Survivors of childhood Hodgkin lymphoma have a 14-fold greater risk for second cancers, compared with the general population, according to newly published data.

The subsequent malignant neoplasms (SMNs) tend to follow specific patterns depending on the patient’s age at treatment, sex, treatment modality, and body region treated.

And although the risk of SMNs appears to be somewhat lower for patients treated in more recent decades, it is still significantly elevated, compared with that of the general population, according to Anna S. Holmqvist, MD, PhD, from Lund University (Sweden), and her colleagues.

“A major goal of the current study was to develop evidence with which to guide the screening of survivors of HL for the development of [solid] SMNs,” the investigators wrote in Cancer.

They examined at data from the Late Effects Study Group, a multinational cohort of patients aged 16 years or younger who were treated for Hodgkin lymphoma and other cancers from 1955 to 1986.

The current report is the third update from an expanded cohort, including data on 1,136 patients with a median follow-up of 26.6 years. The median patient age at diagnosis was 11 years and the patients were followed for 23,212 person-years following the Hodgkin lymphoma diagnosis.

In all, 162 patients developed a total of 196 solid SMNs, including breast cancer in 54 patients, basal cell carcinoma in 34 patients, thyroid cancer in 30, colorectal cancer in 15, lung cancer in 11, other malignancies in 40, and disease site not available in 12 patients.

The cumulative incidence of any solid SMN 40 years after a diagnosis of Hodgkin lymphoma was 26.4%. The standardized incidence ratio for the entire cohort was 14.0, compared with the general population as derived from the Surveillance, Epidemiology and End Results database.

Predisposing factors for breast cancer in females included a Hodgkin lymphoma diagnosis from the ages of 10-16 years, and treatment with radiotherapy to the chest.

The patients at highest risk for subsequent development of lung cancer were males treated with chest radiotherapy before age 10 years. Those at highest risk for colorectal cancer were males and females who had received abdominal/pelvic radiotherapy and high-dose alkylating agents. Patients at highest risk for thyroid cancers were females who had been treated with radiotherapy to the neck before the age of 10.

The cumulative incidence for breast cancer by age 50 years for those at highest risk was 45.3%. The respective cumulative incidences for lung, colorectal, and thyroid cancers by age 50 were 4.2%, 9.5%, and 17.3%.

The investigators noted that patients treated more recently are likely to have received lower doses and volumes of radiotherapy, compared with patients treated in 1970s and earlier. “However, for the cohort of patients treated between 1955 and 1986, it is clear that continued surveillance for [solid] SMNs is essential because their risk continues to increase as these survivors enter their fourth and subsequent decades of life.”

No specific funding source for the study was reported. The authors made no financial disclosures.

SOURCE: Holmqvist AS et al. Cancer. 2018 Dec 17. doi: 10.1002/cncr.31807.