Repeated CT scans of testicular cancer patients are associated with an increased number of secondary cancers among older men, concludes a new study from the University of California, Davis.
CT surveillance of stage I testicular cancers was adopted in the 1980s, when the alternative was surgical removal of the retroperitoneal lymph nodes or chemotherapy, according to the authors.
Younger men in particular feared the potential side effects of surgery or chemotherapy such as ejaculatory dysfunction, bowel adhesions, neuropathy, and other problems, wrote radiology resident Karim Chamie and colleagues in a statement accompanying the release of the study in Cancer (March 15, 2011).
Testicular cancer patients are typically offered three treatment choices following orchiectomy: two doses of chemotherapy, lymph node dissection, or active surveillance, which requires frequent CT scans. National Comprehensive Cancer Network guidelines recommend a total of 15 CT scans in the first five years after surgery to check for new signs of disease.
The retrospective analysis used data from the Surveillance, Epidemiology, and End Results (SEER) database, which included 7,301 men diagnosed with nonseminomatous germ cell tumor (NSGCT) between 1988 and 2006.
The patient cohort was stratified based on whether patients underwent retroperitoneal lymph node dissection. Data were adjusted for covariates using a propensity-scale model, and competing-risks regression analysis was used to estimate cumulative incidence rates per 10,000 patients to predict incidence ratios.
The results showed that more NSGCT patients who have been on active surveillance are diagnosed with secondary malignancies after 15 years than patients receiving aggressive lymph node surgery or chemotherapy.
However, when the analysis was restricted to patients with clinical stage I NSGCT, surveillance only in patients older than 45 years was an independent predictor of developing a second malignancy. For every 10,000 patients with stage I NSGCT who skipped lymph node dissection, "an absolute excess incidence of 22, 52, and 73 secondary malignancies would be diagnosed at five years, 10 years, and 15 years, respectively," the authors wrote in an abstract.
Statistical analysis showed that for every 10,000 patients on active surveillance, 306 would get secondary malignancies, compared with 233 cases if treated with surgery alone -- an increase of 75 malignancies when CT surveillance was included. Fully 30% of patients on active surveillance will go on to develop additional cancers that were not detected on CT scans.
