Survival rates for patients with testicular cancer reveal the disease as highly curable; there is more than a 95 percent survival rate in early-stage disease. However, in a small percentage of patients, the cancer may recur after an initial period of remission, which is known as a late relapse (LR), defined as a disease-free interval of 2 years. Published data on relapse is scarce due to factors involving selection bias, as well as incomplete follow-up data.
To discover more on this issue, researchers investigated the incidence of LR; very late relapses (VLR), which occur after a 5-year, disease-free interval; and extremely late relapses (ELR), which occur after a 10-year disease-free interval in patients with testicular cancer who have utilized the Cancer Registry of Norway and Norwegian Cause of Death Registry. They evaluated missed relapses past a 5-year follow-up scheme. The research, conducted by Torgrim Tandstad, MD, of St. Olav's University Hospital, Trondheim, Norway, was published in the Journal of Clinical Oncology (2022; doi: 10.1200/JCO.2022.40.16_suppl.5008)
The study included a total of 5,712 patients with testicular cancer who were diagnosed between the years 1980 and 2009 (2,978 seminoma and 2,734 nonseminoma). Comparing relapse rates more than 5 years after treatment over two time periods, the patients were further divided into 2,207 patients who were diagnosed from 1980 to 1995, as well as 3,505 patients diagnosed between 1995 and 2009. Details regarding diagnosis, stage, treatment, and follow-up were acquired from medical records. Kaplan-Meyer analysis determined the relapse rates.
Of the included patients, 472 experienced relapse: 186 were seminoma and 286 were nonseminoma. Of these, researchers found a low rate of LR (n=109; 23%), VLR (n=50; 10.5%), and ELR (n=17; 3.5%). LR occurred at a median of 4.7 years (range: 2.0-21.6). Of the relapses, 86 percent occurred within 5 years of follow-up and 14 percent occurred after 5 years.
In clinical Stage I patients, there were 306 relapses (7.9%), with LR occurring in 61 patients (1.9%), VLR in 29 (1.0%), and ELR in 10 (0.5%). Of the 61 patients with LR, eight deaths occurred, including four from testicular cancer (three nonseminoma and one seminoma). The investigators also observed a higher rate of late relapse in patients with Stage I disease who were followed with surveillance (n=1,380) as compared with those who underwent adjuvant therapy (n =2,619) (4.0% vs. 1.0%).
Among 1,713 patients with metastatic testicular cancer, 10.5 percent of patients experienced disease relapse. LR occurred in 3.6 percent of patients, VLR in 1.6 percent, and ELR 10 years in 0.8 percent. In patients with nonseminoma, the rate of VLR was 0.8 percent for those diagnosed after 1995 compared with 2.3 percent for those diagnosed earlier. Twenty-four deaths occurred in 48 patients having metastatic disease with late relapse, including 17 from testicular cancer or its treatment.
The 10-year overall survival (OS) and cancer-specific survival (CSS) rates for the whole unselected relapse population were 76.8 percent and 81.4 percent, respectively. With regards to OS after late relapse among patients with metastatic disease initially treated with chemotherapy, the 10-year OS rate following LR was 49.7 percent for those diagnosed from 1980 to 2009. The 10-year OS rate of patients diagnosed between 1995 and 2009 was 60.9 percent compared with 34.6 percent of patients diagnosed between 1980 and 1994. A similar pattern was observed for CS. The 10-year CSS rate increased from 38.6 percent for those diagnosed between 1980 and 2009 to 64.6 percent for those diagnosed in 1995-2009.
It is important to note this is a study abstract and more research is needed to confirm the findings and understand the underlying mechanisms of late relapses in testicular cancer. Also, the study is based on data from a national registry and may not be generalizable to other populations.
Taken together, in this first population-based series investigating late relapses of testicular cancer with complete data regarding treatment and follow-up, the investigators discovered a low rate of VLR in patients treated according to modern guidelines. The researchers concluded that the keys to improved outcomes are likely centralization of treatment, adherence to guidelines, prospective registration of patients, and subsequent reporting of results.
Moreover, study authors concluded that the broad definition of late relapse should not be used to identify patients as a unique entity with the worst prognosis, as exemplified by the good prognosis of patients with initial metastatic disease relapsing 2-5 years following initial treatment.
Dibash Kumar Das is a contributing writer.