Motivation and emotion/Book/2015/Breast cancer and anxiety in women

Breast cancer and anxiety
How does anxiety impact on women with breast cancer?

Overview

edit
 

Breast Cancer. It is a sensitive topic for just about every one of us. It's a debilitating disease that according to the World Health Organization website, more than 500,000 women die from every year worldwide, making it the most common form of cancer amongst women (Baqutayan, 2012). Women are not the only ones who can develop breast cancer, as men can too. Regardless of gender, the short and long-term effects are substantial, with many patients being forced to make career and relationship sacrifices, and in some cases, the ability to have a child. Sadly, it is not only cancer that directly affects a person. The level of anxiety a patient can experience may also change the way in which they behave and react to various situations. It's something so severe that it can produce another illness on top of breast cancer, which ultimately inhibits a person's ability to function on a day-to-day basis. This chapter will include an in-depth exploration into the two illnesses and how they co-occur, with breast cancer being focused on first.

Breast cancer

edit

The breast is comprised of two types of tissue; glandular and stromal tissue. Glandular tissue contains the milk-producing glands and the ducts, while the stromal tissue includes the fatty and fibrous connective tissues of the breast (as cited in Baqutayan, 2012). Breast cancer develops when an abnormal cell in the glandular tissue grows uncontrollably, which can eventually spread to the underlying chest wall and other parts of the body (as cited in Baqutayan, 2012) if left untreated.

Risk factors

edit

Cancer Australia (2012) released a document that provides information for all women with breast cancer, including the various risk factors. Being a woman, having a family history of three or more first or second-degree relatives with either ovarian or breast cancer, inheriting a defective gene and being 40yrs+ all increase the risk (Cancer Australia, 2012). There is even evidence for lesbian and bisexual women to be at an increased risk (Boehmer, Glickman & Winter, 2012).

Breast cancer awareness

edit
 
Figure 2. A 6-step self-examination

Self-examination is the first step to early diagnosis. It is essential for women to regularly check their breasts every month as it increases survival rate. According to the Cancer Australia website, the changes to look out for include unusual lumps (especially if they appear in only one breast), a change in the size of the breasts, a change in the colour of the skin, such as dimpling or redness, any nipple discharge that occurs without sneezing, a change to the nipple in terms of crusting, an inversion or an ulcer and any unusual pain that doesn't go away (see Figure 2).

Reasons for putting off self-examinations or going through with them may come down to two key theories. Rosenstark's Health Belief Model (as cited in Katz, Meyers & Walls, 1995) and the Theory of Planned Behaviour (Ajzen, 1991) are believed to play a role in self-examination and a woman's perceived susceptibility to cancer.

The health belief model

edit

Rosenstark (as cited in Katz et al., 1995) created the Health Belief Model to explain preventive health behaviour and why people refuse to seek help in detecting a potential disease. The table below highlights the four main perceived concepts from the Health Belief Model, with two additional concepts added by Rosenstock to explain when people want to change a bad habit, i.e. smoking.

Table 1.

Constructs from The Health Belief Model (Glanz, Marcus Lewis & Rimer, 1997).

Concept Definition Application
Perceived susceptability One's opinion of chances of getting a condition Define population(s) at risk, risk levels; personalise risk based on a person's features or behavior; heighten perceived susceptibility if too low
Perceived severity One's opinion of how serious a condition and its consequences are Specify consequences of the risk and the condition
Perceived benefits One's belief in the efficacy of the advised action to reduce risk or seriousness of impact Define action to take; how, where, when; clarify the positive effects to be expected
Perceived barriers One's opinion of the tangible and psychological costs of the advised action Identify and reduce barriers through reassurance, incentives, assistance
Cues to action Strategies to activate "readiness" Provide how-to information, promote awareness, reminders
Self-efficacy Confidence in one's ability to take action Provide training, guidance in performing action

In relation to breast cancer, when a woman believes she's susceptible to the disease and understands the severity of it, the benefit of determining whether she's at risk of developing breast cancer outweighs the barriers of not completing a self-examination or screening protocol, which may be because she's afraid or has no time to. When a woman has high self-efficacy, it's then that she realises she has the confidence to actually go ahead with the cues to action.

