Colorectal cancer screening US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Colorectal cancer screening. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Colorectal cancer screening US Medical PG Question 1: A 35-year-old woman is presenting for a general wellness checkup. She is generally healthy and has no complaints. The patient does not smoke, drinks 1 alcoholic drink per day, and exercises 1 day per week. She recently had silicone breast implants placed 1 month ago. Her family history is notable for a heart attack in her mother and father at the age of 71 and 55 respectively. Her father had colon cancer at the age of 70. Her temperature is 99.0°F (37.2°C), blood pressure is 121/81 mmHg, pulse is 77/min, respirations are 14/min, and oxygen saturation is 98% on room air. Physical exam is unremarkable. Which of the following is the most appropriate initial step in management?
- A. Alcohol cessation
- B. Colonoscopy at age 60
- C. Mammography at age 50
- D. Colonoscopy at age 40 (Correct Answer)
- E. Mammography now
Colorectal cancer screening Explanation: ***Colonoscopy at age 40***
- This patient has a **first-degree relative (father) diagnosed with colorectal cancer at age 70**, which increases her risk compared to the average population.
- Current **USPSTF and ACS guidelines** recommend that individuals with a first-degree relative diagnosed with colorectal cancer at **age 60 or older** should begin screening at **age 40** (or 10 years before the age of diagnosis in the relative, whichever is earlier).
- Since her father was diagnosed at age 70, she should start screening at age 40 (which is 10 years earlier and also the recommended age for those with family history).
- At age 35, she does **not yet need** colonoscopy, but should plan for screening in 5 years.
*Colonoscopy now*
- This is **too early** based on current guidelines.
- Immediate colonoscopy at age 35 is not indicated in an asymptomatic patient whose father was diagnosed at age 70.
- Screening at age 40 provides adequate time for early detection while avoiding unnecessary early intervention.
*Colonoscopy at age 60*
- This is **too late** and ignores the increased risk from family history.
- Delaying screening until age 60 would miss the recommended earlier screening window for patients with first-degree relatives with CRC.
*Alcohol cessation*
- The patient drinks **1 alcoholic drink per day**, which is within recommended limits for women.
- While reducing alcohol consumption has general health benefits, this is not the most urgent preventive measure given her family history of colon cancer.
*Mammography now*
- Screening mammography typically begins at **age 40-50** for average-risk women.
- At age 35 with no specific high-risk factors (no BRCA mutation, no strong early-onset breast cancer family history), mammography is not indicated now.
*Mammography at age 50*
- While this may be appropriate for breast cancer screening depending on guidelines followed, it is **not the priority** given her significant family history of colorectal cancer requiring earlier intervention.
Colorectal cancer screening US Medical PG Question 2: An 18-year-old man presents to his primary care provider before leaving for college. He has no complaints. His past medical history is significant for asthma, acne vulgaris, and infectious mononucleosis at age 16. His home medications include doxycycline and albuterol as needed. His family history is significant for colon cancer in his father at age 50, his paternal grandfather at age 55, and an uncle at age 45. His father underwent testing for mutations in the APC gene, which were negative. There is no family history of dental abnormalities or other malignancy. The patient denies any recent weight loss, abdominal pain, hematochezia, melena, or other changes in the appearance of his stools. This patient should be screened for colorectal cancer (CRC) under which of the following protocols?
- A. Colonoscopy every 5 years beginning at age 40 (Correct Answer)
- B. Colonoscopy every 10 years beginning at age 50
- C. Colonoscopy every 1-2 years beginning at age 25
- D. Prophylactic colectomy
- E. Fecal occult blood testing annually beginning at age 40
Colorectal cancer screening Explanation: ***Colonoscopy every 5 years beginning at age 40***
- The patient has a strong family history of CRC, with a father diagnosed at age 50 and a paternal grandfather at age 55, placing him at increased risk.
