Chapter 73: Approach to the Patient with Cancer¶
Chapter 73 | Part 4: Oncology and Hematology
KEY CLINICAL POINTS¶
- Cancer is a multifactorial disease characterized by uncontrolled cell growth and evasion of normal regulatory mechanisms.
- Age is the most significant risk factor, with 58% of cancer cases occurring in individuals aged >65 years.
- The TNM staging system (Tumor, Node, Metastasis) is the most widely used for cancer staging.
- Supportive care and palliative management are critical components of cancer treatment, improving quality of life.
- Cancer mortality rates have declined globally, but disparities persist among racial/ethnic groups.
1. DEFINITION & OVERVIEW¶
Cancer arises from cellular dysfunction and uncontrolled proliferation, diverging from normal cellular collaboration. It is characterized by malignant transformation, invasion, and metastasis. The disease profoundly impacts patient identity and self-image, often leading to psychological distress.
Table 73-1 Distribution of Cancer Incidence and Deaths for 2021¶
| MALE | FEMALE | ||||
|---|---|---|---|---|---|
| SITES | % | NUMBER | SITES | % | NUMBER |
| Prostate | 29 | 299,010 | Breast | 32 | 310,720 |
| Lung | 11 | 116,310 | Lung | 12 | 118,270 |
| Colorectal | 8 | 81,540 | Colorectal | 7 | 71,270 |
| Bladder | 6 | 63,070 | Endometrial | 7 | 67,880 |
| Melanoma | 6 | 59,170 | Melan,oma | 4 | 41,470 |
| Kidney | 5 | 52,380 | Lymphoma | 4 | 36,030 |
| Lymphoma | 4 | 44,590 | Pancreas | 3 | 31,910 |
| Oral cavity | 4 | 41,510 | Thyroid | 3 | 31,520 |
| Leukemia | 4 | 36,450 | Kidney | 3 | 29,230 |
| Pancreas | 3 | 34,530 | Leukemia | 3 | 26,320 |
| All others | 19 | 200,520 | All others | 21 | 207,440 |
| All sites | 100 | 1,029,080 | All sites | 100 | 972,060 |
Table 73-2 The Five Leading Primary Tumor Sites for Patients Dying of Cancer¶
| AGE, YEARS | RANK | SEX | ALL AGES | UNDER 20 | 20–39 | 40–49 | 50-64 | 65–79 | >80 |
|---|---|---|---|---|---|---|---|---|---|
| 1 | M | Lung | CNS | Colorect al | Colorect al | Lung | Lung | Lung | |
| 1 | F | Lung | CNS | Breast | Breast | Lung | Lung | Lung | |
| 2 | M | Prostate | Leukemi a | CNS | Lung | Colorect al | Prostate | Prostate | |
| 2 | F | Breast | Leukemi a | Cervix | Colorect al | Breast | Breast | Breast | |
| 3 | M | Colorect al | Bone sarcoma | Leukemi a | CNS | Pancrea s | Liver | Colorect al | |
| 3 | F | Colorect al | Soft tissue sarcoma | Colorect al | Lung | Colorect al | Pancrea s | Colorect al | |
| 4 | M | Pancrea s | Soft tissue sarcoma | Testis | Pancrea s | Liver | Bladder | Pancrea s | |
| 4 | F | Pancrea s | Bone sarcoma | CNS | Cervix | Pancrea s | Colorect al | Pancrea s | |
| 5 | M | Liver | Lympho ma | Lympho ma | Esophag us | Esophag us | Liver | Pancrea s | |
| 5 | F | Ovary | Kidney | Leukemi a | Ovary | Ovary | Ovary | Leukemi a |
1.1 Cellular and Molecular Basis¶
Cancer cells exhibit genetic mutations, altered signaling pathways, and resistance to apoptosis. They exploit evolutionary mechanisms of natural selection to outcompete normal cells. Molecular markers (e.g., Ki67, t(8;14) translocation) aid in diagnosis and prognosis.