Theory of planned behaviour

edit
 
Figure 3. Components of the Theory of Planned Behaviour

Formally called the Theory of Reasoned Action, the Theory of Planned Behaviour suggests that intentions to complete an action are predicted by three motivational determinants: attitude, subjective norm and perceived behavioural control (Drossaert, Boer & Seydel, 2003; Rutter, 2000). The determinants on the left relate to the benefits and limitations of performing the behaviour, approval or disapproval from others and the person's judgement of their ability to perform the behaviour (Drossaert et al., 2003). The theory is useful in predicting why patients attend and re-attend screening assessments, yet there are limited studies on why this might be (Drossaert et al., 2003). In the past, women have been more likely to get screened when their families and friends have approved of it and when they had a positive attitude (Drossaert et al., 2003; Rutter, 2000). In the studies above, re-attendance was high, with 91% of women attending the third screening session in Drossaert et al's., (2003) study and 64% compared to 14% of the control group's participants in Rutter's (2000) experiment followed up on their screening.

Understanding what factors promote attendance is important for new beneficial health interventions to improve breast cancer screening protocols. Interventions should focus on changing women's attitudes, their perceived control over the situation and any difficulties they expect to occur when they attend, as these factors explain women's intentions and their actual behaviour (Drossaert et al., 2003).

Treatment

edit

Determining which stage of cancer a woman has ultimately decides which treatment is going to be the most effective. Cancer Australia (2012) highlights the differences between each stage, with relevant methods of treatment. One form of treatment for women in stage I of cancer (when the tumor is <2cm) is to undergo a mastectomy, in which one or both breasts are surgically removed (Maughan, Lutterbie & Ham, 2010). Alternatively, in more recent years breast-conserving surgery has been an option. This method involves removing the tumor without damaging any healthy tissue (Maughan et al., 2010). Radiotherapy follows breast-conserving surgery to ensure that no part of the tumor is still hiding underneath the surface. Results from a study by Clarke et al., (as cited in Maughan et al., 2010, p. 1342) showed that radiation following surgery significantly reduced the five-year local recurrence rate.

Following on from surgery and radiotherapy, chemotherapy is the number one form of treatment for women in stage II with tumors larger than 1-2cm (Cancer Australia, 2012; Maughan et al., 2010), although it is been shown to increase anxiety more than any other form of treatment (Lim, Devi & Ang, 2011). This is likely due to side effects such as nausea, loss of hair, dry skin and fatigue (Carelle et al., 2002). According to Hortobagyi (1998), combined treatment for shorter than 3 months is much less effective than treatment for 4-6 months. The American Cancer Society states that chemotherapy typically lasts 3-6 months, whereas hormone therapy lasts 5-10 years. Adjuvant systematic therapies such as endocrine therapy and tissue-targeted therapy are a few of the many options out there that utilise the use of surgery, therapy or both (Maughan et al., 2010).

Statistics from Cancer Australia (2012) indicate that 88% of Australian women with breast cancer are still alive five years after early diagnosis.

The emotional effects of breast cancer

edit

When first diagnosed, women understandably tend to respond with anxiety (Stark & House, 2000).[Provide more detail]

Many experience a sense of denial and helplessness, which explains why some cancer patients feel that they've lost their self-identity. The psychological issues that can arise from a cancer diagnosis largely depend on gender, age and the type of cancer (Rosen, Rodriguez-Wallberg & Rosenzweig, 2009). For most women, losing their hair, completing regular chemotherapy, infertility and the risk of dying are all huge concerns (Rosen et al., 2009). The greatest concern that's associated with emotional distress is when women are told they have become infertile as a result of their cancer treatment. Being told such devastating news has been shown to have the same emotional impact on a woman as having a life-threatening disease, such as heart disease or AIDS (Domar, Zuttermeister & Friedman, 1993).

A vital way to reduce infertility-related anxiety and depression is for specialists and patients to maintain communication, especially in regards to other fertility options (Domar et al., 1993; Partridge et al., 2004). A number of studies have shown that other options are rarely discussed (Duffy, Allen & Clark, 2005; Partridge et al., 2004; Quinn et al., 2007) which doesn't provide women with the quality of care they require. As suggested by Partridge and colleagues (2004), if there was more focus on infertility issues at diagnosis and on psychosocial and medical interventions during the treatment phase, then the impact of infertility may reduce, leaving breast cancer patients with one less thing to worry about. Other emotional factors that may upset women include the fact they can't return to work for a large period of time and have to see how their cancer affects their friends and families, which unfortunately for some women can cause significant stress when they see their loved ones are struggling.

