The number of Americans alive with a history of cancer—a number now sitting at 13.7 million—will jump to almost 18 million by 2022, finds a new report from the American Cancer Society in collaboration with the National Cancer Institute.

The report finds that even though cancer incidence rates are decreasing, the number of cancer survivors is growing due to the aging and growth of the population, as well as improving cancer survival rates.

The report, published Thursday, says one in three women and one in two men in the U.S. will develop cancer during their lifetime. The three most common cancers among males living with a history of cancer in 2012 are prostate cancer (43 percent), colorectal cancer (9 percent), and melanoma (7 percent). Among women in 2012 with a history of cancer, the three most common cancers are breast (41 percent), uterine (8 percent), and colorectal (8 percent) cancer. In 2022, those proportions are expected to be largely unchanged.

But there’s a potential problem with the seemingly good news: Doctors may not be prepared to handle it. That’s in part because doctors aren’t educated enough on significant long-term effects of cancer treatment.

Common cancer treatment—such as chemotherapy and radiation—can leave long-term effects on the body. Many cancer survivors face blood disorders, cardiovascular problems and muscle pains after going into remission. There’s also emotional and psychological effects.

“With this effort, we review the critical issues related to cancer treatment and survivorship,” says Elizabeth Ward, senior author of the report. “Many survivors, even among those who are cancer free, must cope with the long-term effects of treatment, as well as psychological concerns such as fear of recurrence. As more people survive cancer, it is vital that health care providers are aware of the special needs of cancer patients and caregivers.”