Zagars GK, Pollack A, Pettaway CA
Abramson Cancer Center of the University of Pennsylvania
Last Modified: November 1, 2001
Reviewers: Kenneth Blank, MD
Source: International Journal of Radiation Oncology, Biology, and Physics, October 1, 1998, Vol 43 No. 2 p 517
Prostate cancer is the most common cancer in American males and the second leading cause of cancer death behind lung cancer. When caught early, prostate cancer is often cured with radiation, surgery or both. Advanced prostate cancer is rarely cured but has a prolonged natural history and patients often live years before succumbing to the disease.
Population based statistics have demonstrated that prostate cancer differs in African-Americans when compared to Caucasians. Prostate cancer occurs significantly more often in African-American males than Caucasians (180 per 100,000 versus 134 per 100,000) and African-Americans are more likely to die of prostate cancer (53 deaths per 100,000 versus 24 deaths per 100,000). The difference in mortality is partly explained by the higher incidence but data from the Surveillance, Epidemiology, and End Results (SEER) program reveals African-Americans to have lower five-year survival rates.
Why African-Americans with prostate cancer should fare worse than Caucasians is controversial. Some investigators believe the prostate cancer seen in African-Americans is more aggressive than that which occurs in Caucasians. Others argue that the difference in five-year survival rates stems from the fact that African-Americans present with more advanced disease. To address this issue, investigators at the M.D. Anderson Cancer Center in Houston, Texas reviewed their experience treating over 1,200 men with prostate cancer.
Between 1987 and 1996 1,085 Caucasians and 116 African-Americans males were treated with external beam radiation therapy at the M.D. Anderson Cancer Center. All men had cancer confined to the prostate gland. The two group of patients did not differ with respect to T-stage or Gleason score, but African-Americans did have significantly median higher pre-treatment prostate specific antigen (PSA) levels (14ng/ml versus 9.5ng/ml).
Patients were followed a median of 3.5 years with clinical exams and PSA levels. Survival and relapse analysis failed to reveal an outcome difference between the two groups. Specifically the freedom from clinical or biochemical relapse was similar and the rates of local recurrence and metastasis were similar. Actuarial six-year freedom from relapse was 63% and 61% in African-Americans and Caucasians, respectively. The authors conclude that the outcome of prostate cancer treated with radiotherapy is similar in the two groups and no evidence suggests prostate cancer in African-Americans is more malignant than in whites.