Note: Some citations in the text of this section are followed by a level of evidence. The PDQ editorial boards use a formal ranking system to help the reader judge the strength of evidence linked to the reported results of a therapeutic strategy. (Refer to the PDQ summary on Levels of Evidence for more information.)

Stage II prostate cancer is defined by the following staging systems:

• American Joint Committee on Cancer's (AJCC) TNM classification system:
  • T1a, N0, M0, G2-4.
  • T1b, N0, M0, any G.
  • T1c, N0, M0, any G.
  • T1 (not further specified), N0, M0, any G.
  • T2, N0, M0, any G.
• Jewett staging system: stage A2 or B1 or B2.

Previous versions of the AJCC staging system described a tumor's grade as moderately differentiated, poorly differentiated, or undifferentiated, but these terms are no longer used. G2 is the equivalent of moderately differentiated, and G3-4 is the equivalent of poorly differentiated and undifferentiated.

Treatment information for patients whose disease has the following TNM classifications:

• T1a, N0, M0, G2-4.
• T1b, N0, M0, any G.
• T1c, N0, M0, any G.
• T1 (not further specified), N0, M0, any G.
• T2, N0, M0, G1-2.

A trial has been reported in which 695 men with newly diagnosed well-differentiated or moderately well-differentiated prostate cancers of clinical stages T1b, T1c, or T2 were randomly assigned to receive radical prostatectomy versus watchful waiting.[1] In contrast to prostate cancer patients in the United States, most of the men in this study had been diagnosed clinically, rather than by screening. At a median follow-up of 6.2 years, prostate cancer-specific mortality was 4.6% in the prostatectomy arm of the study versus 8.9% in the watchful waiting arm (P = .02);[1][Level of evidence: 1iiB] however, overall mortality in the two groups was similar (P = .31).[1][Level of evidence: 1iiA] After 10 years, the difference in overall survival (OS) was approximately 73% versus 68%; absolute difference 5.0%; relative risk of death 0.74 (95% confidence interval [CI], 0.56-0.99). This benefit was restricted to men younger than 65 years at the time of surgery (P = .01 in a planned subset analysis of the effect of age on treatment efficacy).[2] A quality-of-life substudy was conducted in 326 of the men in the randomized study.[3] Men filled out questionnaires at a median of about 4 years after study entry. The principal differences in symptoms between the two groups were in sexual and urinary function. In the surgery and watchful waiting groups, 80% versus 45% of the men answering the questionnaire said they seldom or never had erections sufficient for sexual intercourse. Forty-nine percent of men in the prostatectomy arm had urinary leakage at least once a week, 43% used protective aids regularly, and 14% used diapers or urine bags compared to 21%, 10%, and 1%, respectively, in the watchful waiting arm; however, the men on the watchful waiting arm had more obstructive symptoms (e.g., severe symptoms on the American Urologic Symptom Index of 7% in the watchful waiting arm vs. 10% in the prostatectomy arm and moderate symptoms of 42% vs. 24%).[3][Level of evidence: 1iiC]