Intensity-Modulated Radiation Therapy With or Without Decreased Radiation Dose to Erectile Tissue in Treating Patients With Stage II Prostate Cancer

OBJECTIVES:

Primary

• Compare erectile dysfunction in patients with stage T1b-T2c adenocarcinoma of the prostate after treatment with intensity-modulated radiotherapy with vs without dose sparing for erectile tissue.

Secondary

• Compare biochemical freedom from failure rates, as a measure of prostate cancer control, in patients treated with these regimens.
• Compare the quality of life of patients treated with these regimens.
• Determine the association of molecular markers and biochemical freedom from failure rate and other endpoints in patients treated with these regimens.

OUTLINE: This is a randomized, single-blind study. Patients are stratified according to age (≤ 65 vs > 65), prescription radiotherapy dose (74 Gy vs 76 Gy), and frequency of erection during sexual activity within the past 4 weeks (a few times vs sometimes vs most times to always). Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients undergo conventional intensity-modulated radiotherapy (IMRT) once daily 5 days a week for approximately 7.5 weeks.
• Arm II: Patients undergo IMRT with dose restriction to erectile tissue once daily 5 days a week for approximately 7.5 weeks.

Treatment in both arms continues in the absence of unacceptable toxicity or disease metastasis.

Quality of life is assessed at baseline, at 6 and 12 months, and then annually for 4 years

Patients are followed at 3 months and then every 6 months thereafter.

PROJECTED ACCRUAL: A total of 200 patients (100 per treatment arm) will be accrued for this study within 2.5 years.

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the prostate

• Clinical stage T1b-T2c by palpation
• Pretreatment prostate-specific antigen ≤ 20 ng/mL
• Gleason score ≤ 7
• Suitable erectile function, defined as a response ≥ score 2 in question #1 of the International Index of Erectile Function Questionnaire
• No clinical, radiographic, or pathologic evidence of nodal or distant metastatic disease

PATIENT CHARACTERISTICS:

Age

• Not specified

Performance status

• Zubrod 0-1

Life expectancy

• Not specified

Hematopoietic

• Not specified

Hepatic

• Not specified

Renal

• Not specified

Other

• Fertile patients must use effective contraception
• No other active malignancy within the past 5 years except nonmetastatic skin cancer or early-stage chronic lymphocytic leukemia (well-differentiated small cell lymphocytic lymphoma)
• No other medical condition that would preclude study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• Not specified

Endocrine therapy

• Prior androgen-ablation therapy allowed provided total calculated duration ≤ 4 months

Radiotherapy

• No prior pelvic radiotherapy

Surgery

• No prior or planned radical prostate surgery