24/7 Wall St.

Despite progress in managing risks, early detection, and treatment, cancer remains the second-leading cause of death in the United States. More than 1.5 million Americans are diagnosed with cancer every year, and more than half a million die from the disease. The number of new cancer cases is expected to climb to nearly 2 million a year by 2020. At this rate, cancer will be the leading cause of death in the U.S., according to the Centers for Disease Control and Prevention (CDC).

The 10 states with the fewest cancer diagnoses per 100,000 people are New Mexico, Nevada, Arizona, Colorado, Utah, California, Wyoming, Texas, Hawaii, and Alaska. The 10 states with the most new cancer cases for every 100,000 people are Kentucky, Delaware, Louisiana, Pennsylvania, New York, Maine, New Jersey, Iowa, Rhode Island, and Connecticut.

24/7 Wall St. reviewed the age-adjusted cancer incidence rate in every state from data compiled by the CDC. Here’s a closer look at what these states have in common and the factors that might contribute to the ranking of cancer incidence of a particular state.

Click here to see the states with the highest cancer rates.

The 10 states with the fewest new cancer diagnoses per 100,000 people are all in the West. The 10 states with the most new cancer diagnoses per 100,000 are mostly in the Northeast and New England.

Rebecca Siegel, an epidemiologist and strategic director of surveillance information services at the American Cancer Society, offered an explanation. “Western states generally have the lowest cancer incidence rates because of healthier lifestyles like less smoking (except Nevada) and obesity,’’ she said.

Regarding the higher rates of cancer diagnoses in the Northeast, where states such as New Jersey are dealing with a legacy of toxic waste, Siegel said it was “extremely challenging to measure the influence of environmental exposures, such as toxic waste, on the cancer burden, but they are thought to account for a relatively small proportion overall.’’ She added that less industry in the West compared with the Northeast may contribute to the fact that there are lower rates of cancer diagnoses, though she was not aware of any data to support this.

The National Cancer Institute says advancing age is the most important risk factor for cancer overall. According to recent data from NCI’s Surveillance Epidemiology and End Results program, the median age of someone diagnosed with cancer is 66 years.

Five of the 10 states with the fewest cancer diagnoses per capita are among the youngest in the nation: Utah, Alaska, Texas, California, and Colorado. Utah has the youngest median age of any state at 30.6 years, according to the U.S. Census Bureau’s 2015 American Community Survey. The U.S. median age is 37.8 years. Utah also has the fewest total cancer deaths and lung cancer fatalities per 100,000 people of any state as well as the lowest percentage of adults who smoke.

Maine, on the other hand, has the nation’s oldest population with a median age of 44.6 years old. The state also has the sixth-highest incidence of cancer diagnoses a year. In general, the median age of every Northeastern and New England state is above the national median.

Breast cancer is the most commonly diagnosed form of the disease in every state except for Louisiana and Mississippi, where prostate cancer is more frequently diagnosed. However, those are not the most deadly cancers; lung cancer is the most fatal form of the disease in every state.

Incidences of the skin cancer melanoma in Western states — which get more sun than other parts of the country — were not much different than in the rest of the nation, according to data from the NCI. Of the 10 states that report fewer overall cancer diagnoses per 100,000 people, only four have incidences of melanoma above the national rate of 20.7 cases per 100,000 people.

Click here to see the states with the highest cancer rates.