Preparing for Your GI Malignancies Rotation: A Strategic Guide for Hematology-Oncology Fellows

Your GI rotation is coming up, and here's what you need to know upfront: this is going to be a busy rotation. You're going to see a high volume of patients with a wide variety of gastrointestinal cancers, and the pace will be intense. But with the right preparation strategy, you can approach this rotation with confidence and build the systematic framework you'll use throughout your career.

Please Note: This is written in November 2025, so the treatments might change in the future.

What You'll See: The Common GI Malignancies

During your GI malignancies rotation, you'll encounter these cancers regularly:

• Colon cancer

• Rectal cancer

• Anal cancer

• Esophageal cancer

• Gastric cancer

• Gallbladder cancer

• Pancreatic cancer

• Cholangiocarcinoma

Each of these malignancies has its own staging system, treatment algorithms, and molecular considerations. Your job isn't to memorize every detail—it's to understand the broader strokes of how to manage each disease.

The Framework: What You Need to Know for Each Cancer

For every GI malignancy you encounter, you need to be able to answer a consistent set of questions:

1. What stage is the disease? (Localized, locally advanced, or metastatic)

2. What are the key molecular markers or receptor status?

3. What's the treatment approach for each stage?

4. What are the first-line and second-line treatment options?

5. Are there special considerations based on patient performance status?

Let's break this down by disease.

Esophageal Cancer: Know Your Histology

Esophageal cancer comes in two main histologic types, and the histology matters:

Localized Disease

• Squamous cell carcinoma: More common in the upper and middle esophagus

• Adenocarcinoma: More common in the lower esophagus and GE junction

For localized disease, you need to understand the multimodality approach: when to use neoadjuvant chemoradiation, when to consider perioperative chemotherapy, and the role of surgery.

Metastatic Disease

Know the first-line and subsequent treatment options, including:

• Chemotherapy backbones

• The role of immunotherapy (PD-L1 status, MSI status)

• HER2 status for adenocarcinomas

Gastric Cancer: Stage and Receptors Matter

The key questions for gastric cancer are:

Is it localized or metastatic?

Localized Disease

• Understand perioperative chemotherapy approaches

• Know when surgery is appropriate

• Be familiar with adjuvant treatment options

Metastatic Disease

You need to know the receptor status:

• HER2 status: Determines eligibility for HER2-targeted therapy

• PD-L1 and MSI status: Influences immunotherapy decisions

Know the first-line treatment options and how receptor status guides your choice.

Cholangiocarcinoma: A Complex Disease

Cholangiocarcinoma requires attention to multiple factors:

Localized Disease

The critical question: Should you add adjuvant capecitabine?

• Know the indications based on resection status and risk factors

• Understand duration of treatment

Metastatic Disease

You must know:

• First-line treatment: Gemcitabine-cisplatin durvalumab (as of 2025)

• Second-line treatment: Chemotherapy vs. targeted therapy depending on the receptors

• Molecular testing: IDH1, FGFR2 fusions, and other actionable alterations

Pancreatic Cancer: Resectability Is Everything

The single most important determination in pancreatic cancer is: Is it resectable, borderline resectable, or unresectable?

Resectable and Borderline Resectable Disease

Neoadjuvant setting:

• Know regimens like FOLFIRINOX and gemcitabine-based combinations

• Understand when to use each

Adjuvant setting:

• Know the standard regimens (modified FOLFIRINOX, gemcitabine with capecitabine)

• Understand the duration of treatment—this is frequently tested

Metastatic Disease: Performance Status Drives Treatment

Your treatment choice depends critically on performance status:

Good performance status (ECOG 0-1):

• FOLFIRINOX or modified FOLFIRINOX

• Gemcitabine plus nab-paclitaxel

Poor performance status (ECOG 2+):

• Single-agent gemcitabine

• Best supportive care in very poor performance status

Know when to be aggressive and when to prioritize quality of life.

Colon Cancer: Molecular Testing Is Critical

Colon cancer is one of the most common malignancies you'll see, and you need to master it.

Early-Stage Disease: Know Your Adjuvant Indications

Stage II vs. Stage III:

• Understand why Stage III typically gets adjuvant chemotherapy

• Know the risk factors that might push you toward treating high-risk Stage II disease

• Be familiar with adjuvant regimens and duration

Metastatic Disease: Molecular Markers Drive Everything

You must know these molecular markers and how they guide treatment:

RAS status (KRAS and NRAS):

• RAS wild-type: Eligible for anti-EGFR therapy (cetuximab, panitumumab)

• RAS mutant: NOT eligible for anti-EGFR therapy

BRAF V600E mutation:

• Identifies an aggressive subset

• Determines eligibility for BRAF-targeted therapy combinations

MSI-H/dMMR status:

• Makes immunotherapy (pembrolizumab, nivolumab) a preferred option

Sidedness (right-sided vs. left-sided):

• Influences prognosis and treatment choices

Know your first-line options, when to use targeted therapy, and the role of immunotherapy in MSI-high disease.

