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Carcinoembryonic antigen (CEA) is the standard serum marker used to follow response and detect recurrence in colorectal adenocarcinoma. Serial values correlate with tumor burden, though a normal baseline does not exclude disease.
Triple-negative breast cancer lacks estrogen receptor, progesterone receptor, and HER2 expression, so endocrine and anti-HER2 therapies are ineffective. Node-positive disease warrants adjuvant chemotherapy, often with anthracycline and taxane regimens.
Checkpoint inhibitors release brakes on T-cell activity and can cause autoimmune-type inflammation in any organ, most commonly skin, gut, thyroid, and lung. Immune-related colitis is a classic and potentially severe manifestation requiring corticosteroids.
Tumor lysis syndrome results from rapid release of intracellular contents and is defined by the combination of hyperuricemia, hyperkalemia, hyperphosphatemia, and secondary hypocalcemia. Cairo-Bishop criteria incorporate these laboratory abnormalities with or without renal failure.
Anthracyclines such as doxorubicin cause cumulative, dose-related cardiomyopathy through free radical generation and topoisomerase inhibition in cardiomyocytes. Ejection fraction monitoring and a maximum cumulative dose limit reduce this risk.
Activating mutations in EGFR, such as exon 19 deletion or L858R, confer sensitivity to EGFR tyrosine kinase inhibitors like erlotinib, gefitinib, and osimertinib. Testing is standard before first-line therapy in advanced adenocarcinoma.
Carboplatin dosing uses the Calvert formula, which incorporates glomerular filtration rate estimated by creatinine clearance. Cockcroft-Gault is the accepted method for this estimate in most protocols.
Focal external beam radiotherapy provides effective pain relief for localized painful bone metastases, with response in most patients within weeks. Radiopharmaceuticals or bisphosphonates are alternatives for diffuse disease.
Colorectal carcinoma drains via the portal venous system, so the liver is the most frequent site of hematogenous spread. Lung metastases also occur, particularly with rectal tumors.
The TNM system describes tumor size and invasion (T), nodal involvement (N), and distant metastasis (M), and is applied to most solid tumors. It is periodically revised by the AJCC and UICC.
Aprepitant is an NK1 receptor antagonist that blocks substance P signaling and is especially effective against delayed emesis from highly emetogenic regimens. It is typically combined with a 5-HT3 antagonist and dexamethasone.
Superior vena cava obstruction impairs venous return from the head and upper extremities, producing facial and upper limb swelling, distended neck veins, and sometimes dyspnea. Lung cancer and lymphoma are common malignant causes.
Trastuzumab targets the HER2 receptor, so HER2 amplification by in situ hybridization or protein overexpression by immunohistochemistry must be documented. Testing is standard for all invasive breast cancers.
Bleomycin causes dose-related pulmonary toxicity that can progress to fibrosis, so cumulative dose is limited and lung function monitored. It is used in regimens for lymphoma and germ cell tumors.
Combined BRAF and MEK inhibition, for example dabrafenib with trametinib, improves response duration and survival compared with BRAF inhibitor monotherapy in BRAF-mutant melanoma. The combination also reduces cutaneous toxicity from paradoxical MAPK activation.
Febrile neutropenia is a medical emergency requiring prompt empiric broad-spectrum antibiotics, usually an antipseudomonal beta-lactam, after blood cultures are drawn. Delay in treatment increases mortality.
Alpha-fetoprotein is elevated in non-seminomatous germ cell tumors, particularly yolk sac elements, and is used with beta-hCG for diagnosis and monitoring. Pure seminoma typically does not raise AFP.
Longer lifetime exposure to endogenous estrogen, reflected by early menarche and late menopause, increases breast cancer risk. Reproductive factors that reduce estrogen exposure are protective.
Low-risk prostate cancer often follows an indolent course, and active surveillance avoids treatment-related morbidity in patients unlikely to benefit from curative intervention. It involves serial PSA testing and repeat biopsies.
Small cell lung cancer commonly causes ectopic antidiuretic hormone secretion, leading to hyponatremia. It may also cause ectopic ACTH and Lambert-Eaton syndrome.
