Case Study 2

For each question, choose the answer you think is correct. Answers are provided at the end of the page.

​​K.L. is a 50-year-old female with metastatic pancreatic carcinoma; her performance status is ECOG 2. She has been receiving gemcitabine with palliative intent using the GIPGEM​ protocol. She ret​urns to the clinic to see her oncologist today (October 21). 

Her weight on September 3 was 50 kg.

Today’s weight: 46.5 kg     height: 139 cm

Gemcitabine treatment history: Gemcitabine 1400 mg on September 3, 10, 17 and October 1, 8, 15.

Lab results from October 21:

WBC 4.7 (x 109/L)
ANC 2.7 (x 109/L)
Hgb 108 x g/L
Platelets 257 (x 109/L)
Creatinine 64 µmol/L

1. What is the patient’s current BSA, using the Mosteller equation?
  1.   1.43 m2
  2.   1.34 m2
  3.   1.38 m2
  4.   1.31 m2
2. The physician has prescribed 1400 mg IV gemcitabine to be given on October 22. Are the dose and interval of treatment appropriate?
  1. Yes, both the dose and interval are correct.
  2. No, both the dose and interval are incorrect. The dose should be 1340 mg and she should be scheduled for treatment on October 29.
  3. No, the dose is incorrect but the interval is correct. The dose should be 1340 mg.
  4. No, the dose is correct but the interval is incorrect. She should be scheduled for treatment on October 29.
3. K.L.’s ANC = 0.9 (x 109/L) and platelets = 180 (x 109/L) on the day she is due to start Cycle 3, Week 1. How would these lab results affect the dose for Cycle 3?
  1. There would be no change. 
  2. Her dose should be delayed to allow her counts to recover. 
  3. Her dose should be reduced to 1050 mg. 
  4. It is a clinical decision. The oncologist might choose to reduce her dose to 1050 mg or delay treatment. 
4. Which of the following best describes the BC Cancer benefit status of gemcitabine for K.L., considering her diagnosis? Would this change if K.L. had advanced prostate cancer?
  1. Gemcitabine is a Class I drug when used for pancreatic cancer but funding is Restricted for use in prostate cancer and requires case-by-case Compassionate Access Program (CAP) approval for this indication.
  2. Gemcitabine is a Class I drug when used for prostate cancer but requires case-by-case CAP approval for use in pancreatic cancer.
  3. Gemcitabine is a Class I drug when used for both pancreatic cancer and prostate cancer.
  4. Gemcitabine is a Restricted drug when used for both pancreatic cancer and prostate cancer if the patient does not have metastatic disease.
5. Based on the protocol, how long should K.L. continue treatment?
  1. Continue treatment as long as there is evidence of a clinical response, usually a partial response or stable disease associated with symptom improvement (decreased pain, weight gain, improved performance status), or until there is unacceptable toxicity. 
  2. Continue treatment for 6 cycles; if there is no improvement after 6 cycles, consider an alternative protocol. 
  3. Continue treatment for 8 cycles; if there is no improvement after 8 cycles, consider an alternative protocol. 
  4. Discontinue gemcitabine unless a complete response is achieved, as any disease progression is a sign that the tumour is unresponsive to therapy. 

 

​The correct answer is 2. 

Rationale: Mosteller equation (round to 2 decimal places)

(BSA in metres squared) = square root of ((height x weight) divided by 3600) = square root of ((139cm x 46.5kg) divided by 3600) = 1.34 metres squared  

 

The correct answer is 4. 

Rationale:  Based on the GIPGEM protocol, the dose for gemcitabine is 1000 mg/m2/week x 3 weeks on Days 1, 8, and 15, followed by 1 week rest, as the cycle repeats every 28 days.

Calculation of acceptable dose:  The dose based on the calculated BSA (from question 1): 1000 mg/m2 x 1.34 m2 is 1340 mg gemcitabine. The dose ordered by the physician is 1400 mg, which is correct because the initial BSA of 1.39 m2 should continue to be used for subsequent cycles, as per BC Cancer Policy III-10. Dose recalculation for subsequent cycles only needs to be considered if the patient’s weight changes by greater than 10%, or changes enough to result in a dose variance of greater than 5% from the previous dose, or if the patient’s clinical status warrants a dose adjustment. 

​Calculation of acceptable interval:  Patient received Cycle 1 and 2 doses of gemcitabine on September 3, 10, 17 and October 1, 8, and 15. According to the protocol treatment plan, she should be scheduled for a one week rest period before resuming treatment. Therefore, the patient should not be receiving any treatment on October 22. Next scheduled treatment date should be October 29. The patient should be rebooked for the following week with updated bloodwork to be drawn within 48 hours of treatment date (required lab timeframes can be found in the GIPGEM PPPO).

 

The correct answer is 4. 

Rationale: Based on the GIPGEM protocol "Dose Modifications: Hematology" section, if the ANC is between 0.5 to 1.0 (x 109/L) or the platelets are between 50 to 100 (x 109/L), the dose is reduced to 75% or delayed based on clinical assessment. In this scenario, the platelets are normal, however, the ANC is between 0.5 to 1.0 (x 109/L) so this warrants discussion with the prescriber regarding either a decrease in dose or a delay.

Original dose = 1400 mg

75% of 1400 mg = 1050 mg

 

The correct answer is 1. 

Rationale: According to the BC Cancer Benefit Drug list, gemcitabine is a Class I drug in several types of cancer. However, case-by-case approval is required for its use in prostate cancer as that is not a listed indication. Therefore, Compassionate Access Program (CAP) approval must be obtained prior to use of single agent gemcitabine for prostate cancer. 

 

The correct answer is 1. 

Rationale: Based on the GIPGEM protocol "Treatment" plan, treatment is continued as long as there is evidence of a clinical response, usually a partial response or stable disease associated with symptom improvement, or until there is unacceptable toxicity.