As we said, the topic of cancer symptoms is coming to you in two parts with the second being--perhaps--the more interesting questions Google sees. You can read the first part here. Today's installment covers topics like organ donation, cancer recurrence, and cancer transfer.

Can cancer be benign?

No. The opposite of benign is “malignant”, which is an exact synonym for “cancerous”.

Not all tumors are cancerous, they can just be harmless masses of cells like a collection of fluid. Harmless tumors are benign and not cancerous. Moles and warts are also benign tumors. Cancerous tumors, on the other hand, are harmful tumors.

The difference between a benign tumor and a malignant (cancerous) one is that—although both can grow uncontrollably—benign tumors can’t invade other areas of the body.

Can cancer patients donate organs?

It’s common for cancer survivors to want to become organ donors to help others. Cancer patients may also want to become organ donors in the case that they die of their cancer. In either case, whether donated organs can be used depends on the person and the type of cancer they have or had.

Here's an interesting, but only tangentially related fact I couldn't resist sharing:

Living donations include kidneys, liver, lung, intestine, pancreas, heart, and uterus—although most of these are very rare. For instance, hearts are only given as a living organ donation when someone requires a deceased lung donation and doctors feel the donated lungs will work best with the deceased person’s heart. The person receiving the lungs and heart will have their own heart removed and donated.

Now back to the question.

Organ donation from patients with actively spreading—metastasizing—cancer is discouraged. Most people very recently diagnosed with cancer also cannot donate organs, with the exception of brain cancer patients whose cancer hasn’t spread past the brain stem.

Extremely rarely, patients who receive an organ donation from a cancer patient are passed that person’s cancer. Current theories are that this happens because anti-rejection drugs suppress the recipient’s immune system, leaving it unable to kill any cancer cells which may have come with the donated organ. Generally, the risk of spreading cancer via organ donation from a cancer patient is considered low, especially if that organ donor has been cancer free for a long time before the donation occurs.

When it comes to organ donation after death, the American Cancer Society recommends that cancer patients and survivors who want to donate list themselves as organ donors on their driver’s license. After death, doctors and other medical professionals run tests on all organs and tissues to evaluate whether they can be donated.

Let’s talk about blood donation too, while we’re at it.

There aren’t really set rules about this—it depends on the patient and the blood collection center. No studies have found any risk of getting cancer from a cancer patient’s blood donation. The only exception scientists have theorized to this is in patients with weak immune systems who receive a blood donation from a cancer patient—similar to the case with organ donation. Out of an abundance of caution, there are some restrictions for blood donation on cancer patients:

• Cancer patients who are currently receiving treatment cannot donate blood
• Cancer patients whose cancer has returned or is actively metastasizing cannot donate blood
• Cancer patients who have ever had adult leukemia, lymphoma, or Kaposi sarcoma cannot donate blood

For cancer patients whose cancer never metastasized and whose treatment consisted only of surgery, blood donation can be done as soon as they’ve healed from the surgery. For other cancer patients, the rule of thumb is usually that blood can be donated if their treatment ended 1 year ago and the cancer hasn’t returned.

When cancer returns

A cancer might recur after being in remission because some cells from the patient’s cancer were able to remain in the body throughout all previous treatment efforts. Unfortunately, only a few tiny cells really have to escape treatment for this to happen.

Cancer can recur in either the same place it originally happened, nearby, or somewhere else entirely. In a lot of cases, the experience of diagnosis and treatment for a recurrent cancer may be quite similar to the experience the first time a patient had cancer. Often, cancer that comes back to the same area as before or the immediately surrounding area can be cured.

Cancer patients with recurrent disease often say that having cancer for a second time is more difficult to cope with—mentally and emotionally speaking—than it was the first time. However, those patients also have more knowledge and more connections than the first time around, which can make the process less confusing for some.

Are cancer cells contagious?

Cancer is not a contagious disease like an infection or virus—although it can sometimes be caused by infections or viruses. Cancer patients cannot “give” cancer to another person via physical contact, etc. As we’ve discussed, rarely organ transplants from a cancer patient can lead to cancer development in the organ recipient—whose immune system may not be able to kill any cancer cells in the organ. Another rare case of cancer transfer (this is what we call cancer that moves from one person to another) happens extremely seldomly when a pregnant mother has melanoma. Scientists believe it has only happened a few times. In these cases the melanoma transferred from the mother to the fetus, so both had the cancer.

There’s no reason at all to fear “catching” cancer from a patient affected by the disease.

Cancer vs. cyst

Tumors (whether cancerous or benign) and cysts are completely different things. A cyst is a sac filled with air, fluid, or other biological materials. A tumor is a mass of extra cells formed by uncontrollable cell division. Cancer can actually cause cysts.

Why doesn’t cancer affect the heart?

If we think back to how cancer happens, we’ll remember that it’s when cells start dividing uncontrollably due to a mutation during division that essentially turns the brakes off. Heart cancer does sometimes happen, but it’s pretty rare. So rare it’s very difficult to even measure how often it happens. The reason for this is because the cells in human hearts do not divide unless some kind of injury has taken place—allowing very limited possibility for the mutation that turns the brakes off to occur. The heart is also exposed to few carcinogens.

Having said this, it’s a little more common for cancers to spread into the heart from elsewhere, like the lungs or breasts.

Sources

Aller, A. (n.d.). There are many kinds of cancer, so why is there no heart cancer? Retrieved from https://www.scientificamerican.com/article/there-are-many-kinds-of-c/

Can I Donate Blood if I'm a Cancer Survivor? (2016, June 20). Retrieved from https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/blood-transfusion-and-donation/blood-donation-by-cancer-survivors.html

Can I Donate My Organs if I've Had Cancer? (2014, October 16). Retrieved from https://www.cancer.org/treatment/survivorship-during-and-after-treatment/be-healthy-after-treatment/can-i-donate-my-organs.html

Cancer Basics. (n.d.). Retrieved from https://www.worldwidecancerresearch.org/who-we-are/cancer-basics/

Is Cancer Contagious? (2015, July 17). Retrieved from https://www.cancer.org/cancer/cancer-basics/is-cancer-contagious.html

Moynihan, T. J. (2016, July 28). Tumor vs. cyst: What's the difference? Retrieved from https://www.mayoclinic.org/diseases-conditions/cancer/expert-answers/tumor/faq-20057829

Moynihan, T. J. (2018, March 29). Heart cancer: Is there such a thing? Retrieved from https://www.mayoclinic.org/heart-cancer/expert-answers/faq-20058130

Smith, R. P., & Hill-Kayser, C. (2017, October 12). All About Bladder Cancer. Retrieved from https://www.oncolink.org/cancers/urinary-tract/bladder-cancer/all-about-bladder-cancer

Team, V. (2015, July 20). Can You Get Heart Cancer? Retrieved from https://health.clevelandclinic.org/can-you-get-heart-cancer/

What Are Tumors? (n.d.). Retrieved from http://pathology.jhu.edu/pc/BasicTypes1.php?area=ba

When cancer returns: How to cope with cancer recurrence. (2016, November 02). Retrieved from https://www.mayoclinic.org/diseases-conditions/cancer/in-depth/cancer/art-20044575