The substantially elevated risk for various solid tumors extends to 40 years and beyond after childhood Hodgkin lymphoma (HL), a large, ongoing cohort study indicates.
The new study extends the follow-up of the multinational Late Effects Study Group (LESG) cohort, which was established in 1979. This study followed children and adolescents (≤16 years) who were diagnosed with cancer between 1955 and 1979 and included 1136 patients with HL.
The median follow-up is now 26.5 years, which is a substantially longer period since the last update in 2001, when the median follow-up was 17 years.
The study was published online December 17 in Cancer.
The news about secondary cancers after childhood HL continues to be sobering.
The cumulative incidence of any solid subsequent malignant neoplasm (SMN) was 26.4% 40 years after a diagnosis of HL, report the authors, led by Smita Bhatia, MD, MPH, of the University of Alabama at Birmingham.
In the cohort of HL patients, 162 patients had a total of 196 solid SMNs.
These individuals have a 14-fold increased risk of developing a solid SMN compared with the general population, say Bhatia and colleagues.
"Pediatric Hodgkin lymphoma survivors are at a high risk for subsequent solid tumors. This high risk persists for decades," summarized Bhatia in an email to Medscape Medical News.
Receiving radiotherapy was associated with each of the four most common subsequent solid tumors, those of the breast, lung, colon, and thyroid.
"The treatment for pediatric Hodgkin lymphoma has definitely changed. For example, the dose of radiation has been reduced, as has the field of radiation," Bhatia commented.
The individuals in the current cohort were treated with larger doses of radiation than are used now. The study shows that a patient's age and the area of the body that was exposed to radiation were associated with later elevated risk for secondary cancer.
The authors note that risk factors for breast cancer among women were an HL diagnosis at age 10 to 16 years and treatment with chest radiotherapy. Men who were treated with chest radiotherapy when they were younger than 10 years had the highest risk of developing lung cancer.
Patients who had been treated with abdominal/pelvic radiotherapy and high-dose alkylating agents had the highest risk of developing colorectal cancer.
Women who were exposed to neck radiotherapy when they were younger than 10 years had the highest risk for thyroid cancer.
By age 50 years, the cumulative incidence of breast, lung, colorectal, and thyroid cancer was 45.3%, 4.2%, 9.5%, and 17.3%, respectively, among those at highest risk, report the authors.
Breast Cancer 34 Years After Treatment
A press statement from the journal included a comment from a childhood HL survivor who is now a physician and who developed radiotherapy-related breast cancer 34 years after treatment.
"I cannot emphasize enough the importance of these data for the long-term care of survivors, as they not only underscore the necessity of lifelong cancer screening in that population, but also provide a stratification of risk for specific malignancies within subgroups, allowing for a more targeted approach to screening," said Allison Thompson-Graves, MD, who was not involved with the study and was not identified by specialty or location.
Bhatia echoed these words in her comments.
"There are well-developed screening guidelines that should be followed for early detection of those at highest risk of these solid tumors," she said.
Exposure-based and risk-based screening guidelines are available through the Children's Oncology Group.
More Illuminating Data
The study authors provide details of subsequent cancer risk in HL survivors.
For example, the risk for breast cancer in female survivors of HL is 25.8-fold greater than that of the general population; the cumulative incidence among survivors exceeds 20% at 40 years from the time of the diagnosis of HL and exceeds 25% by age 50 years.
The incidence of breast cancer starts to increase at age 25 years, the authors say, and remains elevated at least until age 50 years.
The new article also provides screening advice regarding each of the most common solid tumors. For breast cancer, the authors say: "Taken together, these findings provide additional evidence for initiating surveillance at either 8 years after the diagnosis of HL or at age 25 years, whichever occurs later."
Other studies are following survivors of childhood HL, observe the current study authors. However, the LESG cohort has a unique wrinkle in its follow-up, they say. The cohort includes therapeutic exposures from the time of a diagnosis of HL until the development of the index SMN (including exposures for the management of HL recurrence).
"To our knowledge this differs from the other cohorts that were limited to therapeutic exposure surrounding the initial diagnosis or to the first 5 years after diagnosis," they write.
No funding for the study has been reported. The authors have disclosed no relevant financial relationships.
Cancer. Published online December 17, 2018. Abstract
Medscape Medical News © 2018
Cite this: After 40 Years, 26% of Pediatric HL Survivors Have a Solid Tumor - Medscape - Dec 18, 2018.