Treatment-Related Second Cancers
Treatment-related second cancers (SEER)
It is estimated that more than 10 million cancer survivors are currently alive in the United States, which has led to an increasing focus on the long-term outcome of cancer treatment. REB has a long-standing interest in cancer survivorship research, particularly the role of radiation, chemotherapy, and hormonal treatments in second cancer risk. REB investigators in collaboration with other researchers monitor NCI’s Surveillance, Epidemiology, and End Results (SEER) cancer registry database to assess patterns and trends in the occurrence of second primary cancers. The overall objective is to identify cancer survivors who appear to be at increased risk for developing second primary cancers. These survivors can then be targeted for increased surveillance and primary and secondary prevention strategies.
To facilitate research into the etiology of second cancers, REB has led the development of an interactive PC-based software module (“SIR”) to perform analyses of multiple primary cancers using NCI’s SEER database. The analysis module was added to the SEER*Stat program, a publicly available software package created by NCI that calculates SEER incidence, mortality, and survival rates (http://seer.cancer.gov/seerstat/). The multiple primary cancer module calculates standardized incidence ratios by second cancer site, histology, treatment, sex, race, calendar year, age, time since diagnosis, and registry. REB researchers have used this new software tool to evaluate the risk of second cancers in SEER for several sites, including initial cancers of the uterine corpus and lymphomas, and for childhood cancers, the latter described in more detail below.
Opportunities for addressing second cancer risks in large populations of childhood cancer survivors followed over many years are rare. To quantify risks for developing new malignancies among childhood cancer survivors in the general population, identify links between particular types of first and subsequent cancer, and address the possible role of treatments, REB investigators evaluated the incidence of subsequent primary cancers in a SEER cohort of over 25,000 survivors of childhood cancer during 1973-2002. Survivors were at nearly 6-fold risk of developing a new cancer relative to the general population with a cumulative incidence of second cancers after 25 years of 3.6%. Most common were subsequent primary cancers of the female breast, brain, bone, thyroid gland, and soft tissue, as well as melanoma of the skin and acute non-lymphocytic leukemia. Because SEER includes large numbers of patients diagnosed in recent calendar years, researchers were able to evaluate the late effects associated with newer childhood cancer therapies, showing that the risk for secondary leukemia increased with increasing calendar year of initial cancer diagnosis among survivors of bone or soft tissue sarcoma and non-Hodgkin lymphoma but decreased among Hodgkin lymphoma survivors. Continued follow-up of this large childhood cohort will be critical to determine how the high relative risks seen for solid cancers through adolescence and early adulthood carry through into older ages, when incidence rates of carcinomas increase dramatically.
Opportunities exist for post-doctoral fellows to propose novel analyses of the SEER data to investigate treatment-related second cancers.
Post-doctoral research opportunities
