Family History of Cancer Increases Risk
Researchers found that a survivor of Hodgkin lymphoma has a 2.4-time greater risk of developing a second cancer of any type than the risk of developing cancer for an age and sex-matched person in the general population. This increased risk could remain elevated for 30 years.
However, the most significant factor in the risk of developing a second cancer is whether the survivor has a family history of cancer. In this study, almost one-third of the participants who had Hodgkin lymphoma had at least one first-degree relative who had had cancer. If that relative had lung cancer, the survivor’s risk of developing lung cancer specifically was 3.5 times greater than that of someone without a close relative with lung cancer. In a similar manner, patients with Hodgkin lymphoma with a family history of colorectal or breast cancer had double the risk of developing those cancers themselves. Interestingly, the number of relatives with cancer correlated with the degree of risk of developing second cancers in the Hodgkin lymphoma survivors. If a patient with Hodgkin lymphoma had 2 or more first-degree relatives who had cancer, the risk of developing a second cancer was more than tripled.
With regard to lung cancer, the researchers demonstrated “a greater than additive interaction” between a family history of lung cancer and treatment for Hodgkin lymphoma. They suggest that this might be the result of additional “nongenetic risk factors” such as smoking in the family.1 This finding is important, since it could be the reason that lung cancer still carries the highest risk, even though treatment now involves less radiation therapy. The solution to this problem may be to establish more vigorous programs to reduce smoking in patients with Hodgkin lymphoma.
Age at Diagnosis Is a Factor
The risk of developing a second cancer was also related to the patient’s age at diagnosis — the younger the patient was, the greater the risk. If a woman was younger than 35 years at Hodgkin lymphoma diagnosis, she had a 14% risk of developing breast cancer, and that risk persisted for 30 years. If she was older than 35 years at diagnosis, her second cancer risk was only 3%.
A Note of Caution
The researchers concluded that since the majority of patients with Hodgkin lymphoma are cured of the disease, they no longer see an oncologist. However, since they are at increased risk for developing second cancers, the clinicians these survivors do see should monitor them for sequelae and initiate preventive treatment as necessary.
1. Sud A, Thomsen H, Sundquist K, Houlston RS, Hemminki K. Risk of second cancer in Hodgkin lymphoma survivors and influence of family history. J Clin Oncol. 2017 Mar 13. doi: 10.1200/JCO.2016.70.9709 [Epub ahead of print]