1.2 Clinical Impact¶
Cancer diagnosis disrupts patient identity and social roles. Patients often experience existential distress, with the disease perceived as a betrayal of the body. Psychological and social consequences are significant, requiring holistic management.
2. EPIDEMIOLOGY¶
Cancer is the second leading cause of death globally, with age being the most significant risk factor. Incidence increases exponentially with age, with 58% of cases occurring in individuals >65 years. Disparities exist among racial/ethnic groups, with higher mortality rates in Black populations for certain cancers.
Table 73-3 Cancer Incidence and Mortality in Racial and Ethnic Groups¶
| SITE | SEX | WHITE | BLACK | ASIAN/PA CIFIC ISLANDER | AMERICA N INDIAN | HISPANIC | |
|---|---|---|---|---|---|---|---|
| Incidence per 100,000 Population | All | M | 511.2 | 533.9 | 299.0 | 504.1 | 377.2 |
| SITE | SEX | WHITE | BLACK | ASIAN/PA CIFIC ISLANDER | AMERICA N INDIAN | HISPANIC | |
|---|---|---|---|---|---|---|---|
| Incidence per 100,000 Population | All | F | 499.3 | 409.9 | 307.3 | 465.5 | 351.3 |
| Incidence per 100,000 Population | Breast | M | 134.9 | 129.6 | 104.6 | 115.5 | 100.7 |
| Incidence per 100,000 Population | Colorectal | M | 40.4 | 48.8 | 33.4 | 57.8 | 38.2 |
| Incidence per 100,000 Population | Colorectal | F | 30.5 | 35.0 | 23.7 | 43.7 | 27.2 |
| Incidence per 100,000 Population | Kidney | M | 24.3 | 26.4 | 11.6 | 43.9 | 23.5 |
| Incidence per 100,000 Population | Kidney | F | 12.1 | 13.7 | 5.5 | 23.9 | 13.3 |
| Incidence per 100,000 Population | Liver | M | 11.2 | 17.0 | 18.4 | 27.3 | 20.4 |
| Incidence per 100,000 Population | Liver | F | 4.2 | 5.5 | 6.7 | 12.3 | 8.4 |
| Incidence per 100,000 Population | Lung | M | 765.7 | 72,4 | 40.8 | 67.2 | 34.3 |
| Incidence per 100,000 Population | Lung | F | 54.8 | 45.8 | 28.1 | 58.6 | 24.0 |
| Incidence per 100,000 Population | Prostate | M | 110.7 | 186.1 | 60.9 | 91.9 | 90.9 |
| Incidence per 100,000 Population | Stomach | M | 7.1 | 13.0 | 11.8 | 13.1 | 11.4 |
| Incidence per 100,000 Population | Stomach | F | 3.4 | 7.4 | 6.9 | 7.8 | 7.7 |
| Incidence per 100,000 Population | Cervix | M | 7.2 | 8.6 | 6.0 | 11.4 | 9.7 |
| Incidence per 100,000 Population | Endometrial | M | 27.9 | 28.9 | 21.7 | 30.4 | 25.8 |
2.1 Global Trends¶
In 2024, 2.001 million new cancer cases were diagnosed, with lung cancer being the most common. Breast cancer is the second most common globally but ranks fourth in mortality. Disparities persist, with higher incidence in Asia and lower-income regions.
2.2 Racial/Ethnic Disparities¶
Table 73-3 shows incidence and mortality rates by race/ethnicity. Black populations have higher mortality rates for prostate, stomach, and uterine cancers. Asian populations have lower incidence but higher mortality for certain cancers.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
Cancer arises from genetic mutations, epigenetic changes, and environmental exposures. Key drivers include oncogene activation, tumor suppressor inactivation, and genomic instability. Environmental factors like smoking, radiation, and infections (e.g., HPV, HBV) contribute to carcinogenesis.
