(UroToday.com) The 2024 ESMO annual meeting included a session on testicular cancer, featuring a presentation by Dr. Deep Chakrabarti discussing the Late CT study assessing the utility of CT scans in the long-term follow-up of metastatic non-seminomatous germ cell tumors (NSGCT). Most patients with metastatic NSGCT are cured by platinum-based chemotherapy.
However, a small proportion relapse usually in the first two years, and late relapses can occur with an estimated rate of up to 0.5-1% per year. Late relapses, often due to a chemotherapy-resistant residual teratoma differentiation, highlight the importance of early detection to allow earlier surgical interventions and improve prognosis. Dr. Cakrabarti and colleagues hypothesized that screening metastatic NSGCT patients with ‘late CT scans’ could detect residual/recurrent disease at a treatable stage and reduce the risk of late relapses.
This prospective diagnostic study recruited patients with metastatic NSGCT (RMH stage II-IV) who completed treatment 5-10 years prior to entry and had a CT scan with no evidence of disease following chemotherapy at least 3 years prior. All patients underwent a CT scan of the thorax, abdomen, and pelvis upon entry to the study. Patients with a negative CT had annual follow-ups and a repeat CT at 5 years. Patients with equivocal CTs had a repeat CT in 6 months. The primary endpoint was the rate of CT-detected abnormalities due to NSGCT on initial scan. The following shows the Swimmer plot showing patient follow-up post-initial scan:
There were 195 patients recruited between 2006 and 2021, with the final analysis comprising 192 patients. The median age was 36 (IQR 31-43) years and 93% of patients had a testicular primary malignancy. The primary histology included 47% mixed GCT and 31% embryonal. Primary chemotherapy included BEP (76%) and CBOP-BEP (14%). Overall, 90 (47%) patients underwent surgery, demonstrating mature teratoma (52%) and necrosis/fibrosis (24%). There were 187 patients that underwent an initial CT: 167 were read as normal, 14 equivocal, and 6 abnormal. Recurrence was confirmed in 4 patients with abnormal CT and 1 patient with equivocal CT. The rate of CT-detected abnormality on initial scan was 5/187, 2.67% (95% CI 0.87, 6.13), with a false positive rate of 33%. The following shows the Swimmer plot with recurrence at initial CT scan (n = 5):
The median follow-up since initial scan was 5 years (IQR 4.1-5.1). There were 122 patients that underwent a 5-year CT, which was equivocal in 7/122 but no confirmed recurrence. The rate of CT-detected abnormality at 5-year scan was 0%. Of five patients with a recurrence on initial CT, two had at least a further recurrence (2/5, 40%, 95% CI 5.3%-85.3%). Of 182 patients who were recurrence-free on initial CT, 2/182 had a recurrence within the study period, 1.1% (95% CI 0.13, 3.91). The 5-year overall survival was 97% (95% CI 92-99) and the recurrence-free survival was 99% (95% CI 95-100):
Dr. Chakrabarti concluded his presentation discussing the Late CT study assessing the utility of CT scans in the long-term follow-up of metastatic non-seminomatous germ cell tumors with the following take-home points:
- A late follow-up CT at 5 years post-treatment detects a small but significant number of recurrent germ cell tumors
- Recurrence after a negative late CT is low and further imaging may not be warranted
Presented by: Deep Chakrabarti, MD, Royal Marsden NHS Foundation Trust, Sutton, UK
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2024 European Society of Medical Oncology (ESMO) Annual Meeting, Barcelona, Spain, Fri, Sept 13 – Tues, Sept 17, 2024.