What is the management plan for an adult patient with localized adenocarcinoma of the appendix?

Management of Adenocarcinoma of the Appendix

Right hemicolectomy with regional lymphadenectomy is the standard surgical treatment for localized appendiceal adenocarcinoma ≥2 cm or with any high-risk features, while simple appendectomy alone is sufficient only for well-differentiated tumors <1 cm confined to the appendix without adverse features. 1, 2

Initial Diagnostic Workup

When appendiceal adenocarcinoma is discovered (typically incidentally during appendectomy for suspected appendicitis), immediate histopathological classification is essential to determine the appropriate surgical approach. 3 The diagnosis is rarely made preoperatively—in fact, no patients had the correct diagnosis before surgery in one large series. 4

Required staging investigations include:

• Abdominal/pelvic CT or MRI with IV contrast to assess for distant metastases and peritoneal involvement 3
• Chest CT to exclude pulmonary metastases 3
• Baseline CEA level for adenocarcinomas 3
• Colonoscopy to exclude synchronous colorectal neoplasia 5

Surgical Management Algorithm

For Tumors <1 cm

Simple appendectomy alone is curative if all of the following criteria are met: 1, 2

• Well-differentiated histology
• Tumor confined to appendix
• No breach of serosal surface
• No mesoappendiceal invasion >3 mm
• Not located at base of appendix
• Negative margins
• No lymphovascular invasion

For Tumors 1-2 cm

This size range remains controversial. 2 Right hemicolectomy should be performed if any high-risk features are present: 1, 2

• Breach of serosal surface
• Mesoappendiceal invasion >3 mm
• Location at base of appendix
• Lymphovascular invasion
• Incomplete resection margins
• Poorly differentiated histology

If all features are favorable (G1, Ki-67 <2%, negative margins), some institutions accept appendectomy alone with rigorous surveillance, though this remains debated. 2

For Tumors ≥2 cm

Right hemicolectomy with regional lymphadenectomy is mandatory, even without obvious malignant features, due to significantly higher risk of lymph node metastases. 1, 2 This recommendation holds regardless of tumor grade or differentiation. 5

Secondary Right Hemicolectomy

If initial appendectomy was performed and pathology subsequently reveals adenocarcinoma ≥2 cm or high-risk features, secondary right hemicolectomy should be performed after staging CT/MRI rules out distant disease. 1, 2 This secondary procedure results in upstaging in 38% of patients. 4

Critical Pathology Requirements

At least 12 lymph nodes must be examined in the surgical specimen to adequately stage the disease. 1, 3 This is essential for determining prognosis and need for adjuvant therapy.

Special Histologic Considerations

Goblet Cell Adenocarcinoma (Adenocarcinoid)

These tumors must be managed according to colon cancer protocols, NOT neuroendocrine tumor protocols, as they behave much more aggressively with adenocarcinoma-like biology. 1, 3 Right hemicolectomy is always required regardless of size. 5, 1

Mucinous Adenocarcinoma

Mucinous histology confers better prognosis than colonic-type adenocarcinoma. 4, 6 However, surgical approach remains the same based on size and risk features. 7

Adjuvant Therapy

For node-positive disease (Stage III) or peritoneal involvement, adjuvant chemotherapy using colon cancer regimens is indicated: 5, 3

• FOLFOX (5-FU/leucovorin/oxaliplatin) is preferred 5
• Capecitabine ± oxaliplatin is an alternative 5

The evidence base for chemotherapy in appendiceal adenocarcinoma is weak due to rarity and lack of randomized trials, but extrapolation from colon cancer data supports this approach. 3

Surveillance Protocol

For resected adenocarcinomas, follow colorectal cancer surveillance protocols: 3

• History and physical examination every 3-6 months for 2 years, then every 6 months for years 3-5 3
• CEA monitoring at each visit 3
• CT chest/abdomen/pelvis every 6-12 months for 5 years 3
• Colonoscopy at 1 year, then per standard colorectal cancer guidelines 3

Important Caveats

In women with goblet cell tumors, there is increased risk of bilateral ovarian metastases. Prophylactic bilateral oophorectomy should be discussed, particularly in postmenopausal women. 5, 6

Screen for synchronous malignancies, as 35% of patients develop second primary tumors, with 17% in the gastrointestinal tract. 4, 6

Survival is stage-dependent: 5-year survival ranges from 100% for Stage A to only 6% for Stage D disease. 4 Right hemicolectomy provides superior survival compared to appendectomy alone (68% vs 20% 5-year survival). 4