Ultrasound viable for detecting germ cell tumor relapse

July 1, 2012

Results of a retrospective study provide evidence supporting the use of ultrasound as follow-up imaging to detect relapses in patients with germ cell tumors (GCT).

Chicago-Results of a retrospective study provide evidence supporting the use of ultrasound as follow-up imaging to detect relapses in patients with germ cell tumors (GCT), German oncologists recently reported.

The single-center study, which was presented at the American Society of Clinical Oncology annual meeting in Chicago, included 887 patients followed between January 2001 and November 2011. The follow-up protocol included a single computed tomography scan and chest x-ray at completion of treatment. Then, surveillance was done by abdominal ultrasound, physical examination, and measurement of serum lactate dehydrogenase and tumor markers (beta human chorionic gonadotropin and alpha fetoprotein) at intervals depending on tumor type and risk/stage. CT scan was only repeated if there was evidence of relapse by elevated tumor markers in the presence of a negative ultrasound. First author Arthur Gerl, MD, PhD, performed all of the ultrasounds.

The cohort represented a heterogeneous group in their baseline characteristics. At diagnosis, their ages ranged from <20 years to >50 years, although three-fourths of the men were between 20 and 39 years old. Nonseminona and seminoma tumors were represented about 2:1; slightly over half of the men had stage I disease at presentation, while 30% had stage II disease and about 15% had stage III GCT.

"There is currently no consensus on the best method for follow-up of GCT patients after they complete their initial management. However, abdominal imaging is important considering that about 80% of relapses occur in the abdomen and about half of those occur in the absence of increases in serum tumor markers. While some consider CT scans the gold standard, there is concern about secondary malignancies from cumulative radiation exposure and particularly given the relatively young age of these patients," he said.

"Our data suggest that ultrasound is a reasonable option for follow-up imaging, and its use would have benefits for reducing patient exposure to expensive and potentially harmful CT scans."

Extent of learning curve unknown

Dr. Gerl and colleagues suggested that prospective study is warranted to evaluate the performance of ultrasound follow-up and to try to understand the learning curve for performing the imaging.

"Based on my personal experience, I can attest that early detection of retroperitoneal recurrences with ultrasound depends on appropriate training and improves with cumulative experience.

"Currently, however, it is unclear how many ultrasound tests the examiner needs to perform to develop adequate skill for consistently performing high-quality examination," Dr. Gerl told Urology Times.

He explained that some early recurrences were missed on ultrasound at the beginning of the study. One such mass had a retrocaval location, which is not typically a site for GCT relapse.

"With increasing experience, physicians can gain greater expertise in knowing where to look for recurrences and in identifying smaller masses," Dr. Gerl said.