[katieokell]

I promise this is not a homework question. I preface with this because I'm new to this site, and am very frustrated at the amount of homework questions posted in the Biology section.

I was up late last night finishing a virology essay when it suddenly dawned on me - could you create a more effective and simultaneously less destructive form of chemotherapy? Cancerous growths go through angiogenesis to form new blood vessels so they can ensure a constant supply of blood. Clearly, these new blood vessels are completely superfluous to the body's regular functions.
Would it be possible to cinch off blood vessels on either side of the tumor, and inject only those blood vessels with the chemicals used in chemotherapy? Theoretically, this would have to be done before the tumor cells have begun to spread throughout the whole body, but it could also be extremely effective in treating a tumor. Higher concentrations of drugs could be used with relatively little side effects.

Thoughts?

[ballengerb1]

Most tumors are not detected until they have already established a good blood supply and have mestasticised

[asking]

Hi Katie,
I had the same first thought as ballengerb1, but I am far from expert in this area.

I think you should write to a cancer researcher (or several) and ask this question. If you frame your question respectfully and make it clear you are a student (and not a flake) and I think you are very likely to get an interesting answer. In particular, you might ask for some relevant articles to read.

The best place to locate such a person, that I can think of, is PubMed, which gives abstracts and contacts for the researcher. I can probably help you if this interests you.

[asking]

PS. I am also frustrated by the number of homework questions! They are nearly always the same ones, too. Either a question about genetics or a request for an example of a commensal and a parasite in a particular biome. Why these two topics to the exclusion of all else? :-)

[jem02081]

Hi Katie,
You have a good model in mind & it could work in certain cancer & non-cancerous conditions. For example, cutting off the blood supply is the method used to castrate baby goats & calves. However for cancer, in most circumstances, it would be easier & safer to just surgically remove the tumor.
Tumors are a problem because they are invasive. They invade other tissue. When the do that they take advantage of the existing blood vessels. So it would be difficult to locate all of these blood vessels and surgically cinch them off. However, there is hope that this could be done at the microscopic level with drugs that can cinch off the tumor blood vessels and leave the normal blood vessel untouched. Here are a couple of news story examples
Cancer Treatment Is First to Directly Target Tumor Blood Supply in Patients - New York Presbyterian Hospital
Taking Down Tumors: Vascular Disrupting Agents Entering Clinical Trials -- O'Hanlon 97 (17): 1244 -- JNCI Journal of the National Cancer Institute

There is a lot of research using a variety of methods to deliver anticancer drugs to a tumor. Catheters (google "catheter drug delivery"), antibodies & liposomes come to mind. (see Radioimmunotherapy & Immuno-liposomes sections here Monoclonal antibody therapy - Wikipedia, the free encyclopedia).
I am a cancer research scientist.

[katieokell]

Thanks Jem!
The reason I thought this method might be more beneficial than removing the tumor is that it's nearly impossible to guarantee that all the cells get removed. Even if you only miss one or two cells in removing the tumor, there is a huge chance that those cells will just keep on proliferating and you'll get the tumor back again. I figured that by using the method I mentioned you could ensure that all the cells were destroyed, preventing further growth.
However, the answer seems too simple, and if it were possible or plausible it probably would have been done before.
I'm a fourth year biology student at a university in Canada, and I've sent e-mails to a few cancer researchers at my school, and haven't had any response, which is why I posted here, so I could get feedback on my idea.

[asking]

This may sound strange, but I have a feeling you'll get more replies in the future from researchers who are not at your school. If you want to talk to researchers at your school, I would go to their office hours or make an appointment and take a list of questions. It's important in both emails and face to face visits to acknowledge how busy they are and how much you appreciate them taking the time to answer your questions. This is VERY important. :)

Most methods of cancer treatment involve both surgery and some other method to catch those cells, such as chemotherapy or radiation. It's true that surgery likely misses a few cells, even when the surgeon cuts widely. The problem with localizing the chemo treatment after surgery is that the process of surgery often releases those few cancerous cells into the blood stream, so it's important to track them down wherever they end up, not restrict chemo too locally. On the other hand, as I understand it (and jem will correct me, I hope), with just a few cells in the blood stream, there is an increased opportunity for the immune system will take out the cancerous cells.

[jem02081]

Here is a couple more things to think about.
Sometimes tumors spread by the lymphatic system & sometimes by the blood. You can frequently detect tumor cells circulating in the blood from patients with advanced cancer. Google "Circulating tumor cell" for more info.
When a tumor cell ventures into the bloodstream it is a hostile environment. Besides the immune system the tumor cell is also more likely to die (undergo apoptosis) because of the loss of contact (cell adhesion factors) with nearby normal (stromal) cells. And then the tumor cell needs to colonize another site. See metastasis at Wikipedia,
On the other hand, most tumor cells are incapable of forming a tumor. See “cancer stem cell” in Wikipedia for more information. The tumor stem cell theory is well supported in some tumor types but it’s still a bit controversial.

[asking]

Interesting. I didn't know that cancer cells were unhappy outside the tumor or that most of them are incapable of forming a tumor.

I am going to guess this doesn't apply so much to leukemias?