Testicular Cancer

Overview

Around 95% of testicular cancers are germ cell tumours, which arise from germ cells (cells that give rise to gametes). Germ cell tumours can broadly be divided into:

• Seminoma (~50%):
  • Tumours that arise in the seminiferous tubules of the testis
• Non-seminomatous germ cell tumours (NSGCTs):
  • All other germ cell tumours that are not seminomas (e.g. embryonal carcinoma, yolk sac tumour, teratoma, and choriocarcinoma). 

Non-germ cell tumours can include sex cord-stromal tumours such as Sertoli cell or Leydig cell tumours. 

Relation to biomarkers

Alpha-fetoprotein (AFP) is secreted by the foetal yolk sac during foetal development. Yolk sac tumours, teratomas, or other tumours that contain embryonic-like tissue may secrete AFP. Seminoma does not secrete AFP. Therefore, elevated AFP suggests a non-seminomatous testicular tumour.

Human chorionic gonadotropin (hCG) is secreted by syncytiotrophoblasts in the placenta during pregnancy. Both seminoma and non-seminomatous tumours may transform into syncytiotrophoblasts and secrete hCG.

Lactate dehydrogenase is a non-specific marker of tissue turnover and is found in nearly all tissues in the body. It may be elevated in many different cancers, suggesting increased tumour burden.

Epidemiology

• Over 2000 new testicular cancers are diagnosed yearly
• Testicular cancer most commonly presents between 15-35 years of age but can occur in older people too

Risk Factors

• Whit ethnicity
• Family history
• Undescended testis (cryptorchidism) including its causes
• Subfertility/infertility
• Klinefelter’s syndrome
• Contralateral tumour
• Orchitis due to mumps

Presentation

Overview

Features include:

• Painless testicular lump – in >90% of people
  • There may be some pain or discomfort described as ‘heavy’ or ‘dragging’
• Hydrocele
• Gynaecomastia – if the tumour produces beta human chorionic gonadotropin (beta-hCG):
  • Increased beta-hCG results in increased oestrogen and testosterone production, but oestrogen is produced in larger amounts
• Lymphadenopathy – supraclavicular or retroperitoneal (presents as an abdominal mass):
  • Suggests metastasis
• Back pain – seminomas may metastasise to the para-aortic lymph nodes

Referral and Investigations

Referral

An urgent referral using a 2-week suspected cancer pathway should be made if any of the following apply:

• Non-painful lump or change in shape or texture of the testis
• Ultrasound imaging incidentally finds evidence suggestive of testicular cancer

Consider a direct access ultrasound scan for testicular cancer for people with unexplained or persistent testicular symptoms.

Investigations

Key investigations include:

• Ultrasound – the first-line investigation:
  • Identifies testicular mass
• Blood tests for tumour markers:
  • Alpha-fetoprotein (AFP):
    • May be elevated in non-seminomas, not elevated in seminoma
  • Human chorionic gonadotropin (hCG):
    • May be elevated in seminomas and non-seminomas
  • Lactate dehydrogenase (LDH):
    • Non-specific and may be elevated in many different cancers, not just testicular
    • Increased levels suggest higher tumour burden 

Other tests include:

• Chest X-ray:
  • To screen for lung and mediastinal metastases
• CT scanning:
  • For staging and to screen for metastasis

Differential Diagnoses

See Groin and Scrotal Lumps.

Management

Overview

Management is guided by a multidisciplinary team and depends on if the tumour is a seminoma or non-seminomatous germ cell tumour. Treatment may involve surgery to remove the affected testis (orchidectomy), chemotherapy, and/or radiotherapy.

Monitoring

CT scans, chest X-rays, and tumour markers may be monitored to assess for recurrence.

Complications

• Metastasis – usually the lymph nodes, lungs, liver, and brain
• Subfertility/infertility
• Hypogonadism

Prognosis

• With early diagnosis and management, cure rates are over 90%
• The prognosis is worse with non-seminomatous germ cell tumours
• Choriocarcinomas have the worst prognosis