Rectal Cancer vs. Anal Cancer: A Common Misconception

Here's something that trips up many first-year fellows: Rectal cancer is NOT the same as anal cancer. They are anatomically close but biologically and therapeutically distinct.

Rectal Cancer: Complex Multimodality Treatment

Rectal cancer is typically adenocarcinoma and requires Total Neoadjuvant Treatment (TNT) for locally advanced disease:

1. Chemoradiation (neoadjuvant)

2. Followed by chemotherapy (neoadjuvant)

3. Followed by surgery

4. Plus or minus additional adjuvant treatment

This sequence is designed to maximize tumor response, increase the chance of sphincter preservation, and treat micrometastatic disease early.

Metastatic rectal cancer is treated like metastatic colon cancer—use the same molecular markers and treatment algorithms.

Anal Cancer: Think Squamous Cell

Anal cancer is typically squamous cell carcinoma, not adenocarcinoma. The treatment approach is more similar to squamous cell skin cancer or head and neck cancer.

Localized disease:

• Chemoradiation is the primary treatment (often curative without surgery)

Metastatic disease:

• Treat with regimens similar to those used for metastatic squamous cell carcinoma

• Immunotherapy may play a role

Your Best Friend: The NCCN Guidelines

Here's the good news: You don't need to memorize everything. The NCCN Guidelines are your lifeline.

For each GI malignancy, the NCCN provides:

• Flow charts showing decision algorithms based on stage

• Systemic Treatment Options boxes listing regimens for each stage and line of therapy

When you're preparing or when you're on service and encounter a case, open the guidelines and:

1. Identify the disease stage

2. Find the corresponding algorithm

3. Review the systemic treatment options

4. Understand the decision points—what factors push treatment in one direction versus another

The key is understanding which disease stage you're in and what the big disease categories are. Once you know that, the guidelines will show you the path forward.

Use MeDucation Questions to Guide Your Preparation

One of the most effective ways to prepare is through question-based learning. The MeDucation platform offers questions specifically designed for fellows rotating through GI malignancies.

These questions will:

• Test your understanding of staging and treatment algorithms

• Challenge you on molecular markers and their therapeutic implications

• Present realistic clinical scenarios you'll encounter on the rotation

• Highlight common pitfalls and misconceptions

After answering each question, use it as a springboard:

1. Read the explanation

2. Open the NCCN guideline for that cancer

3. Review the full algorithm, not just the specific scenario

4. Study the systemic treatment options. In every NCCN guideline, navigate to the table of contents and look for the section titled 'Principles of Systemic Therapy' (or similar heading). This section contains organized boxes, with each box listing specific treatment regimens for different disease stages and clinical scenarios.

5. This integrated approach—questions + guidelines + repetition—will build the systematic framework you need.

Don't Get Overwhelmed: Focus on the Framework

It's easy to feel overwhelmed by the volume and complexity of GI malignancies. There are dozens of regimens, countless molecular markers, and nuanced treatment decisions. But remember:

Your goal is not to memorize every detail.

Your goal is to understand:

• The major disease categories (localized, locally advanced, metastatic)

• The key molecular markers that drive treatment decisions

• The first-line treatment approaches for each stage

• Where to look when you need more detailed information

With this framework, you can approach any GI malignancy case systematically. You'll know what questions to ask, what tests to order, and where to find the treatment algorithm.

Final Thoughts

Your GI malignancies rotation will be busy, challenging, and incredibly educational. You'll see a high volume of diverse cases, and the pace will push you. But this is also an opportunity to build expertise in some of the most common cancers in oncology.

By focusing on the broader management strokes, understanding staging and molecular markers, mastering the distinction between similar-sounding diseases (rectal vs. anal cancer!), and using the NCCN guidelines as your reference, you'll navigate this rotation successfully.

And remember: preparation matters. Use MeDucation questions to build your knowledge base before the rotation starts, and continue using them throughout. Each question is a chance to reinforce your systematic approach.

You've got this. The rotation will be busy, but you'll be ready.

Ready to prepare for your GI malignancies rotation? Access the MeDucation question bank and handouts designed specifically for hematology-oncology fellows tackling the complexity of gastrointestinal cancers.