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Colorectal Flashcards

1
Q

CT sim scanning limits

A

L3/4-5 cm beyond anal verge

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2
Q

in what cancer location is kidney constraints most important

A

in the right colon 50% or mored of rt kidney could be in the field therefore its important to spare the left kidney

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3
Q

dose constraint of the kidney

A

2/3 of th kidney should get no more than 18-20Gy

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4
Q

tx options for colorectal

A

3 field: AP and lats with wedges
4 field (AP/PA and lats) used when there is risk of anterior lesions (pros vag)
IMRT

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5
Q

TYPICAL TX BORDERS

A

S: L5/S1
L: 2 CM LAT TO PELVIC BRIM
I: 3-5CM INF OF TUMOUR

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6
Q

Benefits of IMRT over conventional techniques

A
  • dose to small bowel
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7
Q

nodal target volume in IMRT

A

mesolectal, pre sacral and internal iliac

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8
Q

target volume in neo XRT

A

GTV= tumour + enlarged LN
CTV=perirectal, mesorectum, pre sacral space and int IL +2cm sup and inf
PTV=CTV +1cm

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9
Q

target volume in adj XRT

A

CTV same as neoadjuvant but the prep tumour bed

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10
Q

Dose

A

initial dose is 45Gy + boost: 5.4-9Gy to tumour bed in adjuvant tx
5.4 Gy boost in neoadjuvant setting

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11
Q

rectal cancer s&s

A

hematochezia, change in stool caliber and abdo pain

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12
Q

lt sided colon cancer s&s

A

similar to rectal cancer

  • blood in stool
  • change in stool caliber
  • abdo pain
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13
Q

rt sided colon cancer s&s

A
  • n&v
  • abdo pain
  • iron deficiency due to blood loss
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14
Q

1st diagnosis tsts for colorectal ca

A

TRUS, CT, MRI physical exam, proctoscopy, and imaging by

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15
Q

For patient >T2 what extra diagnostic tests should be done

A

chest XRAY, CT or abode and pelvis

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16
Q

DRE position of elderly patients

A

lt lateral debiculitis, when the knees are pulled up sims position is achieved

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17
Q

DRE position for non elderly pts

A

lateral recumbent

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18
Q

DRE position that may be used for women

A

dorsal lithotomy

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19
Q

lab studies done for DX

A

CBC, KRAS, CEA

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20
Q

what tumour marker may be elevated in colorectal cancer

A

CEA- carcinogenig embryonic antigen

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21
Q

what does KRAS determine

A

determines if pt is a candidate for monoclonal antibodies (ex cetuximab)

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22
Q

what is CEA levels what level indicates metastasis

A

these levels should be taken before and after treatment levels should fall after treatment
>20ng/ml can indicate metastasis

