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Year 4 Oncology > Colorectal Cancer > Flashcards

Colorectal Cancer Flashcards

1
Q

Certain genetic mutations have been implicated in predisposing individuals to colorectal cancer, such as what?

A

Adenomatous polyposis coli (APC)

Hereditary nonpolyposis colorectal cancer (HNPCC)

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2
Q

Risk factors for colorectal cancer

A

Increasing age

Male

Family history

IBD

Low fibre diet

High processed meat intake

Smoking

Excess alcohol

Approximately 75% of colorectal cancers are sporadic, developing in people with no specific risk factors.

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3
Q

What is Adenomatous polyposis coli (APC)

A

A tumour suppressor gene, mutation of the APC gene results in growth of adenomatous tissue, such as Familial Adenomatous Polyposis (FAP)

Genetic predisposition to colorectal cancer

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4
Q

What is Hereditary nonpolyposis colorectal cancer (HNPCC)

A

A DNA mismatch repair gene, mutation to HNPCC leads to defects in DNA repair, such as Lynch syndrome

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5
Q

Common clinical features of colorectal cancer

A

Change in bowel habit
Rectal bleeding
Weight loss
Abdominal pain
Symptoms of (iron-deficiency) anaemia.

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6
Q

Right-sided colon cancers – clinical features

A

Abdominal pain
Iron-deficiency anaemia
Palpable mass in right iliac fossa
Often present late

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7
Q

Left-sided colon cancers – clinical features

A

Left-sided colon cancers
Rectal bleeding
Change in bowel habit
Tenesmus
Palpable mass in left iliac fossa or on PR exam

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8
Q

Which sided colon cancer is tenesmus more typical of?

A

Left sided

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9
Q

Which sided colon cancer is rectal bleeding more typical of?

A

Left sided

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10
Q

Which sided colon cancer is more likely to present late?

A

Right sided

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11
Q

When does NICE guidance recommend that patients should be referred for urgent investigation of suspected bowel cancer?

A

≥40yrs with unexplained weight loss AND abdominal pain

≥50yrs with unexplained rectal bleeding

≥60yrs with: iron‑deficiency anaemia or change in bowel habit

Positive occult blood screening test

Rectal or abdominal mass

Aged under 50 with rectal bleeding AND any of the following unexplained symptoms:
Abdominal pain
Change in bowel habit
Weight loss
Iron-deficiency anaemia

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12
Q

Upper vs lower GI cancer - weight loss

A

As opposed to upper GI malignancies, progressive weight loss is usually only present in colorectal cancer cases with associated metastasis (or rarely in sub-acute bowel obstruction)

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13
Q

Main differentials when considering ?colorectal cancer and how they may differ

A

Inflammatory bowel disease – The average age of onset of inflammatory bowel disease is younger (20-40yrs) than with colorectal cancer and typically presents with diarrhoea containing blood and mucus

Haemorrhoids – Bright red rectal bleeding on the pan or surface of the stool but rarely presents with abdominal discomfort or pain, altered bowel habits, or weight loss

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14
Q

How often is FIT offered and for who?

A

In England and Wales, screening is offered every 2 years to men and women aged 60-74 years

For most of the UK a faecal immunochemistry test (FIT) is used

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15
Q

Consequence of a positive FIT?

A

If any of the samples are positive, patients are offered an appointment with a specialist nurse and further investigation via colonoscopy

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16
Q

Investigations in colorectal cancer

A

Routine bloods: FBCs (may show microcytic anaemia (iron def)), LFTs, clotting

Carcinoembryonic Antigen (CEA) - used to monitor disease progression and should be conducted both pre- and post-treatment, screening for recurrence.

Colonoscopy with biopsy + removal of any polyps seen(CT colonography considered if not suitable) - GOLD STANDARD INITIAL INVESTIGATION

Staging following initial diagnosis: CT scan/MRI rectum/Endo-anal ultrasound

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17
Q

Staging investigations in colorectal cancer?

A

CT scan (Chest/Abdomen/Pelvis) to look for distant metastases and local invasion

MRI rectum (for rectal cancers only) to assess the depth of invasion and potential need for pre-operative chemotherapy

Endo-anal ultrasound (for early rectal cancers, T1 or T2 only) to assess suitability for trans-anal resection

Biopsy samples being sent for histology will be assessed using TNM staging, histological subtyping, grading, and assessment of lymphatic, perineural, and venous invasion.

