Statistics and Medicine –
Friends or Foes?
Monika Krzyzanowska MD MPH
Medical Oncologist, Princess Margaret Cancer Centre
Associate Professor of Medicine, University of Toronto
Case
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•
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61 year old male tailor
Presented with iron deficiency anemia
Colonoscopy: tumour in colon
Sent to general surgeon who removed the
primary cancer from the colon
• The surgeon has referred the patient to you
(medical oncologist) for an opinion regarding
what to do next?
What do you need to know to advise
the patient on next steps?
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•
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How serious is the cancer?
What are the “treatment” options?
What are the benefits of treatment?
What are the risks?
Evidence Pyramid
What do you need to know to advise
the patient on next steps?
•
•
•
•
How serious is the cancer?
What are the “treatment” options?
What are the benefits of treatment?
What are the risks?
How serious is the cancer?
PROGNOSIS
Colorectal Cancer Stages
TNM Staging System
• T: depth of invasion into bowel wall
–
–
–
–
T1
T2
T3
T4
Invasion of submucosa
Invasion into muscularis propria
Invasion through muscularis into serosa
Invasion of other organs +/- perforation
• N: regional nodes
– N0
– N1
– N2
No nodal mets
Mets to 1-3 lymph nodes
Mets in  4 nodes
• M: distant metastases
TNM Staging System
Dukes’ Survival (no
tx)
TNM Classification
Stage I
T1N0M0
T2N0M0
A
> 90%
Stage II
IIA
IIB
T3N0M0
T4N0M0
B
60-85%
Stage III
IIIA
IIIB
IIIC
T1-2N1M0
T3-4N1M0
anyTN2M0
C
25-65%
anyTanyNM1
D
5%
Stage IV
Case Revisited
• CT scans – no spread of disease
• Pathology
– Adenocarcinoma
– invading through the muscularis into serosa
– 7/15 LN involved with tumour
Stage: pT3N2M0 (Stage 3)
TNM Staging
Dukes’ Survival (no
tx)
TNM Classification
Stage I
T1N0M0
T2N0M0
A
> 90%
Stage II
IIA
IIB
T3N0M0
T4N0M0
B
60-85%
Stage III
IIIA
IIIB
IIIC
T1-2N1M0
T3-4N1M0
anyTN2M0
C
25-65%
anyTanyNM1
D
5%
Stage IV
Adjuvant! Online
https://www.newadjuvant.com/default2.aspx
What do you need to know to advise
the patient on next steps?
•
•
•
•
How serious is the cancer?
What are the “treatment” options?
What are the benefits of treatment?
What are the risks?
What are the treatment options?
• Do nothing
• Surveillance
• Chemotherapy
http://www.psmag.com/health/evidence-of-a-need-for-change-4241/
Adjuvant Therapy
Treatment given after the primary treatment
to increase the chances of a cure; may
include chemotherapy, radiation therapy,
hormone therapy, or biological therapy.
What do you need to know to advise
the patient on next steps?
•
•
•
•
How serious is the cancer?
What are the “treatment” options?
What are the benefits of treatment?
What are the risks?
Chemotherapy Options
for St 3 Colon Cancer in 2013
• Drug A -- 5-fluorouracil (5-FU)
• Drug B – capecitabine
• Combination therapy (Drug A or B plus
other drugs)
Drug A vs No Treatment
MOSAIC Trial
St II & III
colon
n = 2,246
R
A
N
D
O
M
I
Z
A
T
I
O
N
Drug A – 5FU
Combination
Andre NEJM 2004
Evidence Pyramid
Adjuvant! Online
https://www.newadjuvant.com/default2.aspx
What do you need to know to advise
the patient on next steps?
•
•
•
•
How serious is the cancer?
What are the “treatment” options?
What are the benefits of treatment?
What are the risks?
MOSAIC Trial: Serious Toxicity
Toxicity
5FU
FOLFOX
Neuropathy
0.2
12.4
Neutropenia
4.7
41.1
Diarrhea
6.6
10.7
Vomiting
1.4
5.8
Febrile neutropenia
0.2
1.8
Death
0.5
0.5
MOSAIC Trial: Serious Toxicity
Toxicity
5FU
FOLFOX
Neuropathy
0.2
12.4
Neutropenia
4.7
41.1
Diarrhea
6.6
10.7
Vomiting
1.4
5.8
Febrile neutropenia
0.2
1.8
Death
0.5
0.5
Back to the Case
• 61 year old male tailor
• Stage 3 colon cancer
What would you recommend?
a. Do nothing
b. Surveillance
c. Chemotherapy
Evidence Based Medicine
Guidelines
https://www.cancercare.on.ca/common/pages/UserFile.aspx?fileId=14002
Guideline
Concordance
Statistics & Medicine
• Explain & describe disease
– Natural history
– Risk factors
– Causes
• Evaluate treatments
– Benefit
– Risk
• Communicate with patient
• Assess quality of care
Friends or Foes?