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23
Q

ages

A

60-80

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24
Q

_most common cancer in M, _ most common cancer in W

A

2nd, 3rd

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25
what countries is it most common in
N america, western europe and australia
26
m vs women
mor common in men
27
dietary factors that cause colorectal cancer
high fat, high red and processed meats, low fruit and veg
28
lifestyle factors that cause colorectal cancer
high alcohol consumption, obesity, smoking and low physical activity
29
medical conditions that cause colorectal cancer
``` adenomatous polyps familial adenomatous polyposis IBD, ulcerative colitis gardner syndrome lynch syndrome ```
30
what can reduce risk of colorectal cancer
NSAIDS
31
ulcerative colitis occur in what part of colorectum
rectum and sigmoid colon
32
lynch syndrome occurs in what part of the colorectumand occur in what age
they are right sided and are diagnosed at a young age
33
subtypes of adenomatous polyps which is most commonly associated with colorectum
subtypes: villous or tubular | villous is most commonly associated with colorectal cancer
34
what % of cancer occurs in proximal, distal colon or rectum
45% proximal 40% distal colon 15% rectum
35
white vs blacks in location of tumour
white more commonly get distal colorectal cancer, blacks get proximal tumours
36
8 divisions of the colon
cecum, ascending colon, descending colon, splenic flexure, hepatic flexure, transverse colon, sigmoid colon and rectum
37
what parts of the colon have mesentery what does the indicate
cecum, transverse, and sigmoid colon | means it can be surgically removed
38
what parts of the colon have mesentery where do these tumours spread
ascending descending splenic and hepatic flexures they spread to kidney and pancreas
39
t levels for rectum
s3- puborectalis ring
40
3 divisions of the rectum
up valve, mid vale and lower valve
41
tumours that can be palpated on DE are considered to be
distal tumours of the rectum
42
direct extension occurs in _____ fashion.
rADIAL
43
When what layer is penetrated there is + risk of spread to abode and pelvic structures
serosa
44
peritoneal seeding is more common in colon or rectum cancer?
more common in the colon as the retum is located below the peritoneal reflection
45
how common is LN mets at dx?
50%
46
tumours above anorectal ring metastasize via what LN
mets along int iliac Ln
47
rumours that extent into the anal canal spread via what LN
inf rectal and ext IL LN
48
Distant mets in rectum
sup 1/2 of rectum spreads to liver via portal drainage | inf 1/2 of recum spreads to lung via IVC
49
Rectal cancer recurrence location? and occurs via ? what does this indicate tx wise?
ca recurrence occurs In post portion of the pelvis and occurs via mets to int IL & pre sacral LN there 2 need to be irradiated as they can not be surgically removed
50
most important prognostic indicator
tumour stage
51
do males or females have better prognosis
females
52
what tumour types have worse prognosis
mutinous, singet cell and small cell have worse prognosis
53
are mobile or tethered tumours better prognosis and why?
mobile is better as they are nice easily resectable
54
what is the typical screening for colorectal cancer
Screening starts at age 50 and is as follows: -FOBT (fecal occult blood test) annually -sigmoidoscopy / 5 years -colonoscopy /10 year s double contrast barium enema/ 5 years
55
what people are considered high risk in terms of screening
personal or family history of colorectal ca or adenomatous polyps personal history of IBD or UC family history of FAP or lynch syndrome
56
treatment to T1-2 tumours
Surgery alone is treatment of choice
57
lt hemicolectomy
used for left side of large bowel
58
rt helicolectomy
removes the cecum, ascending colon, hepatic flexure, 1st 1/3 of the transverse colon & part of terminal ileum w fat and LN
59
what locations of the colon can be resected with wide local excision
ascending and descending colon, mid sigmoid and transverse colon
60
what portions of the colon have low and high rates of recurrence after wide local excision and why
ascending and descending colon has high recurrence mid sigmoid and transverse colon are mobile and wide margins are achievable therefore low recurrence rates in these areas
61
what surgical procedure can be used for T1 rectal cancer
local excision
62
what surgery type is SOC of rectal cancer
total mesolectal excision
63
LAR vs APR location location of excision
LAR removes more proximal tumours 6-8 cm from anal verge | apr- USED FOR lesions 5-6 cm from anal verge therefore distal 1/3 ectum
64
which requires colostomy (LAR or APR)
lLAR gets a non permanent ileostomy whole the anamatose heals APR gets a permanent colostomy
65
STAGE 3 COLON CANCER TX
SURGERY THEN ADJUVANT CHEMORADS (FOLFOX) + 50.4-54GY (45gy to pelvis + 4.5-9Gy boost to tumour bed)
66
stage 3 rectak cancer treatment
``` neoadjuvant chemorads (50.4 GY) + continuous infusions of 5FU or capacetabine surgery adjuvant chemotherapy (FOLFOX or capacetabine + oxoplatin) ```
67
what agents are in FOLFOX
5FU oxoplatin leucovrin
68
why is neoadjuvant tx one for rectal cancer (stage 3)
its done to ry to downgrade the need for APR (with permanent colostomy) to LAR with no colostomy needed Also tumour down staging, + respectability and + sphincter preservation
69
treamtmen of stage 4 cancer
FOLFIRI +/- monoclonoal antibodies ex: bvacuziman and cetuximab +/- palliative XRT
70
WHAT agents are in FOLFIRI what is i used for
used for recurrent or metastatic disease | Agents are 5FU, LEUCOVIRIN AND irinitonecan
71
most common pathology
adenocarcinoma in 90-95% of cases
72
what are the 2 staging systems
dukes and TNM
73
side effects relaxing to blood levels in XRT
thrombocytopenia (- platelets) normal levels (165,000-415,000) severely low amount is <20,000` leukopenia (- leukocytes) normal level around 30% (20-40% )
74
what medications can be given to that side effect
antidiahreals (ammonium and kapacotate (OTC) RX- lomotil anorectal creams -proctofoam, proctodesyl
75
what is done tx wise for a patient with churns disease
would only get SX+ CX as pt is too sensitive for XRT
76
WHAT does i indicate if pt has flu like ymptoms
they may have leakage in the bowel wall which causes a fever, the RO will put them on antibiotics bt we can continue tx the patient
77
What would you tell a patient if they told you they were having a mucous discharge?
Explain that this is normal and it is due to the radiation working and breaking down the tumor. Once it gets broken down, it exits through the anus.

Skin Radiation therapy (40 decks)

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