L4: Diagnosis and Treatment of Colorectal Cancer Flashcards
What is the significance of the adenoma carcinoma sequence in colorectal cancer?
ACS shows the progression of CRC from normal cells to metastasis and the various molecular changes that occur along the way. It is a 10-15 year process, which identifies disease progression overtime without medical intervention.
Describe the primary methods used for the diagnosis of colorectal cancer.
FIT test
Colonoscopy
2WW
What are the potential advantages of using the Faecal Immunochemical Test for colorectal cancer screening
Cost effective.
Non invasive.
High sensitivity - can indicate cancer of precancerous lesions.
Accessible - more people can get it and its one test versus previously 6 tests.
Rapid Results - timely information.
Define Lynch syndrome and explain its relevance to colorectal cancer
It is an inherited genetic condition.
It results from mutations in mismatch repair (MMR).
People with lynch syndrome are at higher risk of developing certain cancers.
List the key imaging modalities employed in staging of CRC
CT scan - To see extent of disease and to check liver and lung metastases.
MRI - to evaluate local advanced rectal cancer and surrounding structures and lymph nodes.
Endorectal Ultrasound - evaluating early stage cancer to assess depth of tumour invasion.
PET Scan - combined with CT, esp when we don’t know where the tumour originated.
True or false: The incidence of colorectal cancer is decreasing across all age groups.
False.
True or false: Stage 3 and 4 colon cancer has a notably higher likelihood of emergency presentation.
True.
Discuss the impact of early detection on the 5 year overall survival rtes in colorectal cancer patients.
~98% survival rate in stage 1 CRC.
Able to treat localised cancer.
surgical intervention of localised CRC is more effective.
Surgery can be less invasive depending on the location of the cancer and its characteristics.
Analyse the different management strategies required for colon cancer versus rectal cancer and explain why each approach is distinct.
Colon
- Surgical resection (tumour removal) is primary treatment.
- Adjuvant chemotherapy is used in stage III and high risk stage II based on molecular markers.
- Surveillance follow up colonoscopy and imaging based on risk factors and stage after treatment to monitor for recurrence.
Rectal
- Surgical resection involves more complex procedures.
- Neoadjuvant therapy (chemo and radiation) are commonly used before surgery to shrink tumours.
- Adjuvant therapy may be used if initial treatment was limited to chemo without radiation.
Critically evaluate the role of a MDT in the management of patients with colorectal cancer.
Comprehensive care.
Personalised treatment plans.
Improved outcomes.
Enhanced communication.
limitations and challenges:
- Resource intensive
- Variable quality (inconsistency, team dynamics, expertise, efficiency of communication).
- Ineffective integration of current clinical guidelines and evidence can be complex given the rapid evolution of cancer treatment modalities.
- Emphasis on consensus may suppress innovative or less conventional treatment options.
Explore the potential benefits and drawbacks of routine screening for colorectal cancer in asymptomatic populations.
Early detection.
Reduction in mortality.
Increased awareness.
Cost-effective.
Improved outcomes.
Drawbacks:
False positives.
Over-diagnosis - Some lesions may never become cancer so patients are subjected to unnecessary tests.
Disparity in access and equity - socioeconomic and demographic groups.
Compliance - Getting people to do it.
A 45 year old patient presents with gastrointestinal symptoms. what steps should a physician undertake to assess the likelihood of colorectal cancer?
Assessment of symptoms- bowel movements, abdominal pain, weight, sleeping habits, blood in stool.
Review previous visits and medical history - including polyps and risk factors.
Abdominal checks - lumps, bumps, masses, tenderness.
DRE - digital rectal check for masses and asses for hidden blood.
CBC for anemia.
Liver function test for haptic involvement.
FIT test
Colonoscopy.
Discuss how the presence of poorly differentiated tumours at presentation influences treatment options and prognosis.
PDT indicate more aggressive disease.
Chemo and radiotherapy can be recommended before surgery.
More likely to have combined treatment - surgery and chemo.
May require targeted therapies (molecular targets like pills).
Increased monitoring - follow ups and imaging.
Prognosis:
Poorer outcomes - more aggressive tumours, metastasis, resistance to conventional therapies.
Lower survival rates
Higher risk of recurrance.
Draw and label the adenoma carcinoma sequence. Discuss its significance in colorectal cancer prevention.
