Penile metastasis of prostatic adenocarcinoma: Report of two cases and review of literature

Metastasis to the penis is rare, despite rich vascularisation and complex circulation. These most commonly arise from the prostate and the bladder [1, 2]. It is a debilitating near terminal condition at presentation with a dismal prognosis. Conservative management is generally advocated with emphasis on improvement of quality of life. Therapeutic modalities used include radical penile amputation and radical radiotherapy. We discuss two patients who underwent differing treatment; the presenting features and symptomatology of all other cases reported in the literature have been reviewed.

Ninety-eight cases of penile metastases from prostate cancer were identified in the literature [3–10]. Patients were between 42 to 93 years (average 70 years). Urinary symptoms were noted in 28 patients, varying in severity from urethral bleeding to complete urinary retention. Priapism was reported in half the patients, ten of whom also had urinary retention. In 16 patients, the presenting symptom was penile pain; seven of whom had palpable penile nodules. Of 75 patients, metastases was restricted to the corpora cavernosa in 32 patients, glans penis in 12, urethra in four, skin/prepuce in four and corpus spongiosum in three and 20 having multiple involved areas. Biopsy was the mainstay of diagnosis in all the patients with three having additional cystoscopies. 33 patients underwent surgery such as penile amputation, cystostomy and bilateral orchidectomy. Fifteen patients each received radiation and hormonal treatment. These patients had a poor prognosis with survival documented at between 10 days and 84 months, with an average of 6 months, from presentation.

Metastatic spread from the prostate to the penis occurs by several routes [7, 10], retrograde venous or lymphatic spread, and direct extension are the commonest mechanisms. The most reliable diagnostic modality remains the needle core biopsy; this allows for histological and immunological confirmation of metastatic spread, and evaluation of extent of invasion [5]. Treatment options depend on the general condition of the patient, site and extent of the primary tumour, presence of metastases, and symptomatology. The treatment options available include local excision of the tumour, radiation therapy, bilateral orchidectomy, additional hormonal and/or chemotherapy and, partial or total amputation of the penis. In patients who present with urinary tract outflow obstruction, procedures such as cystostomy or suprapubic catheterisation are of palliative value [7]. Amputation of the penis with urethrostomy formation is to be considered in patients with ulceration, irritating secretion and intractable penile pain for symptom control. In one of our cases treatment followed palliative lines but in the other, subtotal penectomy for severe intractable penile pain, resulted in immediate pain relief and marked improvement in quality of life. Emphasis should be on palliative treatment and improving quality of life in view of the poor prognosis and a 6-month mortality of 80%. Surgery could be a therapeutic option, but only in patients attended with severe intractable pain.