My mother wouldn’t have known she had thyroid cancer had it not been for a routine checkup two years ago. She felt fine, but her doctor found a lump in her neck, and after several tests she got the diagnosis. I was worried, of course, but the research seemed encouraging: Thyroid cancer has one of the highest survival rates of all cancers — 97.9 percent five years after diagnosis, according to the National Cancer Institute.

This gives thyroid cancer a reputation as being a “good” cancer. But as I have learned, cancer survival statistics don’t tell the whole story.

These estimates are based on data from thousands of people, and as with all statistics they can’t gauge the actual risk for a particular individual. What the rosy survival outlook glosses over is the impact of thyroid cancer on a person’s quality of life, which studies have shown can be significant. For my mom, an outwardly healthy 51-year-old at the time of her diagnosis, thyroid cancer has been an emotional and physical challenge, though you wouldn’t know it by looking at her or talking to her.

Robert Smallridge, deputy director of the Mayo Clinic Cancer Center in Jacksonville, Fla., says patients often come to him very worried even though they’ve been told that thyroid cancer is the “good” cancer. This dichotomy often makes them feel that they’re not entitled to complain or even feel bad. “They’re told they’re supposed to feel lucky, but they don’t. They have cancer,” says Smallridge, who is president of the American Thyroid Association.

About 63,000 new cases of thyroid cancer are diagnosed in this country each year. Most of the tumors are slow-growing and small; they originate from cells that produce hormones in the thyroid, a tiny, butterfly-shape gland located in the front of the neck, near the Adam’s apple. Many people have no symptoms other than an enlarged gland, but some have pain in the front of the neck, trouble swallowing, persistent hoarseness or other voice changes, or constant coughing.

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But other cases can be much more aggressive and are associated with worse outcomes, says endocrinologist Leonard Wartofsky,chairman of the Department of Medicine at the Washington Hospital Center. “Like all things in medicine, it depends on the individual case,” he says.

Surgery, then hormones

The first-line treatment is surgical removal of all or part of the thyroid, called a thyroidectomy. My mother had a total thyroidectomy, as well as removal of several cancerous lymph nodes, to prevent her cancer from spreading. The thyroid regulates a number of essential functions, including blood pressure, body temperature, heart rate and metabolism, so when the entire thyroid is removed, patients must take hormone replacement medication. This daily treatment replaces the organ’s vital role of producing and releasing necessary hormones.

The dosing of thyroid replacement hormones varies widely depending on the individual. Too much or too little can produce side effects including fatigue, chest pain, increased heart rate or pulse rate, sweating, nervousness and anxiety, headache, insomnia, diarrhea, vomiting, weight loss and fever.

“The biggest long-term adjustment that I went through — and most people with thyroid cancer go through — is modulating the medication,” says Cherry Wunderlich, 71, of Bethesda, director of outreach for ThyCa, a thyroid cancer survivors’ association.

Wunderlich was diagnosed in 1999 after noticing a hard protrusion on her neck, and she soon had her thyroid removed. But it took much longer to get her medication right, and for the first few years, Wunderlich experienced extreme fatigue.She needed to nap for two to three hours most afternoons during the first year. Eventually, after doctors fine-tuned her dosage, her health began to improve.

My mother also has experienced severe fatigue since going on thyroid replacement medication. She often has to rest after work, and she goes to bed early.

After a thyroidectomy, remnants of thyroid tissue or cancerous cells may be left behind. When this happens — as it did to my mother and Wunderlich — patients have to undergo radioactive iodine treatment to destroy these remaining cells.

After taking the isotope in liquid or pill form, patients are typically isolated at home for up to a week, while the body gives off low amounts of radiation. Patients must avoid close contact with people and pets, sleep alone, clean their dishes by hand, and wash their towels, sheets and clothes separately.

A further cancer risk

Although the radioiodine kills the thyroid cancer cells, it increases the risk of a secondary cancer because it exposes the kidney, bladder and pelvic organs to radiation, Smallridge says. The treatment also can cause short-term side effects including painful swelling of salivary glands, headache, nausea and appetite loss. The worst of my mom’s side effects was the metallic taste, which lingered long after her treatment. An avid cook, she didn’t enjoy food for months.

Even after thyroid cancer is gone, there’s a risk that it will come back: Ten to 30 percent of patients deemed disease-free after initial treatment will develop recurrence or metastases 10 to 20 years after treatment, according to the National Cancer Society.

When David Kalish, of Albany, N.Y., was diagnosed with a rare, aggressive type of thyroid cancer in 1994 at age 32, he had surgery to remove his thyroid, dozens of lymph nodes, part of his trachea, and one of his laryngeal nerves. That procedure has left Kalish permanently hoarse. A year later, he had another surgery to take out more cancerous lymph nodes. And in 1999 he had a third surgery to remove a tumor that had wrapped itself around his remaining laryngeal nerve, threatening his ability to speak.

After all that, Kalish’s battle with thyroid cancer wasn’t over.

“When I was diagnosed in 1994, all the literature said there was a 95 percent cure rate. What I was going through was definitely not in sync with that information,” says Kalish, whose type of thyroid cancer is more aggressive and more deadly than most.

By 2000, Kalish’s cancer had metastasized to his lungs. He underwent three years of traditional chemotherapy, but the cancer continued to spread.

In 2008 Kalish signed up for a clinical trial testing a novel treatment targeting the enzymes that tell cancer cells to grow. The cancer has stopped spreading, although some spots remain in his lungs.

Kalish wrote a comedic novel about his experience with cancer, “The Opposite of Everything,” and is hopeful that science will keep churning out drugs to keep him alive.

No ‘good’ cancer

What I’ve learned from my mother’s diagnosis is that while some other cancers are certainly more deadly, there is no such thing as a “good” cancer.

Or as my mother puts it: “Cancer diagnosis of any kind is still cancer.”

While she is relieved she doesn’t have a more serious type of cancer, it will be years before she’ll know whether she’s truly cancer-free. She needs regular tests to make sure the cancer hasn’t come back. When I ask her about the cancer, she almost always has a positive outlook, but she still regularly experiences fatigue and mood swings from her hormone medication.

Smallridge says patients’ quality of life tends to improve over time as they learn how to cope with what is essentially a chronic disease, the lack of thyroid hormones.

“It’s going to take a while for patients to get through the initial therapy,” Smallridge says. “It’s going to take several years before they can appreciate that they’re going to do well.”

Mullin is a freelance science writer living in the Washington area.