Surgical Oncology and Transplant Surgery
Two linked themes: how tumours behave and are staged, and how organs are allocated, transplanted and monitored. Questions frequently ask you to distinguish grade from stage, or to identify the type and timing of rejection.
Tumour biology and surgical oncology principles
- Hallmarks of cancer include self-sufficiency in growth signals, insensitivity to growth inhibition, evasion of apoptosis, limitless replication, angiogenesis, invasion and metastasis, and altered metabolism.
- Grade describes differentiation; stage describes anatomical extent. Stage predicts prognosis better than grade.
- Spread is local, lymphatic or haematogenous; the pattern differs by tumour (follicular thyroid and renal cell carcinoma favour blood, breast and colon favour nodes and then liver).
- The R status of a resection matters: R0 is microscopically clear, R1 microscopic involvement, R2 macroscopic residual disease.
- Neoadjuvant therapy downstages and tests biology; adjuvant therapy treats micrometastasis after resection.
- Multidisciplinary team discussion should be documented for every cancer; sentinel node biopsy is standard in melanoma and breast cancer.
Transplantation
- Brain death requires irreversible coma of known cause, absent brainstem reflexes and apnoea, with confounders excluded.
- Compatibility: ABO blood group, HLA matching (particularly DR and A/B), and a negative crossmatch - complement-dependent cytotoxicity and flow cytometry.
- Immunosuppression: induction agent, calcineurin inhibitor (tacrolimus), antimetabolite (mycophenolate) and steroid; long-term risks include infection, malignancy and nephrotoxicity.
- Rejection: hyperacute (preformed antibodies, minutes, dusky graft - remove it), acute cellular (days to weeks, fever, graft dysfunction, treat with steroids), chronic (months to years, fibrosis and graft loss).
- Renal transplant workup includes cardiac assessment and exclusion of active infection or malignancy; pre-emptive transplant is better than dialysis where possible. Liver allocation uses the MELD score.
- Post-transplant complications: delayed graft function, vascular thrombosis, urinary leak, biliary stricture, cytomegalovirus and post-transplant lymphoproliferative disease.
Worked example
A kidney recipient remains anuric immediately after reperfusion and the graft looks mottled and dusky. This is hyperacute rejection from preformed antibodies, confirmed retrospectively by a positive crossmatch. There is no effective treatment; the graft is removed and the patient returns to dialysis while awaiting a compatible organ.
Traps that lose marks
Treating grade as stage; forgetting a crossmatch before transplantation; attributing early graft dysfunction to rejection when it could be acute tubular necrosis or vascular thrombosis; missing a fever workup in an immunosuppressed patient.