HPV Vaccine Important Preventive Tool for Survivors of Childhood Cancer
As childhood cancer survivors are at an increased risk of developing second cancers later in life, James Klosky recommends that this population receive the human papillomavirus (HPV) series of vaccines.
A survey of 679 survivors one to five years out of treatment was conducted to evaluate how many received the vaccine compared with their healthy peers. A great disparity was discovered, as survivors — all of whom were between age 13 and 26 — were less likely to receive the vaccine. Researchers also investigated the reasons why many survivors did not receive it.
Klosky, an associate member and director of psychological services in cancer survivorship at St. Jude Children’s Research Hospital, presented the findings from this research at the 2016 Annual Meeting of the American Society of Clinical Oncology (ASCO), a gathering of 30,000 oncology professionals in Chicago. CURE spoke with Klosky at the meeting to discuss the key takeaways and the importance of the HPV vaccine to survivors of childhood cancer.
Can you give an overview of the study and its purpose?
The HPV vaccine is the first vaccine that’s designed to prevent cancers. We are particularly interested in the application of this vaccine amongst survivors of childhood cancers, who are at increased risk for HPV-related cancers in young adulthood relative to their healthy peers.
On average, the onset of these cancers occur seven years earlier in survivors of childhood cancers compared to their healthy peers. Additionally, survivors of childhood cancer have an increased risk of acquiring a second cancer. Therefore, the application of this vaccine is very important. We at St. Jude Children’s Research Hospital do everything we can to protect our survivors from second cancers, and the HPV vaccine is one mechanism we are able to utilize.
Why are second cancers more likely in survivors of childhood cancer?
As a general population, 80 percent of people who are sexually active will be exposed to HPV in their lifetime. For those of us who have a strong immune system, the virus will typically clear out of our systems in approximately two years. Often, there will not be any symptoms. However, for survivors of childhood cancers and other groups that have immune deficiencies, it appears they might be more likely for complications associated with HPV upon infection.
What did this study specifically find? What are the key takeaways?
This study compared survivors of childhood cancer with their peers in the U.S. We analyzed the rates of initiation of the HPV vaccine amongst survivors and then of the U.S. population, focusing on two different groups: those who are 13 to 17 years of age and those who are 18 to 26 years of age.
Within the 18 to 26 age group, the rates of the HPV vaccine initiation were essentially equivalent; 26 percent of survivors had initiated the vaccine whereas 24 percent in the general population had initiated it.
However, there were differences in the 13 to 17 age groups. Among survivors of childhood cancers, only 22 percent had initiated the vaccine compared with 42 percent of the general population.
It is important to note that the HPV vaccine is designed to be administered prior to sexual activity. It is important to get vaccinated as a young teenager because the HPV vaccine is protective, not therapeutic. Therefore, once a patient is exposed to the virus, there is not much we can do about it.
Among survivors of childhood cancers, were there predictors of not initiating the vaccine?
We found the most robust predictor was among survivors who stated their doctors had not recommended the vaccine. And essentially, one of the main messages here is that we really need our physicians to be recommending the vaccine because that should translate into a higher initiation rate.
Another strong influence against receiving the vaccine was hearing about it from a friend. Adolescents often talk about the negative aspects of the vaccine, such as the pain involved when receiving the vaccine and the fact that three vaccines are necessary to complete the protection. Hearing this does not encourage other adolescents to initiate the vaccine.
We also found those who are male and those who had never been sexually active are also more likely not to initiate the vaccine. That’s a bit concerning because although HPV is typically implicated in terms of cervical cancers and a lot of the gynecological-associated cancers, men can also have oropharyngeal cancers, anal cancers, penile cancers and other types of cancers within HPV ideology. Additionally, males are often the carriers.
Finally, those who do not feel receiving the vaccine makes you a responsible or good person are less likely to receive it.
What are the next steps for this project?
Overall, the lack of physician recommendation was most strongly associated with not initiating. Our next step in the research is to create intervention programs to get physicians to make clear recommendations with conviction and confidence to survivors of childhood cancer. This will hopefully translate into more survivors getting protected.
Is there ever a reason to refrain from receiving the HPV vaccine?
The indication of the vaccine is very broad. For survivors of childhood cancer who have had a particularly complex treatment history and are continuing to have severe late effects of childhood cancer, a conversation needs to happen between their oncologist, the family and the patient.
In terms of vaccine programs, they are designed as more of a public health tool; the vaccines should be safe for everyone. If there are any concerns about the vaccine, we want you to talk to your doctor.
Regardless of the direction of the effect, increasing these types of communications will hopefully translate to the best health care for our patients.
What are your hopes for this project?
If we are able to demonstrate the immunogenicity, safety and tolerability of the HPV vaccine among survivors of childhood cancer, we’ll have a platform for a vaccine program within this high-risk group. Protecting survivors from second cancers in any way we can is the ultimate goal. There’s not much I can do about patients’ genetics or other fixed factors, but getting the vaccine is something, behaviorally, I can influence. If I, my group or the consumers of this research have influenced conversations that translate into initiating and completing the three-vaccine series, then this research has been successful.