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LESSON 5.4 WORKBOOK What are the consequences of cancer and cancer treatment? DEFINITIONS OF TERMS Remission – the reduction of cancer symptoms, often considered being “cancer-free” Relapse – the return of symptoms of cancer following a period of being disease-free. For a complete list of defined terms, see the Glossary. Wo r k b o o k Lesson 5.4 The previous lesson on cancer treatment compared the benefits and risks of three types of cancer treatments that focus on the cancer cells themselves. However cancer as a disease affects more than the malignant cells themselves. This lesson will focus on the strategies that are available to treat the symptoms of cancer rather than the cells themselves, and will also discuss strategies that can play a role in preventing cancer developing in the first place. Not all cancers respond to treatment For most of history cancer was considered to be an untreatable disease, and it has only been within the last few hundred years that the potential to treat, if not cure, has been realized. In fact the three most successful types of cancer treatment we have available, surgery, radiation, and chemotherapy were only developed within the last 100 years. It has become clear however that these treatments are still not enough. Some cancers respond to them while others, particularly metastases do not. Understanding how and why some cancers are so resistant to treatment is a major focus of cancer research. As we saw in the last lesson we consider cancer has entered remission following treatment if detection methods can find no evidence of the primary tumor and if disease symptoms have been eliminated or much reduced. Cancers that are detected and treated early enough that they are not yet metastatic often enter full remission. However even cancers that are detected early may only enter partial remission if they are already metastatic. In this case the cells that have been spared may not be detectable but they will continue to proliferate and the cancer will return once the number of cells or tumor burden increases. In the meantime the disease symptoms may be reduced or even eliminated, but this is temporary until the cancer recurs and the patient enters relapse. MC Questions: ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ 1. Which of the following describes the outcome of a cancer that is 'cured'? aa. Reduction. bb. Relapse. cc. Remission. dd. Return. ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ 168 LESSON READINGS Notes: Whether a cancer will remain in remission or will relapse is usually almost impossible to predict. From what we have learned throughout this module it should be clear that the reason for this is that each cancer evolves as a response to the selective pressures it is experiencing and this can be very variable between individual tumors or even between cells in a single tumor. The flip side of this random evolution however is that individual metastatic cells may very well randomly evolve traits that prevent them from forming secondary tumors. In this case the patient will seem like they are experiencing full remission, even though many metastatic cancer cells remain in the body. If these cells remain functionally useless they will likely be killed by the immune system over time. DEFINITIONS OF TERMS Conventional treatment – any treatment typically used by medical professionals to treat cancer (i.e. surgery, radiation, and /or chemotherapy). Intervention study – a study where one group is given a treatment to evaluate the effect of that treatment on people. Wo r k b o o k Lesson 5.4 Figure 1: A model for the evolution of cancer and how different treatments target cancer cells. While surgery is able to remove all cancer cells from an organ, it cannot remove metastatic cells, much like radiation therapy (Rad.), which only targets fast growing cells that are not metastatic. Chemotherapy (Chemo.) can kill some metastatic cells and some cells of the tumor, but is more specific and limited to a subset of cells sensitive to the drug. Figure 1 shows transformation of a normal cell over time, with the boxes indicating the types of cells each type of therapy targets. Surgery is the only therapy that does not target how a cancer cell functions and so it can effectively remove all cancer cells in a primary tumor, but not any metastatic cells. Chemotherapy can kill metastatic cells except those cells that resistant to the chemotherapy (the grey metastatic cell in the picture). If these resistant cells are capable of entering secondary organs, they are likely to lead to relapse. However, if they acquire mutations that prevent them exiting the bloodstream or entering organs, remission will persist. Whether a cancer will go into remission or relapse depends most of all on the driver mutations (red arrows in Figure 1) that allow the cancer cells to acquire traits that will overcome selective pressure. Figuring out which mutations are drivers in the hope of developing more specific drugs is another intense area of research. ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ 169 LESSON READINGS DEFINITIONS OF TERMS Alternative treatment – any treatment that is not a mainstream treatment to cancer (i.e. not surgery, radiation, chemotherapy) that is used instead of a mainstream treatment. Complementary treatment – any treatment that is not a mainstream treatment to cancer (i.e. not surgery, radiation, chemotherapy) that is used along with a mainstream treatment. Antioxidant – a molecule that inhibits the activity of reactive oxygen species to damage DNA. Anti-angiogenic compound – any chemical that inhibits the growth of blood vessels. Wo r k b o o k Lesson 5.4 Treating cancer as a disease MC Questions: Surgery, chemotherapy and radiation therapy are considered conventional treatments for cancer because their effects have been rigorously examined through numerous interventional studies. As we learned in the Metabolic Disorders module, intervention studies are the gold standard for determining whether a treatment is effective. In these studies a population with a disease is provided with a treatment and the outcome is compared with a well-matched control group who also have the disease but who don’t receive the treatment, or receive a different treatment whose outcomes are well known. Without this kind of intervenFigure 2: Yoga is one type of tion study it is impossible to know whether any positive alternative treatment that boosts outcome is caused by the treatment or just correlated with energy and helps the immune it. Few of the many cancer ‘cures’ reported an advertised system in cancer treatment. on the internet and in the non-scientific media have been subjected to this level of scrutiny and so it is impossible to know what the enthusiastic endorsements these alternative treatments often receive really mean. Some alternative treatments that have been studied — such as the active ingredient in apricot pits – have not stood up to rigorous scrutiny, others — such as the Gerson treatment, a strict organic diet with frequent coffee enemas, have never been examined. Patients who rely exclusively on these kinds of alternative treatments are therefore taking a risk. In most cases it makes no difference whether patients receiving conventional treatments also pursue alternative treatments, but in some cases they may interfere with the conventional therapy. It is for this reason that physicians ask patients to inform them of all the therapies they are using. 2. What would you need to show an alternative treatment is a useful strategy to treat cancer? (Circle all correct.) aa. Evidence of efficacy in intervention study. bb. Number of people using treatment. cc. Number of articles written about treatment. dd. A mechanism to explain how treatment works. However, there are intervention studies that show some alternative treatments do work. These include yoga, exercise, acupuncture, acupressure, hypnosis, massage, and musical therapy. It is unlikely that these alternative approaches will lead to full cancer remission without the assistance of surgery, radiation, and chemotherapy, which is why these therapies are called complementary treatments. These approaches may make the painful and traumatic process of mainstream cancer treatment more tolerable. These complementary treatments have also been shown to improve the efficacy of the immune system, which may help conventional treatments achieve cancer remission. Finally, regulation of diet has been shown to be useful in improving cancer treatment outcomes. Chemotherapy and radiation therapy have very toxic effects on the body, and consuming appropriate nutrients is essential to recovering from their side effects. 3. True or false: Yoga, exercise, and massage will improve the efficacy of conventional treatments if performed with these treatments. aa. True. bb. False. ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ 170 LESSON READINGS DEFINITIONS OF TERMS Curative treatment – any type of medical care given where a cure to disease is considered an achievable goal. Diet also plays an important role in cancer prevention. For instance, a high fiber diet correlates with protection against bowel cancer, but how this protection occurs is unclear. Also, consumption of foods rich in antioxidants such as fish, tomatoes, legumes (peas, beans and soy), and dark chocolate, along with drinking green tea and red wine has been shown to decrease cancer risk. Antioxidants are useful to prevent cancer because they help prevent damage to DNA by carcinogens. Foods rich in antioxidants are also known to contain natural anti-angiogenic compounds. So, consumption of foods that prevent DNA damage and decrease angiogenesis is likely to decrease the development and spread of cancer. 4. True or False: Controlling what we eat can prevent the development AND progression of cancer. aa. True. bb. False. Lastly, chronic infection by pathogens have been linked to certain types of cancer. For instance, Hepatitis B is a known cause of liver cancer, and human papilloma virus (HPV) causes cervical cancer and some oral cancers. These cancers can be easily avoided by vaccination against the virus. Furthermore, Helicobacter pylori infection is responsible for an estimated 70-90% of all stomach cancers. Antibiotic treatment of H. pylori before it becomes chronic is a good way to decrease the chance of developing stomach cancer. Simple approaches to prevent infection are a good way of reducing cancer risk significantly. ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ Palliative treatment – treatment for a disease that is considered uncurable where the goal is to reduce symptoms and decrease pain and stress associated with disease. In conclusion, there are many steps that we can make to limit the development of early-onset cancer that appears due to environmental causes and pathogens. Among these are: Hospice – a program /shelter that provides care to decrease pain and symptoms for patients as well as addressing emotional and spiritual needs of the patient. ■■ Not smoking; ■■ Consuming less refined or fatty foods; ■■ Increasing exercise; ■■ Limiting exposure to UV radiation; ■■ Drinking less alcohol; and ■■ Getting vaccinated. Much as we saw in Unit 1, these approaches will not guarantee that you won’t get cancer. They just reduce the risk. And, since cancer treatment is still in its infancy, it makes more sense to take the easy steps that prevent the development of cancer than rely on traumatic cancer treatment options. Wo r k b o o k Lesson 5.4 MC Questions: What do I do if my cancer is incurable? Surgery, radiation, and chemotherapy are performed with the intention of producing cancer remission, and because of this, they are commonly called curative treatment. If cancer is not identified until it is 5. Which of the following is a significant way to prevent the development of cancer? (Circle all correct.) aa. Smoking low-tar cigarettes. bb. Vaccination against H. pylori. cc. Avoiding tanning beds. dd. Regular exercise. ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ 171 LESSON READINGS late stage, it is very difficult to fully treat the disease, and at this point curing the cancer is unlikely. In these instances, doctors recommend a shift in treatment strategy from curative treatment to palliative treatment, or treatment that emphasizes a reduction of symptoms rather than focusing on curing disease. DEFINITIONS OF TERMS Bereavement care – the type of care that provides psychological support for friends, family and loved ones who have lost someone to disease. Figure 3: As individuals live with cancer progressing in severity, the focus of treatment shifts from curative care to palliative care. Once the disease has become so severe that full time medical care is necessary to relieve symptoms, hospice care is recommended. After death, bereavement care is recommended for friends and families of the patient to help deal with psychological stress of losing a loved one. Palliative treatment is not dissimilar from curative treatment, as surgery, radiation, and chemotherapy are still offered, but not so aggressively as to cure the disease. In the case of palliative treatment, just enough treatment is offered to relieve the symptoms of the patient. If the cancer continues to worsen in disease severity and full-time medical care is necessary, it is recommended that patients enter hospice care. Hospices are homes for individuals with significant medical needs where medical support is readily available, but is intended for people with late stage disease. Hospice care has been shown to be much cheaper than hospitalization, but also has been shown to extend life by 3 months more than hospitalization. Wo r k b o o k Lesson 5.4 Once a patient passes away from cancer, it is important to provide support to the family and friends of the patient. This is called bereavement care, which provides psychological support for those who lost a loved one. The view of cancer treatment focusing on palliative, hospice, and bereavement care treats a patient more as a person rather than just focusing on treating the cancer. One of the hardest aspects to consider is the death of a loved one, and this holistic approach has been shown to not only increase the life-span of individuals with cancer, but allows patients to make their own choices on how they should die. MC Questions: 6. Which of the following is an outcome of palliative treatment? (Circle all correct.) aa. Improvement in mental health. bb. Reduction of tumor size. cc. Remission of cancer. dd. Reduction of pain. ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ 7. Which of the following treatments are considered most useful for patients with late-stage cancer? (Circle all correct.) aa. Bereavement care. bb. Curative care. cc. Hospice care. dd. Palliative care. ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ 172 STUDENT RESPONSES What is one advantage and one disadvantage of trying to treat cancer using a holistic approach including palliative and alternative treatments? _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ ____________________________________________________________________________________________________ Remember to identify your sources _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ Wo r k b o o k Lesson 5.4 _____________________________________________________________________________________________________ ___________________________________________________________________________________________ 173 TERMS TERM For a complete list of defined terms, see the Glossary. Wo r k b o o k Lesson 5.4 DEFINITION Alternative treatment Any treatment that is not a mainstream treatment to cancer (i.e. not surgery, radiation, chemotherapy) that is used instead of a mainstream treatment. Anti-angiogenic compound Any chemical that inhibits the growth of blood vessels. Antioxidant A molecule that inhibits the activity of reactive oxygen species to damage DNA. Bereavement care The type of care that provides psychological support for friends, family and loved ones who have lost someone to disease. Complementary treatment Any treatment that is not a mainstream treatment to cancer (i.e. not surgery, radiation, chemotherapy) that is used along with a mainstream treatment. Conventional treatment Any treatment typically used by medical professionals to treat cancer (i.e. surgery, radiation, and /or chemotherapy). Curative treatment Any type of medical care given where a cure to disease is considered an achievable goal. Hospice A program /shelter that provides care to decrease pain and symptoms for patients as well as addressing emotional and spiritual needs of the patient. Intervention study A study where one group is given a treatment to evaluate the effect of that treatment on people. Palliative treatment Treatment for a disease that is considered uncurable where the goal is to reduce symptoms and decrease pain and stress associated with disease. Relapse The return of symptoms of cancer following a period of being disease-free. Remission The reduction of cancer symptoms, often considered being “cancer-free”. 174