- Current guidelines recommend that individuals with a first-degree relative diagnosed with CRC before age 60 should begin screening 10 years before the earliest diagnosis in the family, or at age 40, whichever comes first, with a colonoscopy every 5 years.
*Colonoscopy every 10 years beginning at age 50*
- This protocol is recommended for individuals with an **average risk** for colorectal cancer, which does not apply to this patient due to his strong family history.
- Starting screening at age 50 would be too late given the early onset of CRC in his family.
*Colonoscopy every 1-2 years beginning at age 25*
- This more aggressive screening schedule is typically reserved for individuals with identified **hereditary colorectal cancer syndromes**, such as **Familial Adenomatous Polyposis (FAP)** or **Lynch syndrome**.
- Though there is a strong family history, the negative APC gene testing and absence of other syndromic features (like dental abnormalities) make FAP less likely, and Lynch syndrome would typically involve other cancers.
*Prophylactic colectomy*
- **Prophylactic colectomy** is a major surgical procedure considered in rare cases of very high-risk hereditary syndromes, such as confirmed **Familial Adenomatous Polyposis (FAP)**, where the risk of CRC is almost 100%.
- This patient's family history, while significant, does not meet the criteria for such an extreme measure.
*Fecal occult blood testing annually beginning at age 40*
- While **fecal occult blood testing (FOBT)** is a valid screening method, it is typically used for individuals with average risk or in conjunction with other methods.
- Given the patient's strong family history of early-onset CRC, a **colonoscopy** is the more appropriate and comprehensive screening method.
Colorectal cancer screening US Medical PG Question 3: A 25-year-old woman presents to a physician for a new patient physical exam. Aside from occasional shin splints, she has a relatively unremarkable medical history. She takes oral contraceptive pills as scheduled and a multivitamin daily. She reports no known drug allergies. All of her age appropriate immunizations are up to date. Her periods have been regular, occurring once every 28 to 30 days with normal flow. She is sexually active with two partners, who use condoms routinely. She works as a cashier at the local grocery store. Her mother has diabetes and coronary artery disease, and her father passed away at age 45 after being diagnosed with colon cancer at age 40. Her grand-aunt underwent bilateral mastectomies after being diagnosed with breast cancer at age 60. Her physical exam is unremarkable. Which of the following is the best recommendation for this patient?
- A. Colonoscopy in 10 years
- B. Mammogram now
- C. Pap smear now
- D. Pap smear in 5 years
- E. HPV DNA testing now (Correct Answer)
Colorectal cancer screening Explanation: ***HPV DNA testing now***
- This 25-year-old patient is due for cervical cancer screening and this is the best recommendation.
- **ACOG (2021)** recommends **primary HPV testing every 5 years** for women aged 25-65 as the preferred screening method.
- Although USPSTF guidelines recommend starting HPV testing at age 30, ACOG's updated guidelines support initiating primary HPV testing at age 25, making this the most current evidence-based recommendation.
- Given she is presenting for a new patient physical and cervical cancer screening is due now, initiating HPV testing is appropriate.
*Colonoscopy in 10 years*
- While the patient's father was diagnosed with colon cancer at age 40, this option is **incorrectly timed**.
- Guidelines recommend screening beginning at age 40 OR 10 years before the youngest affected first-degree relative's diagnosis (age 30 for this patient), whichever comes first.
- Since this patient is 25, she would need colonoscopy at age 30 (in 5 years), not in 10 years (age 35).
- However, cervical cancer screening is the more immediate priority right now.
*Mammogram now*
- The patient's grand-aunt had breast cancer at age 60, but this is a **second-degree relative** with late-onset disease.
- This does not meet criteria for early mammography screening at age 25.
- Routine mammography typically begins at age 40 (per ACOG) or age 50 (per USPSTF), unless there is a strong family history in first-degree relatives or genetic mutations (BRCA1/2).
*Pap smear now*
- Pap smear (cytology) is an acceptable screening option for cervical cancer.
