6. Surgical Oncology: Basic Concepts, TNM Staging, Neoadjuvant and Adjuvant Treatment, Onco-Team

I. Basic Concepts of Surgical Oncology

• Surgical oncology: Surgical specialty dealing with diagnosis, staging, operative treatment and follow-up of solid malignant tumors
• Main task → Choose the correct operation in the correct patient at the correct stage
• Cancer treatment is multimodal → Surgery + chemotherapy + radiotherapy + targeted/immuno-/hormonal treatment when indicated

Indications for Surgery

• Relative indication → Benign tumor, premalignant lesion, uncertain diagnosis, symptoms or cosmetic/functional problem
• Absolute indication → Malignant tumor when surgery gives diagnostic, curative or important palliative benefit
• Vital indication → Tumor causes life-threatening complication

• Examples → Bleeding, perforation, bowel obstruction, biliary obstruction/cholangitis, airway obstruction, vascular compression

Operability and Resectability

• Operability refers to the patient
• Depends on general condition → Age, ECOG/WHO performance status, frailty, cardiopulmonary reserve, renal/liver function, nutrition, comorbidities
• Inoperable patient → Patient cannot safely tolerate the planned operation/anesthesia
• Resectability refers to the tumor
• Depends on anatomy and biology → Can the tumor be completely removed with acceptable margins and acceptable morbidity?
• Unresectable tumor → Cannot be removed radically because of local invasion into vital structures or technical/anatomic limits
• Incurable disease → Disseminated/metastatic disease where complete cure is not achievable by surgery alone

• A patient can be operable but the tumor unresectable
• A tumor can be resectable but the patient inoperable

Therapeutic Aim

• Curative surgery → Complete macroscopic and microscopic removal of tumor, usually with regional lymphatic clearance when indicated
• R0 resection → No residual tumor microscopically; best surgical oncological goal
• R1 resection → Microscopic residual tumor
• R2 resection → Macroscopic residual tumor
• Palliative surgery → Tumor cannot be completely cured surgically, but operation improves symptoms/QOL or prevents/treats complications

• Palliative examples → Stoma/bypass for obstruction, hemostasis for bleeding tumor, perforation control, decompression, feeding access, pain relief
• May improve condition so systemic therapy can be given

Goals of Surgical Oncology

• Obtain diagnosis → Biopsy, excision biopsy, staging laparoscopy/thoracoscopy
• Stage disease → Assess local extent, nodal disease and distant metastasis
• Curative resection of primary tumor
• Regional lymph node staging/treatment → Sentinel node biopsy or lymphadenectomy when indicated
• Debulking/cytoreduction in selected tumors
• Reconstruction → Breast reconstruction, GI continuity, flap coverage, functional restoration
• Palliation → Relieve obstruction, bleeding, perforation, pain, infection

Principles of Oncological Surgical Technique

• No-touch technique → Avoid direct compression/manipulation of tumor; reduce tumor cell dissemination
• Early vascular control → Early vein/vascular ligation when anatomically appropriate to reduce hematogenous spread
• Wide local excision → Remove tumor with sufficient macroscopic margin to achieve negative microscopic margin
• En-bloc resection → Remove primary tumor with involved adjacent organs/tissues/lymph nodes in one block
• Do not cut through tumor → Avoid contamination of operative field with tumor cells
• Adequate lymph node management according to tumor type and stage
• Preserve organ function and QOL when oncologically safe
• Use minimally invasive or organ-sparing surgery when it gives equivalent oncological safety

II. TNM Staging and Its Importance

• TNM system: Standardized anatomical cancer staging system
• Describes → Primary tumor extent + regional lymph nodes + distant metastasis
• Purpose → Common language for prognosis, treatment planning and comparison of results
• Exact T/N/M definitions are tumor-specific

Components

Clinical and Pathological Staging

• cTNM → Clinical stage before treatment
• Based on physical exam, endoscopy, imaging, biopsy, labs and staging procedures
• pTNM → Pathological stage after operation
• Based on resected specimen and lymph nodes; often more accurate for local/nodal disease
• yTNM → Stage after neoadjuvant treatment
• rTNM → Stage of recurrent tumor

Stage Groups

• Stage 0 → Carcinoma in situ
• Stage I → Localized early cancer
• Stage II → Larger/deeper local tumor or locally advanced disease without distant metastasis, depending on tumor type
• Stage III → Regional lymph node involvement and/or more advanced local extension
• Stage IV → Distant metastasis

