Genetics and Cancer Quiz

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Questions and Answers

What is the primary genetic basis of Peutz-Jeghers syndrome?

Mutation in the KRAS gene

Mutation in the APC gene

Mutation in the MLH1 gene

Mutation in the STK11 gene (correct)

Which of the following is NOT a common presenting symptom of Peutz-Jeghers syndrome in teens and young adults?

Iron deficiency anemia

Intussusception

Weight gain (correct)

Abdominal pain

What is the estimated lifetime risk of cancer for individuals with Peutz-Jeghers syndrome?

5-15%

15-30%

37-93% (correct)

95-100%

Which of the following is NOT considered a non-modifiable risk factor for colorectal cancer?

Dietary fiber intake Signup and view all the answers

How does the risk of colorectal cancer (CRC) typically differ in individuals with Inflammatory Bowel Disease (IBD) compared to those without IBD?

IBD patients have roughly twice the risk of developing CRC. Signup and view all the answers

What is the primary purpose of staging esophageal cancer?

To rule out the presence of distant metastases. Signup and view all the answers

Which of the following imaging methods is used to stage esophageal cancer, only if a previous study did not show distant metastasis?

PET CT scan Signup and view all the answers

Which of these factors significantly contributes to both treatment and prognosis for esophageal cancer?

Depth of tissue affected, lymph node involvement, and distal metastases. Signup and view all the answers

What is a characteristic feature of Linitis plastica?

Infiltration and thickening of the stomach lining due to diffuse tumor invasion. Signup and view all the answers

What has been identified as one of the key factors contributing to the rapid decline in stomach cancer rates since the 1930s in the US?

Refrigeration, which led to increased fruit/vegetable consumption and less reliance on salting and smoking of food. Signup and view all the answers

What is the approximate annual number of new stomach cancer cases worldwide?

1 million Signup and view all the answers

What is the most prevalent type of stomach cancer?

Adenocarcinoma. Signup and view all the answers

By what percentage is gastric cancer incidence decreasing per year in the United States?

1.5% Signup and view all the answers

Which imaging modality is generally considered the least effective for identifying stomach cancer?

Esophagogastroduodenoscopy (EGD) Signup and view all the answers

According to the information provided, which of the following is associated with the lowest relative risk of gastric cancer?

High fruit intake Signup and view all the answers

What percentage of individuals with an H. pylori infection will develop gastric cancer over their lifetime, based on the information provided?

1-2% Signup and view all the answers

According to a meta-analysis of prevention trials in East Asia, the eradication of H. pylori results in approximately what percentage reduction in gastric cancer incidence?

46% Signup and view all the answers

Which symptom is most characteristic of distal stomach outlet obstruction?

Vomiting Signup and view all the answers

Which of the following is NOT a physical exam finding suggestive of advanced gastric cancer?

Elevated liver enzymes Signup and view all the answers

What is the relationship between H. pylori infection and chronic gastritis, according to the information provided?

Chronic H.pylori infection can cause atrophic gastritis Signup and view all the answers

What laboratory finding is most suggestive of blood loss from a gastric tumor?

Iron deficiency anemia Signup and view all the answers

What are the independent factors associated with an increased risk of HCC?

Type 2 diabetes and obesity Signup and view all the answers

What is the main purpose of HCC surveillance in patients with chronic liver disease?

To detect HCC at an earlier stage for improved survival Signup and view all the answers

Which imaging technique is primarily used for diagnosing HCC?

Ultrasound Signup and view all the answers

What is a characteristic feature of HCC on imaging?

Blood supply via the hepatic artery Signup and view all the answers

What is the 5-year survival rate for patients diagnosed with HCC?

18% Signup and view all the answers

What treatment option is often considered for patients who are not candidates for liver transplant due to underlying liver disease?

Palliative care Signup and view all the answers

Which treatment option aims to deliver chemotherapy directly to the tumor's blood supply?

Chemoembolization Signup and view all the answers

What is a key consideration when treating patients with HCC?

Therapy must be weighed against potential harms Signup and view all the answers

What is the increased risk of colon cancer for obese men compared to normal weight individuals?

50% Signup and view all the answers

Which substance is attributed to 12% of colorectal cancer cases in the U.S.?

Tobacco Signup and view all the answers

What is the percentage increase in colorectal cancer risk for individuals consuming heavy amounts of alcohol?

25-44% Signup and view all the answers

What is a significant benefit of regular NSAID use in relation to colorectal cancer?

20-40% risk reduction Signup and view all the answers

What are the key characteristics of larger polyps concerning colorectal cancer?

More worrisome than smaller polyps Signup and view all the answers

Why is aspirin not recommended as a preventive measure for colorectal cancer?

Due to potential bleeding risks Signup and view all the answers

What characteristic of polyps indicates a higher likelihood of subsequent cancer?

Multiple polyps Signup and view all the answers

During what time frame can adenomatous polyps transform into colorectal cancer?

5-20 years Signup and view all the answers

What is the primary imaging modality used for diagnosing pancreatic cancer?