- **USPSTF (2018)** recommends cytology alone every 3 years for women ages 21-29, or starting HPV-based testing at age 30.
- However, **ACOG (2021)** supports primary HPV testing starting at age 25 as the preferred method.
- While Pap smear now would not be incorrect, HPV DNA testing is the preferred and more current guideline-based approach for this age group.
*Pap smear in 5 years*
- This represents inappropriate delay in initiating cervical cancer screening.
- Screening should begin now, not be deferred for 5 years.
- The 5-year interval applies to primary HPV testing once initiated, not to delaying the start of screening.
Colorectal cancer screening US Medical PG Question 4: A 50-year-old Caucasian man presents for a routine checkup. He does not have any current complaint. He is healthy and takes no medications. He has smoked 10–15 cigarettes per day for the past 10 years. His family history is negative for gastrointestinal disorders. Which of the following screening tests is recommended for this patient according to the United States Preventive Services Task Force (USPSTF)?
- A. Abdominal ultrasonography for abdominal aortic aneurysm
- B. Carcinoembryonic antigen for colorectal cancer
- C. Low-dose computerized tomography for lung cancer
- D. Colonoscopy for colorectal cancer (Correct Answer)
- E. Prostate-specific antigen for prostate cancer
Colorectal cancer screening Explanation: **Colonoscopy for colorectal cancer**
- The **USPSTF recommends screening for colorectal cancer in adults aged 45 to 75 years**. This patient is 50 years old, placing him squarely within this recommended age range for colonoscopy, irrespective of smoking status or other risk factors.
- **Colonoscopy** is a highly effective screening tool for colorectal cancer, allowing for the detection and removal of precancerous polyps.
*Abdominal ultrasonography for abdominal aortic aneurysm*
- The **USPSTF recommends one-time screening for abdominal aortic aneurysm (AAA) with ultrasonography in men aged 65 to 75 years who have ever smoked**. This patient is 50 years old, falling outside the recommended age range for this screening, despite his smoking history.
- The benefit of screening for AAA is primarily for older men with a history of smoking, as the prevalence of AAA significantly increases with age.
*Low-dose computerized tomography for lung cancer*
- The **USPSTF recommends annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years**. This patient has a 10-pack-year smoking history (10-15 cigarettes/day for 10 years ≈ 0.5-0.75 packs/day * 10 years = 5-7.5 pack-years), which does not meet the 20 pack-year threshold.
- While the patient is within the age range, his smoking history is insufficient to meet the criteria for routine lung cancer screening with LDCT.
*Carcinoembryonic antigen for colorectal cancer*
- **Carcinoembryonic antigen (CEA) is a tumor marker primarily used for monitoring the recurrence of colorectal cancer after treatment**, not for initial screening in asymptomatic individuals.
- The USPSTF and other guidelines do not recommend CEA as a screening test for colorectal cancer due to its low sensitivity and specificity in asymptomatic populations.
*Prostate-specific antigen for prostate cancer*
- The **USPSTF recommends that men aged 55 to 69 years should make an individual decision about being screened for prostate cancer with a prostate-specific antigen (PSA) test**, after discussing the potential benefits and harms with their clinician.
- This patient is 50 years old, which is younger than the age range where the USPSTF recommends shared decision-making for PSA screening.
Colorectal cancer screening US Medical PG Question 5: A 46-year-old woman presents to her primary care physician for her annual examination. At her prior exam one year earlier, she had a Pap smear which was within normal limits. Which of the following health screenings is recommended for this patient?
- A. Colorectal screening (Correct Answer)
- B. Blood glucose and/or HbA1c screening
- C. Blood pressure at least once every 3 years
- D. Yearly Pap smear
- E. Bone mineral density screening
Colorectal cancer screening Explanation: ***Colorectal screening***
- **Colorectal cancer screening** is generally recommended to start at age **45 years** for individuals at average risk.