 
Figure 5. October is Breast Cancer Awareness Month

Breast cancer foundations

edit

As breast cancer diagnosis rates have increased over the years, multiple foundations have been formed in support of the disease. The four major Australian breast cancer organisations are listed below. Together, they focus on establishing the best care for women living with breast cancer in order to meet their individual missions.

  1. Breast Cancer Network Australia
  2. National Breast Cancer Foundation
  3. McGrath Foundation
  4. Cancer Australia
"I am the tightening of your chest, the snowballing worries that feel like they might become an avalanche and just bury you in an instant. I am the obsessive, and I'm the compulsive. I'm the voice, you know the one, it's always questioning questioning questioning" - Beyond Blue

Anxiety

edit
 

Anxiety is a serious illness in which persistent fear and/or anxiety interferes with day-to-day life. Fear is a present-oriented mood state that is associated with the "fight or flight" mechanism and escape behaviours, while anxiety is a future-oriented mood state that provokes muscle tension in preparation for a future threat (American Psychiatric Association, 2013). Beyond Blue are a depression and anxiety support service that say anxiety is usually triggered from a stress-induced situation, health problem, substance use or from family history. An anxiety disorder is then diagnosed when this fear or anxiety lasts beyond an acceptable time (i.e. six months or more) and when symptoms cannot be attributed to any physiological effects from some form of medication, medical disorder, or medical condition (American Psychiatric Association, 2013). The six main anxiety disorders are Generalised Anxiety Disorder (GAD), Post-traumatic Disorder (PTSD), Specific Phobia, Obsessive Compulsive Disorder (OCD), Social Anxiety Disorder and Panic Disorder (American Psychiatric Association, 2013).

Symptoms

edit

According to the Beyond Blue website, there are physical and psychological symptoms that aren't normally obvious, but may be apparent over time. Some of these symptoms include excessive worry, restlessness, difficulty concentrating, headaches, muscle tension, nausea, trouble falling asleep and sweating (as cited in Baqutayan, 2012). An anxiety checklist can be accessed here.

Epidemiology

edit

The lifetime prevalence of an anxiety disorder is 17% (Somers, Goldner, Waraich & Hsu, 2006), with the female to male ratio being 2:1 respectively (American Psychiatric Association, 2013). Those who are more at risk are generally younger women with a lack of social support and previous psychological problems (Burgess et al., 2005). Many of the phobia disorders are diagnosed in childhood, with the median diagnosis age for GAD and Panic Disorder being early 30's (American Psychiatric Association, 2013). Generally, anxiety disorders will persist for the majority of a person's life, unless adequately treated.

Treatment

edit

There are self-help, psychological and medical treatments available. Medical treatments are usually supplied first, either alone or in-conjunction with therapy. Antidepressant medication is the most common, as it suppresses symptoms for as long as its taken, however no evidence exists for whether it reduces the underlying risk once a person discontinues their use (Hollon, Stewart & Strunk, 2006). Psychological treatments involve a variety of therapies, such as Cognitive Behavioural Therapy and Interpersonal Psychotherapy and can be as effective as antidepressant medication. Both psychotherapies address social stressors, change thought patterns and help a person manage their anxiety better, which in turn is likely to decrease the chance of relapsing (Hollon et al., 2006).

Self-help treatment involves interventions such as exercise, yoga and a healthy diet, which are effective, but won't work alone. As for social support, it is important for those close to the person to understand the meaning attached to particular events as these are the basis for perceived threat. Education and communication are also important to recognise and respond to when someone is really struggling (Stark & House, 2000).

Breast cancer and anxiety

edit

It is normal for everybody to have anxiety-provoking thoughts at some point in their life, but at what degree is it considered a serious condition?

