DEAR DR. ROACH: My husband recently died from anaplastic thyroid cancer. I always thought thyroid cancer was one of the most successfully treated cancers that exist. Could you please explain the difference between anaplastic thyroid cancer and regular thyroid cancer? Thank you very much. — M.A.S.

ANSWER: I am very sorry to hear of your husband.

Nearly all organs can have multiple types of cancer. Cancers vary by the cell type they start from and by how closely (or poorly) they resemble their original cell. In the case of thyroid cancers, those that are well-differentiated have a very good prognosis. Because well-differentiated thyroid cancer cells still behave to some extent like normal thyroid cells, they will take up iodine, a critical element for making thyroid hormone. Radioactive iodine is an effective treatment, and often used after surgery. The radioactive iodine is taken up and concentrated by the cancer cells, which are subsequently killed by the radiation. Unfortunately, people can still die from conditions that have a very good prognosis, and ANY cancer diagnosis leads to fear and disruption of one’s life, not to mention the sense of betrayal that a person’s body is not behaving as it should.

Anaplastic (literally, “backward growth”) thyroid cancers don’t look much like thyroid tissue at all. The cancer cells grow uncontrolled. They are highly resistant to chemotherapy and radiation, and they don’t take up iodine like healthy thyroid cells or well-differentiated thyroid cancers. They spread early to other organs, especially the lungs, but also to the bone, brain or other sites. As such, the mortality rate from anaplastic thyroid cancer approaches 100%, and half of people diagnosed will succumb within three to seven months. There are chemotherapy treatments that can slow down the growth, but we desperately need better treatments.

Fortunately, anaplastic thyroid cancer is rare, only one or two cases per million people per year.

DEAR DR. ROACH: I have two frying pans with Teflon coating that show signs of wear. Someone said I should not use them, as they can cause cancer. Can you shed some light on this? — H.C.

ANSWER: I have also heard that, but some research shows this to be a myth. It is true that many nonstick pans were made with a chemical (PFOA) that is carcinogenic, and which could be released as a gas if the pans were heated too high. Since 2013, nonstick pans (including those made with Teflon) have been made with different chemicals, which do not increase cancer risk (as far as we know). The pans are safe unless heated to a very high temperature (over 570 F, 300 C).

The flaking of the nonstick material is a different concern, but these particles are not absorbed by the body, and pass through you without interacting. However, it does mean that the pans are due for replacement. If you don’t want to periodically replace your nonstick pans, use stainless steel, anodized aluminum, ceramic or old-fashioned cast iron.