Oncology: Prostate & Colorectal Cancer Flashcards
What do almost all prostate cancers rely on to grow?
Androgens (e.g. testosterone)
What are the majority of prostate cancers?
Adenocarcinomas (95)
Where do the majority of prostate cancers grow?
In the peripheral zone of the prostate
Risk factors for prostate cancer?
- Increasing age
- Family history
- Black African or Caribbean origin
- Tall stature
- Anabolic steroids
- Gene mutations (BRCA II and pTEN)
Location of prostate carcinoma vs benign prostatic hyperplasia?
Prostate adenocarcinoma –> glandular tissue in posterior or peripheral zone
BPH –> centre of gland
Presentation of prostate cancer?
- May be asymptomatic (e.g. diagnosed by routine rectal exam)
- Lower urinary tract symptoms (LUTS) e.g. poor stream, hesitancy, nocturia, dribbling and increased frequency
- Haematuria
- Impotence
- 1 in 5 present with metastatic prostate cancer e.g. anaemia, bone pain, pathological fracture, spinal cord compression, weight loss
Typical rectal examination findings in prostate cancer?
Enlarged, hard, craggy gland (or nodule) –> obliteration of the median sulcus
1st line investigation in suspected prostate cancer?
PR exam
Describe a benign prostate
Smooth, symmetrical, slightly soft, maintained central sulcus (dip in between right and left lobe)
Describe a prostate in protastatic hyperplasia
generalised enlargement
Describe a prostate in protastatis
enlarged, tender, and warm
Describe a cancerous prostate
Firm or hard, craggy, or irregular, with loss of central sulcus, may be a hard nodule –> 2 week wait urgent cancer referral to urology
Bedside investigations in suspected prostate cancer?
1) PR exam
2) Urine dip
What blood test can be done in suspected prostate cancer?
PSA (prostate specific antigen) –> counselling prior due to poor sensitivity and specificity
1st line imaging in prostate cancer?
Mutliparametric MRI
What is PSA produced by?
The epithelial cells of the prostate produce prostate-specific antigen (PSA).
It is specific to the prostate, meaning it is not produced anywhere else in the body.
What is PSA?
PSA is a glycoprotein that is secreted in the semen, with a small amount entering the blood.
Purpose of PSA?
Its enzymatic activity helps thin the thick semen into a liquid consistency after ejaculation
How is PSA testing used in prostate cancer?
A raised level can be an indicator of prostate cancer.
PSA testing may lead to the early detection of prostate cancer, potentially leading to effective treatment and preventing significant problems.
However, research has failed to show that the benefits of using PSA for screening outweigh the risks.
In the UK, when can men request a PSA?
Aged 50 and over
Why is PSA testing unreliable?
PSA testing has a high rate of false positives (75%) and false negatives (15%).
Common causes of a raised PSA?
- Prostate cancer
- Benign prostatic hyperplasia
- Prostatitis
- Urinary tract infections
- Vigorous exercise (notably cycling)
- Recent ejaculation or prostate stimulation
Dangers of false positives in PSA testing?
- Further investigations (including invasive prostate biopsies) which may have complications
- May lead to the unnecessary diagnosis and treatment of prostate cancer that would never have caused problems
Dangers of false negative in PSA testing?
False negatives may lead to false reassurance.
How are the results of an MRI in prostate cancer reported?
On a Likert scale:
1 – very low suspicion
2 – low suspicion
3 – equivocal
4 – probable cancer
5 – definite cancer
What does 4 on the Likert scale indicate?
Probable cancer
Prostate biopsy is the next step in establishing a diagnosis in suspected prostate cancer.
The decision to perform a biopsy depends on what?
1) MRI findings (Likert 3 or above)
2) Clinical suspicion (exam and PSA level)
What Likert score would indicate the need for a prostate biopsy?
3 or above
What are the 2 options for prostate biopsy?
1) Transrectal ultrasound-guided biopsy (TRUS)
2) Transperineal biopsy
What does a TRUS involve?
Involves an ultrasound probe inserted into the rectum, providing a good indicate of the size and shape of the prostate.
Guided biopsies are taken through the wall of the rectum, into the prostate.
What does a transperineal biopsy involve?
Transperineal biopsy involves needles inserted through the perineum. It is usually under local anaesthetic.
