Platelets are blood cells that arrest the flow of
blood in case of bleeding. An excessive platelet count could increase the
chances of suffering from a blood clot. A study conducted in 619 women with
ovarian cancer found that 31% women had an increased number of platelets in the
blood. Survival was nearly halved in
women with ovarian cancer with a high platelet count as compared to those with
normal platelet levels.
Studies in mice revealed that ovarian cancer
directly increases platelet levels. Researchers found that the tumor increased
secretion of a substance called interleukin-6 in mice. Interleukin-6 in turn
brought about an increased production of thrombopoietin by the liver.
Thrombopoietin stimulates the bone marrow to produce new platelets.
Treatment with anti-interleukin-6 antibodies
siltuximab reduced platelet count in mice as well as in a small number of women
with ovarian cancer. The antibodies also reduced tumor growth in mice.
The study thus
suggests that ovarian cancer increases the number of platelets in the blood.
The platelets, in turn, support the growth of the cancer by providing growth
hormones, thereby reducing survival of the patient.
Thus, drugs that inhibit the platelets like aspirin
and heparin could play a role in the treatment of ovarian cancer. They could possibly
prolong survival in these patients.
The antiplatelet drugs however cannot be recommended
for use currently without detailed studies, since they can cause
bleeding when taken along with chemotherapy for the cancer.
points out to one important aspect, that if a person has high platelet count in
the absence of inflammation or iron deficiency, it is important to look out for
the presence of a cancer.
1. Paraneoplastic Thrombocytosis in Ovarian Cancer; Rebecca Stone et al;
N Engl J Med 2012; 366:610-618.