Another step in the diagnostic process is grading the cancer cells - taking a measurement of how fast the tumor is likely to grow and spread. Grading is done in the laboratory with cells taken from the prostate gland during biopsy. The cancer cells are measured by how closely they look like normal cells.

According to the National Cancer Institute, one way of grading prostate cancer is the Gleason System. This grading system is based on a number range from 1 to 5. The lower the number, the lower the grade, and the slower the cancer is growing. High grade tumors (4 and 5) grow more quickly than low grade tumors (1 and 2), and are more likely to spread to other parts of the body.

The Gleason Score represents the sum of the two most common grades observed by the pathologist on a specimen (e.g. Gleason Score = 7 could be 3 + 4 or 4 + 3). The first number is the most frequent grade seen.

• Score 3 is intermediate between low grade and high grade tumor.

• Scores under 4 mean that the cancer cells look similar to your normal cells, and the cancer is likely to be less aggressive.

• Scores 5 to 6 are in the intermediate range. This means that the cancer cells do not look like normal cells, and are more likely to be aggressive and grow faster.

• Score 7 is a moderately poorly differentiated range. This means there are some more aggressive cells and some very aggressive cells.

• Scores 8 to 10 indicate that the cancer cells are more likely to be very aggressive in growth.