[Comparison of two formulae for the calculation of glomerular filtration in the dosage of zoledronic acid]. / Comparación de dos fórmulas de cálculo de filtrado glomerular en la dosificación del ácido zoledrónico.

OBJECTIVE: To validate the use of a formula that does not require the patient's weight (Levey formula) for calculating creatinine clearance in the adjustment of the dosage of zoledronic acid. METHOD: Prospective observational study in which zoledronic acid prescriptions in the Oncology and Haematology departments were recorded over the course of 8 months. The adjustment of the dose of zoledronic acid was carried out in accordance with creatinine clearance obtained using two different equations; the Cockcroft-Gault equation which is based on medical records, and the Levey formula which does not require the patient's weight for the calculation. The results of zoledronic acid dosage from both equations were compared using the SPSS statistics programme, via the comparison of the two measurements using the t Student-Fisher (T-test.) RESULTS: The T-Test provided a t-test value of t = 3,366, with 112 degrees of freedom and a degree of bilateral importance of p = 0.001. The difference between both measurements was d = 0.051 +/- 0.162) and the confidence interval was 95 %, 0.082 to 0.021. From the data obtained in the T-Test, the degree of bilateral importance (p = 0.001 < 0.05) indicated that the results of the test were statistically significant. CONCLUSIONS: The difference between the dosages obtained when comparing both methods of glomerular filtration is statistically significant, although not clinically relevant, therefore the MDRD-4 formula (Levey) could be used if the patient's weight is not available.

[Retrospective analysis of the carboplatin dosage and relationship with toxicity in cancer patients]. / Análisis retrospectivo de la dosificación de carboplatino y relación con su toxicidad en pacientes oncológicos.

OBJECTIVE: To analyse carboplatin dosage in cancer patients in order to establish whether they are over- or underdosed in comparison to the theoretical dose calculations during the first cycle of chemotherapy and to find a relationship between the dosage in the first cycle and dose reduction in subsequent cycles, as a result of adverse effects related to the same. METHOD: Retrospective analysis over a one year period of prescriptions of chemotherapy with carboplatin. Patients were stratified into 4 groups according to body mass index and serum creatinine values. The mean percent error (MPE) was used to determine the relationship between the dose received and the theoretical dose calculation during the first cycle. The Mann-Whitney U test was used to study the possible relationship between patients dosage during the first cycle and dose reduction in subsequent cycles. RESULTS: A total of 86 patients were selected. Only the cohort of patients who were overweight/obese showed significant differences between the theoretical dose calculation and the dose actually received. The mean MPE value with the standard error for this group was 7.963 +- 2.610%. No links were found with the dose reduction in subsequent cycles for this cohort of patients. CONCLUSIONS: Not using adjusted weight or serum creatinine values in the Cockcroft-Gault equation may lead to incorrect doses of carboplatin in obese patients. Studies including a larger number of patients are required to confirm the relationship between overdosing during the first cycle and dose reduction in subsequent cycles, as a result of carboplatin toxicity.

[A review of chemotherapy for metastatic colon cancer]. / Revisión del tratamiento quimioterápico del cáncer de colon metastásico.

OBJECTIVE: To report and discuss the results of clinical trials published concerning chemotherapy for metastatic colorectal cancer in order to elucidate and define treatment guidelines. METHOD: The biomedical and pharmaceutical database EMBASE was searched for phase-II and -III clinical trials or metaanalysis that examined chemotherapy for mCRC (January 1998-January 2006). RESULTS: 5-fluorouracil still maintains its preponderant role after 40 years, and its modulation by adding folinic acid or administering it in more prolonged infusions has managed to slightly increase survival in these patients, as well as to improve the drug s toxicity profile. The development of irinotecan first, and then oxaliplatin has lengthened survival by a few months when in combination with 5-fluorouracil and folinic acid-based regimens. All patients should have access to these two drugs guaranteed during the course of the disease, as it will increase survival. Raltitrexed fails to improve survival, and also diminishes quality of life in these patients; hence its use has been relegated to clinical trials. Bevacizumab, combined with classic chemotherapy regimens, attains slightly longer survivals. Results from studies with cetuximab are not that conclusive, and its use should be restricted to patients with relapsing disease after irinotecan and no other treatment options left. CONCLUSIONS: New drugs for metastatic colorectal cancer open up new therapy lines allowing increasingly improved survival. However, optimal schemes, as well as their order of administration, have yet to be fully devised.