What essential knowledge about gastric cancer should an Indian surgical postgraduate have?

Essential Knowledge for Indian Surgical Postgraduates: Gastric Cancer

Epidemiology & Presentation Patterns in India

Indian gastric cancer patients present predominantly with locally advanced disease (stages III-IV), with the antrum being the most common site (60-79%), and a median age of 55-60 years with 4:1 male predominance. 1, 2, 3, 4

• The northern Indian population has higher incidence compared to southern regions, though southern India still reports gastric cancer as a leading malignancy 5
• Most common presentations are pain abdomen, gastric outlet obstruction, and weight loss 2, 3, 4
• Unlike Western countries showing a shift to proximal cancers, Indian data shows persistent predominance of distal gastric tumors 5, 4
• Stage distribution at presentation: Stage III (47.6-49%), Stage IV/metastatic (18-28%), with only 1-2% presenting at Stage II 1, 4

Must-Know Diagnostic Workup

Every patient requires upper GI endoscopy with multiple biopsies, contrast-enhanced CT chest/abdomen/pelvis, complete blood counts, and liver/renal function tests as essential baseline investigations. 6, 7, 8, 1

Core Investigations (Essential)

• White light endoscopy with multiple biopsies from tumor for histopathological confirmation—this is mandatory before any treatment 8, 1
• CT scan (multi-detector or helical) of abdomen/pelvis with oral and IV contrast 6, 7, 1
• CT chest or chest X-ray 1
• Complete blood counts, renal and liver function tests 6, 7, 1
• Nutritional assessment and ECOG performance status documentation 7

Advanced Staging (Good to Know)

• Endoscopic ultrasound (EUS) is preferred for early-stage disease or when distinguishing early vs. locally advanced disease, with sensitivity 0.86 and specificity 0.90 for T-staging 6, 7, 8
• Staging laparoscopy with peritoneal washings is recommended for all potentially resectable cases (stages IB-III) to detect occult peritoneal metastases—this identifies 20-30% of patients with peritoneal disease missed on CT 6, 7
• PET-CT may upstage patients but has high false-negative rates in mucinous and diffuse/signet-ring histology 6, 7

Common Pitfall: Proceeding to surgery without laparoscopy in potentially resectable cases misses occult peritoneal disease in 20-30% of patients 7

Surgical Principles (Must Know)

D2 gastrectomy with adequate lymphadenectomy (≥15 nodes) is the standard surgical approach in India, with subtotal gastrectomy for distal tumors and total gastrectomy for proximal lesions. 6, 1, 2

Operative Standards

• Distal (antral) tumors: Subtotal gastrectomy with D2 lymphadenectomy 6, 1, 2
• Proximal tumors: Total gastrectomy with D2 lymphadenectomy 6, 1
• Lymph node harvest: Minimum 15 nodes required for adequate staging—inadequate harvest results in stage migration and inaccurate prognostication 7
• Curative (R0) resection rates should exceed 30% 6

D2 Lymphadenectomy Specifics

• Proximal/cardia/GE junction: Include paraesophageal, perigastric, suprapancreatic, and celiac lymph nodes 6
• Body: Include perigastric, suprapancreatic, celiac, splenic hilar, porta hepatic, and pancreaticoduodenal nodes 6
• Distal/antrum: Include perigastric, suprapancreatic, celiac, porta hepatic, and pancreaticoduodenal nodes 6

Organ Preservation

• Spleen and distal pancreas should NOT be removed for cancers in distal two-thirds of stomach 6
• Distal pancreas removed only with direct invasion in proximal stomach cancers where curative resection still possible 6
• Splenectomy considered only for proximal stomach tumors on greater curvature/posterior wall close to splenic hilum 6

Perioperative Outcomes to Achieve

• Hospital mortality: <10% for total gastrectomy, <5% for subtotal gastrectomy 6
• Anastomotic leak rate: Should not exceed 5% 6
• Indian data shows wound infection (6.1%) and anastomotic leak (5.9%) as predominant morbidities with overall morbidity 16.7% and 30-day mortality 2.9% 2

Common Pitfall: Significant numbers of Indian patients are deemed inoperable on table due to advanced disease—emphasizes need for better preoperative staging with laparoscopy 5

Pathology & Staging (Must Know)

Use TNM 2002/AJCC staging system with clear understanding of T-stage definitions and nodal burden classification. 6, 7

