Systemic Effects of Chemo Flashcards
What is the most common dose-limiting side effect of chemo? Why?
- Myelosuppression
- All types of blood cells divide rapidly regardless of development stage and are therefore very vulnerable
What chemo agents are likely to cause myelosuppresion?
- Because AA’s and nitrosurea’s affect both cycling or non-cycling, they are most likely to destroy bone marrow stem cells
- Antimetabolites, vinca alkaloids and antitumor antibiotics are cell cycle specific and so cause less severe myelosuppresion
- Combination therapies tend to cause more severe suppression
- Anti-angiogenic agents and targeted therapies can also cause a more mild suppression
- High risk in tumor cells of the bone marrow and previous chemo/rad
What are colony stimulating factors?
- Exogenous type stimulates stem cells in the bone marrow to grow and differentiate into different colonies of blood cells
- In Ca care most often refers to stimulating production of WBC’s, especially neutrophils
Why is chemo induced anemia less frequent than neutropenia?
- RBC lifespan of 120 days, therefore the marrow has time to recover before the number of circulating RBC’s decreases
- If a stimulating factor (EPO) is given, it is typically after ~4 weeks post treatment, and primary purpose is to avoid transfusion
Why does thrombocytopenia occur?
- Platelet life span is 7-10 days, and penia usually appears 8-14 days after chemo along with neutropenia
- Chemo may be temporarily stopped if platelets drop below 50,000 to 75,000 cells/mm
What stimulating factors are given for chemo induced thrombocytopenia?
Interleukin-II (increases stem cell proliferation) and is given until cells >50,000 before next cycle
What levels of WBC would chemo be withheld?
- WBC between 1000-3000 cells/mm or if absolute neutrophil count (ANC) is less than 1000 to 1500 cells/mm (under 1500 is the official definition for neutropenia)
- Life threatening ANC is <500 cells/mm
Why might we not see the standard signs of infection in a patient with neutropenia?
- Major function of neutrophils is phagocytosis > invasion of pathogens can increase in frequency in severity while in a neutropenic state, particularly around days 7-10
- Typical signs of infection may be inhibited, making the only sign a fever
- Neutrophils usually cause the overt signs of infection like inflammation and redness
What are the advantages of using colony stimulating factors to improve neutrophil counts?
- Doesn’t change the rate of decline but it does improve the recovery rate and shortens the duration of neuropenia, reducing risk of mortality and morbidity from infections
- Full doses of chemo can be used
How do we manage myelosuppression?
- Monitor labs and alter chemo dose/schedule as needed
- Assessment and education for infection prevention and identification of febrile neutropenia
- Avoid dental care and other procedures if able to during periods of neutropenia
- Appropriate hygiene (hand washing, avoid touching face, oral care)
- Safe food handling (maintain appropriate temperatures, wash all foods, avoid food sources with high risk exposure to bacteria like street vendors)
- Colony stimulating factors, particularly for neutropenia (granulate-CSF)
- Monitor VS when indicated (eg. daily temperature)
What causes diarrhea in chemo?
- causes necrosis of the cells lining the intestinal crypt, causing ++ wall inflammation
- Without crypt cells replacement of GI cells are hampered and the surface for absorption is reduced - therefore imbalance with absorption causes diarrhea
- Diarrhea can cause other problems like lethargy, weakness and electrolyte imbalance; without management can cause malnutrition, dehydration and CV collapse
What is the difference between early onset and late onset diarrhea?
- Early onset is within 24 hours and late is >24 hours
- Early onset can be managed with atropine; usually cramping, watery eyes, rhinitis and salivation is also present
- Late can be prolonged and lead to potentially fatal dehydration and electrolyte imbalance if not managed
- Must be treated immediately with immodium
What are the recommendations for immodium dosages?
Two tablets (4 mg) after 1st loose stool, then one tablet (2 mg) q2h until diarrhea free for 12 hours
What special considerations must be made for immune-mediated adverse reactions and diarrhea?
- imAE’s can cause severe and fatal immune-mediated adverse reactions of the multiple systems, but especially GI (enterocolitis, perforations)
- Permanent d/c of treatment is recommended for severe reactions
- Onset usually occurs during beginning of treatment but may occur months after last dose
What are prevention and management techniques for diarrhea?
- Encourage monitoring stool quality and frequency (will determine if severe and needs escalation of care to hospital)
- Encourage 10-12 cups fluids/day
- Increase soluble fiber (peeled fruits, bananas, white rice/pasta) and decrease insoluble fiber (skins of fruits and vegs, leafy greens, nuts/seeds)
- Small, frequent meals
- Avoid spicy foods, deep fried/greasy foods, alcohol
- Avoid meds that can cause or worsen diarrhea (eg. laxatives, maxeran) in collab c MRP
- Take immodium
- Protect skin integrity to perianal skin
- Hand hygiene
- If diarrhea not resolving in 24 hours, and/or S&S of fever/infection present, seek urgent care to r/o other causes (eg. cdiff) and to receive appropriate supports (eg. IV fluids, labs, etc.)