Table 73-6 Tumor Markers¶
| TUMOR MARKERS | CANCER | NONNEOPLASTIC CONDITIONS |
|---|---|---|
| Hormones | Human chorionic gonadotropin | Gestational trophoblastic disease, gonadal germ cell tumor, Pregnancy |
| Hormones | Calcitonin | Medullary cancer of the thyroid |
| Hormones | Catecholamines | Pheochromocytoma |
| Oncofetal Antigens | a Fetoprotein | Hepatocellular carcinoma, Cirrhosis, hepatitis, gonadal germ cell tumor |
| Oncofetal Antigens | Carcinoembryonic antigen | Adenocarcinomas of the colon, pancreas, lung, breast, ovary, Pancreatitis, hepatitis, inflammatory bowel disease, smoking |
| Enzymes | Prostatic acid phosphatase | Prostate cancer, Prostatitis, prostatic hypertrophy |
| Enzymes | Neuron-specific enolase | Small-cell cancer of the lung, neuroblastoma |
| Enzymes | Lactate dehydrogenase | Lymphoma, Ewing’s sarcoma, Hepatitis, hemolytic anemia, many others |
| Tumor-Associated Proteins | Prostate-specific antigen | Prostate cancer, Prostatitis, prostatic hypertrophy |
| Tumor-Associated Proteins | CA-125 | Ovarian cancer, some lymphomas, Menstruation, peritonitis, pregnancy |
| Tumor-Associated Proteins | CA 19-9 | Colon, pancreatic, breast cancer, Pancreatitis, ulcerative colitis |
| Tumor-Associated Proteins | CD30 | Hodgkin’s disease, anaplastic large-cell lymphoma |
| Tumor-Associated Proteins | CD25 | Hairy cell leukemia, adult T-cell leukemia/lymphoma |
3.1 Genetic and Molecular Mechanisms¶
Mutations in oncogenes (e.g., RAS, MYC) and tumor suppressors (e.g., TP53, BRCA) drive malignant transformation. Epigenetic alterations (e.g., DNA methylation, histone modification) also contribute to cancer progression.
3.2 Environmental and Lifestyle Factors¶
Smoking, alcohol consumption, obesity, and exposure to carcinogens (e.g., asbestos, UV radiation) increase cancer risk. Infections like HPV, HBV, and H. pylori are linked to specific cancers (e.g., cervical, liver, gastric).
4. CLINICAL FEATURES¶
Symptoms vary by cancer type but include weight loss, fatigue, pain, and organ-specific manifestations. Psychological and social impacts are profound, with patients often experiencing anxiety, depression, and altered self-image.
4.1 Common Symptoms¶
Weight loss, fatigue, pain, and systemic symptoms (e.g., cachexia, paraneoplastic syndromes) are prevalent. Localized symptoms depend on tumor location (e.g., jaundice for liver cancer, hematuria for bladder cancer).
4.2 Psychological Impact¶
Patients often experience existential distress, fear of recurrence, and altered self-perception. Depression affects ~25% of cancer patients, with higher rates in those with greater functional impairment.
5. DIFFERENTIAL DIAGNOSIS¶
Differential diagnosis includes infectious diseases, benign tumors, and other malignancies. Conditions like infections (e.g., cholecystitis), metabolic disorders, and non-malignant tumors must be considered.
6. INVESTIGATIONS & DIAGNOSIS¶
Diagnosis relies on imaging (CT, MRI), biopsy, and tumor markers. Staging systems (e.g., TNM) guide treatment decisions. Pathologic staging involves surgical evaluation of tissue and lymph nodes.
