General Information About Testicular Cancer
Beta-HCG: Elevation of the beta subunit of hCG is found in approximately 14% of the patients with stage I pure seminoma prior to orchiectomy and in about half of patients with metastatic seminoma.[11,12,13] Approximately 40% to 60% of men with nonseminomas have an elevated serum beta-hCG.
Significant and unambiguously rising levels of AFP and/or hCG are an indication of relapsed germ cell tumor in most cases and are an indication for treatment even in the absence of radiological evidence of metastatic disease. Nonetheless, tumor-marker elevations do need to be interpreted with caution. For example, false-positive hCG levels can result from cross reactivity of the assay with luteinizing hormone, in which case an intramuscular injection of testosterone should result in normalization of hCG values. There are also clinical reports of marijuana use resulting in elevations of serum hCG and some experts recommend querying patients about drug use and retesting hCG levels after a period of abstinence from marijuana use. Similarly, AFP is chronically mildly elevated in some individuals for unclear reasons and can be substantially elevated by liver disease.
LDH: Seminomas and nonseminomas alike may result in elevated lactate dehydrogenase (LDH) but such values are of less clear prognostic significance because LDH may be elevated in many different conditions unrelated to cancer. A study of the utility of LDH in 499 patients with testicular germ cell tumor undergoing surveillance after orchiectomy or after treatment of stage II or III disease reported that 7.7% of patient visits had elevations in LDH unrelated to cancer, whereas only 1.4% of visits had cancer-related increases in LDH. Of 15 relapses, LDH was elevated in six and was the first sign of relapse in one. Over 9% of the men had a persistent false-positive increase in LDH. The positive predictive value for an elevated LDH was 12.8%.
A second study reported that among 494 patients with stage I germ cell tumors who subsequently relapsed, 125 had an elevated LDH at the time of relapse. Of these 125, all had other evidence of relapse: 112 had a concurrent rise in AFP and/or hCG, one had CT evidence of relapse prior to the elevation in LDH, one had palpable disease on examination and one complained of back pain that led to imaging that revealed retroperitoneal relapse. Measuring LDH thus appears to have little value during surveillance of germ cell tumors for relapse. On the other hand, for patients with metastatic NSGCT, large studies of prognostic models have found the LDH level to be a significant independent predictor of survival on multivariate analysis.[10,16]
Staging and Risk Stratification
There are two major prognostication models for testicular cancer: staging, and for risk-stratification of men with distant and/or bulky retroperitoneal metastases, the International Germ Cell Cancer Consensus Group classification. The prognosis of testicular germ cell tumors is determined by the following factors:
- Histology (seminoma vs. nonseminoma).
- The extent to which the tumor has spread (testis only vs. retroperitoneal lymph node involvement vs. pulmonary or distant nodal metastasis vs. nonpulmonary visceral metastasis).
- For nonseminomas, the degree to which serum tumor markers are elevated.