 
Figure 7. The effects of anxiety on the body

It can be difficult to determine the level of anxiety that is present in cancer patients (Stark & House, 2000), especially as the diagnosis of anxiety in cancer is often a subjective judgement (Stark & House, 2000) and is complex because it overlaps with other symptoms such as fatigue and pain (Baqutayan, 2012). Stressful factors such as hormonal changes, fertility fears, changes in body image, financial problems and numerous hospital visits are broadly classified into four causal categories; physical, psychological, social and environment, which inevitably makes it more difficult for professionals to determine what is a normal level of anxiety and what constitutes a disorder (Lim et al., 2011). Holland (1989) states that it is completely normal to experience anxiety for 7-10 days after receiving terrible news, although as the threat of cancer has varied over the years, it can affect the levels of what is considered to be normal anxiety as well. In a Canadian study conducted by Ashbury, Findlay, Reynolds and McKerracher (1998), 77% of patients within two years of treatment recalled experiencing anxiety. This was also found by Burgess et al., (2005) who found that 50% of women had depression, anxiety, or both in the year after diagnosis. The percentage of women experiencing anxiety is equivalent to that of the general female population (Burgess et al., 2005), meaning that although the degree of anxiety may not be enough to diagnose a breast cancer patient with an anxiety disorder as well, the severity of anxiousness is high.

When there's little to no anxiety present in the initial stages of cancer, it can also be a reason for concern, as the main period in which anxiety is generally reduced is during the remission stage (Stark & House, 2000). This point of transition is still challenging to define (Stark & House, 2000), but is made easier when questionnaires such as the Responses to Stress Questionnaire (Pediatric Cancer version) are used. This questionnaire includes 12 cancer-related stressor questions (i.e. changes in personal appearance, continual hospital visits) and various coping scales to assess a range of different patients with cancer, including children and adolescents (Compas et al., 2014). When an anxiety disorder is present in a breast cancer patient, an effective treatment is mindfulness-based therapy. The use of mindfulness, yoga and other relaxation techniques has proven to reduce anxiety and improve quality of life and overall mood (Hofmann, Sawyer, Witt & Oh, 2010).

When an actual anxiety disorder is present, it can persist until five years after breast cancer diagnosis but is generally due to the patient and not the cancer (Burgess et al., 2005) which has lead researchers into determining who is primarily at risk of developing an actual anxiety disorder while having breast cancer as well.

Who is at risk?

edit

Specific groups of women may be more prone to developing anxiety when they have breast cancer already. One example is excessive worrying, which can act like a double edged sword. Constantly worrying about the smallest issues can produce a negative frame of mind which makes it difficult to focus on what matters and pushes loved ones further away. Yet on the other hand, more worrying can be positive in relation to screening for breast cancer in the first place. McCaul, Schroeder and Reid (1996) found that higher worry in women meant they were more likely to perform a self-examination or get a mammogram. Burgess et al., (2005) found that in the long-term, anxiety was higher in women who weren't in an intimate relationship, had severe non-cancer related difficulties, an earlier episode of anxiety, depression, or both after diagnosis and were of a younger age, which is still in line with studies conducted back in 1986 and 1994 (Burgess et al., 2005). Therefore, characteristics such as strength, hope and faith will help patients remain positive, along with social support. When these factors are present in women with severe anxiety, it can greatly increase their life expectancy (Baqutayan, 2012).

The financial and social costs

edit

The costs of breast cancer and anxiety are substantial, but increase even more when they're both present. Discharging a patient from hospital to a general practice can be costly and difficult, which may be due to the severity of the breast cancer or reluctance from an anxious patient (Thomas, Glynne-Jones, Chait & Marks, 1997). However, most of the cost goes to the professionals who care for the patient. A breast cancer patient who has anxiety as well will have a large team of people that include psychologists, general practitioners, surgeons, nurses and radiation oncologists (Cancer Australia, 2012). Most women feel they must continue working in order to pay for the care that each of these professionals provide in addition to travel and medication costs. When this isn't possible, it puts a financial strain on the patient and their family, which often sees a social disruption to social functioning and relationships according to Matthews (as cited in Raque-Bogdan et al., 2015, p. 10). The most concerning part is that the health expenditure for 2004-2005 was $331 million for women with breast cancer in Australia (Cancer Australia, 2012) and that is excluding anxiety-related costs. For these reasons, it is important to maintain a connection with loved ones and discuss insurance with the selected health fund, as well as how to manage medical costs (Cancer Australia, 2012).


 
Take home messages
  1. Breast cancer and anxiety are two separate, yet very connected entities
  2. Both illnesses have a physiological and psychological impact on a person
  3. Recognising the symptoms is the first step to battling cancer and anxiety
  4. You are never alone, there is help out there!

