Testicular Germ Cell Tumor

 

• Background

  Pathology

  • 95% of testicular cancers are germ cell tumours (GCT).
  • Other types include sex cord-gonadal stromal tumours (Leydig or Sertoli cells), and mesenchymal tumours.
  • GCTs grow quickly but are therefore highly curable as are very sensitive to chemotherapy, even in extensive mets or relapse.
  • Testicular GCTs are divide into seminomas (50%) – arising from germ cells – and non-seminomatous GCTs (NSGCT, 50%), which include teratomas (mature, differentiated tissue) and choriocarcinomas (placental tissue).

  Epidemiology

  • 1 in 200 lifetime risk.
  • Peak onset age 20-40. Teratoma commoner <30, seminoma commoner >30.

• Signs and symptoms

  Scrotal:

  • Painless solid unilateral lump, or testicular enlargement. Occasionally, reduction in testicle size.
  • Scrotal pain or dragging sensation (20%).
  • May cause secondary hydrocele.
  • On examination: a firm lump in the scrotum which you can get above (unlike hernia), and which does not transilluminate (unlike cyst).

  Other features:

  • Gynaecomastia (5%) if β-hCG producing.
  • Back ache if spread to para-aortic lymph nodes.
  • Ureteric obstruction.
  • Systemic: weight loss, fatigue.
  • Lung spread: SOB, SVC obstruction.

• Risk factors

  • Family history.
  • Cryptorchidism. Orchidopexy partially reduces risk.
  • Klinefelter's and other causes of infertility.
  • Testicular atrophy e.g. post trauma, mumps orchitis.
  • Infantile hernia.

• Differential diagnosis

  Scrotal lumps:

  • Epididymal cyst
  • Hernia
  • Varicocele
  • Hydrocele
  • Haematocele

  Testicular pain or swelling:

  • Epididymo-orchitis.
  • Torsion
  • Leukaemia or lymphoma infiltration.

• Investigations

  Initial:

  • Scrotal US.
  • CXR: may show bilateral hilar lymphadenopathy or cannonball mets.

  Tumour markers, BAL:

  • β-hCG: 65% of NSGCT, 15% of seminoma.
  • AFP: 80% of NSGCT.
  • Very specific if both β-hCG and AFP are elevated. Also help guide prognosis. Check they both return to normal post-surgery: hCG within 24h (but can initially rise after chemo due to lysis), and AFP within 5 days.
  • LDH: measures 'bulk' of disease and rapidity of growth.

  Diagnosis by orchiectomy (not biopsy) and histology.

  Staging after diagnosis:

  • Contrast CT chest, abdo, pelvis.
  • CT brain if lung mets or hCG >10,000.
  • Stages: 1 testis, 2 nodes below diaphragm, 3 nodes above diaphragm, 4 mets.

• Management

  Surgery for all suspected testicular cancer:

  • orchiectomy via inguinal approach and insert prosthesis. Inguinal approach allows cord clamping first and prevents seeding of scrotal skin.
  • Consider biopsy of contralateral testicle, especially if atrophic or age <30. May show carcinoma in situ (5%), which can be treated by radiotherapy or (ideally) removal.

  Post-surgery for localised disease (stage 1):

  • Surveillance alone for low risk stage 1.
  • Seminoma: para-aortic radiotherapy or single-dose carboplatin for higher risk stage 1 seminoma (rete testis infiltration or tumour size ≥4 cm).
  • NSGCT: BEP chemotherapy if high risk or unwilling for surveillance.

  Lymph nodes and metastases (stages 2-3):

  • Adjuvant BEP chemotherapy: Bleomycin, Etoposide, cisPlatin.
  • Other cisplatin based regimens can also be used in NSGCT e.g. VIP: Vinblastine, Ifosfamide, cisPlatin.
  • Adjuvant radiotherapy for stage 2 seminoma.

  Fertility issues:

  • Offer sperm storage, especially if undergoing chemo or radiotherapy, but even unilateral orchiectomy reduces sperm quality.

• Complications and prognosis

  5 year survival: 95%.

  Relapse:

  • Seminoma: very treatment-sensitive, only 1% relapse.
  • NSGCT: 30% relapse, usually in abdominal lymph nodes, so need intensive surveillance with clinical examination, serum markers, CXR, and CT.

  Treatment complications:

  • CVD including hypertension due to nephrotoxicity.
  • Bleomycin: pneumonitis, pulmonary fibrosis.
  • Secondary cancer: haematological if chemo (5 year latency), solid tumours if radiotherapy (10-15 year latency).
  • Psychosexual issues.