Normal epithelium
Hyper-proliferate epithelium
Adenoma phase:
Early
Intermediate
Late
The carcinoma phase:
Carcinoma
Metastasis
MMR accelerates mutational burden
Create a flow chat of the diagnostic pathway for CRC, including the role of the 2WW pathway.
GP Referral after assessing symptoms and medical history.
2WW - 2 week wait. a referral system.
Assessment by specialist (i.e., gastroenterologist or oncologist) to review systems and medical history.
Investigations (i.e., CT, MRI, sigmoidoscopy/colonoscopy).
Biopsy if abnormalities are found.
Pathology review to study biopsy.
Diagnosis - based on the investigation results.
Staging tests.
Treatment planning.
Start of treatment.
Follow up and monitoring.
What challenges do GP’s face in stratifying patients for colorectal cancer risk based on symptoms?
The early symptoms are similar to other GI disorders.
FIT test is still new and GPs are still learning which people should be referred.
Patience may be reluctant to get tested.
Time constraints on GP.
Availibility of testing - i.e., scans and hospital waiting times.
Socioeconomic, cultural, and background reasons can affect peoples willingness to seek medical advice.
How might genetic testing for Lynch syndrome alter patient management and family screening strategies?
Invite them for regular screening. (Cascade testing).
Educate them about early symptoms and seeking medical advice.
Can advice on diet and healthy lifestyle choices to limit their chances of developing cancer.
Can encourage aspirin usage.
Summarise the findings related to the changing incidence of colorectal cancer in younger populations.
Increasing incidence in younger people.
Likely due to effective testing, prevention strategy.
Young people have more late stage diagnosis - due to lack of testing, and higher prevalence of misdiagnosis.
Potential causes:
Changing diets.
Sedentary lifestyles and obesity.
Altered microbiome and environmental factors.
Genetic predisposition and familial syndromes.
What are the implications of studies showing the reduced risk of colorectal cancer mortality in screened groups?
Examine the effectiveness of FIT screening
High sensitivity and specificity - can detect precancerous legions.
Non-invasive and convenient - can do at home and send away for results.
Reduced false positives - FIT has lower rates of this compared to old tests.
Cost effective - minimises the need for more expensive tests like colonoscopy which come with needing staff.
Improved detection rates - studies show populations that have FIT ar diagnosed sooner and have better prognosis.
Discuss how awareness and education about Lynch Syndrome can lead to earlier diagnosis and better outcomes for affected individuals.
People will know their family history and can use this to inform med. professionals.
This make it easier for the NHS to track these patients and offer them screening for different types of cancer.
Awareness means people can make informed health and lifestyle decisions in order to limit their exposure to known carcinogens.
Early diagnosis = early intervention.
The earlier a patient is diagnosed, the less likely it is that the cancer has metastasised. Mortality rates are lower for patients detected early. Lung cancer, for example, has a 9/10 death rate for late stage diagnosis, but. 1 in 10 death rate for early diagnosis.
Assess how molecular diagnostics can impact the treatment strategies for CRC.
Targeted therapy - find specific mutations.
Stratifying treatment options - Drs can decide on the best treatment modality.
Biomarkers - can predict how well patients respond to specific treatments. i.e., MSI-H
Eligibility for clinical trials - based on mutations in their tumours.
Minimal Residual Disease Detection - can detect circulating tumour DNA in the blood.
What are the public health implications of a national CRC screening program?
The likelihood of developing cancer is 1 in 2 for many cancers. This means that cancer will effect everyone in their lifetime - directly or indirectly.
By having a national screening program, healthcare providers can detect cancer in people before it spreads to other parts of the body - thus improving life expectancy and outcomes for patients.
CRC is a silent cancer in the early stages and causes symptoms not too dissimilar to other benign conditions so patients may not seek medical advice until later symptomatic stages and we know that later stages have lower mortality rates 1 year, 3 years and 5 years post occurrence.
Later stages also linked to recurrence of cancer in the future and worse outcomes for patients.
Having a S.P means we detect cancers early, and we can also monitor rates in the population and predict - in theory - who and where are more likely to get it.
We can offer monitoring for high risk patients through screening for lynch syndrome.
we can increase public awareness of the disease, and symptoms to see the doctor about.