- This patient is 46 years old, making immediate colorectal screening appropriate based on current guidelines.
*Blood glucose and/or HbA1c screening*
- **Blood glucose or HbA1c screening** for diabetes is recommended starting at age **35 for all adults** or earlier if there are risk factors such as obesity or a family history of diabetes.
- While this patient is 46, this screening should have already been initiated, and it is not the *most* uniquely recommended screening for this specific age that might have been overlooked.
*Blood pressure at least once every 3 years*
- **Blood pressure screening** should be performed **at least annually** for adults aged 40 and older, or more frequently if there are risk factors.
- Screening only every 3 years is insufficient for a 46-year-old patient.
*Yearly Pap smear*
- **Pap smear frequency** has changed; for women aged 30-65 with normal results, screening is recommended every **3 years** with cytology alone, or every 5 years with high-risk HPV testing alone or co-testing.
- A yearly Pap smear is no longer typical practice for a woman with normal prior results and no specific risk factors.
*Bone mineral density screening*
- **Bone mineral density (BMD) screening** for osteoporosis is typically recommended for women starting at age **65 years** or earlier if they have significant risk factors.
- This patient is 46 years old and has no mentioned risk factors, so BMD screening is not routinely indicated at this age.
Colorectal cancer screening US Medical PG Question 6: A 19-year-old woman presents to the physician for a routine health maintenance examination. She has a past medical history of gastroesophageal reflux disease. She recently moved to a new city to begin her undergraduate studies. Her father was diagnosed with colon cancer at age 46. Her father's brother died because of small bowel cancer. Her paternal grandfather died because of stomach cancer. She takes a vitamin supplement. Current medications include esomeprazole and a multivitamin. She smoked 1 pack of cigarettes daily for 3 years but quit 2 years ago. She drinks 1–2 alcoholic beverages on the weekends. She appears healthy. Vital signs are within normal limits. Physical examination shows no abnormalities. Colonoscopy is unremarkable. Germline testing via DNA sequencing in this patient shows mutations in DNA repair genes MLH1 and MSH2. Which of the following will this patient most likely require at some point in her life?
- A. Celecoxib or sulindac therapy
- B. Surgical removal of a desmoid tumor
- C. Prophylactic proctocolectomy with ileoanal anastomosis
- D. Annual colonoscopy beginning at 20–25 years of age (Correct Answer)
- E. Measurement of carcinoembryonic antigen and CA 19-9 yearly
Colorectal cancer screening Explanation: ***Annual colonoscopy beginning at 20–25 years of age***
- This patient's family history of multiple cancers at young ages (father with colon cancer at 46, uncle with small bowel cancer, grandfather with stomach cancer) combined with **germline mutations in MLH1 and MSH2** is highly indicative of **Lynch syndrome (hereditary non-polyposis colorectal cancer - HNPCC)**.
- Individuals with Lynch syndrome have a significantly increased risk of colorectal cancer, and screening with **annual colonoscopies starting at a young age (20-25 years or 2-5 years younger than the earliest age of diagnosis in the family)** is crucial for early detection and prevention.
*Celecoxib or sulindac therapy*
- **NSAID therapy** (like celecoxib or sulindac) is sometimes used for **chemoprevention in familial adenomatous polyposis (FAP)** to reduce polyp burden, especially in attenuated FAP.
- However, this patient's presentation and genetic findings point to **Lynch syndrome**, for which NSAID chemoprevention is not the primary or most effective strategy compared to surveillance.
*Surgical removal of a desmoid tumor*
- **Desmoid tumors** are benign but locally aggressive soft tissue tumors that are a characteristic **extracolonic manifestation of familial adenomatous polyposis (FAP)**, especially in patients with mutations in the APC gene.
- This patient has **Lynch syndrome**, which is associated with different extracolonic cancers (e.g., endometrial, ovarian, gastric, small bowel), but **desmoid tumors are not a typical feature of Lynch syndrome**.