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18
Q

Role of biopsy in colorectal cancer

A

Biopsy samples being sent for histology will be assessed using TNM staging, histological subtyping, grading, and assessment of lymphatic, perineural, and venous invasion.

Increasingly, samples are also routinely being assessed for varying tumour-based markers (including mismatch-repair testing), to aid in the identification of Lynch syndrome and to optimise potential chemotherapy regimes.

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19
Q

Dukes Stage A colorectal cancer

A

A Confined beneath the muscularis - limited to the bowel wall

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20
Q

Dukes Stage B colorectal cancer

A

Extension through the muscularis propria - extending through the bowel wall

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21
Q

Dukes Stage C colorectal cancer?

A

Involvement of regional lymph nodes

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22
Q

Dukes Stage D colorectal cancer?

A

Distant metastasis

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23
Q

General principles of management in colorectal cancer?

A

All patients should be discussed with the multidisciplinary team (MDT).

The only definitive curative option is surgery, although chemotherapy and radiotherapy have an important role as neoadjuvant and adjuvant treatments, alongside their role in palliation.

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24
Q

Mainstay of curative management of colorectal cancer?

A

Surgery is the mainstay of curative management for localised bowel cancer. The general plan in most surgical management plans is suitable regional colectomy, to ensure the removal of the primary tumour with adequate margins and lymphatic drainage, followed either by primary anastomosis or formation of a stoma

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25
Q

When is colorectal cancer managed with right hemicolectomy or extended right hemicolectomy

A

Caecal tumours or ascending colon tumours

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26
Q

What does a right hemicolectomy involve?

A

During the procedure the ileocolic, right colic, and right branch of the middle colic vessels (branches of the SMA) are divided and removed with their mesenteries

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27
Q

When is colorectal cancer managed with an extended right hemicolectomy

A

Transverse colon tumour

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28
Q

What surgical approach may be used to manage a caecal tumour?

A

Right hemicolectomy

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29
Q

What surgical approach may be used to manage an ascending colon tumour?

A

Right hemicolectomy

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30
Q

What surgical approach may be used to manage a transverse colon tumour?

A

Extended right hemicolectomy

31
Q

When is colorectal cancer managed with a left hemicolectomy

A

Descending colon tumour

32
Q

What surgical approach may be used to manage an descending colon tumour?

A

Left hemicolectomy

33
Q

When is colorectal cancer managed with a Sigmoidcolectomy?

A

Sigmoid tumour

34
Q

What surgical approach may be used to manage a sigmoid tumour?

A

Sigmoidcolectomy

35
Q

What does a left hemicolectomy involve?

A

The left branch of the middle colic vessels (branch of SMA/SMV), the inferior mesenteric vein, and the left colic vessels (branches of the IMA/IMV) are divided and removed with their mesenteries

36
Q

What does a sigmoidcolectomy involve?

A

In this instance, the IMA is fully dissected out with the tumour in order to ensure adequate margins are obtained.

37
Q

What surgical approach may be used to manage a high rectal tumour >5cm from the anus?

A

Anterior Resection

38
Q

When might a anterior resection be used?

A

high rectal tumour >5cm from the anus

39
Q

What does an anterior resection involve?

A

This approach is favoured as leaves the rectal sphincter intact if an anastomosis is performed (unlike AP resections). Often a defunctioning loop ileostomy is performed to protect the anastomosis and reduce complications in the event of an anastomotic leak, which can then be reversed electively four to six months later

40
Q

What does an Abdominoperineal (AP) Resection involve?

A

This technique involves excision of the distal colon, rectum and anal sphincters, resulting in a permanent colostomy

41
Q

What surgical approach may be used to manage a low rectal tumour <5cm from the anus?

A

Abdominoperineal (AP) Resection

42
Q

When might an abdominoperineal resection be performed?

A

Low rectal tumour <5cm from the anus

43
Q

When is a Hartman’s procedure performed?

A

This procedure is used in emergency bowel surgery, such as bowel obstruction or perforation.

This involves a complete resection of the recto-sigmoid colon with the formation of an end colostomy and the closure of the rectal stump

44
Q

What does a Hartman’s procedure involve?

