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This section provides an overview of the symptoms and usual treatment path for nine cancers frequently diagnosed in Canada. International Classification of Disease (ICD-9) coding is provided for each cancer type. Literature on these cancers was used to develop generic descriptions for three prognostic categories; these descriptions are provided in the At diagnosis section. These nine cancers are the three most common cancers in each prognostic category. An overview of two types of leukemia is also provided.
Stomach (gastric) cancer (ICD-9
In 2002, an estimated 1,800 men and 1,000 women were diagnosed with stomach cancer in Canada. The ratio of deaths to new cases was 70%, making this type of cancer the third worst in terms of overall prognosis, after pancreatic and lung cancer. Most cases are diagnosed at an advanced stage, with a high likelihood of spread to adjacent organs, such as the spleen or pancreas. The tumour can also spread directly into the esophagus or the duodenum. In approximately half of the resected cases, invasion into the lymphatic system is seen.
Stomach cancer incidence has been decreasing in North America, although it is considered epidemic in Japan, Eastern Europe and South America. During the last two decades, even with the overall decrease, there has been an increase in proximal gastric cancers (those in the upper part of the stomach), which generally have a poorer prognosis than cancers in the body or outlet of the stomach. Stomach cancer has been associated with salted or smoked meat and fish, nitrates in the drinking water, smoking cigarettes and diets low in animal protein and fat. In addition, there is an increased risk of gastric cancer for those who have undergone partial removal of the stomach (subtotal gastrectomy) for ulcer disease and for those who have pernicious anemia.
Patients may present with a variety of symptoms, including weight loss, fatigue, loss of appetite and epigastric discomfort, at which time, a barium study or flexible upper endoscopy (with biopsy) is generally performed. For the small proportion with localized disease (less than 10%), curative surgery is the treatment of choice, but there is considerable debate as to the benefits of total versus subtotal gastrectomy and the degree of lymph node dissection (lymphadenectomy) required. Post-gastrectomy symptoms can include difficulty swallowing, bloating, diarrhea, flushing after eating and weight loss. Those who have only part of the stomach removed experience fewer of these symptoms and thus report having a better quality of life than patients who undergo a total resection. Chemotherapy (5-fluorouracil plus cisplatin) has become the standard treatment for advanced gastric cancer. Palliative surgery is considered when patients suffer from pain, hemorrhage, perforation or obstruction, but is associated with a high level of post-operative 150 morbidity.
In 2002, an estimated 17,600 new cases (9,500 men and 8,100 women) were diagnosed in Canada making colorectal cancer (CRC) the third most common cancer for each gender. In that year, there were an estimated 6,600 colorectal cancer deaths, with a ratio of deaths to new cases of 37% (fairly good prognosis).
Environmental factors, and especially dietary intake, may cause or promote colorectal cancer, which usually occurs in men and women over 40 years of age. Diets high in calories, cholesterol and fat and low in fibre appear to place individuals at higher risk of developing this disease. High alcohol consumption and certain occupational exposures can also increase the risk, in addition to inherited syndromes.
Many patients with CRC exhibit no symptoms, which highlights the importance of early detection programs and screening. Cases detected through screening are more likely to be treated at an earlier stage, with greater likelihood of cure. Approximately one-third of cases are diagnosed at each of three stages: localized stage, with regional nodal involvement or with distant metastatic disease. The liver is frequently the site of colorectal cancer metastasis. Symptomatic colon cancer presents with intermittent abdominal pain, nausea or vomiting, whereas symptomatic rectal cancer is more likely to present with rectal bleeding. Generally, rectal cancer, which represents almost one-third of all CRC cases, has a worse prognosis than colon cancer.
Surgery is the major treatment for those diagnosed with non-metastatic colon cancer. Lymph node dissection assists staging and can be therapeutic. Sphincter-sparing surgery for patients with early rectal cancer should always be considered before radical resection. The treatment objective for patients with locally advanced rectal cancer is to resect (remove) the tumour completely while attempting to minimize functional impairment and morbidity, such as impotence, urologic dysfunction and the need for a permanent colostomy (the surgical creation of an opening between the colon and the surface of the abdominal wall). Whereas almost one-third of rectal cancer patients will require a permanent colostomy, most colon cancers can be treated without one. Physical symptoms exhibited prior to surgery, such as loss of appetite, rectal bleeding, urgency of bowel movement and psychological distress, diminish following treatment.
For rectal cancer, adjuvant radiation therapy and chemotherapy can reduce the risk of local recurrence, but have associated toxicities. Depth of bowel-wall invasion and nodal status are used as indicators of the risk of local failure. There is a synergistic effect between combined radiotherapy and chemotherapy (chemoirradiation) in the treatment of rectal cancer. The combination reduces the risk of local failure and distant extrapelvic recurrence.
Some colon cancer patients can benefit from adjuvant chemotherapy following surgical resection. The standard therapy for advanced systemic colorectal cancer is combination chemotherapy (particularly 5-fluorouracil or 5-FU and folinic acid with or without another drug). Since the majority of patients who recur do so within two years of their initial treatment, routine follow-up, preferably with colonoscopy, is generally initiated.
Patients managed successfully by surgery may live normal lives. However, if a colostomy is necessary, patients may limit their social activities for fear of embarrassment. Sexual relations are frequently impaired. Metastatic colorectal cancer is commonly associated with weight loss, loss of appetite, pain and progressive loss of strength and general well-being.
The pancreas is located behind the stomach and in front of the first and second lumbar vertebrae, in the upper abdomen. In 2002, an estimated 1,550 men and 1,700 women were diagnosed with pancreatic cancer in Canada. The median age at diagnosis was 70 years of age. The ratio of deaths to new cases for pancreatic cancer was 99%, making it the cancer with the poorest prognosis for survival. This is partially explained by the inability to diagnose this cancer until after it has become locally advanced (40% of cases involve invasion of the duodenum or peripancreatic soft tissue and regional lymph nodes) or has metastasized (40% of cases have visceral involvement, usually to the liver). Fewer than 20% of cases are confined to the pancreas at the time of diagnosis and are potential candidates for resection.
The risk of pancreatic cancer rises as the amount and duration of cigarette smoking increase. Diets high in fat or meat consumption and with low intakes of fruits and vegetables add to the risk of this type of cancer. In addition, increased incidence appears to be associated with chronic pancreatitis, diabetes mellitus and some occupations that involve long-term exposure to solvents and petroleum compounds. Data on the impact of coffee and alcohol consumption are inconclusive. Recently, obesity and physical inactivity have also been shown to be associated with pancreatic cancer.
Patients with pancreatic cancer generally present with obstructive jaundice and upper abdominal or back pain. Marked loss of appetite, glucose intolerance, weight loss and fatigue are also common symptoms. Since so few patients are surgical candidates, accurate preoperative assessment of resectability is critical. Surgery generally involves removal of the pancreas, duodenum, gallbladder and bile duct (pancreaticoduodenectomy). This is generally followed by gastrointestinal reconstruction, which can be associated with various complications, including delayed gastric emptying and wound infection. In addition, patients may experience post-operative weight loss, thirst, frequent urination, fatigue and diabetes. Almost all patients experience pain, often described as gnawing, persistent, intense and devastating, during the course of their disease, to the point where some patients’ will to live may be undermined. Patients with locally advanced and metastatic disease may benefit from chemotherapy, particularly from the drug gemcitabine.
In 2002, an estimated 12,000 men and 8,800 women were diagnosed with lung cancer in Canada, making this disease the second most common form of cancer for both genders. Almost 80% of all cases diagnosed were over 60 years of age. The estimated 18,400 deaths from lung cancer in 2002 (10,700 men and 7,700 women) represent almost 28 per cent of all cancer deaths in Canada, making this disease the leading cause of cancer death. The ratio of deaths to new cases for lung cancer was 88%, compared with 48% for all cancers, placing it in the “poor prognosis” category.
The predominant risk factor contributing to lung cancer is the number of cigarettes smoked and the duration of smoking. In addition, exposure to carcinogens such as asbestos, radon, passive smoke, hydrocarbons, chromium and nickel all appear to increase lung cancer risk. The choice of therapy for lung cancer is determined by the histological cell type—small cell or non-small cell—and the extent of disease at diagnosis. Non-small cell lung cancer accounts for over 80% of cases diagnosed. Almost two-thirds of all lung cancers are diagnosed at advanced stages, which limits therapeutic options.
Early stage non-small cell lung cancer is usually treated surgically, by lobectomy (removal of a lobe of the lung) or pneumonectomy (removal of the whole lung). Many of those diagnosed with locally advanced non-small cell lung cancer disease will receive radiotherapy in combination with chemotherapy. Patients diagnosed with metastatic disease are often dealing with high levels of comorbidity due to concomitant smoking-related illness and receive palliative chemotherapy and terminal care.
Small cell lung cancer cases are generally treated with chemotherapy and radiotherapy. Most with limited disease small cell lung cancer also receive prophylactic cranial irradiation, which is associated with a transient increase in fatigue, nausea and vomiting.
Lung cancer patients often present with a persistent cough, dyspnea (difficult or laboured breathing), decreased appetite and pain from pleural or chest wall involvement. Over 80% of those diagnosed with inoperable non-small cell lung cancer complain of fatigue, depressed mood and decreased energy. Reduced lung capacity as a result of surgery, radiation or underlying lung disease due to smoking often leads to reduced physical and role functioning.
Breast cancer is the most common malignancy affecting Canadian women (male breast cancer is uncommon and is not reviewed here). In 2002, an estimated 20,500 women were diagnosed with breast cancer and 5,400 died of the disease. The ratio of deaths to new cases was 26%, making this cancer among those with the best prognosis. Whereas incidence rates have leveled off since the early 1990s, mortality rates have been declining for over a decade.2
Risk factors that contribute to breast cancer are early age at menarche, nulliparity or late age at the time of first full-term pregnancy, late menopause, exposure to environmental toxins, genetic predisposition, and the use of hormone replacement therapy. Evidence of the impact of diet and excessive use of alcohol are inconclusive.
In approximately 80% of cases, patients present with a palpable breast mass and have the diagnosis confirmed with a fine needle biopsy. Because of improved screening programs such as mammography, early stage breast cancer now represents almost 90% of all incident cases (small-to-medium-sized tumour, no or limited nodal involvement and no evidence of distant metastasis). Therapeutic options are dependent upon the stage of the disease at presentation, the age (almost 80% of cases occur in women aged 50 and older) and menopausal status of the patient, and the hormone receptor status of the tumour.
The majority of early stage breast cancers are treated surgically with breast-conserving surgery (excision of the primary tumour and adjacent breast tissue), followed by radiotherapy. Women diagnosed with loco-regional disease generally receive a modified radical mastectomy (excision of the breast with axillary node dissection) and many are now treated with pre-operative chemotherapy and post-operative radiotherapy. Standard therapies for metastatic breast cancer include hormonal therapy or chemotherapy.
Because breast cancer is among the more slow-growing tumours, life expectancy is often measured in years or decades, rather than in months. The quality of life of individuals with breast cancer is greatly influenced by the self-esteem issues experienced by the patient due to changed body image and altered sexual functioning. Following surgery, many women experience considerable arm morbidity due to arm swelling (lymphedema), as well as fear of cancer recurrence. Those undergoing chemotherapy and radiotherapy often exhibit chronic fatigue, nausea or pain, hot flashes and mood alterations, which interfere with well-being.
Prostate cancer is the most frequent form of cancer diagnosed among Canadian men. In 2002, an estimated 18,200 cases were diagnosed, and 4,300 men died of the disease. Almost one-third of men over 50 years of age who die of other causes are found to have prostate cancer at autopsy. However, this type of cancer should not be considered a benign disease, since, if left untreated, it continues to progress slowly, but steadily.3 Incidence increases more rapidly with age for prostate cancer than for any other cancer. Almost half of new cases and about 85% of deaths occur in men over 70 years of age.
The rise in the number of cases detected in the early 1990s can partially be explained by the increased use of screening techniques, such as the measurement of prostate-specific antigen (PSA) levels and transrectal ultrasonography (TRUS). Because tumour growth is promoted by androgens, men with high testosterone levels are at greater risk of developing prostate cancer. Diets with high monounsaturated fat intake, exposure to cadmium and genetic predisposition are also risk factors.
Because the prostate gland surrounds the urethra, patients with prostate cancer often have difficulty urinating, with symptoms such as hesitancy, incomplete bladder emptying or blood in the urine. They may also experience pain or sudden impotence. The decision to manage early prostate cancer by treatment or by careful observation is controversial, since the two most common treatments for localized cancer, radical retropubic prostatectomy (removal of the prostate) or radiation therapy can result in urinary incontinence and/or erectile dysfunction.
Locally advanced prostate cancer is usually treated with external-beam radiation therapy and androgen ablation therapy (chemical castration). Treatments with curative intent are often unsuccessful, since many patients already have occult metastases.
When prostate cancer metastasizes, it spreads to lymph nodes and bone in over 80% of cases, which may require palliative radiation therapy for bone pain as well as androgen ablation therapy. Side effects include hot flashes, increased fatigue, loss of libido, impotence and weight gain.
Complications of long-term treatment are osteoporosis, depression and loss of muscle mass. Patients who have undergone prostatectomy may restrict social activities because of their concern over urinary incontinence. “Prostate cancer patients perceive pain, fatigue, impaired sexual life, urinary frequency and incontinence, and reduced professional life as having the greatest impact on the quality of their lives.”4 The emotional and cognitive burden of prostate cancer can affect self-esteem, self-image, masculinity and sexuality.
In 2002, an estimated 5,000 new cases of bladder cancer were diagnosed (3,700 men and 1,300 women, most of whom were age 70 and over), making this the sixth most common cancer in Canada. It is considered a preventable disease since most cases result from exposure to environmental carcinogens. Both amount and duration of cigarette smoking have been shown to be correlated with bladder cancer incidence. There is also a high occupational risk for people exposed to aryl amines, such as those used in the paint, rubber and dye industries. The male to female ratio of bladder cancer is approximately three to one, but, in areas where cigarette smoking is common amongst women, this gap can narrow. Because the ratio of deaths to new cases for bladder cancer is 30%, compared with 48% for all cancers, this site is classified as one that has a very good prognosis. It should be noted that the ratio for women with bladder cancer is less favourable, at 36% (fairly good prognosis).
Hematuria (blood in the urine) and irritative symptoms such as urinary frequency are the most usual indicators. Cystoscopy and biopsy are the common methods of diagnosis. On presentation, almost 80% of all bladder cancers are considered to be superficial (limited to the mucous membrane lining, submucosa or connective tissue below). While low grade tumours rarely progress, bladder carcinomas are frequently multifocal (multiple areas of cancer) and can affect the entire urothelial tract. Higher grade muscle-invading tumours are much more likely to metastasize. Transurethral resection (TUR) can offer local control for most superficial bladder lesions, but cannot prevent recurrence.
While bladder preservation is always desirable, cystectomy (partial or complete removal of the bladder), high-dose local irradiation, intravesical (within the bladder) immunotherapy and/or chemotherapy are often used to treat locally invasive, non-metastatic bladder cancer. For men, radical cystectomy involves not only removal of the bladder, but part of the urethra, the prostate and regional pelvic lymph nodes, which can lead to sexual dysfunction when nerve-sparing surgery is not performed. For women, radical cystectomy generally includes removal of the bladder, ovaries, uterus, entire urethra, lymph nodes and a segment of the vaginal wall. Following cystectomy, the patient must undergo the installation of a bladder substitute or urinary diversion, which may be associated with incontinence, impotence in men, and recurrent infection. For those with regionally invasive disease who are not considered good candidates for cystectomy, radiotherapy alone is a treatment option, but combined modality therapies can also be considered.
Patients with advanced cancer may experience hemorrhage, pelvic or flank pain, or rectal obstruction with constipation. Radiotherapy or chemotherapy can reduce symptoms and the administration of combination chemotherapy can extend survival for some patient populations.
In 2002, an estimated 2,500 men and 1,500 women were diagnosed with renal cancer, the seventh most frequently diagnosed cancer in Canada. Renal cell cancer is the most common type of kidney cancer, representing approximately 85% of all cases. The ratio of deaths to new cases was 36% (fairly good prognosis), compared with the average of 48% for all cancers. Most cases are diagnosed between the ages of 50 and 70 years. Risk factors include living in an urban setting, cigarette smoking, analgesic abuse, obesity and exposure to environmental toxins (asbestos and cadmium).
Approximately 45% of patients present with localized disease, 25% have locally advanced cancer and 30% present with metastatic disease (generally in the lung, bone, or brain). In many cases, renal cancers are discovered incidentally during radiographic procedures such as ultrasound or computed tomography. Often, patients are asymptomatic until the disease has become more advanced, at which time, they may present with pain, hematuria (blood in the urine) and flank mass.
Either radical or partial nephrectomy (complete or partial removal of the kidney) is the standard treatment for localized renal cancer. Removal of the lymph nodes (regional lymphadenectomy) is generally performed at the same time. While lymph node dissection is useful for staging, there is ongoing debate as to whether it prolongs survival. Radical surgery includes removal of the kidney and surrounding tissues, including the adrenal gland. When both kidneys are involved, one is removed and a partial nephrectomy is performed on the remaining organ, if possible. Radical surgery and dialysis with possible later renal transplantation is a less favoured option.
While localized kidney cancer is often cured by surgery, treatment for metastatic disease is generally unsuccessful. Palliative surgery for metastatic renal cancer rarely cure5 the disease but may increase survival. Palliative radiotherapy may relieve pain, but renal cell carcinoma appears to be chemotherapy-resistant and not responsive to hormonal therapy.
Many patients with renal carcinoma develop systemic symptoms: anemia due to loss of blood in the urine, fever, fatigue, malnutrition, wasting and weight loss.
In 2002, an estimated 6,300 Canadians (3,400 men and 2,900 women) were diagnosed with non-Hodgkin’s lymphoma (NHL), the fifth most frequently diagnosed cancer in Canada. The ratio of deaths to new cases was 45% (fairly good prognosis). The median age at diagnosis is 65 years, but incidence peaks in the 80 to 85 year age group.
NHLs are a diverse group of cancers originating in the lymphoid system, which includes the lymph nodes as well as extranodal sites such as the stomach, small intestine, skin and brain. Lymphocytes are produced by the lymph nodes to provide immunity against infection: B cell lymphocytes produce antibodies and T cell lymphocytes provide cell-based immunity. Exposure to environmental toxins, viruses and congenital or acquired immunosuppression can cause lymphocytes to develop into malignant lymphomas, with B cell lymphomas being more common than T cell. NHLs develop in up to 30% of those infected with human immunodeficiency virus (HIV) and almost half are associated with the Epstein-Barr virus infection. Patients undergoing organ transplantation and receiving immunosuppressive drugs are very likely to develop NHL.
NHLs are somewhat paradoxically divided into “indolent” (incurable) and “aggressive” (potentially curable) lymphomas. Indolent lymphomas usually present with widespread involvement of the lymph nodes, spleen, liver or bone marrow and are considered incurable. However, they tend to grow slowly and as many as half of those diagnosed may have their initial therapy deferred for several years (“watch and wait”). For some patients, this lack of treatment may create stress and anxiety. For most patients with indolent NHL, the primary goal of therapy is to achieve lengthy survival with a good quality of life. When typical lymphoma symptoms such as weight loss, fever and sweating appear, treatment becomes necessary. Weakness, malaise, poor appetite, decreased stamina, in addition to uncomfortable lymphadenopathy (swelling of the lymph nodes) are commonly present.
Early stage indolent NHLs are treated with either chemotherapy or localized radiation therapy. Those with advanced stage symptomatic disease are often treated with either a single chemotherapy agent or a combination of drugs, with almost three-quarters achieving a complete remission. However, the vast majority will become resistant to treatment and will eventually relapse. Approximately 40% of indolent cases will convert to diffuse aggressive lymphoma.
Approximately three-quarters of patients with “aggressive” NHL present with advanced stage disease, which can progress rapidly. However, if a patient achieves a complete response, cure can still be achieved. The treatment standard is single agent chemotherapy, with or without involved field radiation for early stage cancer, and combination chemotherapy alone for advanced stage. Combination chemotherapy is known to produce many toxicities, including hair loss, nausea, fatigue, constipation and bone marrow suppression. For patients who relapse after achieving a remission, salvage chemotherapy followed by autologous bone marrow transplantation is the only treatment that can produce long-term remission.
Leukemia is a cancer of the body’s blood-forming tissues, including the bone marrow and lymphatic system. The word means “white blood” in Greek, since the blood takes on a whitish tone as abnormal white blood cells (lymphocytes) accumulate and block the production of normal blood cells in the bone marrow. Leukemia is categorized according to the type of white blood cell that is involved (lymphoid or myeloid) and how rapidly it develops (acute or chronic). In this disease, the production of red blood cells and platelets is also affected, which can lead to fatigue from anemia or bleeding or easy bruising due to impaired ability to form blood clots.
In 2002, an estimated 3,650 new cases of leukemia (2,100 men and 1,550 women) were diagnosed in Canada. In adults, there are four major types of leukemia: acute lymphocytic (ALL), acute myeloid (AML), chronic lymphocytic (CLL) and chronic myeloid (CML). Although there is a perception that leukemia is a disease of children, adults are ten times more likely to develop it. In 2002, it was estimated that fewer than 350 children were diagnosed with leukemia in Canada.
Little is known about the causes of leukemia, although post-natal exposure to radiation (therapeutic doses for medical conditions or military radiation exposure) has been suggested as a risk factor for acute leukemias. Leukemia develops more frequently in men, Caucasians and those in higher socio-economic groups and has been linked to exposure to benzene and other toxins, radon, cigarette smoke and certain viruses. Those born with Down’s syndrome have a twenty-fold risk of developing leukemia. Chromosome damage due to the administration of chemotherapeutic agents has been linked to the development of secondary leukemias.
While leukemia can present in a variety of ways, anemia, thrombocytopenia (low blood platelets) and severe and persistent fatigue are common presenting signs and symptoms. An enlarged liver and spleen and swollen lymph nodes may also be present. A bone marrow aspiration and biopsy are required to establish a definitive diagnosis of leukemia. As the name implies, acute leukemias tend to have a more sudden onset of symptoms, whereas chronic leukemias are more gradual in their onset and run a more indolent course. This chapter includes two types of leukemia: chronic lymphocytic leukemia (CLL), the most common leukemia among adults, and acute lymphoblastic leukemia (ALL), the most common leukemia among children.
Chronic lymphocytic leukemia (CLL)
Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the western world. CLL is considered a disease of the elderly; it is rarely diagnosed before the age of forty (90% of cases of all chronic leukemias are over fifty). The low incidence of CLL in Asian countries is thought to be due to genetic differences, rather than environmental factors.
CLL is always suspected when there is an excess of lymphocytes in the blood, as well as the bone marrow. Many cases of CLL are diagnosed during a routine blood test. Because patients with early stage CLL are often asymptomatic, and can live for long periods without requiring therapy, it is often difficult to determine when to initiate treatment. As an example, early stage indolent or “smoldering” CLL has a survival equivalent to an age-and sex-matched healthy population. However, the natural history of CLL can be extremely variable.
Chronic leukemia cells are often slow to multiply and are therefore less sensitive to chemotherapy. However, it is generally believed that symptomatic CLL (fever, unintended weight loss, profuse night sweats and enlarged lymph nodes) should be treated with systemic therapy usually consisting of alkylating agents, sometimes combined with purine analogues or monoclonal antibodies. Those diagnosed with more aggressive, advanced disease (approximately 25% of CLL cases) are at high risk for rapid progression and lower survival.
There is no evidence that long term systemic therapy is beneficial. Because of the advanced age of most CLL patients, only about 10% of them qualify for bone marrow transplantation. It is generally offered to those who are less than fifty-five years of age. Patients with CLL are thought to be at higher risk of developing second malignancies, such as lung cancer or cancer in the gastrointestinal tract. The most frequent cause of death for CLL patients is severe systemic infections, such as pneumonia or septicemia.
Childhood acute lymphoblastic leukemia (ALL)
Leukemia is the most common form of childhood malignancy, accounting for 30% of all childhood cancer. The incidence of leukemia is increased in children with certain chromosomal abnormalities. Over three-quarters of the cases of childhood leukemia are acute lymphoblastic leukemia (ALL). The peak incidence of ALL is between three and six years of age and the disease is more common in boys. Twenty per cent of cases are acute myeloid leukemia and less than 5% are chronic myeloid leukemia (CLL is rarely diagnosed in children).
Children with leukemia are generally symptomatic one to six weeks prior to diagnosis. The symptoms reflect the degree to which the bone marrow has been infiltrated with leukemic white cells. Anemia and thrombocytopenia (reduced platelet count) are present in more than two-thirds of patients; these lead to easy fatigability, headache and malaise, as well as bruising and bleeding from the gums and nose. Skin pallor, fever, bone tenderness and enlarged lymph nodes are common.
In the 1950s, when children were diagnosed with leukemia, there were few treatment options and those therapies available were intended to palliate the symptoms, not cure the disease. Today, as a result of extensive basic and clinical research, therapy commonly achieves a complete remission, which implies a return to normal in the blood counts and bone marrow. “Remission induction therapy” generally includes several chemotherapy drugs, which can induce complete remission within four weeks of initiation of therapy. More than ninety per cent of children with ALL achieve complete remission after three to four weeks of induction therapy, compared with 60% to 80% of adults. With timely, adequate and intensive treatment, over 70% of children with ALL are now cured. Infections, organ dysfunction and hair loss are common adverse events during remission induction therapy.
A complete remission is followed by high doses of postinduction chemotherapy, which is designed to kill any remaining leukemia cells in the bone marrow, lymphatic system or blood stream. Prophylactic chemotherapy and/or radiotherapy is routinely directed to the central nervous system; otherwise, this would be a common site of spread. After complete remission is achieved, a period of “maintenance therapy” is begun to eliminate all residual leukemia cells and prevent relapse. Maintenance therapy consists of a variety of chemotherapeutic regimens, and can last from two to four years.
During induction chemotherapy, severely low blood cell counts result in most patients experiencing fever, thus requiring broad spectrum antibiotic treatments and red blood cell and platelet transfusions. Despite prophylactic antibiotics and platelet transfusions, induction chemotherapy can still result in death from infection and hemorrhage. The prognosis of those who fail to achieve remission, or relapse after achieving remission, is poor. Approximately one-third of patients who relapse will achieve a second remission, which is generally of shorter duration than the first. While controversial, bone marrow transplantation is often attempted for selected patients in first remission.