*Prophylactic proctocolectomy with ileoanal anastomosis*
- **Prophylactic proctocolectomy** is the standard preventive surgery for individuals with **familial adenomatous polyposis (FAP)** to prevent the inevitable development of colorectal cancer due to hundreds to thousands of polyps.
- While Lynch syndrome carries a high risk of colorectal cancer, prophylactic colectomy is generally **not recommended as the initial management** given that surveillance via colonoscopy allows for removal of precancerous polyps and early-stage cancers, reserving surgery for when clinically indicated.
*Measurement of carcinoembryonic antigen and CA 19-9 yearly*
- **Carcinoembryonic antigen (CEA) and CA 19-9** are **tumor markers** that can be elevated in certain cancers (e.g., colorectal for CEA, pancreatic/biliary for CA 19-9).
- However, these markers have **poor sensitivity and specificity for screening healthy, asymptomatic individuals** at high risk for cancer and are primarily used for monitoring disease recurrence or treatment response in diagnosed cancers. They are not recommended for routine surveillance in Lynch syndrome.
Colorectal cancer screening US Medical PG Question 7: A 60-year-old patient presents to the urgent care clinic with complaints of pain and abdominal distention for the past several weeks. The pain began with a change in bowel habits 3 months ago, and he gradually defecated less until he became completely constipated, which led to increasing pain and distention. He also mentions that he has lost weight during this period, even though he has not changed his diet. When asked about his family history, the patient reveals that his brother was diagnosed with colorectal cancer at 65 years of age. An abdominal radiograph and CT scan were done which confirmed the diagnosis of obstruction. Which of the following locations in the digestive tract are most likely involved in this patient’s disease process?
- A. Small bowel
- B. Ascending colon
- C. Rectum
- D. Sigmoid colon (Correct Answer)
- E. Cecum
Colorectal cancer screening Explanation: ***Sigmoid colon***
- This patient's symptoms—**progressive constipation, abdominal distention, weight loss**, and a family history of colorectal cancer—strongly suggest a **colorectal malignancy** causing obstruction.
- The **sigmoid colon** is the most common site for colorectal cancer, especially those presenting with obstructive symptoms due to its narrower lumen compared to the proximal colon.
*Small bowel*
- While small bowel obstruction can cause similar symptoms, **primary small bowel cancers are rare** and typically present differently, often with episodes of partial obstruction.
- The history of a **change in bowel habits preceding complete constipation** is more indicative of a colonic mass.
*Ascending colon*
- Cancers in the **right colon (ascending and cecum)** tend to present with symptoms like **iron deficiency anemia, fatigue, and occult bleeding**, rather than obstruction, due to its wider lumen and more fluid stool.
- **Obstruction is less common** as an initial presentation in this location.
*Rectum*
- Rectal cancers often cause **changes in bowel habits, tenesmus, and hematochezia** (bright red blood per rectum).
- While obstruction can occur, the sigmoid colon is a more frequent site for tumors causing **progressive obstructive symptoms** as described.
*Cecum*
- Similar to the ascending colon, cancers in the **cecum** are more likely to present with **anemia and vague abdominal discomfort** rather than overt obstruction.
- The **wider diameter** of the cecum allows tumors to grow quite large before causing obstructive symptoms.
Colorectal cancer screening US Medical PG Question 8: A 34-year-old woman with no significant prior medical history presents to the clinic with several days of bloody stool. She also complains of constipation and straining, but she has no other symptoms. She has no family history of colorectal cancer or inflammatory bowel disease. She does not smoke or drink alcohol. Her vital signs are as follows: blood pressure is 121/81 mm Hg, heart rate is 77/min, and respiratory rate is 15/min. There is no abdominal discomfort on physical exam, and a digital rectal exam reveals bright red blood. Of the following, which is the most likely diagnosis?
