Cancer is a group of diseases that we may never be able to cure completely, but scientists are optimistic that vaccines, personalized medicine, and smart lifestyle choices will help prevent and treat a much greater proportion of cases than currently happens.

Whether a person’s cancer can be cured depends on the type and stage of cancer, the type of treatment they can get, and other factors. Some cancers are more likely to be cured than others, but each cancer needs to be treated differently as there isn’t just one cure for cancer. A cure means that cancer has gone away with treatment, no more treatment is needed, and the cancer is not expected to come back. A doctor can rarely be sure that cancer will never come back. In most cases, it takes time to know if the cancer might come back. However, the longer a person is cancer-free, the better the chance that the cancer will not come back. More often, when treatment appears to be successful, doctors will say the cancer is “in remission,” rather than “cured.”

Remission is a period of time when the cancer is responding to treatment or is under control. Some people think that remission means the cancer has been cured, but that may not always be the case. Remissions can last anywhere from weeks to years. Treatment may or may not continue during remission, depending on the type of cancer.  Complete remissions may go on for years and, over time, the cancer may be thought to be cured. The mortality of cancer patients is slightly decreasing, but the increase in incidence is not compensated by the decrease in mortality. There are still a large number of cases coming up every year, and if we really want to do something against cancer in the future, we need to stop the increase.

We know there are a number of cancer risk factors that can be avoided. At this moment, we also know of about 20% of cancers where infections are involved. We can not only effectively immunize patients against these types of cancer, but virtually eradicate them. In the next few years, cancer will become the leading cause of death in the United States, and later in this century, it is likely to be the top cause of death worldwide. The shift marks a dramatic epidemiological transition: the first time in history that cancer will reign as humankind’s number-one killer.

It’s a good news/bad news story. Cancer is primarily a disease of aging, and the dubiously good news is that we are living long enough to experience its ravages. Cancer’s new ranking also reflects public health’s impressive gains against infectious disease, which held the top spot until the last century, and against heart disease, the current number one. As every public health professional knows, on a population level, the only way to substantially reduce the incidence and mortality of any disease is through prevention. And on a broad scale, we have made far less progress preventing cancer than preventing its predecessor scourges. We tamed infections with sanitation and vaccines, abetted by antibiotics. We tamed heart disease through smoking cessation, better medical management of risk factors such as high cholesterol, and improved interventions for a condition that has clear points of intervention and responds more readily to lifestyle changes.