The Many Levels of Personalized Pediatric Oncology Treatment
Jeffrey D.Hord, MD, Editorial Board Member, Pediatrics in Review
The term “personalized medicine” is used frequently today throughout medical publications
and in marketing materials and can be defined in a variety of ways. Most often, we
think of personalized medicine as the relatively new process of sequencing tumor DNA
and then trying to identify a new agent to target the identified genetic mutation.
However, I think of the personalization of childhood cancer treatment as starting
5 or 6 decades ago and continuing to evolve today.
Treatment was first targeted to the histology of the tumor and then to the disease
stage or risk group. Many factors are considered when determining a patient’s risk
group, and these factors may include the physical location of the tumor, the age of
the patient, and prior therapy. Beyond the impact age may have on risk group, the
age of the patient should also be taken into consideration when developing a treatment
plan and consulting services for patient support. As Drs Allen-Rhoades, Whittle and Rainusso1 note in their overview of pediatric solid tumors, treatment of cancer in an adolescent or young adult patient is not likely to be
successful unless accompanied by specialized support services.
Another level of personalization of treatment occurs when modifying chemotherapy doses
based on toxic side effects. Currently, we most often assess the patient’s rate of
metabolism in a rudimentary fashion by prescribing a standard dose of chemotherapy
and then changing the dose based upon how the patient tolerates it. We are beginning
to understand the genetic basis for this variation in metabolism, and I suspect in
the near future we will be able to assess a patient’s ability to metabolize a certain
medication through genetic testing and use this information to customize dosing from
the onset of therapy.
In the Index of Suspicion discussion of a 6-year-old boy with sickle cell disease who was also diagnosed with Hodgkin
lymphoma, Drs Zaidi, Henry and Callaghan3 note that the duration and intensity of therapy may be personalized based on an individual
patient’s response to therapy. The duration of therapy for Hodgkin lymphoma is influenced
by how long it takes for a patient’s PET scan to become negative. This individualized
response-based therapy has allowed for both continued excellent outcomes as well a
reduction in treatment-related toxicity. Such response-based treatment planning has
also become standard in the treatment of other malignancies.
So, while we have moved into the age of molecular characterization of tumors and are
starting to use this “fingerprint” to influence treatment recommendations, this is
not the start of personalized medicine in pediatric oncology; it is just the next
level of personalization.
Allen-Rhoades W, Whittle SB, Rainusso N. Pediatric Solid Tumors in Children and Adolescents:
An Overview. Pediatr Rev. 2018 Sept;39(9):444-452. doi: 10.1542/pir.2017-0268.