Conclusion

edit

To conclude, everyone will experience anxiety to some degree in their life, but not everyone will go through what it is like to have breast cancer. The trauma of dealing with a breast cancer diagnosis leaves most women shocked, frightened and devastated which also affects those around them.

Ways of staying positive depend on a woman's level of optimism and self-efficacy, which according to the Health Belief Model and the Theory of Planned Behaviour explain why some women handle their cancer better than others. Despite the social and economic costs, there are wonderful foundations that promote awareness and support for those in need, and with the advancement in treatment options, it might not be long before treatment is specified to each woman's individual tumor characteristics (Maughan et al., 2010), or even better, a cure for breast cancer is finally found.

Overall, future research would benefit from focusing on models of motivation and emotion to explain health behaviour and by addressing the various psychological problems that can arise in anxious women with advanced breast cancer (Burgess et al., 2005).

See also

edit

References

edit
Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50(2), 179-211. doi:10.1016/0749-5978(91)90020-T

American Cancer Society. (2015). Treatment of invasive breast cancer, by stage. Retrieved from http://www.cancer.org/cancer/breastcancer/detailedguide/breast-cancer-treating-by-stage

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author

Ashbury, F. D., Findlay, H., Reynolds, B., & McKerracher, K. (1998). A Canadian survey of cancer patients’ experiences: are their needs being met? Journal of Pain and Symptom Management, 16(5), 298-306. doi:10.1016/S0885-3924(98)00102-X

Baqutayan, S. M. S. (2012). The effect of anxiety on breast cancer patients. Indian Journal of Psychological Medicine, 34(2), 119-123. doi:10.4103/0253-7176.101774

Beyond Blue. (2015). Get to know anxiety. Retrieved from Beyond Blue website: https://www.beyondblue.org.au/transcripts/get-to-know-anxiety

Boehmer, U., Glickman, M., & Winter, M. (2012). Anxiety and depression in breast cancer survivors of different sexual orientations. Journal of Consulting and Clinical Psychology, 80(3), 382-395. doi:10.1037/a0027494

Burgess, C., Cornelius, V., Love, S., Graham, J., Richards, M., & Ramirez, A. (2005). Depression and anxiety in women with early breast cancer: five year observational cohort study. Bmj, 330(7493), 702-705. doi:10.1136/bmj.38343.670868.D3

Cancer Australia. (2015). Breast changes. Retrieved from http://canceraustralia.gov.au/affected-cancer/cancer-types/breast-cancer/awareness/breast-changes

Cancer Australia. (2012). Guide for women with early breast cancer. Retrieved from http://canceraustralia.gov.au/publications-and-resources/cancer-australia-publications/guide-women-early-breast-cancer

Carelle, N., Piotto, E., Bellanger, A., Germanaud, J., Thuillier, A., & Khayat, D. (2002). Changing patient perceptions of the side effects of cancer chemotherapy. Cancer, 95(1), 155-163. doi:10.1002/cncr.10630

Compas, B. E., Desjardins, L., Vannatta, K., Young-Saleme, T., Rodriguez, E. M., Dunn, M., ... & Gerhardt, C. A. (2014). Children and adolescents coping with cancer: Self-and parent reports of coping and anxiety/depression. Health Psychology, 33(8), 853-861. doi:10.1037/hea0000083

Domar, A. D., Zuttermeister, P. C., & Friedman, R. (1993). The psychological impact of infertility: a comparison with patients with other medical conditions. Journal of Psychosomatic Obstetrics and Gynaecology, 14, 45-52. Retrieved from http://www.massgeneral.org/bhi/assets/pdfs/publications/Domar%201993%20J%20Psychosom%20Obstet%20Gynaecol.pdf

Drossaert, C. H. C., Boer, H., & Seydel, E. R. (2003). Prospective study on the determinants of repeat attendance and attendance patterns in breast cancer screening using the theory of planned behaviour. Psychology and Health, 18(5), 551-565. doi:10.1080/0887044031000141207

Duffy, C. M., Allen, S. M., & Clark, M. A. (2005). Discussions regarding reproductive health for young women with breast cancer undergoing chemotherapy. Journal of Clinical Oncology, 23(4), 766-773. doi:10.1200/JCO.2005.01.134

