context: Prostate cancer starts when cells in the prostate gland grow out of control. Those cells can spread to other parts of the body and affect healthy tissue. This can happen for several reasons. When prostate cancer is discovered early, treatment usually works. Most men are able to live cancer-free for many years. But sometimes, treatment doesn't work and prostate cancer can slowly grow. This can happen after surgery (called a radical prostatectomy) or radiation therapy. Sometimes called a chemical recurrence, it's when the cancer survives inside the prostate or reappears and spreads to other tissues and organs. The cancer is usually microscopic and grows very slowly. You and your doctor will work together to keep an eye on the cancer as it grows. You may come up with a new treatment plan. Because prostate cancer cells usually grow very slowly, some men might not need treatment right away. Your doctor might suggest something called "watchful waiting" or "active surveillance." Your doctor will still do regular blood tests and exams to keep an eye on your cancer. This plan is usually for men who don't have symptoms and whose cancer is expected to grow slowly. The risk with this approach is that the cancer might grow and spread between checkups. This could limit which treatment you could take and if your cancer can be cured. When you're diagnosed with cancer, like any medical issue, it's important that you follow your treatment plan. That can mean scheduling regular checkups or, if radiation therapy is part of your regimen, being sure to go to all scheduled radiation visits. If you miss some of them, you may have a greater chance that your cancer will spread. In one study, for example, men who missed two or more sessions during their treatment had a greater chance that their cancer would come back. That was even though they eventually finished their course of radiation. Experts disagree on whether all men should get tested for prostate cancer and at what age screenings and the discussions about them should take place. Exams such as a prostate-specific antigen ( PSA) test can help find cancer early. But there are questions about if the benefits of screening tests always outweigh the risks. Some groups suggest that men at a normal risk for prostate cancer should have prostate screening tests when they turn 50. Some men might want to get tests earlier if they have risk factors that make them more likely to get prostate cancer. The U. S. Preventive Services Task Force ( USPSTF) says that testing may be appropriate for some men age 55 to 69. They recommend that men talk to their doctor to discuss the potential risks and benefits of being tested. The American Cancer Society recommends starting screenings at age 50, possibly earlier if at high risk. But first, men should discuss the pros and cons of the PSA test with their doctor to decide if it's right for them. The American Urological Association says if you are a man age 55 to 69, you should talk to your doctor about the benefits and risks of a PSA test. The group also adds: PSA screening in men under age 40 is not recommended. Routine screening in men between ages 40 and 54 at average risk is not recommended. To reduce the harms of screening, a routine screening interval of two years or more may be preferred over annual screening in those men who have decided on screening after a discussion with their doctor. As compared to annual screening, it is expected that screening intervals of two years preserve the majority of the benefits and reduce over diagnosis and false positives. Routine PSA screening is not recommended in men for most men over 70 or any man with less than a 10 to 15 year life expectancy. There are some men age 70 and older who are in excellent health that may benefit from prostate cancer screening. Early prostate cancer usually has no symptoms. You may go to see the doctor when you have trouble urinating or pain in your hips and back. That's when prostate cancer may be discovered. After that, your doctor may find out that your cancer has already spread beyond your prostate. If that's a possibility, you may be asked to take a test like a: Bone scan MRI Ultrasound CT scan PET scan Knowing if your cancer has spread will help your doctor work with you to choose your best treatment.