Table 73-4 Karnofsky Performance Index¶
| PERFORMANCE STATUS | FUNCTIONAL CAPABILITY OF THE PATIENT |
|---|---|
| 100 | Normal; no complaints; no evidence of disease |
| 90 | Able to carry on normal activity; minor signs or symptoms of disease |
| 80 | Normal activity with effort; some signs or symptoms of disease |
| 70 | Cares for self; unable to carry on normal activity or do active work |
| 60 | Requires occasional assistance but is able to care for most needs |
| 50 | Requires considerable assistance and frequent medical care |
| 40 | Disabled; requires special care and assistance |
| 30 | Severely disabled; hospitalization is indicated, although death is not imminent |
| 20 | Very sick; hospitalization is necessary; active supportive treatment is necessary |
| PERFORMANCE STATUS | FUNCTIONAL CAPABILITY OF THE PATIENT |
|---|---|
| 10 | Moribund, fatal processes progressing rapidly |
| 0 | Dead |
Table 73-5 Eastern Cooperative Oncology Group (ECOG) Performance Scale¶
| ECOG grade | Description |
|---|---|
| 0 | Fully active, able to carry on all predisease performance without restriction |
| 1 | Restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature |
| 2 | Ambulatory and capable of all self-care but unable to carry out any work activities. Up and about >50% of waking hours |
| 3 | Capable of only limited self-care, confined to bed or chair >50% of waking hours |
| 4 | Completely disabled. Cannot carry on any self-care. Totally confined to bed or chair |
| 5 | Dead |
6.1 Diagnostic Tests¶
Imaging (CT, MRI, PET), biopsy, and tumor markers (e.g., PSA, CA-125) are critical. Molecular testing (e.g., FISH, NGS) identifies genetic abnormalities for targeted therapies.
6.2 Staging Systems¶
TNM staging (Tumor, Node, Metastasis) is the gold standard. Other systems include Dukes for colorectal cancer and Ann Arbor for lymphoma.
7. MANAGEMENT & TREATMENT¶
Treatment is multidisciplinary, combining surgery, chemotherapy, radiation, and supportive care. Palliative care is essential for advanced disease. Personalized approaches based on staging and biomarkers are critical.
7.1 Curative vs. Palliative Therapy¶
Curative approaches (surgery, chemo, radiation) are used for early-stage disease. Palliative care focuses on symptom management and quality of life for advanced or metastatic cancer.
7.2 Treatment Modalities¶
Surgery, chemotherapy, radiation, immunotherapy, and targeted therapies are used based on tumor type and stage. Neoadjuvant therapy may precede definitive treatment.
8. PROGNOSIS & COMPLICATIONS¶
Prognosis depends on stage, biomarkers, and patient comorbidities. Complications include treatment toxicity, infections, and late effects (e.g., secondary cancers, organ failure). Long-term follow-up is essential for recurrence detection.
8.1 Survival and Recurrence¶
5-year survival rates vary by cancer type. Early-stage cancers have higher cure rates, while advanced disease is associated with poor prognosis. Recurrence risk is highest within the first 2 years post-treatment.
8,2 Treatment-Related Complications¶
Chemotherapy toxicity (e.g., myelosuppression), radiation side effects, and surgical complications (e.g., infections, organ dysfunction) are common. Late effects include secondary malignancies and endocrine disorders.
9. SPECIAL CONSIDERATIONS¶
Special populations require tailored approaches. Pregnancy, pediatric cancers, and geriatric patients face unique challenges. Racial disparities in cancer outcomes persist, necessitating equitable care strategies.
9.1 Pregnancy and Cancer¶
Cancer during pregnancy requires balancing maternal and fetal risks. Chemotherapy and radiation may be delayed until postpartum. Certain cancers (e.g., breast, cervical) have higher incidence in pregnant women.
9.2 Pediatric and Geriatric Patients¶
Pediatric cancers often present with atypical symptoms and require dose-adjusted therapies. Elderly patients face higher risks of treatment toxicity and comorbidities, requiring careful risk-benefit analysis.
10. KEY POINTS & CLINICAL PEARLS¶
- Age is the most significant cancer risk factor, with incidence increasing exponentially with age.
- TNM staging is critical for treatment planning and prognosis.
- Palliative care improves quality of life and should be integrated early in advanced disease.
- Tumor markers (e.g., PSA, CA-125) aid in diagnosis and monitoring.
- Multidisciplinary care and patient-centered communication are essential for optimal outcomes.