Definition of Curative Resection
Curative resection is defined by two fundamental criteria: complete removal of the primary tumor with negative margins and negligible risk of lymph node metastasis. 1
Core Principles
The assessment of curability requires evaluation of both:
- Completeness of primary tumor removal - ensuring all cancer tissue is excised with clear margins 1
- Nil possibility of lymph node metastasis - confirming the tumor characteristics predict minimal to no risk of nodal spread 1
Specific Criteria for Endoscopic Resection (Gastric Cancer)
Standard Curative Resection
For standard absolute indications, a resection is curative when ALL of the following are met: 1
- En-bloc resection (single-piece removal)
- Tumor size ≤2 cm
- Histologically differentiated-type adenocarcinoma
- Depth limited to mucosa (pT1a)
- Negative horizontal margin (HM0)
- Negative vertical margin (VM0)
- No lymphovascular infiltration (ly(-), v(-))
Expanded Indication Curative Resection
For tumors meeting expanded criteria, curative resection requires: 1
- En-bloc resection
- HM0, VM0
- ly(-), v(-)
- Plus specific size/depth criteria depending on tumor characteristics:
- Differentiated-type, no ulcer, >2 cm diameter
- Differentiated-type with ulcer, ≤3 cm diameter
- Undifferentiated-type, no ulcer, ≤2 cm diameter
- Differentiated-type with minimal submucosal invasion (SM1, <500 microns)
Surgical Resection Principles
General Surgical Criteria
For surgical resection with curative intent, the goal is R0 resection - meaning all gross and microscopic disease is removed with negative margins. 1, 2, 3
Key surgical requirements include: 1, 2
- Adequate resection margins (typically 5-6 cm from tumor in gastric cancer)
- Appropriate lymphadenectomy (removal of at least 25 lymph nodes for proper staging in gastric cancer)
- En-bloc resection when feasible (particularly important for recurrent disease)
- No macroscopic residual disease
Critical Pitfalls to Avoid
Piecemeal resection is generally non-curative unless it involves a differentiated-type carcinoma meeting all other criteria, and even then requires careful consideration for additional surgical treatment. 1
Mixed histology tumors require special attention: 1
- Differentiated tumors with undifferentiated components >2 cm are non-curative
- Any undifferentiated component in submucosal invasion renders the resection non-curative
- These cases mandate additional surgical treatment
Positive margins (HM1) as the sole non-curative factor in differentiated-type carcinoma may be managed with repeat endoscopic treatment or close observation in select cases, given the very low risk of lymph node metastasis, but this requires informed patient consent. 1
Non-Curative Resection
Any resection failing to meet the above criteria is considered non-curative and typically requires additional surgical treatment. 1
The presence of lymphovascular invasion, positive margins, or tumor characteristics suggesting higher risk of nodal metastasis automatically classifies the resection as non-curative, necessitating further intervention to optimize patient outcomes.