What is the best course of management for a female patient with a descending colon mass, suspected colorectal cancer, presenting with blood-streaked stools, and having a history of abdominal pain, with an allergy to a medication, and a family history of melanoma and hypertension?

Management of Descending Colon Mass with Suspected Colorectal Cancer

Immediate Surgical Management

This patient requires urgent surgical resection via left hemicolectomy or sigmoidectomy with en bloc removal of the primary tumor, associated mesocolon, vessels, and regional lymph nodes, with at least 5 cm margins on either side of the tumor. 1

Preoperative Preparation

• Complete staging workup must be performed before surgery, including:

  • Blood counts, liver and renal function tests, and carcinoembryonic antigen (CEA) 1
  • CT scan of chest and abdomen to evaluate for metastatic disease 1
  • Chest X-ray 1
  • Complete colonoscopy to rule out synchronous lesions (if not already fully visualized) 1
  • Clinical examination with particular attention to liver, pelvis, and ovaries 1

• Bowel preparation should include hypertonic solution washout combined with low-residue diet and intravenous broad-spectrum antibiotics 1

• Document the medication allergy carefully in the preoperative assessment to avoid perioperative complications 1

Surgical Technique

• Median laparotomy incision is recommended with thorough intraoperative examination of the liver, pelvis, and ovaries, with sampling or frozen section of any suspicious masses 1

• For descending colon tumors, perform left hemicolectomy or sigmoidectomy depending on exact tumor location, ensuring wide resection with at least 5 cm margins on either side of the tumor 1

• Resect at least 12 lymph nodes to adequately stage the disease and avoid under-staging; fewer than 12 nodes examined increases risk of missing stage III disease and withholding necessary adjuvant chemotherapy 1

• En bloc resection is mandatory if the tumor has invaded neighboring organs 1

• Laparoscopic approach may be considered for left-sided cancers only if performed by experienced surgeons, with no prohibitive adhesions, and no locally advanced disease, acute obstruction, or perforation 1

Special Considerations for This Patient

• Partial obstruction status requires careful assessment; if significant obstruction or perforation is present, surgical approach must be modified based on patient stability and tumor location 1

• Family history of melanoma should prompt careful examination for synchronous lesions and consideration of genetic counseling postoperatively, though this does not alter immediate surgical management 1

Postoperative Pathologic Assessment and Staging

Pathologic evaluation must include 1:

• TNM staging with depth of penetration (T), lymph node status (N), and distant metastases (M)
• Histologic grade (G1-G4)
• Resection margin status (proximal, distal, and radial margins)
• Presence of perineural invasion, lymphatic or vascular invasion
• Tumor deposits and extramural involvement

Adjuvant Therapy Decision Algorithm

Stage III Disease (Any T, N1-2, M0)

• Adjuvant chemotherapy is mandatory with 6-month course of fluoropyrimidine-based regimen 1
• Preferred regimen: 5-fluorouracil/leucovorin plus oxaliplatin, which significantly improves 3-year disease-free survival compared to 5-FU/LV alone 1
• Alternative: Capecitabine monotherapy, which is at least as effective and less toxic than bolus 5-FU/LV 1

Stage II Disease (T3-4, N0, M0)

• Consider adjuvant chemotherapy if high-risk features are present 1:
  • T4 tumor
  • Poorly differentiated or undifferentiated histology
  • Vascular or lymphatic invasion
  • Obstruction or perforation at presentation (this patient has partial obstruction)
  • Fewer than 12 lymph nodes examined

Given this patient's partial obstruction, adjuvant chemotherapy should be strongly considered even if final pathology shows stage II disease. 1

Stage I Disease (T1-2, N0, M0)

• No adjuvant chemotherapy required 1

Surveillance Protocol

• History and physical examination: Every 3 months for 2 years, then every 6 months for years 3-5 1

• CEA monitoring: Every 3 months for 2 years, then every 6 months for years 3-5, only if patient is candidate for aggressive curative surgery should recurrence occur 1

• Colonoscopy: At 1 year post-resection (or 3-6 months postoperatively), then annually if neoplastic polyps found; if colon is clear, repeat at least every 3 years 1

• Liver imaging: Ultrasonography every 6 months for 3 years, then at years 4 and 5 1

• CT chest and abdomen: Only when clinically indicated for suspected recurrence, not routine surveillance 1

Critical Pitfalls to Avoid

• Do not delay surgery for extensive additional workup beyond basic staging; this patient has been symptomatic for 2 months with progressive symptoms 1

• Do not perform inadequate lymph node harvest; fewer than 12 nodes examined leads to under-staging and potential under-treatment 1

• Do not ignore the partial obstruction; this is a high-risk feature that may require modified surgical approach and influences adjuvant therapy decisions 1

• Do not forget intraoperative examination of liver and pelvis with frozen section of suspicious lesions, as synchronous metastases affect prognosis and treatment 1