Cancer and Exercise

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Cancer and Exercise

• B. Elizabeth Delasobera, MD
• Sports Medicine Fellow

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Outline

• The mechanism for how exercise can prevent cancer
• The evidence for exercise and increased cancer
  survival
• The exercise prescription for cancer patients and
  survivors

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Cancer Review

• Excessive, uncontrolled cellular proliferation
  with potential for metastasis
• Symptoms can be local or systemic
• Variety of treatments
• Surgery, Radiation, Chemotherapy, Immunotherapy
• Designed to attempt remission or cure, or for
  disease control or symptom relief

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Mechanism for Cancer Reduction with Exercise

• Physical activity lowers levels of biologically
  available sex hormones
• Decreased lifetime exposure to endogenous sex
  hormones -gt decreased risk of hormone-related
  cancers
• Breast, endometrial, ovaries, prostate, testes

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Mechanism for Cancer Reduction with Exercise

• Exercise decreases endogenous insulin production
• Higher levels of circulating insulin linked with
  several cancers
• Exercise associated with decreased levels of IGF
• High levels of IGF-1 a/w several cancers (colon,
  prostate, breast, lung)

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Mechanism for Cancer Reduction with Exercise

• Adiposity and Cancer Risk
• Increased fat associated with increased risk of
  cancers of colon, kidney, esophagus, endometrium,
  thyroid, post-menopausal breast
• Physical activity decreases colon transit time
• Decreases colonic exposure to carcinogens in
  stool
• Level of physical activity inversely related to
  levels of C-reative protein
• NSAID use in physically active
• NSAID use appears to decrease colon cancer risk

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The EvidenceExercise and Cancer Risk

• Breast Cancer
• Invasive Breast Cancer risk decreased by 15-50
  among physically active women
• Women lt 40yo exercising 4 hrs/week or more during
  reproductive years had 50 risk reduction
• Postmenopausal women with higher rates of
  recreational activity have lower incidence of
  breast cancer
• Confirmed in over 30 studies in multiple
  demographic and population groups
• Studies focused solely on in situ Breast Cancer
  have shown similar reductions in risk
• Estrogren receptor negative cancer seem to be
  most reduced with exercise

Bernstein L, AACR Education Book 2008225-231
(2008)
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The EvidenceExercise and Cancer Risk

• Breast Cancer
• Greatest reduction is risk found with exercise
  during reproductive years, strenuous activity, at
  least 5 hours per week
• Estrogen receptor-negative Breast Cancer responds
  better to exercise than receptor-positive cancer
• Meta-analysis revealed a dose-response
  relationship of 6 decrease in relative risk for
  each additional hour of physical activity per
  week
• Monninkhof EM, et al. Epidemiol 20071813757.

Bernstein L, AACR Education Book 2008225-231
(2008)
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The Evidence Exercise and Cancer Survival

• Breast Cancer Survival Meta-Analysis
• 24 - 67 reduction in total deaths and 50
  reduction in breast cancer recurrence in women
  who are physically active
• Best effect in women who underwent equivalent of
  brisk walking 3h per week
• Effect observed in pre and post-menopausal,
  overweight and normal weight women, and those
  with stage I-III disease

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The EvidenceExercise and Cancer Risk

• Colon Cancer
• 43 out of 51 studies demonstrated decreased risk
  of colon cancer in the most physically active
  participants
• Risk reduction averaged 40-50, up to 70
• Consistent risk reduction despite differing study
  designs and populations and types of exercise
• Greater effect in men vs. women
• Hormone supplementation in postmenopausal women
  also has protective effect
• Unclear exercise effect on rectal cancer

Bernstein L, AACR Education Book 2008225-231
(2008) Friedenreich CM, et al. J Nutr
1323456-3464, 2002.
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The Evidence Exercise and Cancer Survival

• Colon cancer survival
• 3h per week of moderate physical activity after
  colon cancer diagnosis
• 39-59 decreased risk of colon cancer death
• 50-63 decreased risk of total death
• Effect essentially unchanged across age, sex,
  BMI, disease stage, age at diagnosis
• Meyerhardt JA, et al. J Clin Oncol
  200624353541

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The EvidenceExercise and Cancer Prevention

• Prostate Cancer
• Less consistent data, risk reduction averaged 10
  - 30
• Poor understanding of natural history of Prostate
  Cancer
• Exercise can also reduce risk of BPH
• Exercise lowers severity of disease and
  fatalities from prostate cancer
• Likely that very high level of exertion early in
  life needed to influence implicated hormones

Bernstein L, AACR Education Book 2008225-231
(2008)
Friedenreich CM, et al. J Nutr 1323456-3464,
2002.
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The EvidenceExercise and Cancer Prevention

• Endometrial Cancer
• Strong association with Breast Cancer
• Fewer/lower quality studies
• Majority still show decreased risk of endometrial
  cancer with increased physical activity
• Risk Reduction varied 0 90, average 30 - 40
• Majority of studies show dose response effect

Bernstein L, AACR Education Book 2008225-231
(2008) Friedenreich CM, et al. J Nutr
1323456-3464, 2002.
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The EvidenceExercise and Cancer Prevention

• Lung Cancer
• Physical activity probably decreases risk of lung
  cancer, but effect not well-established
• Meta-analysis shows 13 risk reduction with
  moderate recreational physical activity and 30
  decreased risk with strenuous activity
• Studies may not reflect differences in smoking
  habits

Tardon A, et al. Cancer Causes Control
20051638997.
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The EvidenceExercise and Cancer Prevention

• Limited and/or insufficient evidence
• Ovarian Cancer
• Testicular Cancer
• Renal Cell Cancer
• Pancreatic Cancer
• Thyroid Cancer
• Melanoma

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Survivors and Obesity

• Improvements in treatment means more survivors
• 11 million cancer survivors in US alone
• Obesity and a sedentary lifestyle prevalent among
  cancer survivors (Irwin ML, BJSM 20094332-38)
• Higher than general population
• Increases risk of cancer recurrence and death
• In breast cancer survivors, obesity assoc w/ 50
  increase in cancer recurrence and death (Kroenke
  CH, et al. J Clin Oncol 20052313708)
• Cancer survivors die from non-cancer related CVD
  and DM2 at a higher rate than the general
  population

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So Are Cancer Pts Exercising?

• Despite these well documented dramatic effects,
  the great majority of cancer survivors do not
  participate in regular physical activity
• Many cancer survivors decrease their physical
  activity after diagnosis
• Women with breast cancer exercise, on average, 2
  hours less per week 1 year after diagnosis than
  pre-diagnosis.

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Recs for Exercising with Cancer

• Goal is to preserve and possibly improve function
• Must be individualized
• Tailor to level of function
• Accommodate for periods of increased fatigue and
  cycles of treatment
• Make exercise an integral part of everyday life

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Recs for Exercising with Cancer

• 30-50 of breast cancer deaths among
  post-menopausal women can be attributed to being
  overweight
• Cancer survivors die of non-cancer causes at a
  higher rate than persons in the general
  population (CV dz, DM, etc)

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Recs for Exercising with Cancer

• Special Considerations for Cancer and Exercise
• Cancer treatment can cause osteoporosis bony
  metastases may weaken bone higher risk of
  pathologic fracture
• Be aware of Hickman cathethers, Port-a-caths,
  other access lines
• If platlet count is below 50k, consider risk of
  bleeding
• Consider concomitant effects of CVD and anemia

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Recs for Exercising with Cancer

• Medications That Can Effect Exercise Tolerance
• Glucocorticoids may cause muscle weakness and
  wasting
• Growth factors may cause bone pain
• Chemotherapy may cause anemia, fatigue, and
  nausea possibly myopathies and neuropathies
• Anthracyclines can cause cardiomyopathy, heart
  failure and coronary vasospasm
• Radiation may cause skin breakdown, muscle and
  joint constriction, and cardiopulmonary fibrosis

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Recs for Exercising with Cancer
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Recs for Exercising with Cancer

• American Cancer Society Recs
• While getting adjuvant treatment recs 3-5
  days/week for 20-30 mins tailored to fitness
  level and tx side effects (ex, walking,
  resistance training, yoga)
• Survivors use ACSM sports prescription guidelines
  (keep in mind any limitations based on prior
  slides)

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Recs for Exercising with Cancer

• Things to Keep in Mind with Return to Sport
• Immunocompromised? (neutropenia, on chemo, etc)
• At risk of bleeding? (platlet count, coags, meds)
• At risk of CV issues? (meds)
• Neck check

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Summary

• Multiple biologic explanations for benefits of
  exercise with respect to cancer risk reduction
  and survival
• Exercise and Cancer Prevention
• Convincing evidence for increased activity and
  prevention of colon, breast, and prostate cancer
• Probable evidence for endometrial and lung cancer
• Insufficient evidence for all others

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Summary

• Exercise and Cancer Survival
• Increasing numbers of survivors in population
• Decreasing physical activity among survivors
• Increased physical activity significantly lowers
  cancer recurrence and total death in survivors
• Exercise Prescription
• Must be individualized
• Many confounding factors (be aware of meds and
  side effects)
• Keep it simple, make it regular, progress
  gradually

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