- 95% of testicular tumours are germ cell tumours (GCTs); 95% of GCTs originate in the testicle, 5% are primary extra-gonadal.
- Testicular cancer is the most common malignancy among males aged 20–39; 5-year relative survival is ≈95%.
- All adult invasive GCTs arise from germ cell neoplasia in-situ (GCNIS), except spermatocytic seminoma.
- Cryptorchidism raises risk in the ipsilateral testis 4–6×; orchidopexy before puberty lowers risk to 2–3×; contralateral testis risk is also slightly increased (RR ≈1.74).
- Increased copies of the short arm of chromosome 12 (i(12p)) are a universal finding in testicular and extra-gonadal GCTs; spermatocytic seminoma does not demonstrate i(12p).
- Seminoma comprises 52–56% of GCTs and occurs in the 4th–5th decade; NSGCT comprises 44–48% and occurs at a younger age.
- AFP is produced by yolk sac tumour, embryonal carcinoma, and teratoma — NEVER by pure seminoma or choriocarcinoma; pure seminoma with elevated AFP is treated as NSGCT.
- hCG is produced by choriocarcinoma, embryonal carcinoma, and ≈15% of seminomas; levels >10,000 IU/L are usually choriocarcinoma.
- Tumour marker half-lives: AFP 5–7 days, β-hCG 24–36 hours; LDH is non-specific and reflects bulk of disease.
- Painless scrotal mass is the most common presentation; 10–20% present with symptoms of metastatic disease.
- Lymphatic drainage of the testis crosses retroperitoneal midline from right to left — right testis tumours drain primarily to inter-aortocaval nodes; left testis tumours drain primarily to para-aortic nodes.
- Trans-scrotal orchiectomy is contraindicated due to scrotal violation, which increases risk of pelvic/inguinal nodal metastasis and local recurrence.
- Testis-sparing surgery may be considered for masses <2 cm with equivocal imaging/negative markers, a solitary testis, or bilateral synchronous tumours; ≈50–80% of TSS specimens contain concomitant GCNIS.
- GCNIS can be managed by orchiectomy, low-dose (18–20 Gy) radiotherapy, or surveillance — radiation preserves Leydig function but causes permanent sterility of the treated testis.
- Chest x-ray is acceptable in suspected CS I seminoma; CT chest is required for NSGCT, rising post-orchiectomy markers, or any other evidence of metastasis.
- AJCC 8th edition seminoma pT1 sub-stages: pT1a <3 cm, pT1b ≥3 cm; pT2 includes LVI or invasion of hilar soft tissue/epididymis/tunica vaginalis; pT3 = spermatic cord soft tissue invasion; pT4 = scrotal invasion.
- IGCCCG classifies metastatic GCT into good/intermediate/poor prognosis (no poor category for seminoma); based on primary site, non-pulmonary visceral metastases, and post-orchiectomy marker levels at initiation of chemotherapy.
- CSIA/IB seminoma: preferred is surveillance; alternatives are para-aortic radiotherapy (20 Gy) or single-dose carboplatin (1 cycle).
- CSIA/IB NSGCT: options are surveillance (preferred for CSIA), primary RPLND, or BEP×1–2 — risk factors for relapse on surveillance are predominant embryonal carcinoma and lymphovascular invasion.
- CSIIA/IIB seminoma: dog-leg radiotherapy (25–35 Gy) or BEP×3 / EP×4; bulky (>3 cm) or multifocal disease favours chemotherapy.
- CSIIC and III GCT: induction chemotherapy by IGCCCG risk — BEP×3 or EP×4 for good-risk, BEP×4 for intermediate/poor-risk; VIP×4 substitutes for BEP×4 if compromised pulmonary function.
- Post-chemotherapy residual mass histology in NSGCT: ≈40% necrosis/fibrosis, ≈45% teratoma, ≈15% viable malignancy — teratoma is chemoresistant and must be resected.
- Post-chemotherapy seminoma residual masses: 90% necrosis, 10% viable; observe if <3 cm; use FDG-PET if >3 cm — PET-positive → surgery, PET-negative → observe.
- FDG-PET has NO role in evaluating post-chemotherapy residual masses in NSGCT.
- Growing teratoma syndrome: enlarging metastases with declining/normalised tumour markers during chemotherapy — interrupt chemo and resect.
- Radical orchiectomy is performed via an inguinal approach with high ligation of the spermatic cord at the internal inguinal ring; the vas deferens should be ligated separately to facilitate later RPLND retrieval.
- Ilioinguinal nerve (L1) provides sensation to anterior scrotum, root of penis, and upper medial thigh — preserve during orchiectomy.
- Full bilateral RPLND template boundaries: superiorly the diaphragm crura/renal vessels, inferiorly the iliac bifurcation/ureter crossing, laterally the ureters.
- Nerve-sparing RPLND preserves antegrade ejaculation in 90–100% of patients; the post-ganglionic sympathetic fibres at L1–L4 coalesce in the superior hypogastric plexus and drive emission and bladder neck closure.
- Bleomycin-exposed patients undergoing surgery are at risk for postoperative respiratory distress — use low FiO₂ and conservative intraoperative fluid resuscitation.
- Chylous ascites occurs in 0.2–2% of primary RPLND and 2–7% of PC-RPLND; manage with paracentesis, low-fat/MCT diet, octreotide, indwelling drain, or TPN.
- Primary mediastinal NSGCT is more often yolk sac, associated with Klinefelter syndrome, less chemo-sensitive, and has a poorer prognosis than testicular NSGCT; primary mediastinal seminoma behaves like testicular seminoma.
- Brain metastases are associated with choriocarcinoma and very high hCG levels — choriocarcinoma is highly vascular and may haemorrhage during chemotherapy (4–10% intracranial haemorrhage death rate).
- Non-germ cell tumours comprise 5% of testicular tumours; ≈90% of sex-cord stromal tumours (Leydig, Sertoli, granulosa) are benign — metastatic disease is the only reliable criterion of malignancy.
- Non-Hodgkin lymphoma is the most common testicular neoplasm in men aged >50; bilateral involvement occurs in 35% of cases.
- Most common metastases to the testis are from prostate, lung, melanoma, colon, and kidney.
- Adenomatoid tumour is the most common paratesticular tumour; liposarcoma is the most common adult paratesticular sarcoma — manage paratesticular sarcoma with wide inguinal resection and consider adjuvant radiotherapy for liposarcoma.
- Late toxicity of platinum-based chemotherapy and/or subdiaphragmatic radiation: hypogonadism, infertility, cardiovascular disease, and secondary malignancy — patients need lifelong primary care follow-up.