- A. Colorectal cancer
- B. Ulcerative colitis
- C. Anal fissure
- D. External hemorrhoids
- E. Internal hemorrhoids (Correct Answer)
Colorectal cancer screening Explanation: ***Internal hemorrhoids***
- **Painless bright red blood** per rectum, especially with **constipation and straining**, is highly characteristic of internal hemorrhoids.
- Internal hemorrhoids are located **above the dentate line**, making them typically painless, and they often prolapse during defecation, causing bleeding.
*Colorectal cancer*
- While colorectal cancer can cause bloody stool, it is less likely in a **34-year-old woman with no family history** and no other systemic symptoms like weight loss or abdominal pain.
- The bright red blood associated with straining points away from an upper GI bleed, which is more typical of many colorectal cancers.
*Ulcerative colitis*
- Ulcerative colitis typically presents with bloody diarrhea, abdominal pain, and tenesmus, which are **not mentioned** in this patient's history.
- It is a chronic inflammatory condition, and the isolated symptom of bright red blood with constipation is not classic for UC.
*Anal fissure*
- An anal fissure would cause **severe pain during defecation** due to a tear in the anal canal, which is absent in this patient.
- While an anal fissure can cause bright red blood, the lack of pain makes it less likely than hemorrhoids.
*External hemorrhoids*
- **External hemorrhoids are usually painful or itchy** and located below the dentate line.
- They also can cause bleeding, but the absence of pain and bright red blood suggests internal hemorrhoids which are more likely to bleed painlessly.
Colorectal cancer screening US Medical PG Question 9: A 65-year-old man presents to his primary care physician for a yearly checkup. He states he feels he has been in good health other than minor fatigue, which he attributes to aging. The patient has a past medical history of hypertension and is currently taking chlorthalidone. He drinks 1 glass of red wine every night. He has lost 5 pounds since his last appointment 4 months ago. His temperature is 99.2°F (37.3°C), blood pressure is 147/98 mmHg, pulse is 80/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam reveals an obese man in no acute distress. Laboratory values are ordered as seen below.
Hemoglobin: 9 g/dL
Hematocrit: 27%
Mean corpuscular volume: 72 µm^3
Leukocyte count: 6,500/mm^3 with normal differential
Platelet count: 193,000/mm^3
Serum:
Na+: 139 mEq/L
Cl-: 101 mEq/L
K+: 4.3 mEq/L
HCO3-: 25 mEq/L
BUN: 20 mg/dL
Glucose: 99 mg/dL
Creatinine: 1.1 mg/dL
Ca2+: 9.0 mg/dL
AST: 32 U/L
ALT: 20 U/L
25-OH vitamin D: 15 ng/mL
Which of the following is the best next step in management?
- A. Counseling for alcohol cessation
- B. Vitamin D supplementation
- C. Colonoscopy (Correct Answer)
- D. Exercise regimen and weight loss
- E. Iron supplementation
Colorectal cancer screening Explanation: ***Colonoscopy***
- The patient presents with **microcytic anemia** (hemoglobin 9 g/dL, MCV 72 µm^3) and **unexplained weight loss** in an elderly male, which is highly suggestive of **gastrointestinal bleeding**, often due to **colorectal cancer**.
- A **colonoscopy** is the definitive diagnostic and therapeutic procedure for evaluating the lower gastrointestinal tract for sources of bleeding and identifying/removing suspicious lesions.
*Counseling for alcohol cessation*
- While chronic alcohol use can contribute to various health issues, including some anemias (e.g., folate deficiency), the patient's presented **microcytic anemia** is not typical for alcohol-related causes.
- The patient's reported alcohol intake of one glass of red wine nightly is generally considered moderate and less likely to be the primary cause of his symptoms and lab findings.
*Vitamin D supplementation*
- The patient has a **low 25-OH vitamin D level (15 ng/mL)**. However, this finding, while important for bone health and overall well-being, does not explain his microcytic anemia or unexplained weight loss.
