For each question, choose the answer you think is correct. Answers are provided at the end of the page.
P.N. is a 66-year-old female diagnosed with adenocarcinoma of the colon, which is now metastatic to the liver. The oncologist has determined that infusional fluorouracil is not suitable for this patient. First line treatment for her advanced disease will be given with GIAVCAPB.
Weight: 77 kg Height: 150 cm
Lab results taken 24 hours prior to first treatment:
WBC 8.4 (x 109/L)
ANC 4.4 (x 109/L)
Platelets 318 (x 109/L)
Hgb 105 g/L
| Bilirubin 7 µmol/L
LDH 225 U/L
ALT 47 U/L
Alk Phos 263 U/L | Creatinine 111 µmol/L
Sodium 136 mmol/L
Potassium 4.0 mmol/L
Albumin 40 g/L |
DPYD: Variants identified
VARIANT 1: DPYD:c.1905+1G>A [DPYD*2A, null allele]
VARIANT 2: none
Predicted CPIC activity Score: 1.0 (range: 0 – no activity -> 2.0 full activity)
Predicted CPIC DPYD phenotype: intermediate metabolizer
BPMH:
Ramipril 2.5 mg orally once daily
Atorvastatin 5 mg orally once daily
Metformin 500 mg orally twice daily
- The dose should be 1790 mg PO BID × 14 days, ordered as 1700 mg PO BID × 14 days
- The dose should be 895 mg PO BID × 14 days, ordered as 800 mg PO BID × 14 days
- The dose should be 895 mg PO BID × 14 days, ordered as 900 mg PO BID × 14 days
- The dose should be 1790 mg PO BID × 14 days, ordered as 1800 mg PO BID × 14 days
- LFTs are within normal limits, and P.N. can receive the dose as prescribed
- LFTs are elevated due to liver metastases, and the dose should be reduced by 75%, as capecitabine is extensively metabolized by the liver
- LFTs are elevated, which is a common occurrence with liver metastases, and capecitabine should be discontinued
- LFTs are elevated due to liver metastases, but P.N. can receive the doses as prescribed
After the fourth cycle of capecitabine, P.N. develops peeling, redness, and pain on both of her hands. She is diagnosed with Grade 3 Palmar-Plantar Erythromatosus (PPE), also known as hand-foot syndrome. Her oncologist decides to delay subsequent capecitabine doses until her pain resolves, and also reduce the capecitabine dose for the next cycle. Thirty days following the fourth cycle, her PPE symptoms have resolved and the oncologist prescribes capecitabine 1477 mg PO daily × 14 days.
Lab results 24 hours prior to treatment:
WBC 6.7 (x 109/L)
ANC 2.4 (x 109/L)
Platelets 360 (x 109/L)
|
- The interval is correct, but the dose should be 650 mg PO BID × 14 days
- The interval is too long, and the dose should be 700 mg PO daily × 14 days
- The interval is too long, and the dose should be 650 mg PO daily × 14 days
- The capecitabine should be discontinued for this patient
- Notify prescriber and advise to hold bevacizumab
- Notify prescriber and advise to permanently discontinue bevacizumab as she is in a hypertensive crisis
- Notify prescriber and advise to proceed with bevacizumab today but increase her ramipril dose to 5 mg daily
- Ask P.N. to go for a walk and come back to check her blood pressure again before notifying prescriber
- Withhold bevacizumab and proceed with 24 hour urine collection
- Hold dose and recheck 24 hour urine every 2 weeks, resume therapy when less than or equal to 2 g/24 hour
- No action needed, administer bevacizumab dose as scheduled, urine protein is within normal limits
- Administer bevacizumab dose as scheduled. Collect 24-hour urine for determination of total protein within 3 days before the next scheduled bevacizumab administration.
Answer 1
The correct answer is 2.
Rationale:
BSA calculation
BSA = 1.79 m2
Creatinine Clearance (Where N = 1.04 for females)
= N x (140-age) x weight (kg)
Serum creatinine (micromol/L)
= 1.04 x (140-66) x 77
111
CrCl = 53.4 mL/min
500 mg/m2 x 1.79 m2 = 895 mg BID x 14 days
Capecitabine dose follows dose banding using the table provided, so the appropriate dose is 800 mg.
As only 150 mg and 500 mg tablets of capecitabine exist, the patient should receive 1 x 500 mg tablet along with 2 x 150 mg tablets to make up each individual dose.
Answer 2
The correct answer is 4.
Rationale: Although ranges for liver function tests can vary from lab to lab, P.N.’s LDH, ALT, and Alk Phos values are considered elevated. This may be attributed to her liver metastases, which can result in elevated liver function tests.
Since capecitabine is primarily metabolized by the kidneys, not by the liver, no dose reductions are required and P.N. can receive the drug as ordered.
Answer 3
The correct answer is 1.
Rationale: Based on the GIAVCAPB protocol “Dose Modifications: 2. Hand-Foot Skin Reaction” section, the interval since the last treatment is correct, as treatment should be stopped and delayed until the reaction has resolved to a grade 0-1 level.
The dose should be reduced to 75% of initial dose for this first event occurrence of Grade 3 hand-foot skin reaction. The oncologist modified from 895 mg to 671 mg (75% dose), and dose banding brings this to 650 mg.
Answer 4
The correct answer is 3.
Rationale: Based on the GIAVCAPB protocol “Dose Modifications: 7. Hypertension” section, for blood pressure greater than 160/100 and no symptoms, proceed with 100% bevacizumab dose, notify the physician, and start or adjust antihypertensive therapy. P.N.’s blood pressure readings have been higher at home as well. Therefore, she needs an increase in the dose of her anti-hypertensive medication.
Answer 5
The correct answer is 4.
Rationale: Based on the GIAVCAPB protocol “Dose Modifications: 6. Proteinuria” section, for urine dipstick 2+, administer bevacizumab dose as scheduled. Collect 24-hour urine for determination of total protein within 3 days before the next scheduled bevacizumab administration. These 24-hour urine results will be used to determine the next cycle’s dose of bevacizumab, according to the second table listed in the “Dose Modifications: 6. Proteinuria” section of this protocol.