What are the main risks of a prostate biopsy?
1) Pain (particularly lower abdominal, rectal or perineal pain)
2) Bleeding (blood in the stools, urine or semen)
3) Infection
4) Urinary retention due to short term swelling of the prostate
5) Erectile dysfunction (rare)
What can be used to look for bony mets in prostate cancer?
Isotope bone scan (also called a radionuclide scan or bone scintigraphy)
What happens in an isotope bone scan?
1) A radioactive isotope is given by intravenous injection
2) A short wait (2-3 hours) to allow the bones to take up the isotope
3) A gamma camera is used to take pictures of the entire skeleton.
How do bony mets appear onn an isotope bone scan?
Metastatic bone lesions take up more of the isotope, making them stand out on the scan.
What garding system is used in prostate cancer?
Gleason Grading System
This is specific to prostate cancer.
What is the Gleason Grading System based on?
The Gleason grading system is based on the histology from the prostate biopsies.
What does a greater gleason score indicate?
The greater the Gleason score, the more poorly differentiated the tumour is (the cells have mutated further from normal prostate tissue) and the worse the prognosis is.
The Gleason score will be made up of two numbers added together for the total score (e.g. 3 + 4 = 7).
What are these 2 numbers?
1) The first number is the grade of the MOST PREVALENT PATTERN in the biopsy
2) The second number is the grade of the second most prevalent pattern in the biopsy
What Gleason score is considered low risk for prostate cancer?
6 is considered low risk
What Gleason score is considered intermediate risk for prostate cancer?
7 (3 + 4 is lower risk than 4 + 3)
What Gleason score is considered high risk for prostate cancer?
8 or above
What staging system is used for prostate cancer?
TNM staging system
Describe the ‘T’ aspect in the TNM staging system (TX to T4)
TX – unable to assess size
T0 - no evidence of 1ary tumour
T1 – too small to be felt on examination or seen on scans
T2 – contained within the prostate
T3 – extends out of the prostate
T3a - extracapsular extension (unilateral or bilateral)
T3b - tumour invades seminal vesicle(s)
T4 – spread to nearby organs
Describe the ‘N’ aspect in the TNM staging system (NX to T1)
NX – unable to assess nodes
N0 – no nodal spread
N1 – spread to lymph nodes
Describe the ‘M’ aspect in the TNM staging system
M0 – no metastasis
M1 – metastasis
M1a - non-regional lymph node(s)
M1b - bone(s)
M1c - other or multiple site(s) with or without bone disease
Treatment options in prostate cancer?
- Surveillance or watchful waiting in early prostate cancer
- External beam radiotherapy directed at the prostate
- Brachytherapy
- Hormone therapy
- Surgery
What is a key complication of external beam radiotherapy in prostate cancer?
Proctitis (inflammation in the rectum) caused by radiation affecting the rectum.
This can lead to pain, altered bowel habit, rectal bleeding and discharge.
What can be given to help reduce inflammation in prostatitis?
Prednisolone suppositories
What does brachytherapy involve in prostate cancer?
Implanting radioactive metal “seeds” into the prostate –> this delivers continuous, targeted radiotherapy to the prostate.
Side effects of brachytherapy in prostate cancer?
- Cystitis and proctitis (inflammation in nearby organs)
- Erectile dysfunction
- Incontinence
- Increased risk of bladder or rectal cancer
What is the aim of hormone therapy in prostate cancer?
Aims to reduce the level of androgens (e.g., testosterone) that stimulate the cancer to grow.
Give 2 classes of drugs used in hormone therapy options in prostate cancer
1) Androgen-receptor blockers such as bicalutamide
2) GnRH agonists such as goserelin (Zoladex) or leuprorelin (Prostap)
What class of drug is goserelin?
GnRH agonists
What class of drug is bicalutamide?
Androgen-receptor blockers
Side effects of hormone therapy in prostate cancer?
Hot flushes
Sexual dysfunction
Gynaecomastia
Fatigue
Osteoporosis
What are the 2 surgical options in prostate cancer?
1) Bilateral orchidectomy
2) Radical prostatectomy
What does a radical prostatectomy involve?
Involves a surgical operation to remove the entire prostate.