- Addressing the **anemia and weight loss** takes precedence as these symptoms point to a more urgent, potentially life-threatening condition.
*Exercise regimen and weight loss*
- The patient is obese and has hypertension, for which an **exercise regimen and weight loss** would be beneficial for overall health and blood pressure management.
- However, these interventions **do not address the microcytic anemia and unexplained weight loss**, which are more pressing concerns requiring immediate investigation.
*Iron supplementation*
- The **microcytic anemia** strongly suggests **iron deficiency**, and iron supplementation would eventually be part of treatment.
- However, **iron supplementation** without identifying and treating the underlying cause of iron loss (e.g., gastrointestinal bleeding) would be insufficient and could delay a crucial diagnosis.
Colorectal cancer screening US Medical PG Question 10: A 46-year-old man presents with increasing fatigue and weakness for the past 3 months. He works as a lawyer and is handling a complicated criminal case which is very stressful, and he attributes his fatigue to his work. He lost 2.3 kg (5.0 lb) during this time despite no change in diet or activity level. His past history is significant for chronic constipation and infrequent episodes of bloody stools. Family history is significant for his father and paternal uncle who died of colon cancer and who were both known to possess a genetic mutation for the disease. He has never had a colonoscopy or had any genetic testing performed. Physical examination is significant for conjunctival pallor. A colonoscopy is performed and reveals few adenomatous polyps. Histopathologic examination shows high-grade dysplasia and genetic testing reveals the same mutation as his father and uncle. The patient is concerned about his 20-year-old son. Which of the following is the most appropriate advice regarding this patient's son?
- A. The son doesn't need to be tested now.
- B. An immediate colonoscopy should be ordered for the son.
- C. Screening can be started by 50 years of age as the son’s risk is similar to the general population.
- D. The son should undergo a prophylactic colonic resection.
- E. A genetic test followed by colonoscopy for the son should be ordered. (Correct Answer)
Colorectal cancer screening Explanation: ***A genetic test followed by colonoscopy for the son should be ordered.***
- Given the patient's strong family history of **colon cancer** with a known genetic mutation and the patient's own diagnosis of **high-grade dysplasia** and the same mutation, his son is at a significantly increased risk.
- **Genetic testing** will determine if the son has inherited the mutation, and if positive, early and regular **colonoscopic surveillance** is crucial due to the highly aggressive nature of familial colon cancer syndromes.
*The son doesn't need to be tested now.*
- This statement is incorrect because the son is at a very high risk of inheriting a **known pathogenic genetic mutation** that predisposes to colon cancer.
- Delaying testing could lead to a delayed diagnosis of potentially cancerous or pre-cancerous lesions, missing the opportunity for **early intervention**.
*An immediate colonoscopy should be ordered for the son.*
- While a colonoscopy may be warranted, the initial step should be **genetic testing** to confirm the presence of the mutation.
- If the genetic test is negative, the urgency and frequency of colonoscopies would be different, potentially aligning with general population guidelines or slightly earlier, but not necessarily immediately at age 20 without genetic confirmation.
*Screening can be started by 50 years of age as the son’s risk is similar to the general population.*
- This advice is dangerously incorrect, as the son's risk is *not* similar to the general population due to a strong and **documented family history** of colon cancer with a **known genetic mutation**.
- Waiting until 50 years of age would likely result in delayed detection of advanced adenomas or even cancer, as familial syndromes typically present at a much **younger age**.
*The son should undergo a prophylactic colonic resection.*
- **Prophylactic colonic resection** is a major surgical procedure and is typically reserved for individuals with established diagnoses of certain high-risk syndromes, such as **Familial Adenomatous Polyposis (FAP)**, often after they have developed numerous polyps.
- This decision should only be made after **genetic confirmation** of the mutation, thorough evaluation of polyp burden, and shared decision-making with the patient and multidisciplinary team, and not as an initial step.
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