Diagnosis increasing, but many questions left unanswered
By Heidi Kiec
When Rebecca Smith felt a lump on her neck the Friday of Memorial Day weekend in 2013, she spent the next three days being paranoid that it was lymphoma.
“When I found out I had papillary thyroid cancer, it was a relief to me,” says Smith, who because of her career in healthcare, asked that her name be changed to not draw unnecessary attention to her situation. She admits that the cancer diagnosis was still scary, but she had watched two friends go through papillary thyroid cancer and knew that the prognosis was very good.
Ranking as the fifth leading cancer in women diagnosed in 2014, thyroid cancer has an overall five-year survival rate of 98 percent. About eight out of 10 thyroid cancers are papillary cancers, which are rarely fatal.
In the United States, diagnosis rates for thyroid cancer from 2006 to 2010 increased 5.4 percent in men and 6.5 percent in women, cementing its place as the most rapidly increasing cancer in the country. The American Cancer Society estimated 62,980 people would be diagnosed with thyroid cancer in 2014, and an estimated 1,890 deaths were expected. Of those new cases, three out of four would be women.
Much is still unknown about thyroid cancer including why the diagnosis levels are increasing and why it targets women more than men.
Raymon Grogan, MD, director of the Endocrine Surgery Research Program at the University of Chicago Medical Center calls it “a mystery to the medical community.”
“Certainly some of the rise in thyroid cancer is due to increased detection either through imaging or on pathologic diagnosis; it’s undeniable,” Grogan says. “But the question [remains], is its entire rise due to increased detection?
That’s not really as clear.”
Some critics feel there’s been an overdiagnosis or overtreatment of thyroid cancer. But in the United States, there is no national screening program for thyroid cancer, so the majority of thyroid nodules unintentionally discovered by imaging are known as incidentalomas—tumors found incidentally through imaging tests like CT scans or neck ultrasounds, done for reasons unrelated to thyroid dysfunction. The increased use of these refined ultrasounds and imaging techniques may account for an increase in papillary thyroid cancer diagnoses, but it’s debatable whether that’s the only reason for the growing numbers.
Grogan points to an increase in large tumors, like Smith’s, an increase in metastasis to lymph nodes in the neck as well as to distant metastatic diseases outside the neck. That may point to a reason other than an increase in technology’s ability to detect more tumors.
“Another possibility is that there is an unknown environmental factor that is somehow changing the biology of the thyroid cancer itself and is causing an increase in the incidence, but currently there is no definitive proof of that hypothesis” Grogan says. “It is also important to note that the debate over why thyroid cancer rates are increasing is overshadowing a more pressing concern; namely, what to do about these small, seemingly innocuous thyroid cancers that are being diagnosed more frequently. It is likely that not all of them need aggressive treatment like surgery, but we have no way of knowing which are the indolent versus aggressive cancers. For physicians and patients, this is a more urgent question to be answered.”
The scientific community is currently stumped as to what those possible environmental factors are, but research is being conducted on a variety of topics.
“We have to be really careful calling things ‘overdiagnosed,’ because we don’t know, until we reach the point of knowing more about every kind of thyroid cancer, which ones can just be watched,” says pathologist Carey August, MD, at Advocate Illinois Masonic. “It can be misleading for the public when they are told these cancers are being overtreated because then people become hesitant to be appropriately evaluated and to receive what is currently considered to be the appropriate therapy.”
Autopsies often find that people had thyroid cancer at the time of their death, although the cancer was never diagnosed or caused any problems. The findings lead some to believe that treatment paradigms should be changed.
To diagnose thyroid malignancies, pathologists read slides from fine needle aspiration biopsies. In some cases, the diagnosis of a cancer is certain. In other cases, the pathologist reports a designation that indicates the magnitude of risk of cancer in the patient’s thyroid. If a patient does, in fact, have a thyroid cancer, the risk of death may be related to etiology (cause), the molecular underpinnings of the lesion, patient’s age or even gender, August says.
While papillary carcinomas have a high survival rate, there are multiple subtypes with different rates of aggressiveness. “You can’t necessarily tell from a fine needle aspiration which tumors will be deadly,” August says.
Some patients can be watched and have frequent ultrasounds, while those with a concern for malignancy are recommended for lobectomies, a partial removal of the thyroid lobe, or thyroidectomies, removal of the entire thyroid.
“Once a pathologist has either a lobe of the thyroid with the tumor in it, or the whole thyroid with the tumor in it, we can identify the aggressive variants,” August says.
Smith’s case is somewhat unique because she felt a lump in her neck and sought out a diagnosis. She went through a series of ineffective diagnosis procedures and inconclusive results, she says, before finding her way to Northwestern Memorial Hospital, where a thyroid surgeon immediately informed her that there were two nodules on her thyroid.
“I’d had five people feel my neck, and not one of them said that. Why? Nobody knew,” Smith says.
“It’s not common to have symptoms for thyroid cancer,” says Anthony Yang, MD, a surgical oncologist at Northwestern Medicine who did not treat Smith. “A lump in the neck is the most common symptom, but often people have no symptoms, and a tumor has been detected some other way.”
Yang, Grogan and August all agree that the best advice for a thyroid cancer patient is to go to a center where thyroid cancers are seen and treated regularly, if not exclusively.
Smith had two small tumors on her thyroid and one large metastasized tumor not on her thyroid. She underwent a thyroidectomy and right neck dissection.
She remembers her surgeon’s macabre pep talk: “This will not kill you. You will die years and years from now from something else.” She’s part of the 98 percent survival rate, but that didn’t make her recovery any easier.
Smith spent several months physically and emotionally adjusting to the thyroid hormone supplements, which are now a daily lifelong ritual because of her thyroidectomy and the radioactive iodine treatment she underwent a few months after surgery. Radioactive iodine is another big controversy in the world of thyroid cancer; it’s extremely effective but makes the patient radioactive for a short period of time and, in higher doses, can cause cancer.
The questions about thyroid cancer linger, and the debates rage on. Even though the reason for the cancer’s increase is unclear, the outlook for patients with thyroid cancer is generally good. As far as Smith is concerned, she’s happy her treatment has been successful, and she’s glad to be moving on with her life. +
