Research from Oxford University reveals that there is insufficient evidence to support the use of tumor markers for detecting the recurrence of testicular cancer in patients who have undergone surgery for an initial tumor.1
Testicular cancer is considered highly curable, with more than 98% of men who have undergone treatment living for more than 10 years. However, the incidence of testicular cancer is increasing: in the UK, 7 out of every 100,000 men are diagnosed with the condition each year, and most are aged under 35. The number of relatively young survivors means that ongoing surveillance for recurrent disease is particularly important.
Brian Nicholson, University of Oxford.
To assess the performance of biomarkers in diagnostic tests for testicular tumors, researchers performed a systematic review of data from more than 1,200 patients collected by nine different research studies. The studies assessed three biomarkers that are currently cited in European guidelines on surveillance for testicular cancer recurrence: blood ?-fetoprotein (AFP), human chorionic gonadotropin (HCG), and lactate dehydrogenase (LDH).
The results of the nine studies were mixed. While two of the markers (AFP and HCG) showed some diagnostic potential, many recurrent tumors would be missed using these markers alone.
The Oxford review thus highlights the importance of using diagnostic strategies that also incorporate clinical examination and imaging, rather than relying solely on the results of biomarker tests.
“There’s a lot of debate about how to make sure patients are followed up safely after treatment for cancer, to make sure that cancer is detected as soon as possible if it comes back,” explains Brian Nicholson, GP, a clinical researcher in primary care health sciences at the University of Oxford. “Important questions include what tests to do, how often they should be taken and, importantly for us, whether they could safely be done in general practice.”
Thomas Fanshawe, University of Oxford.
Many of the studies included in the review were small, and some studies concentrated on just one tumor type, which makes the results difficult to generalize. The researchers report that there is little evidence to support the threshold values currently used to signify whether a biomarker is elevated above the normal range. For these reasons, the review authors assessed the quality of several of the studies as low.
“What this review tells us is that there is great uncertainty over the current best use of blood tests when following up patients who have survived testicular cancer, so it would be difficult to give GPs clear guidance,” says Nicholson. “There are many patients being followed up right now in the UK and abroad—we should find smart ways to combine their data to inform best practice.”
“This review demonstrates how difficult it can be to perform rigorous evaluations of diagnostic biomarkers,” adds Thomas Fanshawe, PhD, a senior medical statistician at the University of Oxford. “Although not intended as a replacement for clinical experience, our results suggest there is more work to be done to decide how tumor markers can best be used in surveillance strategies for detecting recurrent disease.”
Reference
- Nicholson BD, Jones NR, Protheroe A, et al. The diagnostic performance of current tumor markers in surveillance for recurrent testicular cancer: a diagnostic test accuracy systematic review. Cancer Epidemiol. 2019;59:15–21; doi: 10.1016/j.canep.2019.01.001.