Aim of a radical prostatectomy?
cure prostate cancer confined to the prostate
What are 2 key complications of a radical prostatectomy?
1) erectile dysfunction
2) urinary incontinence
Prognosis of prostate cancer?
Prostate cancer survival of men with low risk localised prostate cancer is excellent (99%) at 10 years whether they choose active surveillance, radiotherapy or surgery.
Prostate cancer 10 year survival (all UK patients) is around 84%.
Metastatic disease - 3.5 years.
Give some risk factors for colorectal cancer
- FH
- Familial adenomatous polyposis (FAP)
- Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome
- IBD
- Increased age
- Diet (high in red and processed meat and low in fibre)
- Obesity and sedentary lifestyle
- Smoking
- Alcohol
What is familial adenomatous polyposis (FAP)?
FAP is an autosomal dominant condition involving malfunctioning of the tumour suppressor genes called adenomatous polyposis coli (APC).
It results in many polyps (adenomas) developing along the large intestine.
These polyps have the potential to become cancerous (usually before the age of 40).
What 2 inherited conditions can increase risk of colorectal cancer?
- FAP
- HNCC
How is FAP inherited?
Autosomal dominant
What gene is implicated in FAP?
Tumour suppressor genes called adenomatous polyposis coli (APC)
Management of FAP?
Patients have their entire large intestine removed prophylactically to prevent the development of bowel cancer (panproctocolectomy).
How is HNPCC inherited?
Autosomal dominant
What is HNPCC?
It is an autosomal dominant condition that results from mutations in DNA mismatch repair (MMR) genes.
Patients are at a higher risk of a number of cancers, but particularly colorectal cancer.
Unlikely FAP, it does NOT cause adenomas and tumours develop in isolation.
What genes are implicated in HNPCC?
DNA mismatch repair (MMR) genes
Red flag symptoms for bowel cancer?
- Change in bowel habit (usually to more loose and frequent stools)
- Unexplained weight loss
- Rectal bleeding
- Unexplained abdominal pain
- Iron deficiency anaemia (microcytic anaemia with low ferritin)
- Abdominal or rectal mass on examination
Which IBD is more associated with bowel cancer?
Ulcerative colitis
Which mutation is asscoiated with the development of benign adenomas in the colon?
APC mutations
Where do most colorectal cancers occur?
- 40% in rectum
- 20% in sigmoid colon
- 6% in caecum
and the rest in the remaining colon
NICE two week wait referral guidelines for colorectal cancer:
a) Over 40 years with ABDO PAIN and unexplained WEIGHT LOSS
b) Over 50 years with unexplained RECTAL BLEEDING
c) Over 60 years with a CHANGE in bowel habit or iron deficiency ANAEMIA
N.B. Iron deficiency anaemia on its own without any other explanation (i.e. heavy menstruation) is an indication for a “two week wait” cancer referral for colonoscopy and gastroscopy (“top and tail”) for GI malignancy.
Patients may present acutely with obstruction if the tumour blocks the passage through the bowel.
How may this present?
This presents a surgical emergency with vomiting, abdominal pain and absolute constipation.
How can GI malignancy lead to iron deficiency anaemia?
They can cause microscopic bleeding (not visible in bowel movements) that eventually lead to iron deficiency anaemia.
What test is used to look for blood in stools?
Faecal immunochemical tests (FIT) –> these look very specifically for the amount of human haemoglobin in the stool.
When would FIT tests be used?
FIT tests can be used as a test in general practice to help assess for bowel cancer in specific patients who do not meet the criteria for a two week wait referral.
For example:
a) Over 50 with unexplained weight loss and no other symptoms
b) Under 60 with a change in bowel habit
Also used for the bowel cancer SCREENING program in England.
Who is offered FIT tests for bowel cancer screening?
In England, people aged 60-74 are sent a home FIT test to do every 2 years.
If home FIT test results come back positive, what is the next investigation?
Colonoscopy
What risk factors would indicate someone to be invited for a colonoscopy at regular intervals to screen for bowel cancer?
FAP, HNPCC or inflammatory bowel disease
What is the gold standard investigation in colorectal cancer?
Colonoscopy
What does a colonoscopy involve?
It involves an endoscopy to visualise the entire large bowel.