Bisphosphonates such as zoledronic acid and the RANK ligand inhibitor denosumab reduce osteoclast activity and lower the risk of fracture, hypercalcemia, and need for radiotherapy. Dental evaluation is advised before starting to prevent osteonecrosis of the jaw.
Chronic hepatitis B can cause hepatocellular carcinoma through viral integration and oncogenic effects even in the absence of cirrhosis. Hepatitis C, alcohol, and hemochromatosis typically require established cirrhosis.
Palliative care focuses on symptom control, psychosocial support, and quality of life for patients and families, and can be delivered alongside disease-directed therapy. It is not limited to end-of-life care.
Sotorasib and adagrasib are selective KRAS G12C inhibitors approved for previously treated KRAS G12C-mutant non-small cell lung cancer. The mutation must be confirmed by molecular testing.
Hodgkin lymphoma is characterized by Reed-Sternberg cells, large binucleate cells with prominent nucleoli, in an appropriate inflammatory background. Immunophenotype typically includes CD15 and CD30 positivity.
Anthracyclines such as doxorubicin cause cumulative, dose-dependent cardiomyopathy through iron-mediated free-radical generation and topoisomerase II beta inhibition in cardiomyocytes. Risk rises with total cumulative dose and is aggravated by mediastinal radiation and trastuzumab. Cardiac function is typically monitored with echocardiography or MUGA scanning.
Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme for catabolism of 5-fluorouracil, and partial or complete deficiency markedly raises exposure to the drug. Affected patients can develop severe mucositis, diarrhea, cytopenias, and even fatal toxicity after standard doses. Pretreatment testing for DPYD variants or DPD activity helps guide dose reduction.
Bevacizumab is a humanized monoclonal antibody that binds vascular endothelial growth factor A, preventing its interaction with endothelial receptors and thereby suppressing tumor angiogenesis. It is used in several tumor types, including colorectal, lung, and renal cancers. Characteristic toxicities include hypertension, proteinuria, bleeding, and impaired wound healing.
In postmenopausal women with hormone receptor-positive early breast cancer, aromatase inhibitors are a standard adjuvant endocrine option and are somewhat more effective than tamoxifen alone. They work by blocking peripheral conversion of androgens to estrogen. Tamoxifen remains an alternative, particularly when aromatase inhibitor toxicity or osteoporosis is a concern.
Follicular lymphoma is a low-grade B-cell lymphoma characterized by a nodular growth pattern of germinal center cells, most often carrying the t(14;18) translocation that places BCL2 under immunoglobulin heavy-chain control. This leads to overexpression of the anti-apoptotic protein BCL2. It typically presents as painless lymphadenopathy in older adults.
Hyperleukocytosis in acute leukemia can cause leukostasis with pulmonary and cerebral vascular compromise, most often when the blast count is very high. Rapid cytoreduction with chemotherapy, sometimes preceded by leukapheresis, is the mainstay of urgent management. Supportive measures include hydration, avoidance of unnecessary red cell transfusions that raise viscosity, and tumor lysis prophylaxis.
Anti-Hu antibodies are associated with paraneoplastic sensory neuronopathy and encephalomyelitis, most often in the setting of small cell lung cancer. Patients develop painful sensory loss and gait instability. Anti-Yo is instead linked to paraneoplastic cerebellar degeneration, particularly with gynecologic and breast cancers.
Demonstration of malignant cells on pleural fluid cytology establishes the diagnosis of malignant pleural effusion, although sensitivity varies by tumor type and repeat sampling may be needed. Exudative criteria such as a high protein ratio only indicate exudation and are nonspecific. Lymphocyte-predominant exudates can result from tuberculosis, heart failure, or malignancy.
Carcinoembryonic antigen (CEA) is the standard serum marker used to monitor response and detect recurrence in colorectal cancer, particularly after resection of a CEA-producing tumor. It lacks sufficient sensitivity and specificity for screening. Rising CEA during follow-up should prompt restaging imaging.
Lutetium-177 PSMA-617 is a beta-emitting radioligand that binds prostate-specific membrane antigen and delivers radiation selectively to prostate cancer cells. It improves survival in previously treated PSMA-positive metastatic castration-resistant prostate cancer. Radium-223 instead targets bone metastases through calcium-mimetic uptake.
