精巣摘出術後はサーベイランスで十分である （Abstract # 4502）

A long-term study of men with stage I seminoma, a common form of testicular cancer, suggests that surveillance for cancer recurrence, rather than additional chemotherapy or radiation therapy, is sufficient for the vast majority of men who have undergone successful surgery for their cancer. Researchers found that 99.6 percent of patients who underwent surveillance only were alive 10 years after their initial diagnosis.

Surveillance entails five years of scheduled physical exams, chest X-ray exams, CT scans and blood tests. In Denmark, where this study was conducted, surveillance is the follow-up strategy of choice. Avoiding additional treatments spares patients of associated harmful side effects, such as a potential risk of secondary cancers, including gastrointestinal cancers and leukemia, following radiotherapy.

"To our knowledge, this study is the largest to address this issue in patients with stage I seminoma, and with the longest follow-up. Now we have solid proof that surveillance is safe and appropriate for most patients with this particular cancer," said Mette Saksø Mortensen, M.D., a Ph.D. student at the Department of oncology at the Copenhagen University Hospital in Copenhagen, Denmark. "We also characterized key prognostic factors for relapse, which can help us identify "high-risk" patients who may need adjuvant therapy instead of surveillance. However, in general, seminoma stage I patients can safely be followed on a surveillance program."

Using a nationwide clinical database, researchers identified 1,822 patients with stage I seminoma followed on a five-year surveillance program in Denmark. By linking the patient files with national registries they were able to follow the patients for a median period of 15.4 years. All patients had initial surgery to treat their primary cancer. Overall, 355 of 1,822 patients (19.5 percent) experienced a relapse, which was treated with radiotherapy (216 patients), chemotherapy (136 patients) or surgery (3 patients). The 10-year cancer-specific survival was 99.6 percent. This rate means that for every 1,000 men followed on a surveillance program, only four die within 10 years.

Researchers found that tumor size larger than 1.5 inches, spread to blood or lymphatic vessels, and elevated levels of a blood marker called human chorionic gonadotropin increased the risk of relapse. These factors had been associated with high-risk patients in prior, smaller studies.

Seminoma accounts for about half of testicular cancer cases. Testicular cancer is rare in the general population, but it is the most common solid tumor among young men. The typical initial treatment for the disease is orchiectomy.

"This important study is one of several recent reminders that sometimes "less is more" in patient care. Opting for surveillance spares patients, most of whom are young men, from the harmful side effects of chemotherapy and radiation without diminishing their chances for a long and healthy life," said ASCO President-Elect Clifford A. Hudis, M.D..

This research was supported in part by The Danish Cancer Society, The Danish Cancer Research Foundation and the Preben and Anna Simonsen Foundation.