Any suspicious lesions can be biopsied to get a histological diagnosis, or tattoo in preparation for surgery.
What does a sigmoidoscopy involve?
Sigmoidoscopy involves an endoscopy of the rectum and sigmoid colon only.
When may a sigmoidoscopy be used instead of a colonoscopy?
This may be used in cases where the only feature is rectal bleeding.
(obvious risk of missing cancers in other parts of the colon)
What investigation may be considered in patients less fit for a colonoscopy?
CT colonography - this is a CT scan with bowel prep and contrast to visualise the colon in more detail
Benefits vs disadvantages of a CT colonography in suspected colorectal cancer?
Benefits - may be considered in patients less fit for a colonoscopy
Disads - less detailed and does not allow for a biopsy.
What investigation can be used to look for metastasis and other cancers (in colorectal cancer)?
Staging CT scan involves a full CT thorax, abdomen and pelvis (CT TAP).
What tumour marker can be used for predicting relapse in patients previously treated for bowel cancer?
Carcinoembryonic antigen (CEA)
What classification is used to staging colorectal cancer?
TNM
Describe ‘T’ stages of TNM staging for colorectal cancer (TX-T4)
TX – unable to assess size
T1 – submucosa involvement
T2 – involvement of muscularis propria (muscle layer)
T3 – involvement of the subserosa and serosa (outer layer), but not through the serosa
T4 – spread through the serosa (4a) reaching other tissues or organs (4b)
Describe ‘N’ stages of TNM staging for colorectal cancer (NX-N2)
NX – unable to assess nodes
N0 – no nodal spread
N1 – spread to 1-3 nodes
N2 – spread to more than 3 nodes
Describe ‘M’ stages of TNM staging for colorectal cancer (MX-M1)
M0 – no metastasis
M1 – metastasis
What are some management options for colorectal cancer?
- Surgical resection
- Chemo
- Radiotherapy
- Palliative care
Give some surgical options for colorectal cancer
- Curative
- Palliative (reduce size of tumour and improve symptoms)
Types of surgery:
- Laparoscopic surgery
- Robotic surgery
- Open surgery
Advantages of laparoscopic surgery?
Gives better recovery and fewer complications compared with open surgery.
Colorectal surgery can involving creating an end-to-end anastomosis or a stoma.
What are these two?
Anastomosis –> sewing the remaining ends back together
Stoma –> bringing the open section of bowel onto the skin
What is removed in a right hemicolectomy?
Caecum, ascending and proximal transverse colon (see zero to finals for pics)
What is removed in a left hemicolectomy?
Distal transverse and descending colon
What is removed in a high anterior resection?
Sigmoid colon (may be called a sigmoid colectomy).
What is removed in a low anterior resection?
Signkoid colon and upper rectum (but sparing rectum and anus)
What is removed in an abdomino-perineal resection (APR)?
Rectum and anus (plus or minus sigmoid colon) and suturing over the anus.
This leaves the patient with a permanent colostomy.
What is Hartmann’s procedure?
What is removed?
Is usually an emergency procedure that involves the removal of the rectosigmoid colon and creation of an colostomy.
The rectal stump is sutured closed.
The colostomy may be permanent or reversed at a later date.
What are some common indications for a Hartmann’s procedure?
Acute obstruction by a tumour, or significant diverticular disease.
Complications of surgery for colorectal cancer?
Bleeding, infection and pain
Damage to nerves, bladder, ureter or bowel
Post-operative ileus
Anaesthetic risks
Laparoscopic surgery converted during the operation to open surgery (laparotomy)
Leakage or failure of the anastomosis
Requirement for a stoma
Failure to remove the tumour
Change in bowel habit
Venous thromboembolism (DVT and PE)
Incisional hernias
Intra-abdominal adhesions
What is low anterior resection syndrome?
Low anterior resection syndrome may occur after resection of a portion of bowel from the rectum, with anastomosis between the colon and rectum.
It can result in a number of symptoms, including:
- Urgency and frequency of bowel movements
- Faecal incontinence
- Difficulty controlling flatulence
What investigations may be done in follow up after curative colorectal surgery?
- Serum carcinoembryonic antigen (CEA)
- CT thorax, abdomen and pelvis
What is the most common type of colorectal cancer?
Adenocarcinoma
