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• Is there a role for oral supplementation of vitamin C, vitamin E and selenium in the prevention of cisplatin-induced toxicities (specifically ototoxicity and nephrotoxicity) in patients with solid tumors receiving cisplatin chemotherapy?

• Cancer patients receiving either single agent cisplatin or combination chemotherapy

 

• Prior chemotherapy
• Supplementation with vitamin C, E or selenium 30 days prior to inclusion in the study
• Use of antioxidants other than vitamins C and E and selenium during chemotherapy
• Creatinine clearance <1.33 ml/s (<80ml/min)
• Karnofsky performance status <50%

Recruitment

• Between February 1995 and August 1997, patients were randomized in double blind manner into two groups.
• Fifty patients were recruited initially, 2 dropped out secondary to death from progression of cancer
• Remaining 48 patients were from various groups of cancer: Testicular cancer (16), osteosarcoma (13), gastrointestinal cancer(6), urogenital cancer (5), head and neck cancer (5) and melanoma (3)

Design

•  Double-blind randomization into two groups:
  • Patients who received supplementation with vitamin C, E and selenium referred to as "antioxidant micronutrients" 
  • Patients who received placebo
  • Tumor types were equally divided in both groups
• Both groups were given 100cc of a vanilla flavored milky beverage which contained 3.42g protein, 7.92g carbohydrate, and 0.05g fat twice daily.
  • Drink was provided once daily 7 days before the start of chemotherapy until three weeks after completion date of chemotherapy.
  • 25 patients were randomized to drink the beverage containing 1000 mg vitamin C (L-ascorbic acid), 400 mg of Vitamin E(dl-a-tocopherol-acetate) and 100 ug selenium(sodium selenite).
  • 23 patients in the placebo group received same beverage without antioxidants.
  • Patients filled out checklists each day for record of compliance.
• Patients received a 1-5 day cycle of IV administered chemotherapy repeated every 21 days
  • Patients were provided with IV hydration of 0.9% sodium chloride and 5% glucose to reduce cisplatin induced nephrotoxicity.
  • Aminoglycosides and amphotericin, known nephrotoxic or ototoxic medications, were not provided to patients
• Blood sampling
  • Plasma concentrations of antioxidant micronutrients and MDA were measured before and 7 days after the start of supplementation as well as during the chemotherapy period
  • Primary and secondary measures ie creatinine clearance, conduction threshhold at 8.0 dB, blood hemoglobin, white blood cell count and platelets were measured at the start of each cycle of chemotherapy and two months after completion of chemotherapy
• Analytical methods
  • Total vitamin C, reduced and oxidized vitamin C, vitamin E and malondialdehyde(MDA) were measured using high performance liquid chromatography(HPLC).
  • Markers of oxidative stress included the ratio of reduced and oxidised vitamin C and plasma concentrations of MDA.
  • Cholesterol, triglycerides, magnesium and creatinine values were determined on a clincal chemical analyzer.
  • Plasma selenium ws determined by atomic absorption spectroscopy.
  • Functional activity of vitamin E as defined by the lipid standardized vitamin E  plasma concentration (vitamin E/lipids ration) was calculated as the plasma vitamin E concentration divided by the sum of the plasma concentrations of cholesterol and triglycerides.
  • Overall micronutrient antioxidant scores (ranging from 3-6) were determined for each patient based on the patients' individual plasma concentrations of vitamin C,E and selenium on day 1 of the first chemotherapy cycle. Patients were assigned an arbitrary value of 2 or 1. Two indicated that their plasma concentrations were more than the median value for the whole group and one indicated that their value was less than the median value for the whole group.
• Renal and hearing function
  • Renal function was determined by creatinine clearance values.
  • Renal tubular function was determined by plasma magnesium concentrations.
  • Audiological examination was performed prior to start of chemotherapy and prior to each cycle of chemotherapy.

Blinding used (if applicable)

•  Patients were randomized in a double blind manner into two separate groups

Intervention (if applicable)

•   Supplementation with vitamin C, E, and selenium

Statistical Analysis

•  80% power for the expectation of effect-sizes of 0.8 or more
• For comparison of the values of parameters of individual patients during one particular cycle and the values on day 1 of two distinctive cycles
• Comparison of mean values of parameters between both study groups, Independent Student's t-test was used.
• Mann-Whitney U test was used for comparisons between both study groups in relation to categorical parameters.
• Relations between various parameters regarding antioxidants and oxidative stress and parameters indicating chemotherapy-induced toxicity used Bivariate Pearson's correlation coefficients.
• Significance established at P<0.05.