TNM Classification

• T1: Invades lamina propria or submucosa 7
• T2: Invades muscularis propria or subserosa 7
• T3: Penetrates serosa without invading adjacent structures 7
• T4: Invades adjacent structures 7
• N1: 1-6 regional lymph nodes 7
• N2: 7-15 regional lymph nodes 7
• N3: >15 regional lymph nodes 7

Histopathology

• 90% are adenocarcinomas: Divided into diffuse (undifferentiated) and intestinal (well-differentiated) types 6, 7
• Adenocarcinoma NOS is most common histological type in India (93%) 2
• Diffuse type: Poorly differentiated, discohesive cells with signet-ring morphology, worse prognosis 6
• Intestinal type: Forms mass lesion, tubular/glandular pattern, better prognosis 6

Prognostic Factors

• Lymphovascular invasion (LVSI) and lymph nodal burden are the most significant risk factors for recurrence and death in Indian population 2
• Most Indian patients have T4 tumors (55.9%) and nodal metastases (74%) at presentation 2

Biomarker Testing (Must Know for Advanced Disease)

Universal MSI/MMR testing is recommended in all newly diagnosed patients, with HER2, PD-L1, and CLDN18.2 testing mandatory if advanced/metastatic disease is documented or suspected. 6, 1

• HER2 testing: Mandatory in metastatic disease—directly impacts trastuzumab eligibility 6, 7, 1
• MSI by PCR/NGS or MMR by IHC: Universal testing recommended 6
• PD-L1 testing: Required if advanced/metastatic disease 6
• CLDN18.2 testing: Recommended if advanced/metastatic disease 6
• NGS: Should be considered via validated assay 6

Common Pitfall: Omitting HER2 testing in advanced disease delays targeted therapy initiation 7

Treatment Algorithms by Stage

Early Stage (IA/IB, N0)

Surgery alone is recommended for early-stage disease, with adjuvant treatment guided by final histopathology. 1

• Endoscopic resection (ER) is essential for accurate staging of T1a/T1b cancers and may be therapeutic 6, 8

Locally Advanced (IB N+ to IIIC)

Neoadjuvant chemotherapy should be considered to downstage disease, followed by surgery and adjuvant chemotherapy as part of perioperative regimen. 1

• This approach addresses the reality that most Indian patients present with locally advanced disease 2, 5
• Neoadjuvant chemotherapy with cisplatin and 5-FU improves short-term survival over surgery alone 6
• Preoperative chemoradiation may improve long-term survival 6

Stage IV/Metastatic

Assess for chemotherapy versus best supportive care on individual basis based on performance status and organ function. 1

• ECF regimen (Epirubicin 50 mg/m², Cisplatin 60 mg/m², 5-FU continuous infusion) is one of the most active and well-tolerated combinations 6
• 5-FU may be replaced with capecitabine if no gastric outlet obstruction 1
• Cisplatin may be replaced with oxaliplatin 1
• Alternative regimens include oxaliplatin, irinotecan, docetaxel, and oral fluoropyrimidines 6

Indian Context: Only 76-80.5% of Indian patients complete all 6 planned cycles of adjuvant chemotherapy, highlighting compliance challenges 2, 4

Multidisciplinary Management (Must Know)

Multidisciplinary treatment planning is mandatory before initiating therapy, comprising surgeons, medical and radiation oncologists, gastroenterologists, radiologists, and pathologists. 6, 7

• Treatment should only be undertaken in specialized units with large case volumes and sufficient surgical/intensive care experience 6
• Quality of life at presentation should be assessed and considered in treatment planning 6

Follow-Up Protocol

Clinical examination at each visit with yearly CT chest/abdomen/pelvis; symptom-driven visits are recommended rather than intensive surveillance. 6, 1

• There is no evidence that regular intensive follow-up improves outcomes 6
• History, physical examination, and blood tests performed if symptoms of relapse occur 6

Indian-Specific Considerations (Good to Know)

• Survival outcomes: Median survival 10.4-23 months, with 2-year overall survival 31% and 3-year survival 22% in Indian cohorts 2, 4
• Dietary factors: Wide variation in lifestyle from northern to southern India affects risk patterns 3, 5
• Resource limitations: EUS and other technical advancements remain sparse in India 5
• Screening programs: Not widely implemented due to logistical challenges 5
• H. pylori: Test and eradicate in all patients with early gastric cancer if positive 6