Secondary Cancer Risk Doubles for Adolescent and Young Adult Survivors

Researchers reported that individuals who survived cancer during adolescence and young adulthood face a risk of developing a new, different cancer that is twice as high as the general population.

The study, which analyzed the health outcomes of 24,459 patients over more than 30 years, aimed to quantify the long-term risks associated with a cancer diagnosis between the ages of 15 and 39. This research provides a comprehensive look at the health challenges these survivors may face decades after their initial treatment, highlighting that approximately one in six survivors developed a subsequent primary neoplasm within 30 years.

Main data that support the findings

The study found that among the 24,459 people who had cancer in adolescence and young adulthood, 1,442 developed at least one subsequent primary neoplasm. For those who survived at least five years after their initial diagnosis, the risk of developing a new cancer was two times higher than what would be expected in the general population. This equates to 35.7 excess cancer cases for every 10,000 person-years of follow-up.

The cumulative incidence of a subsequent primary neoplasm reached 17.7% at 30 years postdiagnosis for five-year survivors, which was significantly higher than the expected 11.2% in the general population. The risk was highest among survivors of specific initial cancers. Those originally diagnosed with cancer of the oral cavity, lip or pharynx had a 30-year cumulative incidence of 28.9%. Survivors of breast cancer followed closely at 27.3%, while those who had colon cancer or Hodgkin lymphoma faced risks of 23.5% and 22.7%, respectively.

Researchers noted that the types of new cancers discovered were most frequently breast, digestive, hematopoietic or respiratory cancers. Specifically, among five-year survivors who developed a new cancer, 28.4% were diagnosed with breast cancer, 12.8% with digestive organ cancers, 8.7% with hematopoietic system cancers and 8% with respiratory organ cancers.

Demographic data showed that individuals who developed a subsequent primary neoplasm were more likely to be female, older at the time of their first diagnosis and originally diagnosed with breast cancer. For the overall group that developed a subsequent cancer, 65.3% were female and 46% were between the ages of 35 and 39 at the time of their first diagnosis. The risk also varied by sex; while male survivors had a significantly higher standardized incidence ratio than females, the absolute burden of excess cancers was comparable between the two groups.

Trial details

The Alberta Adolescent and Young Adult Cancer Survivor Study was a retrospective, population-based cohort study. It included all individuals in the province of Alberta, Canada who were diagnosed with a first primary neoplasm between Jan. 1, 1983 and Dec. 31, 2017. To be included, patients had to be between the ages of 15 and 39 at the time of their initial diagnosis.

The researchers used the Alberta Cancer Registry to identify participants and track outcomes. The study excluded nonmelanoma skin cancers and in situ tumors, with the exception of in situ bladder cancers. For the purpose of this research, a subsequent primary neoplasm was defined as a new invasive cancer that met specific coding rules, ensuring that disease recurrence or progression was not counted as a new cancer.

Follow-up for participants continued until they developed a subsequent primary neoplasm, emigrated, died or reached the study end date of Dec. 31, 2017. The median follow-up time for the entire group was 7.4 years, but the study included data for up to 30 years of follow-up to capture long-term effects.

Safety

The study identified that certain treatment regimens were associated with a higher risk of late effects. Specifically, initial treatment plans that included radiotherapy generally resulted in the largest absolute excess risks for new cancers. Among survivors of Hodgkin lymphoma, there was a higher incidence of digestive organ cancers, which the researchers linked to the established effects of subdiaphragmatic radiation. Similarly, the risk of endocrine, respiratory and breast cancers was higher in Hodgkin lymphoma survivors, suggesting that chest irradiation can affect multiple organs years after the initial therapy.

The findings also highlighted that subsequent cancers in these survivors often appear at a much younger age than in the general population. In Canada, the median age for a breast cancer diagnosis in the general population is 62 years, but for survivors of adolescent and young adult cancer, the median age for a subsequent breast cancer was 48.1 years. A similar trend was seen in colorectal cancer, diagnosed at a median of 50.2 years in survivors versus 70 years in the general population, and lung cancer, diagnosed at 58.4 years versus 72 years.

While treatment exposures are considered a primary contributor to these risks, researchers also noted that genetic and lifestyle factors play a role in the development of subsequent cancers. Because of the increased risk and the younger age of onset, the study suggests that earlier, risk-based screening and specialized survivorship care plans may be necessary for this population.

Editor's note: This article is for informational purposes only and is not a substitute for professional medical advice, as your own experience will be unique. Use this article to guide discussions with your oncologist. Content was generated with AI, reviewed by a human editor, but not independently verified by a medical professional.

References

“Subsequent primary neoplasm risk among survivors of cancer in adolescence and young adulthood: a population-based study from Alberta, Canada” by Dr. Arafat UI Alam et al., Canadian Medical Association Journal.

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