A Gleason score of 7 means the cancerous cells are slightly abnormal and have an intermediate risk for spreading aggressively, according to WebMD. Gleason scores range from 2 to 10, and ratings between 2 and 4 mean that the cells are somewhat normal and have little risk of spreading quickly.
In order for a Gleason score to be determined, a patient has a prostate biopsy, explains WebMD. The biopsied tissue is examined under a microscope, and a pathologist studies the most common tumor patterns. The tumor patterns are given a grade of 1 to 5, which are then combined to create the Gleason score.
Patients with Gleason scores over 8 have a highly aggressive type of prostate cancer, and patients with scores under 6 have cancer that is not nearly as rapid, states the American Cancer Society. Therefore, patients that have a Gleason score of 7 are right on the cusp of the two, meaning that the cancer is still strong and aggressive, yet is slow enough to allow the patient to seek treatment.
In some cases, a Gleason score of 7 can mean that the cancer hasn't spread to the lymph nodes or any other part of the body, explains the American Cancer Society. It is important to look at all other factors, including PSA levels, when diagnosing prostate cancer and one's prognosis.