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Key Words

Testicular cancer; nonseminomatous germ cell tumors; computed tomography (CT). (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary.)

Summary

During the follow-up period after surgery, two computed tomography (CT) scans were just as effective as five CT scans in detecting relapse for patients with a certain kind of low-risk, early-stage testicular cancer.

Source

American Society of Clinical Oncology (ASCO) annual meeting, Atlanta, June 5, 2006 (see the meeting abstract).

Background

In men under 60, 95 percent of testicular tumors originate in the germ cells, the sperm-forming cells within the testicles. There are two types - seminomas and nonseminomas - that occur in about equal numbers and that differ in how they appear and spread.

Computed tomography (CT) scans are an important part of follow-up visits for men who choose surveillance instead of further treatment after surgery for stage I testicular nonseminomatous germ cell tumors (NSGCT). But since CT scans are costly and deliver a substantial amount of radiation to the body, it’s important to determine the minimum number of postoperative CT scans needed to safely follow patients.

The Study

Between 1998 and 2003, researchers from 32 centers in the United Kingdom, Norway, Australia, and New Zealand enrolled 414 patients with low-risk, stage I testicular NSGCT in this phase III trial. In consultation with their doctors, the patients had decided to forgo further treatment after surgery.

Patients were randomly assigned to follow-up routines containing either two abdominal CT scans (at three and twelve months after surgery) or five abdominal CT scans (at three, six, nine, twelve, and twenty-four months after surgery). For statistical reasons, more patients were needed in the two-scans group (247) than in the five-scans group (167).

All other surveillance tests, including chest x-rays, physical examinations, and blood tests, were performed with equal frequency in the two groups. Follow-up visits occurred monthly during the first year, every other month during the second year, and every three to six months thereafter. The investigators recorded the stage of disease at relapse for any patient whose cancer recurred. They also compared overall survival, what type of test first detected relapse, and the time to diagnosis of relapse between the two groups.

The trial was a cooperative effort of the Testis Cancer Clinical Studies Group, part of the United Kingdom’s National Cancer Research Institute. The study’s lead author is G.M. Mead, D.M., from the Mount Vernon Cancer Centre in Middlesex, England.

Results

At a median follow-up of 40 months, the investigators had detected 37 relapses (15 percent of patients) in the two-scans group and 33 relapses (20 percent of patients) in the five-scans group. Recurrent tumors were approximately the same size at detection in both groups, and showed up in similar locations.

Importantly, the investigators found that patients in the two-scans group were no more likely to be diagnosed at relapse with an intermediate- or poor-prognosis tumor than was the more frequently scanned group – that is, fewer scans did not allow more serious disease to occur unnoticed. No deaths were reported in either group.

(Note: final results from the trial were subsequently published in the April 10, 2007, Journal of Clinical Oncology; see the journal abstract.)

Comments

Because there was no evidence that relapses were detected earlier in the five-scans group, said Mead, “there is no clear advantage to more-frequent CT scans in follow-up” of patients with early-stage, low-risk disease.

“In properly selected patients this appears to be a reasonable surveillance strategy,” agreed James Gulley, M.D., Ph.D., from the National Cancer Institute’s Center for Cancer Research.

Limitations

The patients enrolled in the trial were at a lower risk of relapse than the average patient with testicular NSGCT, explained Mead during the ASCO presentation. About 40 percent of all patients with testicular NSGCT have tumors that have spread to the blood vessels (called vascular invasion), which pose a higher risk of recurrence. Only 10 percent of patients in this trial had tumors with vascular invasion.

This limitation was also highlighted by NCI’s Gulley, who stated that “given the low numbers of patients with high-risk disease in this study, the results should not be used to make recommendations” for higher-risk patients.

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