June 11, 2010 (Chicago, Illinois) — The American Society of Clinical Oncology (ASCO) has issued a guideline on the use of serum tumor markers in the diagnosis, treatment, and management of germ cell tumors in men, which include, most commonly, testicular cancer.
The germ cell tumors clinical practice guideline was announced at a press conference here at the organization's 2010 Annual Meeting.
This is the newest guideline on the use of biomarkers for specific cancers from ASCO — with more to come as part of an "expanded series" of guidelines on biomarkers.
The initial 2 guidelines on biomarkers were on breast (2007) and gastrointestinal cancers (2006).
Why has ASCO chosen germ cell tumors, which are rare — with fewer than 9000 cases annually in the United States — for their third tumor marker guideline?
According to the panel of authors of the guideline, which was published online June 7 in the Journal of Clinical Oncology, it is "because of the large volume of publications and the long history of using serum concentrations of human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP), and lactate dehydrogenase (LDH) to guide management decisions for patients with GCT."
In short, there is clinical value in using biomarkers to help manage patients with germ cell tumors, the authors explain.
|Dr. Timothy Gilligan|
At the press conference, the new guideline's lead author, Timothy D. Gilligan, MD, from the Cleveland Clinic in Ohio, said that these 3 biomarkers for germ cell tumors "play a critical role in the management of these tumors."
He also hinted that some tumor markers might not be as clinically useful as the germ cell tumor markers.
Medical tests that measure tumor biomarkers are not as rigorously examined by the US Food and Drug Administration (FDA) as drugs are, he explained.
The FDA doesn't require that marker products improve outcome.
"The FDA doesn't require that marker products improve outcome. The products are only required to measure what they claim to measure," he told reporters at the press conference.
He called for "better evidence about whether tumor markers for other cancers help provide better care for patients." Specifically, he called for proof that the tumor-marker products "improve medical outcomes or quality of life."
The stakes can be high when patients undergo biomarker tests, Dr. Gilligan noted.
"Medical tests are dangerous," he said. "They can lead to a waterfall of further tests and unnecessary treatment."
Dr. Gilligan cited the use of prostate-specific antigen (PSA) as a screening test for prostate cancer as an example of a problematic biomarker that has produced overdiagnosis and overtreatment of disease. The introduction of the PSA screening test in the mid-1980s led to an estimated 1 million cases of overdiagnosis of prostate cancer by 2009, as reported by Medscape Oncology.
Dr. Gilligan called for improved tests to detect cancer. "We need better tests to detect treatable cancers earlier so that treatment will be more effective."
The future of tumor biomarkers promises to be busy, suggested Dr. Gilligan. "This is a big area of research. There are a lot of new products coming out along these lines," he said.
What's New in Germ Cell Tumor Markers
The expert panel convened by ASCO, which included Dr. Gilligan, conducted a systematic review of medical research literature, in partnership with Cancer Care Ontario, to develop the new recommendations on germ cell tumors and related serum tumor markers.
Germ cell tumors might be rare but they are also among the most curable cancers, with more than 90% of men cured, according to Dr. Gilligan. Germ cell tumors most commonly start in sperm-producing cells in the testicles. Testicular cancers are typically detected when the patient notices a swelling or irregularity in the shower or when dressing, Dr. Gilligan explained.
Testicular cancer is curable in most cases.
"Testicular cancer is curable in most cases, but proper management is key because the stakes are high, both for survival and quality of life," said Dr. Gilligan in a press statement.
AFP, hCG, and LDH should not be used to screen for germ cell tumors, to help decide whether orchiectomy is needed, or to make treatment decisions for patients with cancer of unknown origin, notes the guideline.
This news about the latter practice — using germ cell tumor markers to choose a chemotherapy regimen for patients with a cancer of unknown primary — is worth highlighting, noted Dr. Gilligan "This has been the practice, but the literature does not support use of tumor markers for this," he said.
The other most notable new recommendation, said Dr. Gilligan, is about serum tumor markers: they should not be used as part of "surveillance for stage I seminomas."
The diagnosis of germ cell tumors in men is divided into 2 different types — seminoma and nonseminoma, said Dr. Gilligan.
Generally, seminomas are relatively slow-growing; nonseminomas tend to grow and spread more quickly and are treated differently.
Seminoma cells do not produce AFP. As a result, concentrations above the normal range of AFP can occur in patients with nonseminomas but not in those with pure seminoma. In contrast, hCG and LDH concentrations above the normal range can occur with any germ cell tumor histology, write the authors of the new guideline.
A rise in these markers generally indicates disease relapse in patients who have been treated, said Dr. Gilligan.
However, as noted above, Dr. Gilligan and his colleagues recommend against using these markers as part of surveillance in stage I seminomas.
Dr. Gilligan has disclosed no relevant financial relationships.
J Clin Oncol. Published online June 7, 2010. Abstract
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Cite this: ASCO® to Boost Biomarker Guidelines; First Up, Germ Cell Tumors - Medscape - Jun 11, 2010.