A

This involves a complete resection of the recto-sigmoid colon with the formation of an end colostomy and the closure of the rectal stump

45
Q

Colorectal cancer presenting with bowel obstruction can be relieved how?

A

A decompressing colostomy or endoscopic stenting, after which staging and patient status can be optimised

46
Q

Role of chemotherapy in colorectal cancer?

A

Chemotherapy is indicated typically in patients with advanced disease (adjuvant chemotherapy in Dukes’ C colorectal cancer has been found to reduce mortality by 25%). Systemic therapy for metastatic colorectal cancer is tailored with patient-specific and disease-specific predictive markers.

An example chemotherapy regime for patients with metastatic colorectal cancer is FOLFOX, comprised of Folinic acid, Fluorouracil (5-FU), and Oxaliplatin, which has been demonstrated to significantly improvement in 3-year disease-free survival for patients with advanced colon cancer.

Newer biologic agents or immunotherapies are being developed and used to growing success.

47
Q

What is the FOLFOX chemotherapy regime for patients with metastatic colorectal cancer?

A

Folinic acid, Fluorouracil (5-FU), and Oxaliplatin

48
Q

Role of radiotherapy in colorectal cancer management?

A

Radiotherapy can be used in rectal cancer (it is rarely given in colon cancer due to the risk of damage to the small bowel), most often as neo-adjuvant treatment, and can be given alongside chemotherapy.

It is of particular use in patients with rectal cancers which look on MRI to have a “threatened” circumferential resection (i.e. within 1mm). They can undergo pre-operative long-course chemo-radiotherapy to shrink the tumour, thereby increasing the chance of complete resection and cure; time interval to surgery is then approximately 8-10 weeks.

Due to certain cases achieving complete response with chemo-radiotherapy, some patients with rectal cancer will opt for a rectal preserving treatment approaches, where a “watch-and-wait” strategy is employed with the omission of radical surgery and close surveillance.

49
Q

Is radiotherapy used more often in rectal or colon cancer? Why?

A

Radiotherapy can be used in rectal cancer (it is rarely given in colon cancer due to the risk of damage to the small bowel), most often as neo-adjuvant treatment, and can be given alongside chemotherapy.

50
Q

Strong risk factors of colorectal cancer?

A

Increasing age

Heridiatry syndromes (FAP, Lynch syndrome, juvenile polyposis, Peutz-Jeghers syndrome)

Increased alcohol intake

Smoking tabacco

Processed meat

Obesity

Previous exposure to radiation

IBD

51
Q

Hereditary syndromes which increase the risk of colorectal cancer?

A

Familial adenomatous polyposis

Hereditary nonpolyposis colorectal cancer

(Lynch Syndrome)

Juvenile polyposis

Peutz-Jeghers syndrome

52
Q

Weak risk factors for colorectal cancer?

A

Lack of dietary fibre

Limited physical activity

Asbestos exposure

Red meat (non-processed)

53
Q

TNM staging of colorectal : T

A

Tis - carcinoma in situ/intramucosal cancer

T1 - extends through the mucosa into the submucosa

T2 - extends though the submucosa into the muscularis

T3 - Extends through the muscularis into the subserosa

T4 - extends into neighbouring organs or tissues

54
Q

TNM staging of colorectal : N

A

N0 - no regional lymph node involvement

N1 - metastasis to 1-3 regional lymph nodes

N2 - metastasis to 4 or more regional lymph nodes

55
Q

TNM staging of colorectal : M

A

M0 - no distant mets
M1 - distant mets

56
Q

Patients with Duke’s stage C or stage III (T1-4, N1-2, M0) colon cancer benefit from what management?

A

Adjuvant chemotherapy and surgical rescetion

57
Q

fColorectal cancer patients without lymph node involvement but with high risk features (such as vascular or perineural invasion) also show improved survival with what additional management?

A

Adjuvant chemotherapy

58
Q

What does FIT stand for?

A

Faecal immunochemical test

59
Q

When might it be useful to request a faecal occult sample ?

A

Aged > 50 with either:
Unexplained abdominal pain
Unexplained weight loss weight loss
Aged > 60 with any form of anaemia
Aged under 60 with:
Changes in their bowel habit
Iron-deficiency anaemia

60
Q

In what situations may someone come to the attention of oncology services with colorectal cancer?