CT scan of abdomen Signup and view all the answers

Which blood test marker is most commonly elevated in pancreatic cancer?

CA 19-9 Signup and view all the answers

What are the common symptoms associated with pancreatic cancer?

Painless jaundice and abdominal pain Signup and view all the answers

What is the typical prognosis for patients with pancreatic cancer?

Only surgery offers a chance for cure Signup and view all the answers

Which of the following factors is NOT commonly associated with pancreatic cancer?

High-fat diet Signup and view all the answers

What is the significance of CEA levels in colorectal cancer diagnosis?

Helpful for monitoring treatment success Signup and view all the answers

What type of pancreatic cancer constitutes the majority of cases?

Ductal adenocarcinoma Signup and view all the answers

Which of the following statements about the presentation of pancreatic cancer is true?

Obstructive jaundice is common in head tumors Signup and view all the answers

What is the purpose of performing a Whipple's procedure?

To resect the primary lesion in pancreatic cancer Signup and view all the answers

When evaluating for colorectal cancer, which tumor marker can indicate a worse prognosis?

Carcinoembryonic Antigen (CEA) Signup and view all the answers

Study Notes

GI Malignancies Overview

This lecture covers recognizing, evaluating, and treating patients with gastrointestinal (GI) malignancies.
Emphasis is placed on risk factors and prevention, highlighting the role of primary care physicians.
The presentation covers esophageal cancer, stomach cancer, small bowel cancer, colorectal cancer, and pancreatic cancer.

Esophageal Cancer

In the U.S., approximately 16,000 people die from esophageal cancer annually, with 81% being men.
It's the 7th leading cause of cancer death in men and mostly affects men older than 50.
Lifetime risk is 1 in 125 for men and 1 in 417 for women.
Two main subtypes are squamous cell carcinoma and adenocarcinoma.

Squamous Cell Carcinoma (ESCC)

Globally, ESCC accounts for 90% of esophageal cancers, especially in Asia, Africa, and South America.
It principally affects the upper and middle esophagus.
Risk factors include poor nutrition, smoking, alcohol, hot tea, radiation, nitrites, and lye exposure.
In the US, alcohol/smoking and African American race are significant risk factors.

Adenocarcinoma (EAC)

EAC was less than 10% of esophageal cancers in the U.S. during the 1960s, but has rapidly increased, becoming the #1 cause in North America and Europe.
75% of EAC cases occur in the distal esophagus near the lower esophageal sphincter (LES).
Risk factors include GERD and obesity.
Barrett's esophagus is often a precursor to this cancer.

Stomach Cancer

In the U.S., approximately 26,500 new cases of stomach cancer are diagnosed annually, with 60% being men.
It results in 11,130 deaths annually with an average age of diagnosis at 68.
Globally, ~1 million new cases occur yearly, accounting as the 3rd leading cause of cancer deaths (~782,000/yr).
It is the most common infection-related cancer.

Stomach Cancer Trends

Stomach cancer was the leading cause of cancer death in the U.S until around 1930.
Declines in rates are attributed to refrigeration, improving sanitation, and widespread antibiotic use, reducing H. pylori infection.

Small Bowel Cancers

In the U.S., small bowel cancers account for 3% of GI cancers (~90% of the surface area).
11,790 new cases and 1,960 deaths occur yearly in the U.S.
Histologically, carcinoid tumors account for ~37% of small bowel cancers, along with adenocarcinoma (~37%), lymphomas (~17%), and sarcomas (typically GIST) at ~8%.

Predisposing Factors for GI Cancers

Celiac disease: Increased risk of GI lymphoma (risk decreased with gluten-free diet)
Crohn's disease: Usually involving the distal ileum.
Hereditary syndromes: Lynch syndrome (HNPCC), FAP, Peutz-Jeghers syndrome.

Colorectal Cancer (CRC)

Colon cancer accounts for ~106,970 new cases yearly in the US; rectal cancer accounts for ~46,050.
The combined 52,550 deaths yearly make it the 2nd most frequent cancer death.
Lifetime risk for colon cancer is around 4% with a median age at detection of 66.

CRC Trends

CRC incidence and mortality in those over 65 is declining (3.3%/yr), while middle-aged adults (50-65 yrs) show an increasing incidence (1%/yr) but declining deaths.
In younger adults (< 50), incidence and mortality are increasing (2% and 1.3%/yr respectively).

CRC Risk Factors

Non-modifiable: Age, ethnicity, heredity, Inflammatory Bowel Disease (IBD)
Modifiable: Diet, lack of physical activity, alcohol, smoking, obesity, low socioeconomic status.
Family History: ~30% of CRC patients have a family history, and this is linked to increased risk.
Heredity and Medical History (e.g., Lynch syndrome, familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome) increase risk significantly.

CRC and Diet

Diet may impact CRC risk and gut microbiome function.
Specific dietary triggers are difficult to pinpoint due to inaccuracies in self-reported dietary data.
A link exists between diet and other behaviors that may also influence CRC risk.

