Fewer CT Scans May Suffice in Testicular Cancer Follow-up

Zosia Chustecka

April 16, 2007

April 16, 2007 — It may be possible to reduce the number of computed tomography (CT) scans in the first year of follow-up after orchidectomy for a type of testicular cancer, a new trial suggests.

The proposal comes from the United Kingdom Medical Research Council Trial TEO8, headed by Gordon Rustin, MD, from Mount Vernon Cancer Center, Northwood, Middlesex, and reported in the April 10 issue of the Journal of Clinical Oncology.

The trial was conducted in 414 patients with stage I nonseminomatous germ cell tumors, and the group reports that results for men who had 2 CT scans were similar to those who underwent 5 CT scans.

"CT scans at 3 and 12 months after orchidectomy should be considered a reasonable option in low-risk patients," they conclude.

The researchers note that reducing the number of CT scans would reduce the total radiation dose and hence would lower the risk for radiation-induced second tumors. They cite estimates that 5 whole-body CT scans could induce 1 second cancer in every 200 patients, which is equivalent to the mortality rate from stage I testis cancer.

Less frequent CT scans would also lower costs, adds an accompanying editorial, written by Ronald de Wit, MD, from the Erasmus University Medical Center, in Rotterdam, the Netherlands. He agrees that fewer CT scans as suggested by the researchers may be considered in a patient with a low risk for recurrence and a positive initial serum tumor marker who has a staging CT scan with no suspicion of nodal disease in the ipsilateral retroperitoneal landing zone.

However, the editorial criticizes several aspects of the trial and questions the wisdom of reducing surveillance in this "setting of curative oncology." It suggest that the "safest option remains keeping to the strict surveillance protocols, with reassessment investigations at regular intervals, as have evolved during the [past] 2 decades."

Trial Showed Noninferiority

The trial was designed to show noninferiority of the 2-scan schedule compared with the 5-scan schedule.

Results at Median Follow-up of 40 Months

Outcome
2 CT Scans, n (%)
5 CT Scans, n (%)
Relapses
37/247 (15)
33/167 (20)
Relapse with intermediate prognosis
2 (0.8)
1 (0.6)

No patient had a poor prognosis at relapse, and no deaths were reported. Dr. Rustin and colleagues comment that the trial supports a lack of benefit for more frequent CT scans.

One of the criticisms that the editorial levels at the trial is over the end point that was used — the number of relapses with an intermediate or poor prognosis at relapse. The difference between nonseminoma with a good and a worse prognosis depends merely on serum marker concentrations (which identify an intermediate prognosis) or on the presence of nonpulmonary visceral metastasis (which indicates a poor prognosis). "It is thus very unlikely that this end point can be used as a primary measure to guide us in determining whether intervals between CT scans can be increased," Dr. de Wit remarks.

The impact of postponing the CT scan would be better reflected by the size of retroperitoneal nodal disease at the time of detection, he comments. This was reported in the article, but the data are difficult to interpret, because most recurrences were detected at the 3-month evaluation point, and this was identical in the 2 groups. "It is doubtful that a noninferiority conclusion can be made on the basis of the few patients relapsing in each arm beyond 3 months," he comments.

The editorial points out that retroperitoneal nodal disease that grows and remains unchecked for several months would require surgery that could have been avoided if it had been detected earlier. Such surgery in just 1 or 2 patients "would completely nullify any cost savings from the reduced CT scan frequency," Dr. de Wit writes. Plus, it would be very difficult to confront a patient with a retroperitoneal mass at 12 months representing potentially lethal disease, when an extra scan at 6 months could have detected it when it was much smaller, he adds.

J Clin Oncol. 2007;25:1310-1315 , 1308-1309.

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