statistics and medicine – friends or foes?

Statistics and Medicine – Friends or Foes?

Monika Krzyzanowska MD MPHMedical Oncologist, Princess Margaret Cancer CentreAssociate Professor of Medicine, University of Toronto

Case

• 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?

• 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 Invasion of submucosa– T2 Invasion into muscularis propria– T3 Invasion through muscularis into serosa– T4 Invasion of other organs +/- perforation

• N: regional nodes– N0 No nodal mets– N1 Mets to 1-3 lymph nodes– N2 Mets in 4 nodes

• M: distant metastases

TNM Staging System

TNM Classification Dukes’ Survival (no tx)

Stage I T1N0M0T2N0M0

A > 90%

Stage II IIAIIB

T3N0M0T4N0M0

B 60-85%

Stage III IIIAIIIBIIIC

T1-2N1M0T3-4N1M0anyTN2M0

C 25-65%

Stage IV anyTanyNM1 D 5%

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

TNM Classification Dukes’ Survival (no tx)

Stage I T1N0M0T2N0M0

A > 90%

Stage II IIAIIB

T3N0M0T4N0M0

B 60-85%

Stage III IIIAIIIBIIIC

T1-2N1M0T3-4N1M0anyTN2M0

C 25-65%

Stage IV anyTanyNM1 D 5%

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

RANDOMIZATION

Combination

Drug A – 5FU

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 nothingb. 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?