I have posted quite a lot about the importance of D-dimer in the past 5+ years, but the recent post from 5_plus_4, "I almost died Tuesday" had me thinking that perhaps some basic information on coagulation issues needs to be reposted periodically, particularly for new members. No-one should die, or almost die, because of an avoidable blood clot.
The first thing to note is that doctors know that cancer increases the risk of an embolism. They do not monitor patients (via D-dimer) or even warn patients of increased risk, but they do know how to treat patients after a venous thromboembolism (VTE) event. Such treatments are considered too dangerous to use prophylactically - hence the silence.
D-dimer - Wikipedia [1]:
"D-dimer ... is a fibrin degradation product .., a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis.
"D-dimer concentration may be determined by a blood test to help diagnose thrombosis. Since its introduction in the 1990s, it has become an important test performed in people with suspected thrombotic disorders, such as venous thromboembolism. While a negative result practically rules out thrombosis, a positive result can indicate thrombosis, but does not exclude other potential causes. Its main use, therefore, is to exclude thromboembolic disease where the probability is low."
Studies.
A study from Austria [2a], (published before many here were diagnosed,) tells the story:
"In a prospective, observational, cohort study of 821 patients with newly diagnosed cancer or progression of disease who did not recently receive chemotherapy, radiotherapy, or surgery were enrolled and followed for a median of 501 days".
There were 101 PCa cases.
"VTE occurred in 62 patients (7.6%)." i.e. 62 of 821 - they don't report by cancer type
"Interestingly, a systematic activation of coagulation is observed in patients with cancer, and this activation leads to augmented thrombin generation followed by fibrin formation. It has been suggested that fibrin may contribute to tumor growth and to processes that lead to tumor invasion and metastasization by promoting angiogenesis and formation of a protective fibrin shield on malignant tumor cells, which makes tumor cells resistant to endogenous defense mechanisms."
This last sentence is particularly important, since control of fibrin may dramatically reduce or limit metastasis.
"High D-dimer levels were associated with VTE in a population-based cohort study, and prospective studies have shown that D-dimer levels are predictive of recurrence in patients without cancer."
"There was no routine screening for VTE. Objective imaging methods were performed to confirm or exclude the diagnosis only when a patient developed symptoms of VTE."
... the usual benign neglect ...
"{pulmonary embolism} was fatal in four patients (6.4% of VTE events)."
"Overall, the cumulative probabilities of VTE in the total study population were 5.7% after 6 months and 7.9% after 1 year."
More from Vienna [2b]:
High D-dimer levels are associated with poor prognosis in cancer patients
***
Thrombosis due to cancer is sometimes detected before the cancer:
[3] A case of cerebral venous thrombosis as the presenting sign of occult prostate cancer
& elevated D-dimer alone may occur before cancer diagnosis:
[4] Elevated D-dimers are also a marker of underlying malignancy and increased mortality in the absence of venous thromboembolism
so altered coagulation is an early event in PCa.
Plasmin - Wikipedia [5]:
"Plasmin is an important enzyme ... present in blood that degrades many blood plasma proteins, including fibrin clots. The degradation of fibrin is termed fibrinolysis."
While plasmin will eventually clear a clot that is not growing, it is not up to dealing with a chronically active clot.
Nattokinase - Wikipedia [6]:
"Nattokinase ... is an enzyme extracted and purified from a Japanese food called nattō. Nattō is produced by fermentation by adding the bacterium Bacillus natto, which also produces the enzyme, to boiled soybeans. While other soy foods contain enzymes, it is only the nattō preparation that contains the specific nattokinase enzyme.
"When in contact with human blood or blood clots, it exhibits a strong fibrinolytic activity."
[7] A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles
"D-dimer concentrations at 6, and 8 hours, and blood fibrin/fibrinogen degradation products at 4 hours after NK administration elevated significantly"
[8] Nattokinase decreases plasma levels of fibrinogen, factor VII, and factor VIII in human subjects
Healthy men have a certain level of fibrinogen in circulation in case that sudden bleeding requires fibrin to plug the leak. In PCa, inflammation sends the level of fibrinogen much higher than it should be. Nattokinase can counter that.
***
I periodically get a D-dimer test. There is a reference range, but I have zero tolerance. I want to keep the number as close to zero as possible.
The standard nattokinase dose is 2,000 FUs (fibrinolytic units), but that is unlikely to be sufficient for anyone with cancer. The D-dimer test is essential IMO.
-Patrick
[1] en.wikipedia.org/wiki/D-dimer
[2a] ascopubs.org/doi/10.1200/JC...
[2b] ncbi.nlm.nih.gov/pmc/articl...
[3] pubmed.ncbi.nlm.nih.gov/200...
[4] pubmed.ncbi.nlm.nih.gov/206...
[5] en.wikipedia.org/wiki/Plasmin
[6] en.wikipedia.org/wiki/Natto...
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