Competency Quiz # 4

Along with imaging studies and biopsy-cytology,tumor markers are playiing an improtant role in cancer diagnosis and treatment. These are products in the blood either produced directly by the tumor or reflecting the body's reaction to the tumor. Some of the well-known ones are PSA

The three leading cancer-related deaths in the global population are due to lung (17.8%), stomach (10.4%), and liver (8.8%). The industrialized countries account for the highest rates while the lowest rates tend to be in the northern Africa and southern and eastern Asia. Worldwide cancer rates are expected to increase in the near term because of aging populations and unhealthy lifestyles such as smoking and probably obesity. Tobacco use alone is responsible for 10 million deaths per year and is estimated to double by 2020. Althught cancer rates (usually expressed as number per 100,000 population) in the US have declined somewhat, there has been an increase in lung cance3r amoung wormen and general rise in liver cancer.

Cancer statistics are published annually by the ACS and are expressed as incidence and prevalence. Incidence refers to the number of new cancers of a specific site or type in a population per year. The numbers may refer to a general population or be divided in subgroups based on age, geography, gender, ethnicity, socioeconomic group, or other distinguishing categories.

Nausea and or vomiting are vrey common in terminal cancer patients and every effor should be made to offer relief from this discomforting symptom. There are many causes. GI irritation, obstruction, or hepatobiliary disease are all possible,a dn treatment may require a change of diet,oral antacids, or bowel decompression. Chemoherapy and radiation are notorious causes and may be emeliorated with a variety of antiemetic crugs. Other drugs such as opioids, antibiotics, or anticonvulsants may also be emetogenic. Increased inracranial pressure from a brain primary or meastatic tumor and cerebral edemal may also lead to nausea and vomiting. Fluid and electrolyte imbalances and hpercalcemia may be at fault and require correction if possible. Finally psychogenic factors such as fear and anxiety may be responsible and should be addressed with appropriate medication.

Rapid killing of tumor cells by cytotoxic therapy, especially in leukemia and lymhomas, can lead to an accelerated release of intracellular potassium, phosphate, and nucleic acid into the circulation. Phosphate binds to calcium, resulting in hypocalcemia, and the nucleic acids are converted to uric acid, resulting in hyperuricemia. This pattern may lead to cardiac arrhythmias and renal and or multiorgan dysfunction. Prevention with hypouricemic drugs (e.g. allopurinol) and IV hydration to maintain a urine flow of 150 to ml per hour prior to treatment is recommended. Alkalization of the urine with bicarbonate is also helpful.

The most common cause of error by nurses (including oncology nurses) is that of dispensing medication; failure to give the prescribed drug, administration of the wrong drug, or a dosing mistake. In the late 1990s, the Institute of Medicine issued a study that claimed 98,000 hospital deaths annually were caused by medication errors; a recent follow-up showed that not much has changed. Certainty in administering medications is particularly important for oncology nurses who deal with chemotherapy drugs that have a high mortality and mobidity rate if wrong dose or drug is given. Incomplete or absent documentation in the record is another possible source of negligence that may lead to patient injury. Failure to educate or patient or monitor the patient in restraints are both deviations from the standard of care but are less common.

Nearly all chemotherapeutic drugs have acute and long term side-effects. While many of the acute effects are short-livd or reversible, some of the long term effects are not. Factors that may influence chronic toxicity are cumulative dose of the drug, he nature of the tumor, combination with other drugs or radiation, and the presence of underlying disease prior to the cancer treatment. Methotrexate and actinomycin D may cause hepatic fibrosis or cirrhosis. Liver biopsy is sometimes indicated in patients who have received these dugs and develop abnormal liver function tests. Cardiotoxicity is the chief long-term side effect of doxorubicin, which is subject to cumulative dose and any underlying heart disease. Pulmonary fibrosis is the main consequence of bleomycin and peripheral neuorpathy of vincristine. long term follow-up is indicated for any cnacer survivor who has received chemotherapy.

Ondansetron (Zofran) is an antiemetic drug used to prevent or treat nausea and vmiting during or after chemotherapy.

Choosing the correct empiric antibiotic therapy for cancer patients wih fever and neutropenia is a complex matter and to some extent depends on a high degree of suspicion as to the source and nature of the infecion. It also requires some knowledge of the bacterial profile within a particular institution. For high-risk patients, an IV infusion of an antipseudomal cephalasporin or penicillin or a carbapenem may be used. use of vancomycin is controversial unless there is a strong suspicion of meticillin-resistant Stahpylococcus aureus (MRSA). This is because frequent orr prolonged us of vancomycin has led to the development of resistant organisms, especiallyenterococcus. Fluoroquinolones such as ciprofloxacin or levofloxacin may be used but should not be used alone.

VZV and CMV are two viruses that may attack at this late stage. VZV causes a typical zoster rash (shingles) while the latte may invade pulmonary or hepatic sites. Aspergillus is a fungus that ma infect sinuses and lungs, skin, and cns, but usually during the initial year after BMT