Glanz, K., Marcus Lewis, F. & Rimer, B.K. (1997). Theory at a glance: a guide for health promotion practice. National Institute of Health

Hofmann, S. G., Sawyer, A. T., Witt, A. A., & Oh, D. (2010). The effect of mindfulness-based therapy on anxiety and depression: A meta-analytic review. Journal of Consulting and Clinical Psychology, 78(2), 169-183. doi:10.1037/a0018555

Holland, J. C. (1989). Anxiety and cancer: The patient and the family. Journal of Clinical Psychiatry, 50(11), 20-25. Retrieved from http://psycnet.apa.org/psycinfo/1990-12708-001

Hollon, S. D., Stewart, M. O., & Strunk, D. (2006). Enduring effects for cognitive behavior therapy in the treatment of depression and anxiety. Annual Review of Psychology, 57, 285-315. doi:10.1146/annurev.psych.57.102904.190044

Hortobagyi, G. N. (1998). Treatment of breast cancer. New England Journal of Medicine, 339(14), 974-984. doi:10.1056/NEJM199810013391407

Katz, R. C., Meyers, K., & Walls, J. (1995). Cancer awareness and self-examination practices in young men and women. Journal of Behavioral Medicine, 18(4), 377-384. doi:10.1007/BF01857661

Lim, C. C., Devi, M. K., & Ang, E. (2011). Anxiety in women with breast cancer undergoing treatment: a systematic review. International Journal of Evidence‐Based Healthcare, 9(3), 215-235. doi:10.1111/j.1744-1609.2011.00221.x

Maughan, K. L., Lutterbie, M. A., & Ham, P. S. (2010). Treatment of breast cancer. American Family Physician, 81(11), 1339-1346. Retrieved from http://www.goodsamim.com/resprog/internalmedicine/Academic%20Half%20Day/April%202013/Breast%20Cancer%20April%209%20Lecture%203.pdf

McCaul, K. D., Schroeder, D. M., & Reid, P. A. (1996). Breast cancer worry and screening: some prospective data. Health Psychology, 15(6), 430-433. doi:10.1037/0278-6133.15.6.430

Quinn, G. P., Vadaparampil, S. T., Gwede, C. K., Miree, C., King, L. M., Clayton, H. B., ... & Munster, P. (2007). Discussion of fertility preservation with newly diagnosed patients: oncologists’ views. Journal of Cancer Survivorship, 1(2), 146-155. doi:10.1007/s11764-007-0019-9

Raque-Bogdan, T. L., Hoffman, M. A., Ginter, A. C., Piontkowski, S., Schexnayder, K., & White, R. (2015). The work life and career development of young breast cancer survivors. Journal of Counseling Psychology, 1, 1-15. doi:10.1037/cou0000068

Rosen, A., Rodriguez-Wallberg, K. A., & Rosenzweig, L. (2009). Psychosocial distress in young cancer survivors. Seminars in Oncology Nursing, 25(4), 268-277. doi:10.1016/j.soncn.2009.08.004

Rutter, D. R. (2000). Attendance and reattendance for breast cancer screening: a prospective 3-year test of the theory of planned behaviour. British Journal of Health Psychology, 5, 1-13. doi:10.1348/135910700168720

Somers, J. M., Goldner, E. M., Waraich, P., & Hsu, L. (2006). Prevalence and incidence studies of anxiety disorders: a systematic review of the literature. Canadian Journal of Psychiatry, 51(2), 100-113. Retrieved from http://ww1.cpa-apc.org/Publications/Archives/CJP/2006/february/sommers-RP.asp

Stark, D. P. H., & House, A. (2000). Anxiety in cancer patients. British Journal of Cancer, 83(10), 1261-1267. doi:10.1054/bjoc.2000.1405

Thomas, S. F., Glynne‐Jones, R., Chait, I., & Marks, D. F. (1997). Anxiety in long‐term cancer survivors influences the acceptability of planned discharge from follow‐up. Psycho‐Oncology, 6(3), 190-196. doi:10.1002/(SICI)1099-1611(199709)6:3<190::AID-PON274>3.0.CO;2-0

World Health Organization. (2015). Cancer. Retrieved from World Health Organization website: http://who.int/mediacentre/factsheets/fs297/en/

edit

For more information or assistance, visit: