# Exercise as it relates to Disease/Effects of exercise on breast cancer recovery
## Breast Cancer Prevalence

Worldwide, breast cancer is the most common cause of cancer related death in women. Prevalence is greater in more developed western countries; whereas the rates in less developed countries are low but increasing. In 2002, more than 4.4 million women were reportedly living with breast cancer, while in 2008, estimates showed 1.38 million new cases of breast cancer were diagnosed, with 458,000 breast cancer related deaths. While breast cancer predominantly effects the female population, males are also susceptible, with 1500 new cases diagnosed annually in the United States alone.

## Risk Factors for Breast Cancer

While it is hard to decipher the exact cause of breast cancer, there are a number of risk factors associated with its development. It has been suggested that the incidence of breast cancer increases with age, with incidence rates roughly doubling every 10 years through until around the age of 50 when menopause occurs, following menopause, the rate increase substantially slows. Family history also plays a role in increasing the risk of breast cancer. Research suggests the risk was significantly greater for women with first-degree relatives with breast cancer. This risk factor also increased with the number of first degree relatives whom had breast cancer. Additional personal risk factors for breast cancer include race, ethnicity, BMI, physical activity, alcohol use and smoking.

## Common Treatments and Interventions

Among the most common, successful treatments for breast cancer is radiation therapy and hormone control. The use of breast conserving treatment, which includes a partial mastectomy and radiation therapy on residual breast tissue, as an alternative for a full mastectomy for early-stage breast cancer has increased due largely to its cosmetic results. Multiple high-quality randomized trials has demonstrated the use of radiation therapy to play a crucial role in supporting breast conservation, enhancing local-regional control and improving the chance of survival, with approximately 120,000 breast cancer patients treated with radiation annually.
Aside from radiation therapy, the development and implementation of diverse selective endocrine therapies has led a shift from ablative surgery and chemotherapy to a more targeted, less aggressive form of breast cancer treatment. The endocrine therapies have reportedly been better tolerated and have improved both quality of life and mortality in patients suffering from hormone-responsive disease.
The use of diet and exercise interventions for breast cancer survivors helps to promote a healthy lifestyle. These interventions are commonly aimed at increasing levels of daily physical activity, increasing fruit and vegetable intake and optimizing healthy lifestyle practices. Diet and exercise interventions have proven to reduce co-morbidities in cancer survivors and can protect against the recurrence of cancer-specific mortality.

## Benefits of Exercise for Breast Cancer Recovery

Exercise interventions for breast cancer recovery should be used to help preserve or restore physical and psychological functions that are adversely affected by cancer related therapies. Benefits from exercise based interventions for individuals recovering from breast cancer include improvements in cardiorespiratory fitness, greater peak oxygen consumption, better physical functioning and a reduction in the symptoms of fatigue. It is a combination of these characteristics that leads to an increase in quality of life, which for people recovering from breast cancer should be an outcome held in high regard.

## Considerations for Exercise and Breast Cancer Recovery

Before commencing any exercise program, it is important for the prescribing practitioner or fitness professional to have an understanding of common therapeutic approaches to treating cancer. As a whole, most cancer patients will undergo some form of surgery, whether it be major or minor. Furthermore, around 50% or cancer patients will undergo some form of radiation therapy throughout their treatment. In addition to the abovementioned treatments, breast cancer patients will often be exposed to hormone therapies, with the type and duration of the treatment assigned on an individual basis. To prescribe a safe and effective exercise intervention, the specifics of the cancer diagnosis and treatment must be acknowledged. Further insight into pre-diagnosis fitness levels may also help to distinguish body systems adversely affected by therapies used. Other changes from breast cancer therapies may also include, but are not limited to, second cancers, fatigue, pain, changes to the cardiorespiratory and endocrine systems, and musculoskeletal variations.

## Exercise Recommendations

Prior to the commencement of an exercise programming, adequate testing from a medical team should be conducted. For breast cancer patients, this should include an evaluation of peripheral neuropathies, musculoskeletal morbidities and assessment of the risk of fractures. Following satisfactory outcomes from medical evaluations, low to moderate intensity aerobic exercise, performed 3-5 times per week for at least 20 minutes per session, should be conducted with the aim to return the patient to regular daily activities. Resistance exercise selection should be dynamic in nature and use both eccentric and concentric contractions. Resistance training should be conducted 1-3 times per week and incorporate 6-10 exercises, with 1-4 sets per muscle group. Intensity for resistance training should be between 50-80% of 1 repetition maximum.

## Further reading

* National Cancer Institute: Guidelines urge exercise for cancer patients, survivors
* ASCM Roundtable discussion on Exercise Guidelines for cancer survivors
* Breast cancer Network Australia

## References

* 1 2 Key, T. J., Verkasalo, P. K., & Banks, E. (2001). Epidemiology of Breast Cancer. 2(3).
* ↑ Veronesi, U., Boyle, P., Goldhirsch, A., Orecchia, R., & Viale, G. (2005). Breast Cancer. 365(9472)
* 1 2 Sainsbury, R. (2013). The Development of Endocrine Therapy for Women with Breast Cancer. 39(5).
* ↑ Giordano, S. H., Buzdar, A. U., & Hortobagyi, G. N. (2002). Breast Cancer in Men. 137(8).
* ↑ McPherson, K., Steel, C. M., & Dixon, J. M. (2000). Breast Cancer - Epidemiology, Risk Factors and Genetics. 321(7270).
* 1 2 Nelson, H. D., Zakher, B., Cantor, A., Fu, R., Griffin, J., O'Meara, E., & et. al. (2012). Risk Factors for Breast Cancer for Women Aged 40 to 49 years. 156(9).
* ↑ Shimozuma, K., Ganz, P. A., Petersen, L., & Hirji, K. (1999). Quality of Life in the First Year After Breast Cancer Surgery: Rehabilitation Needs and Patterns of Recovery. 56(1).
* ↑ Smith, B. D., Pan, I.-W., Shih, Y.-C. T., Smith, G. L., Farris, J. R., Punglia, R., & et.al. (2011). Adoption of Intensity-Modulated Radiation Therapy for Breast Cancer in the United States. 103(10).
* ↑ Denmark-Wahnefried, W., Clipp, E. C., Lipkus, I. M., Lobach, D., Clutter Snyder, D., Sloane, R., & et.al. (2007). Main Outcomes of the FRESH START Trial: A Sequentially Tailored, Diet and Exercise Mailed Print Intervention Among Breast and Prostate Cancer Survivors. 26(19).
* ↑ Stevinson, C., Lawlor, D. A., & Fox, R. K. (2004). Exercise Interventions for Cancer Patients: A Systematic Review of Controlled Trials. 15.
* 1 2 3 McNeely, M. L., Campbell , K. L., Rowe, B. H., Klassen, T. P., Mackey, J. R., & Courneya, K. S. (2006). Effects of Exercise on Breast Cancer Patients and Survivors: A Systematic Review and Meta-Analysis. 175(1).
* 1 2 Courneya, K. S., Mackey, J. R., Bell, G. J., Jones, L. W., Field, C. J., & Fairey, A. S. (2003). Training in Postmenopausal Breast Cancer Survivors: Cardiopulmonary and Quality of Life Outcomes. 21(9).
* ↑ Courneya, K. S. (2003). Exercise in Cancer Survivors: An Overview of Research. 35(11).
* 1 2 3 4 5 6 7 Schmitz, K. H., Courneya, K. S., Matthews, C., Denmark-wahnefried, W., Galvao, D. A., Pinto, B. M., & et.al. (2010). American College of Sports Medicine Roundtable on Exercise Guyidelines for Cancer Survivors. Special Communication.
* 1 2 3 Hayes, S. C., Spence, R. R., Galvao, D. A., & Newton, R. U. (2009). Australian Association for Exercise and Sport Science Position Stand: Optimising Cancer Outcomes Through Exercise. 12.