more likely to be similar.

It is also becoming more common for pediatric and adult patients to be included in the same clinical trials, as is currently being done in treatment trials for Ewing sarcoma.

“Ewing sarcoma in a 15-year-old is probably the same disease one sees in a 25-year-old,” said Dr. Lee. “There’s a lot more emphasis on pooling those patients in whatever clinical trials we do, whether the trial is sponsored by an adult treatment group or a pediatric group. The adult treatment groups are getting a lot better at lowering the age limits on their trials, and the pediatric groups are getting better at increasing the limits on their trials. So there are more patients enrolled and more common treatments pushed forward.”

The need for adequate sample sizes in studies of childhood cancers has also led to multi-institutional collaboration. “In pediatrics, cancer is much less common than in adults, so we had to learn early on to pool together across multiple centers to get enough patients to actually move the field forward,” Dr. Lee said.

“The ‘chemo brain’ that adults describe when they’re getting chemotherapy, which makes them really forgetful and causes problems, isn’t always temporary in children.”
— Dr. Dean Lee

Clinical studies of treatments for some cancers in adults have the opposite problem; for adult patients with commonly occurring cancers that have well-established treatment regimens, physicians may be hesitant to recommend participation in a trial. Individual oncologists or institutions may see enough patients with a particular type of cancer to develop their own standards of what constitutes good therapy, making the need for clinical trials seem less apparent.

Survivorship

Regardless of whether they participate in a clinical trial, pediatric patients make trip after trip to hospitals for treatment and follow-up, which essentially robs them of significant parts of their childhood. It is therefore not surprising that adult survivors of childhood cancers rarely want to relive their difficult past, and this reluctance can complicate the unique set of survivorship issues they face.

“I think sometimes kids who’ve spent years in the hospital, where the focus of their life was their cancer, don’t want to be constantly reminded of their cancer once they have been cured,” Dr. Lee said. “They just want to move on. It’s at least one reason that we don’t have very good long-term follow-up in survivorship clinics for former pediatric patients.”

Another problem facing survivors of pediatric cancers is health insurance coverage. A child’s cancer treatment is almost always covered by his or her parents’ insurance or by Medicaid. Until recently, many such patients lost their coverage in their late teens or early 20s and did not qualify for new plans because their cancers were considered to be preexisting conditions. Dr. Franklin said this has begun to change as provisions of the Affordable Care Act are taking effect.

Oncologists are well aware of the differences between adult and pediatric cancer patients and are making great strides toward narrowing these differences. One way that MD Anderson has done this is by establishing survivorship clinics (see OncoLog, January 2012). Dr. Franklin said that although cancer survivorship programs for children are quite common in the United States, survivorship programs for adult cancer patients are not. MD Anderson has made such an adult program a goal, creating survivorship clinics to help patients of all ages adjust to life after cancer treatment.

While differences remain in the treatment success rates for children and adults with cancer, clinical research and a focus on survivorship continue to benefit both groups of patients.

Common Childhood and Adult Cancers

In the United States, the most common cancers in children are:

  • leukemia,
  • brain and other central nervous system tumors,
  • neuroblastoma,
  • Wilms tumor,
  • lymphoma,
  • rhabdomyosarcoma,
  • retinoblastoma, and
  • bone cancer (osteosarcoma and Ewing sarcoma).

The most common cancer sites in adults are:

  • skin,
  • prostate,
  • breast,
  • lung and bronchus, and
  • colon and rectum.

Source: American Cancer Society.

For more information, contact Dr. Anna Franklin at 713-792-6620 or Dr. Dean Lee at 713-563-5404.

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