An important question in the management of patients with
cancer is early identification of the individual who following 'curative' primary
therapy will develop recurrence. Another question is which of several alternative treatments is most appropriate. If the patient at risk can be identified early more aggressive and appropriate
adjuvant chemotherapy can be initiated to insure remission or longer periods of disease free survival. In this review the role of tissue and/or serum
enzyme activities in this regard is considered.
Enzymes alone or in combination with
tumor markers or other factors may be used. Lactic
dehydrogenase (LDH) is perhaps the most common clinical
enzyme used in
cancer patients for prognostic purposes. It has an important role in
germ cell tumors and in association with
chorionic gonadotropin and can predict response to
therapy and the prospects of remission. LDH is a valuable prognostic marker in
lymphoma,
leukemia and in
colon cancer. Patients can be stratified into treatment protocols based on LDH activity. The stage of cellular proliferation can be evaluated by assay of
thymidine kinase in the serum of patients with
Hodgkins Disease and in
Lymphoma. An important new marker,
Cathepsin D in breast tissue may be useful in predicting women with
breast cancer who are at risk for early recurrence.