Cancer and increased blood clot formation in veins sometimes coexist. Deep vein thrombosis, or DVT, can be the first sign of cancer's presence in the body. Low molecular weight fractionated heparin has been used to prevent blood clot-related complications in patients already diagnosed with cancer. But low molecular weight heparin might also have a preventive and protective role from cancer formation and especially from cancer metastasis. How low molecular weight heparin and other anti-thrombotic medications might reduce cancer risks and death from cancer?
Cancer is a known risk factor of thrombosis, particularly venous thrombosis. So, cancer is a solid risk factor. It is much stronger than those risks that I mentioned before. So certainly, thrombosis is a risk, particularly during the active phase of chemotherapy, and particularly for certain types of cancer - cancers of the GI tract, pancreatic cancer. But I think in any cancer, particularly during chemotherapy and during surgery, prophylaxis with the low molecular weight heparin or with new direct oral anticoagulants is important. We will mention that later. As much as heparin is concerned, together with the direct oral anticoagulant, it is a treatment of choice. The use of low molecular weight heparin and direct oral anticoagulant (DOAC) is the treatment of choice. Some patients, despite this precaution, develop thrombosis in cancer. It has been shown that compared with vitamin K antagonists, the risk of bleeding exists in patients who have to undergo chemotherapy. They are sometimes thrombocytopenic or frail. It has been demonstrated that low molecular weight heparin is the best weapon to prevent and treat thrombosis. It is debatable, even though recently it has been shown that Direct Oral Anticoagulants are equivalent to low molecular weight heparin. I don't think there's solid evidence that DOACs (NOACs) are superior. But of course, direct oral anticoagulants have the advantage. You don't have to puncture your belly. So frequently, there are some advantages of direct oral anticoagulants. So people are convinced they are slightly superior. This is what I think from the point of view of prevention of thrombosis in patients with cancer. It is also for the treatment of thrombosis in those who have cancer and develop thrombosis.
You also mentioned briefly the issue of whether thrombosis can be the first early sign of the presence of cancer. And this is a very controversial issue because it is true. It is the basis of also my clinical experience that sometimes, a suspicion for cancer was aroused by the presence of thrombosis. But it has been shown that an extensive screening and search for cancer in patients who have no cancer already diagnosed but who develop thrombosis is probably not worthy. So, of course, if I added thrombosis to the fact that I may have a stronger risk factor for cancer, which is my age, I would have worried. But I would not have undergone a broad extensive screening for cancer because it has been shown that the screening is not cost-effective in picking up cancer. And, most importantly, screening for cancer after thrombosis finding doesn't affect the course of cancer that will eventually develop. So that is the message.
Another thing that you discussed in your introduction is whether or not low molecular weight heparin or other anticoagulants are effective in the treatment of cancer. And there are experimental data that show that inhibiting coagulation and thrombosis may help to avoid the metastasis of cancer, particularly the occurrence of metastasis. I can tell you that to my knowledge, it is not, as you probably saw, my cup of tea in terms of my publications. But I think I know quite well the medical literature [on this topic]. I don't think that there is an attempt to give an anticoagulant, including low molecular weight heparin or unfractionated heparin, to prevent cancer. So if anything, these drugs are given for prophylaxis of thrombosis, but not to control the metastasis and elimination of cancer in patients who have already developed cancer. So from that point of view, the experimental data [for therapy of cancer with anticoagulants] that were quite promising have been quite disappointing. I'm not sure that this opinion will be shared by everybody. But what I can tell you for sure is that I don't know of any better treatment of cancer than with the multiple drugs, with the surgery, with radiotherapy that also encompasses the use of anticoagulants. If anticoagulants are given in those situations, they can prevent thrombosis. Anticoagulants are not given to prevent the dissemination of cancer. So that is my candid opinion on this very crucial topic. Of course, there were a lot of expectations, but I think that the clinical studies in humans can be quite disappointing. [Anticoagulants] often caused more problems than they wanted to prevent.
Aspirin, you know, part of the antiplatelet effect of aspirin. There is some data that shows aspirin might prevent the formation of kind of cocoons around the metastasizing cancer cells. And that's how there are some statistics in the studies of aspirin that might show that there is a little bit less of metastasis in people with an already established cancer diagnosis. But of course, it's speculation.
Thank you. You mentioned the story of aspirin. That is a little bit different, too, because, of course, we are dealing with an antiplatelet agent, not with an anticoagulant. That story [of aspirin in cancer] is more significant and promising, even though it is not yet consolidated. Many people take aspirin. And they take aspirin for any reason, primary or secondary prevention of cardiovascular disease. And there are two huge studies done on thousands and thousands of people. It has been observed that for those people who regularly took aspirin for primary or secondary prevention, there was a lower incidence of cancer. So it is the incidence, it is an occurrence of cancer, particularly of the digestive tract, particularly cancer of the colon. But cancer incidence was lower also in the digestive tract, but also of other organs, particularly the bladder, not the gallbladder, the urinary bladder. These are promising data. And now they are clinical studies that are ongoing, and they want to specifically tackle this issue. I haven't seen them published yet. But certainly, let us say that if it is necessary for other reasons, it takes an [low-dose] aspirin a day to get this [cancer prevention] effect. It might help prevent the onset of cancer, particularly cancers of the gastrointestinal tract. I think it is rather promising. However, to tell you the truth, I would not give a drug that has some side effects unless there is another indication to take it. So [aspirin is indicated] as primary prevention in people with a risk of thrombosis because of other risk factors. Particularly it is true for venous thrombosis or as secondary prevention in people who have already developed a stroke or coronary artery disease. So this is my personal opinion.