Americans have a 1 in 3 chance of developing cancer in their lifetime, and a 1 in 5 chance of dying from it.

But despite the disease's prevalence, cancer is not always well understood. Below are five things that the doctors and nurses at the University of Michigan Rogel Cancer Center believe everyone should know about cancer.

1. When cancer spreads from a primary tumor to another part of the body, it's still that original type of cancer.

If a patient with breast cancer, for example, has cancer cells break away from their original tumor and spread to their liver, brain, bones or lungs — a process known as metastasis — she or he is still considered to have breast cancer rather than liver cancer, brain cancer, or any other type of cancer.

This distinction is important because cancers that start in breast tissue have different characteristics than cancers that start in liver or lung tissue. Doctors make treatment decisions based on the characteristics of a patient's primary tumor type, as well as the unique characteristics of the patient's individual disease.

2. New immunotherapy treatments — which help the body's own immune cells detect and attack cancer — have shown great promise. But they're not a magic bullet.

In recent years, the cancer treatment world has been abuzz about immunotherapy. And it's shown many promising results, especially in combination with chemotherapy — doubling the median survival time for patients with lung cancer in one clinical trial, for example.

But patients should understand that immunotherapy treatments are not appropriate for every situation. The appropriateness of immunotherapy depends on the type of cancer and the features of an individual patient's disease.

"Yes, immunotherapy is new and exciting and has opened new possibilities in the field of cancer care," says Kim Zapor, R.N., a nurse with the Rogel Cancer Center's Cancer AnswerLine. "But in spite of successes for specific types of cancer, there is a lot of work still to be done in the laboratory and through clinical trials."

To learn more about immunotherapy, visit the National Cancer Institute's information webpage on immunotherapy treatment and the Roger Cancer Center's page on immunotherapy research.

3. Delays in lab results and in formulating a treatment plan can be frustrating, but in most cases taking the time to make a considered plan won't affect outcomes.

It can be difficult to wait for lab results, to find out if you or a loved one has cancer or whether a previously treated cancer has returned. And although fear, anxiety and other emotions might be running high, this is normal.

And when results do come back, there may be a desire to start attacking the cancer right away. But it's also important to begin treatment with a clear, informed treatment plan — which may include additional tests, or even a second medical opinion.

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A cancer diagnosis is a whirlwind, says Steven Katz, M.D., M.P.H., a professor of medicine and of health management and policy at the University of Michigan. Yet, even though few cancer decisions need to be made as if it's a medical emergency, most are treated as such.

"I'm not talking about waiting months," Katz says. "I'm talking about an extra visit. Take time to discuss options with your spouse. Get a second opinion if you're not sure. We don't need to make all decisions during their first encounter with their doctor."

To learn more, read the Rogel Cancer Center's webpage on diagnosis and decision making and listen to the cancer center's podcast on stress and anxiety around diagnosis.

4. Seeking a second opinion can be helpful.

Whether you're at a medical crossroads or considering a change in the course of treatment, your doctor should be open to considering options both locally and at other cancer centers. In the end, the decision to change treatment teams or centers is your call.

"A second opinion can often be a valuable part of your cancer treatment," says Michael Sabel, M.D., the William W. Coon Collegiate Professor of Surgical Oncology in the Department of Surgery and chief of the Division of Surgical Oncology at Michigan Medicine. "Today, there are multiple treatment options available. Different institutions, different doctors have different approaches. Sometimes having a second set of eyes on radiology images and pathology reports can be critical to determining what's going to be the best treatment for you."

Here are some times when you might want to seek a second opinion:

• When you want confirmation of the correct diagnosis — especially for rare or late-stage cancers.

• To get the expertise of a doctor who specializes in a particular type of cancer — especially for rare cancers.

• When your treatment goals differ from your doctor's, or when the treatment offered has unacceptable side effects or risks.

• If your cancer isn't responding to your current treatments and you want to explore what other options may exist, including clinical trials.

Get more information about second opinions on Cancer.net's webpage on seeking a second opinion and by visiting CancerCare's website.

5. The stage of a patient's cancer at the time of diagnosis is a critical piece of information.

A cancer's stage is a label given at the time of diagnosis that describes the extent of a patient's cancer and how far it's spread into nearby tissues and lymph nodes.

A cancer's stage is a key factor in determining a course of treatment — whether, for example, surgery is going to be a good first-line option.

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There are actually several different staging systems, and some are specific to certain types of cancer.

It's common to describe a cancer's stage in numerical terms, ranging from 0 to 4. They're often written with Roman numerals. Stage 0 is used to designate abnormal, pre-cancers called carcinoma in situ. By stage IV, the cancer has spread to distant parts of the body; this is also known as metastatic cancer.

For patients with metastatic cancer, treatment decisions usually focus on extending life and maintaining quality of life, rather than trying to cure their disease.

"I always stress to patients with stage IV disease that I want to do everything I can to help them live as long as they can, while still maintaining quality of life, allowing them to do the things they want to do," says Lynn Henry, M.D., Ph.D., the breast oncology disease lead at the Rogel Cancer Center. "We do our best to make sure that we adjust treatment schedules to allow people to attend graduations or family reunions, or a trip they want to be able to take."

Visit the American Cancer Society's webpage on the advanced stages of cancer for more information.

If you have more questions about cancer, call the Cancer AnswerLine at 800-865-1125 to talk to a registered oncology nurse.