• Stage grouping is not identical for all cancers; always use tumor-specific staging rules

Importance of TNM Staging

• Determines resectability and operability planning
• Guides treatment sequence → Upfront surgery vs neoadjuvant therapy vs systemic/palliative treatment
• Shows need for adjuvant treatment after surgery
• Provides prognosis and survival estimate
• Allows comparison of therapeutic modalities and hospital outcomes
• Helps evaluate response to treatment
• Defines eligibility for clinical trials
• Supports communication in the onco-team and with the patient

III. Neoadjuvant and Adjuvant Oncological Treatment

• Oncological treatment may be given before or after surgery according to stage, histology, molecular subtype and patient condition
• Main modalities → Chemotherapy, radiotherapy, chemoradiotherapy, targeted therapy, immunotherapy, hormone therapy

Neoadjuvant Treatment

• Definition: Oncological treatment given before definitive surgery
• Can include chemotherapy, radiotherapy, chemoradiotherapy, targeted therapy or immunotherapy depending on tumor type
• Goal → Downstage/downsize tumor to make surgery possible or less radical
• Can convert unresectable/borderline resectable disease to resectable disease
• Treats micrometastases early
• Allows assessment of tumor response → Prognostic information
• May increase chance of R0 resection and organ preservation

• Examples → Rectal cancer chemoradiotherapy/total neoadjuvant treatment, locally advanced breast cancer systemic treatment, esophageal cancer chemoradiotherapy, borderline pancreatic cancer therapy in selected cases
• Risk → Disease progression during treatment, toxicity, delay of surgery, fibrosis making surgery harder

Adjuvant Treatment

• Definition: Oncological treatment given after curative-intent surgery
• Goal → Destroy residual microscopic disease and reduce recurrence risk
• Indicated according to pathological stage, margin status, nodal status, tumor biology and patient fitness
• Common forms → Chemotherapy, radiotherapy, targeted therapy, immunotherapy, hormonal therapy

• Examples → Adjuvant chemotherapy in node-positive colon cancer, trastuzumab for HER2-positive breast cancer, tamoxifen/aromatase inhibitor for hormone receptor positive breast cancer, radiotherapy after breast-conserving surgery
• Benefit must be balanced against toxicity, age, comorbidities and patient preference

Other Treatment Concepts

• Definitive oncological treatment → Non-surgical curative-intent treatment, e.g. chemoradiotherapy for selected tumors
• Palliative systemic therapy → Controls metastatic/incurable disease, prolongs survival and improves symptoms
• Salvage surgery → Operation after failed non-surgical treatment or recurrence
• Watch-and-wait / active surveillance → Selected cases only, strict protocol and follow-up required

IV. Onco-Team and Its Importance

• Onco-team / multidisciplinary tumor board: Group of specialists who discuss cancer patients and create a shared treatment plan
• Especially important because cancer treatment is staged, multimodal and tumor-specific
• Decision is based on diagnosis, TNM stage, histology, biomarkers, patient condition and patient preference

Core Members

• Surgical oncologist / organ-specific surgeon
• Medical oncologist
• Radiation oncologist
• Radiologist / nuclear medicine specialist if needed
• Pathologist / molecular pathologist
• Gastroenterologist, pulmonologist, gynecologist, urologist or other organ specialist depending on tumor type
• Specialist oncology nurse / stoma nurse / breast care nurse
• Dietitian / nutritionist
• Psychologist or psychiatrist
• Genetic counselor when hereditary syndrome is possible
• Palliative care specialist, social worker, physiotherapist, pharmacist as needed

Importance

• Creates evidence-based, consensus-driven treatment plan
• Improves decision-making by combining surgical, medical, radiation, imaging and pathology expertise
• Prevents undertreatment and overtreatment
• Chooses correct treatment sequence → Neoadjuvant, surgery, adjuvant, palliative or follow-up
• Ensures personalized care → Stage, biology, patient condition, comorbidities, social background
• Improves communication between specialties and with the patient
• Supports patient education, psychological care, nutrition and rehabilitation
• Improves outcomes, QOL and patient satisfaction

Practical Onco-Team Questions

1. What is the exact diagnosis and histology?
2. What is the TNM stage?
3. Is the tumor resectable?
4. Is the patient operable?
5. Is the treatment aim curative or palliative?
6. Is neoadjuvant treatment needed before surgery?
7. What operation gives oncological safety with best function/QOL?
8. Is adjuvant treatment needed after surgery?
9. What follow-up plan is required?