Comparison of changes in serum prostate specific antigen in prostate cancer patients treated either with flutamide or stilboestrol monotherapy

Abstract

Prostate cancer is a disease of males. Though commoner in the elderly, cases are beginning to be reported in the younger population. It is the
commonest cancer diagnosed in males. Risk factors include ageing, genetic/familial factors, racial predilection, increased fat diet, and hormonal imbalance. It is a slow-growing tumour but can be associated with severe morbidity. The commonest histologic type is adenocarcinoma (>95%). When detected early, cure may be possible. Prostate-specific antigen (PSA) is the major serum marker used to monitor progress of the disease and its' response to therapy. Several treatment modalities have been used in the management of prostate cancer. This includes watchful waiting, prostatectomy, radiotherapy, hormone therapy, and chemotherapy. These treatment options are not without devastating and sometimes life-threatening adverse effects; hence the choice of therapy depends on patient's age, stage of disease, other co-morbidities, and even patient's choice.
Aims and Objectives: This study aimed at establishing the variation in PSA among patients with advanced CaP treated either with Flutamide
or Stilboestrol monotherapy in UCTH, Calabar. This helped in choosing an agent with better patient compliance, better therapeutic effect, minimal side-effects, and cost-effectiveness.
Method: All newly diagnosed prostate cancer patients in the Division of Urology, Department of Surgery, UCTH, Calabar that met certain inclusion criteria were treated either with Flutamide or Stilboestrol monotherapy over a period of one year. Patients enrolled into the study were shared into two equal groups based on certain considerations. Response to therapy was monitored by conducting a three-monthly PSA check and results from the groups compared.
Results: Fifty patients were enrolled into the study. The mean age was 70.12±8.93, and age range was 51-93 years. The peak age range was 61-70 years constituting 40.0% of total number of patients. The decline in serum PSA caused by flutamide and stilboestrol during each quarter of the year was 8.0%, 12.0%, 12.0%, 4.0% and 28.0%, 4.0%, 28.0%, 4.0% respectively. Overall flutamide caused a 36.0% reduction and stilboestrol 64.0% reduction in serum PSA over the period. In all, stilboestrol caused a greater decline in serum PSA compared to flutamide, and this became statistically significant at 9 months (p=0.044) and one year (p=0.048) of therapy.
Conclusion: Patients who are on androgen deprivation therapy for CaP have their serum PSA reduced by either flutamide or stilboestrol monotherapy. However, over time, the PSA is more rapidly reduced by stilboestrol monotherapy compared to flutamide monotherapy.

Keywords: Prostate Cancer, Flutamide, Stilboestrol, PSA.