Surgical Oncology
Surgical Oncology tests the language of staging, the logic of multidisciplinary treatment and the principles that distinguish a cancer operation from a simple excision.
Core principles
- Stage before you cut: TNM (T for tumour size or depth, N for regional nodes, M for metastasis) drives the plan.
- R0 means no residual tumour with negative margins; R1 microscopic residual; R2 macroscopic residual. Aim for R0 with an en-bloc resection and adequate margins.
- Lymphadenectomy is both staging and therapeutic; sentinel node biopsy is standard for clinically node-negative breast cancer and melanoma.
- Neoadjuvant therapy downsizes locally advanced disease and tests tumour biology; adjuvant therapy treats micrometastatic disease after resection.
Tumour-specific anchors
- Rectal cancer: T3 or node-positive disease receives neoadjuvant chemoradiotherapy then total mesorectal excision; a complete clinical response may permit watch-and-wait.
- Oesophageal cancer: stage with CT, PET and endoscopic ultrasound; neoadjuvant chemoradiotherapy then oesophagectomy for locally advanced disease.
- Breast: triple assessment; breast-conserving surgery plus radiotherapy is equivalent to mastectomy for suitable tumours.
- Colorectal liver metastases: resect when R0 is achievable with an adequate future liver remnant; five-year survival approaches 40%.
- Melanoma: Breslow thickness and ulceration determine margins (1-2 cm) and sentinel node eligibility.
Worked example
A 58-year-old has a mid-rectal adenocarcinoma staged T3N1M0 with no metastases. The correct plan is neoadjuvant long-course chemoradiotherapy, restaging, then total mesorectal excision with sharp mesorectal dissection - operating first risks a positive circumferential margin and local recurrence.
Traps
Confusing R1 with M1; staging after rather than before resection; offering surgery alone for locally advanced rectal cancer; forgetting that a positive circumferential resection margin predicts local recurrence independent of nodal status.