Timing of Measurements

• Blood specimens were drawn:
  •  One day before  start of first, second and fourth chemotherapy courses,
  • Within 24 hours after completion of chemotherapy infusions on the last day of hospital admissions(usually on day 2-5 pending chemotherapy regimen) for the first and fourth chemtherapy course
  • At the nadir days of the first and fourth chemotherapy course in the outpatient department (usually between days 8 and 15) 
  • And at 2 and 12 months after completion of chemotherapy 

Dependent Variables

• Variable 1: Acute(during chemotherapy) and long term (2 and 12 months after completing chemotherapy) nephrotoxicity measured by the decrease in calculated creatinine clearance 
• Variable 2: Acute and long term ototoxicity measured by the the loss of high-tone hearing.
• Variable 3:  bone marrow toxicity 
  • Chemotherapy induced anemia measured by blood hemoglobin
  • Lecocytopenia measured by serum white blood cell count
  • Thrombocytopenia measured by platelet levels

Independent Variables

25 patients were randomized to drink milky beverage containing 1000 mg vitamin C (L-ascorbic acid), 400 mg of Vitamin E (dl-a-tocopherol-acetate) and 100 ug selenium(sodium selenite) twice per day 

Control Variables

 

 

Initial N: 50, 2 withdrawn second to early death

Attrition (final N):

• 48: 41 male, 7 female
• No significant differences between groups with respect to gender.

Age:

• In placebo group: median age 42
• In supplementation group: median age 44
• No significant differences between groups with respect to age.

Ethnicity:

• Study performed in the Netherlands, no other information provided about ethnicity of patients

Other relevant demographics:

•  Remaining 48 patients were from various groups of cancer: Testicular cancer (16), osteosarcoma(13), gastrointestinal cancer(6), urogenital cancer(5), head and neck cancer(5) and melanoma(3)
• Tumor types were equally distributed over the two groups.
• Observed tumor responses for the patients were equally divided over the two arms.

Anthropometrics

• No significant differences between the groups with regards to anthropometric parameters

Location: Netherlands

 

Table 1. Plasma concentrations of antioxidant micronutrients and MDA before and 7 days after the supplementation 

Parameters	Normal values	Placebo Day -7	Placebo Day 1	pavalue	Supplement Day-7	Supplement Day 1	pavalue	pbvalue
Total vitaminC	11-100umol/l	58.6+/-48.7	51.5+/-35.6	NS	48.1+/-34.7	121.3+/-52.7	<0.001	<0.001
Oxidized vitaminC	umol/l	7.4+/-4/6	6.5+/-3/7	NS	5.4+/-3.2	14.7+/-9.3	<0.001	<0.001
Reduced vitaminC	umol/l	51.2+/-47.9	45.0+/-33.5	NS	42.7+/-32.3	106.6+/-52.2	<0.001	<0.001
Reduced/oxidized vitamin C		9.2+/-15.1	7.1+/-4.1	NS	7.6+/-4.2	9.0+/-4.4	NS	NS
Vitamin E	18.0-1.94mmol/l	26.6+/-8.7	26.4+/-9.2	NS	26.0+/-7.6	60.0+/-25.1	<0.001	<0.001
Cholesterol	3.9-7.3mmol/l	4.6+/-1.1	4.5+/-0.9	NS	5.2+/-1.9	5.1+/-1.7	0.374	0.106
Triglycerides	0.8-1.94mmol/l	1.1+/-0.5	1.1+/-0.5	NS	1.1+/-0.6	1.3+/-0.8	0.046	NS
Vitamin E/lipids	umol/mmol	4.8+/-1.6	4.8+/-1.5	NS	4.3+/-1.0	9.5+/-2.7	<0.001	<0.001
Selenium	0.8-1.4umol/l	1.1+/-0.3	1.0+/-0.3	NS	1.3+/-0.4	1.5+/-0.5	<0.001	<0.001
Malondialdehyde(MDA)	0.5-1.3umol/l	1.1+/-0.4	1.2+/-0.5	NS	1.4+/-0.7	1.2+/-0.4	NS	NS

• Day 7 indicates before supplementation
• Day 1 indicates after 7 days of supplementation just before the start of chemotherapy
•  p^avalue for comparison between values of day -7 and day 1 within the same randomization group (paired samples Student's t-test. NS, non-significant
• p^bvalue for comparison between values of day 1 of both randomization groups(independent-samples Student's t-test). NS, non-significant.