A

Positive faecal occult sample requested (due to >50 - unexplained abdominal pain or weight loss, >60 any for of anaemia, under 60 with iron def aneamia or changes in bowel habit)

Other symptoms may include tenesmus, change in stool form (thin, small stools) and abdominal distension.

Patients may also be identified by the current bowel screening programme which offers a faecal immunochemical test (FIT) every 2 years to all men and women aged 60 – 74.

More rarely, patients may present as a clinical emergency as a consequence of carcinoma, such as large bowel obstruction.

61
Q

Colon cancer: Stage 1-4 disease management (assuming pt suitable for surgery)

A

Surgical resection ± post-operative chemotherapy

+ STAGE IV (mets): pre-operative chemotherapy may also be performed.
The staged colectomy and resection of metastatic disease is performed after pre-operative chemotherapy.

62
Q

Management of rectal cancer (assuming pt suitable for surgery)

A

For patients with rectal cancer suitable for surgery: Anterior resection for tumours >8 cm from the anal canal or involving the proximal 2/3 of the rectum. Abdomino-perineal (AP) resection for tumours <8 cm from the anal canal or involving the distal 1/3 of the rectum.

Patients with stage III disease benefit from post-operative chemotherapy.

Patients with stage IV disease benefit from post-operative chemoradiotherapy

63
Q

How might patients with colorectal not suitable for surgery be managed?

A

Management is with chemotherapy (FOLFOX or FOLFIRI i.e. oxaliplatin/irinotecan plus folinic acid plus fluorouracil are the preferred regimens).

New monoclonal antibody therapies are becoming available. Note that NICE concluded that cetuximab (anti-EGFR), is cost effective

Stenting for obstructing tumours of the sigmoid colon or rectum

64
Q

If the colorectal cancer patient presents with acute bowel obstruction, what interim measure might be used?

A

a Hartmann’s procedure may be required as an interim measure (resection of the rectosigmoid colon with formation of a temporary end colostomy and anorectal stump).

65
Q

Familial adenomatous polyposis genetic abnormality + inheritance

A

Caused by a mutation in the adenomatous polyposis coli (APC) gene and has an autosomal dominant inheritance pattern.

66
Q

How are patients with familial adenomatous polyposis managed and why?

A

Patients develop hundreds of adenomatous polyps in their teens and are virtually guaranteed to develop colorectal cancer by their 20s, unless they undergo prophylactic proctocolectomy.

Note that there is a high risk of developing duodenal cancer, so patients undergo regular endoscopic surveillance.

67
Q

What is Gardener’s syndrome?

A

Gardener’s syndrome is a variant of FAP in which patients may also develop epidermal cysts, supernumerary teeth, osteomas, and thyroid tumours.

68
Q

How is HNPCC/Lynch syndrome managed and why?

A

Patients have an 80% risk of developing colorectal cancer by their 30s.

There is increased risk of additional cancers such as gastric, endometrial, breast, and prostate cancer.

Patients are managed with regular endoscopic surveillance.

69
Q

HNPCC/Lynch syndrome - genetic abnormality and inheritance?

A

Is caused by a mutation in the mismatch repair genes MLH1/MSH2 and has an autosomal dominant inheritance pattern.

70
Q

Peutz-Jeghers syndrome genetic abnormality and inheritance?

A

Is caused by a mutation in the STK11 gene and has an autosomal dominant inheritance pattern.

71
Q

How are patient with Peutz-Jeghers syndrome managed and why?

A

The risk of neoplastic transformation of hamartomatous polyps is low, but many polyps are present so patients are at increased risk of developing colorectal cancer.

They are managed with regular endoscopic surveillance.

72
Q

How and when do patients with Peutz-Jeghers syndrome usually present?

A

Patients typically present in their teens with mucocutaneous pigmentaiton and hamartomatous polyps.

73
Q

What genetic condition warrants prophylactic proctocolectomy?

A

Familial adenomatous polyposis (FAP) - mutation in the adenomatous polyposis coli gene, which otherwise virually guarentees development of colorectal cancer before the patient turns 20

Year 4 Oncology (15 decks)

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