CRC and Food Associations

Lower risk: Calcium from dairy sources, whole grains/fiber, fruits and vegetables, vitamin D
Higher risk: Processed meats, red meat, refined carbohydrates, processed sugar

Why CRC death rates decreasing in older adults?

Removal of precancerous polyps during screening
Discovery of cancers at earlier stages
More effective treatments have been developed

Why CRC death rates increasing in younger adults?

Increased sedentary lifestyle
Dietary factors
Obesity
Other (unknown) exposures

Pancreatic Cancer

Approximately 64,050 new cases and 50,550 deaths occur yearly in the US.
It is a highly lethal cancer, ranked 11th most common, but 3rd leading cause of cancer death.
The lifetime risk is approximately 1 in 64 (1.6%), with a median age at diagnosis of 71.

Pancreatic Cancer - General Aspects

85% of cases are ductal adenocarcinomas (exocrine), with 60-70% located in the head, and 20-25% in the body or tail.
The KRAS gene is often mutated in 90% of pancreatic cancers.
Key risk factors are smoking and chronic pancreatitis; diabetes (DM) often present in 50% of patients, often recent onset.
There is not a standardized screening method.

Pancreatic Cancer - Presentation

Most common symptoms are asthenia (severe fatigue and weakness), abdominal pain (often radiating to the back), anorexia, and weight loss.
Presentation varies depending on the tumor location. Head tumors often cause painless jaundice, with light stools, dark urine, and itching (pruritis). Body and tail tumors generally do not present with detectable symptoms until the disease is more advanced.

Pancreatic Cancer - Physical Exam

Epigastric tenderness
Jaundice (yellowing of the skin)
Abdominal mass or palpable liver
Ascites (fluid accumulation in the abdomen)
Non-tender palpable gallbladder (Courvoisier’s sign)
Left supraclavicular lymph nodes (Virchow's node)
Sister Mary Joseph's node (periumbilical)
Thrombophlebitis (Trousseau's sign)

Pancreatic Cancer - Blood Tests

Anemia
Elevated alkaline phosphatase, bilirubin, and GGT if biliary obstruction is present
Elevated amylase and lipase (less likely in pancreatic cancers)
Elevated blood sugar
Elevated tumor markers (CA 19-9: 70-85% and CEA: 30-40% sensitivity), but not used for initial diagnosis, useful in monitoring treatment.

Pancreatic Cancer - Imaging

Abdominal CT scan is the standard for diagnosis, having 100% sensitivity if the lesion is >2cm and 75% if <2cm.
MRI and MRCP may reveal missed lesions.
EUS (Endoscopic Ultrasound) with potential biopsy is a standard procedure.
PET scans may identify smaller metastases.

Pancreatic Cancer - Treatment

Surgery (Whipple's procedure) is the only cure possibility.
Resectability is determined by tumor and vessels involvement; only 15-20% of patients qualify initially for surgery, with very limited overall survival from treatment.
Supportive care (chemotherapy, radiation, stenting of the bile duct) are common due to limited options when metastasis spread is large.

Hepatocellular Carcinoma (HCC)

In the U.S., approximately 41,210 new cases and 29,380 deaths occur yearly, ranking as the 6th most common cause of cancer death.
Worldwide, HCC is among the most common cancer deaths (~700,000 per year).
A large prevalence exists in SE Asia and sub-Saharan Africa.

HCC and risk factors

Hepatocellular carcinoma typically presents in people with cirrhosis from any cause, which carries a 1-8% annual risk.
Some critical risk factors include (but are not limited to): HBV, HCV, obesity and metabolic syndrome.

HCC and Cirrhosis

HCC often develops in people with cirrhosis and chronic liver disease.
Cirrhosis from any cause carries a risk of 1-8% annual HCC rate.

HCC Trends

HCC rates in the U.S. have tripled since 1980; death rates are also increasing.
Obesity and diabetes (DM) are major contributors and relate to non-alcoholic fatty liver disease (NAFLD)

Hepatocellular Carcinoma (HCC) - Diagnosis

HCC is identified by detectable radiologic features in chronic liver disease without biopsy being necessarily needed.
HCC possesses a hepatic artery blood supply, unlike benign liver nodules which use the portal vein.
Contrast CT will show tumor enhancement in arterial phase and washout in venous phase, supporting the diagnosis.

Hepatocellular Carcinoma (HCC) - Prognosis and Treatment

HCC is ranked as the 2nd most deadly cancer.
5-year survival often is less than 18%; median survival is around 6-20 months.
Treatment options involve resection, ablation (radiation and injection of ethanol), transplantation, chemoembolization (chemotherapy via tumor's arterial blood supply), and systemic chemotherapy and immunotherapy (often used in later disease stages).

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Description

Test your knowledge on the genetic basis of Peutz-Jeghers syndrome and its relation to cancer risk. This quiz covers key concepts related to cancer staging, symptoms, and risk factors associated with esophageal and colorectal cancers. Perfect for students and professionals in the medical field looking to refine their understanding of these critical topics.