1.Vitamin C,E and selenium and MDA did not differ between the two groups on day -7. But at day 1, antioxidant levels in supplemented group increased to significantly higher levels compared to day -7 and to the levels of the placebo group at day 1.

2. Levels of vitamin C, E and E/lipid ratios significantly decreased at the nadir day of cycle 1 in both groups of patients following first chemotherapy.

3. At the nadir day of cycle 1 and during chemotherapy, vitamin C and E levels remained significantly higher in the supplemented group as compared to the placebo group.

4. Selenium levels in the supplemented group did not change significantly throughout the study period.

5. Twenty two (6 in the placebo group and 16 in the intervention group)of the 48 patients did not drink the study beverage for the duration of the study. Eleven of the 22 patients stopped drinking the beverage at the first chemotherapy cycle. Nausea and upper abdominal complaints and dislike of the taste of the beverage were the primary reasons for disliking the beverage.

 

Table 2. Primary and Secondary outcome measures determined at each chemotherapy cycle and 2 months after cessation of chemotherapy

Parameters	Placebo Cycle1	Cycle2	Cycle4	2months	Supplementation Cycle1	Cycle2	Cycle4	2months
Measured creatinine clearance (ml/s)	1.73+/-0.72	1.72+/-0.58	1.65+/-0.63	1.43+/-0.47b	1.97+/-0.58	2.02+/-0.78	1.77+/-0.63	1.65+/-0.65b
Conduction threshold at 8.0dB	19.5+/-16.3	25.1+/-21.5b	31.0+/-23.3b	32.2+/-25.7b	27.1+/-19.0	28.8+/-19.2	37.5+/-22.5b	42.5+/-25.8
Blood hemoglobin (mmol/l)	8.1+/-1.2	7.2+/-0.8b	6.8+/-1.0b	7.8+/-1.1b	8.4+/-0.9	7.4+/-0.8b	6.8+/-0.7b	7.6+/-1.1b
White blood cell count((109 cells/l)	8.1+/-3.6	8.6+/-17.7	4.9+/-2.8b	5.9+/-1.8b	7.3+/-1.9	4.4+/-1.8b	6.2+/-5.6	5.7+/-2.1b
Platelets (109 cells/l)	322+/-114	386+/-167	294+/-115	231+/-66b	277+/-95	332+/-187	267+/-108	228+/-110b

• Data represent means +/- SD
• ^aNo significant differences were found between the study arms for all parameters
• ^bP<0.05 for comparison within each study arm between values of the first chemotherapy cycle and the subesquent time points(paired Student's t-test)

1. No significant differences were found between the placebo group and the supplementation group with regards to decrease in creatinine clearance and loss of hearing tone both during and following chemotherapy.

2. Blood hemoglobin, white blood cell count and platelets at the start of each cycle of chemotherapy and two months after completion of chemotherapy did not differ significantly between the two study groups.

3. Patients with higher reduced/oxidized vitamin C ratios at the start of chemotherapy had significantly less loss of high tone hearing and less decrease in creatinine clearance after chemotherapy than in patients with a lower ratio.

4. Patients with highest micronutrient antioxidant score at the start of chemotherapy had less loss of high tone hearing than patient with a lower score.

• Patients in the intervention group did not have less nephrotoxicity, ototoxicity or bone marrow toxicity than control patients.
• Patients with higher antioxidant micronutrient score (whether or not they received supplementation or placebo), higher reduced/oxidized vitamin C ratio and/or lower MDA levels at the start and during the first cycle of chemotherapy had less ototoxicity and less nephrotoxicity. However, these higher levels were not maintained during chemotherapy.
• Supplemention with antioxidants did not have an adverse effect on patient's clinical response as there were no supplementation related toxicities reported and clinicial remissions were equally divided in both groups.
• Failure of intervention to protect against chemotherapy-induced toxicity could be attributed to:
  • 46% of all patients and 64% of intervention patients failed to drink the study beverage throughout the entire study period.
  • Higher consumption of antioxidants (than what was supplemented) via chemotherapy-induced oxidative stress and renal loss of vitamin C.

 

Industry:

Numico Research BV Food Company:

• Timing of intervention prior to chemotherapy should be a consideration
• Higher daily dose of antioxidants may have been warranted
• Addition of other antioxidants which may contribute synergistically
• May have needed a longer period of supplementation prior to start of chemotherapy
• Poor compliance
• Various tumor types even though equally distributed over the two arms