Checkpoint inhibitors release brakes on T-cell activity and can produce immune-related adverse events affecting the skin, gut, lungs, liver, and endocrine organs. Immune-related colitis is a well-recognized and potentially severe complication that may require corticosteroids. Early recognition and prompt treatment are essential.
Gabapentin is an anticonvulsant that reduces neuropathic pain and is commonly used as an opioid-sparing adjuvant in cancer-related neuropathy. It is titrated gradually and monitored for sedation and renal dosing. Nonsteroidal anti-inflammatory drugs may help bone pain but do not treat neuropathic mechanisms.
Human T-cell lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma, an aggressive malignancy of CD4-positive T cells. It is endemic in parts of Japan, the Caribbean, and South America. Transmission occurs through vertical, sexual, and blood-borne routes.
ROS1 rearrangements define a molecular subset of non-small cell lung cancer that responds to ROS1-directed tyrosine kinase inhibitors such as crizotinib. ROS1 and ALK share structural homology, so several ALK inhibitors also have activity. Confirmatory testing is needed before therapy.
Chronic Helicobacter pylori infection is a major risk factor for gastric adenocarcinoma, particularly non-cardia tumors, through chronic inflammation and progression to atrophic gastritis and intestinal metaplasia. Eradication reduces risk. Other risk factors include smoking, high salt intake, and pernicious anemia.
Immune checkpoint inhibitor plus tyrosine kinase inhibitor combinations, such as pembrolizumab with axitinib, are standard first-line treatment for advanced clear cell renal cell carcinoma. They exploit the immunogenic nature of renal cell carcinoma and the angiogenic dependence of the tumor. Single-agent tyrosine kinase inhibitors remain options in selected patients.
Malignant lymph nodes tend to be firm or hard, painless, and progressively enlarging, often exceeding two centimeters and sometimes fixed to surrounding tissues. Tenderness, fluctuation, and rapid regression with infection suggest an inflammatory cause. Persistent or supraclavicular nodes warrant biopsy.
For hormone receptor-positive, HER2-negative metastatic breast cancer without visceral crisis, endocrine therapy is the preferred initial systemic approach. Combining endocrine therapy with a CDK4/6 inhibitor improves progression-free and overall survival. Chemotherapy is reserved for visceral crisis or endocrine resistance.
When a solitary pulmonary nodule is highly suspicious and technically accessible, obtaining a tissue diagnosis guides management and avoids unnecessary surgery. Image-guided core biopsy provides histology and may allow molecular testing. The choice between biopsy and resection depends on probability of malignancy, patient fitness, and lesion location.
High-dose methotrexate can precipitate in renal tubules, causing acute kidney injury that further impairs drug clearance and worsens systemic toxicity. Aggressive hydration, urine alkalinization, and leucovorin rescue are used to prevent and mitigate this. Serum methotrexate levels guide continued rescue.
Bulky, chemosensitive tumors carry a high risk of tumor lysis syndrome, so vigorous hydration and close monitoring of potassium, phosphate, calcium, and uric acid are essential. Allopurinol or rasburicase is added for high-risk patients. Electrolyte abnormalities are corrected as they arise.
Chronic pancreatitis is a recognized risk factor for pancreatic ductal adenocarcinoma, likely through repeated cycles of inflammation, fibrosis, and epithelial injury. Other risk factors include smoking, obesity, diabetes, and certain hereditary syndromes. The absolute risk remains low but is higher than in the general population.
PARP inhibitors exploit synthetic lethality in cells with homologous recombination deficiency due to BRCA mutations, and maintenance therapy improves progression-free survival in advanced ovarian cancer. They are used after response to platinum-based chemotherapy. Germline and somatic BRCA testing guide selection.
Sentinel lymph node biopsy identifies the first lymph node draining the tumor and allows pathologic assessment for metastasis with less morbidity than full axillary dissection. A negative sentinel node generally spares the patient complete nodal clearance. It stages the regional basin rather than distant disease.
BRAF V600E mutations in colorectal cancer are associated with poor prognosis and reduced benefit from EGFR-directed antibodies, though they do not absolutely preclude their use. RAS mutations are the strongest negative predictor, so RAS testing is mandatory. Patients with BRAF-mutant disease may be considered for targeted combinations.