Susan Guisto and Judith G. Villablance, MD, Children’s Hospital Los Angeles wrote an article on Delayed diagnosis

Every year, approximately 1 in 10,500 children from birth to 15 years of age are diagnosed with cancer in the United States. Most pediatricians will likely encounter only one to three cases throughout their professional lifetime. Even though a pediatrician may never see a case of cancer in his or her practice, it is important to understand what to look for, how to evaluate patients and to ensure follow-up and timely referrals to specialists. As a result, pediatricians can play a critical role in minimizing delayed diagnoses to give patients the best possible outcomes.