Oral Board Case: Rectal Cancer

What are the key components of your history and physical in this patient before any further workup?

Expected answer

Characterize bleeding, bowel-habit change, weight loss, and pain, and assess for acute problems (complete obstruction, massive bleeding) that would require immediate intervention. Critically, I assess baseline sphincter/continence function (a restorative proctectomy is very morbid in a patient with poor baseline continence) and baseline sexual/urinary function. Abdominal exam for distention (obstruction) or organomegaly (metastasis). DRE to define distance from anal sphincter complex to the distal tumor, fixation/tethering, and anterior-vs-posterior location. I also take a full family history given the strong family history of colorectal cancer.

Why is rigid proctoscopy in the office essential, and what does it add beyond flexible endoscopy?

Expected answer

Rigid proctoscopy allows precise measurement of tumor distance from the anal verge and localization, which flexible endoscopy cannot do accurately. This precise distance drives the decision about whether a sphincter-sparing low anterior resection is feasible versus abdominoperineal excision. It is a critical step in the surgical workup of any rectal or left-sided colon cancer and should be complemented by tattooing the lesion for later identification.

A large sessile rectal polyp is found on colonoscopy at an outside hospital. What is the correct diagnostic approach and what mistake must be avoided?

Expected answer

For a large sessile lesion where complete endoscopic excision cannot be ensured, staging should precede any attempt at tissue removal. The critical error to avoid is a piecemeal 'excision' of a large polyp that returns as adenocarcinoma with a positive margin — this creates edematous, inflamed tissue planes that severely compromise accurate T-staging, and T-stage determines who benefits from neoadjuvant therapy. Small pedunculated or sessile polyps under 2 cm can be removed by polypectomy with confident complete excision. Regardless, the site must be tattooed.

How do you complete clinical TNM staging once adenocarcinoma is confirmed?

Expected answer

Labs: CEA and CBC (LFTs routinely obtained but not essential). Local staging (T and N): transrectal ultrasound or MRI with a dedicated rectal cancer protocol — TRUS is somewhat better for early T1 vs T2 lesions, while MRI better defines distance to the sphincters and the distance to the mesorectal fascia (threatened circumferential resection margin). Distant staging: CT chest/abdomen/pelvis with oral and IV contrast to evaluate for metastases. PET is reserved for indeterminate lesions on axial imaging.

How would you manage a small T1 rectal cancer (<3 cm, <40% circumference), and what must you counsel the patient about?

Expected answer

A small, well-differentiated T1 lesion may be treated with full-thickness transanal excision if technically feasible without compromising the lumen. The patient must be counseled that transanal excision does NOT include a lymphadenectomy — up to ~12% of T1 lesions harbor regional nodal disease that would upstage them to stage III. If final pathology shows poor differentiation, lymphovascular invasion, mucinous or signet-ring histology, or a higher-than-expected T-stage, further treatment (completion proctectomy with TME, and chemoradiation/chemotherapy per stage) is required.

A patient has a clinical T3 N1 mid-rectal adenocarcinoma. What is your treatment sequence and why?

Expected answer

This is stage III (node-positive) extraperitoneal rectal cancer, so neoadjuvant therapy is standard: preoperative long-course chemoradiation (or short-course radiation, though long-course is preferred when the CRM is threatened and NCCN advises against short-course in T4 disease), followed by total mesorectal excision. Neoadjuvant radiation confers a significant reduction in local recurrence and, in stage III, a survival benefit at 10 years per the Dutch trial. Definitive proctectomy should follow radiation by roughly 8–12 weeks. Because distant recurrence remains ~30%, many centers now front-load systemic combination chemotherapy (total neoadjuvant therapy) as well.

What is total mesorectal excision and why is it the oncologic standard?

Expected answer

TME is sharp dissection along the avascular plane outside the mesorectal fascial envelope, removing the rectum with its intact surrounding mesorectum (containing the draining lymph nodes) as a unit. It produces a negative circumferential resection margin, which is strongly associated with reduced local recurrence. Preserving the intact fascial envelope and avoiding cutting into the tumor/mesorectum is the surgical breakthrough responsible for much of the improved local control in modern rectal cancer care.

The patient presents acutely with a complete large bowel obstruction from the rectal cancer. How do you manage this?

Expected answer

Complete large bowel obstruction from rectal cancer is a surgical emergency requiring colonic decompression. Options include a loop sigmoid (diverting) colostomy or an endoluminal rectosigmoid stent as a bridge to definitive treatment — the stent must sit proximal enough that its distal end does not impinge on the anorectal ring. If the proximal colon is ischemic or perforated, a subtotal colectomy with end ileostomy and mucous fistula may be needed. Emergent proctectomy is rarely required. This decompression preserves the option of proper staging and neoadjuvant therapy before definitive resection.

How would you approach a patient found to have resectable liver metastases (stage IV)?

Expected answer

M1 disease is no longer automatically unresectable. Patients with resectable liver (and sometimes limited extrahepatic) metastases may be candidates for curative resection — R0 hepatic metastasectomy carries 5-year survival as high as ~71% in some series. This requires multidisciplinary evaluation with hepatobiliary and medical oncology to determine sequencing of chemotherapy, chemoradiation, and surgery. For oligometastatic disease many begin with systemic chemotherapy, restage at ~3 months, and if stable/improved proceed with chemoradiation and resection; unresectable disease is managed with palliative chemotherapy, with rare conversion to resectable.

What is your surveillance plan after curative-intent treatment?

Expected answer

History and physical with CEA every 3–6 months for 2 years, then every 6 months to complete 5 years. CT chest/abdomen/pelvis with contrast every 6–12 months for 5 years. Colonoscopy at 1 year; if an advanced adenoma is found, repeat in 1 year, otherwise at 3 years and every 5 years thereafter. Patients treated by transanal excision alone (stage II–IV) additionally need rigid proctoscopy and TRUS or rectal MRI at each visit for local surveillance.