ABSTRACT
OBJETIVO: Avaliar o impacto clínico e os custos do tratamento adjuvante para câncer de mama com superexpressão do receptor 2 do Fator de Crescimento Epidérmico (HER-2). MÉTODOS: Foram obtidas medidas de eficácia (sobrevida livre de doença em 3 anos) dos ensaios de fase III com trastuzumabe para o câncer de mama HER-2 positivo: um estudo finlandês (FinHER), dois americanos (National Surgical Adjuvant Breast and Bowel Project - NSAPB-31 e North Central Cancer Treatment Group N9831) e dois multinacionais (Herceptin Adjuvant, HERA e Breast Cancer International Research Group, BCIRG-006), e calculadas medidas de impacto clínico: redução de risco e número necessário para tratar (NNT). Foram estimados os custos com medicamentos antineoplásicos nestes diferentes regimes terapêuticos. RESULTADOS: A redução absoluta de risco com uso do trastuzumabe foi maior no estudo FinHER (11,7 por cento; IC 95 por cento: 2,2 por cento a 21,2 por cento). O NNT no FinHER foi 8 (IC 95 por cento: 3 a 28), 8 (IC 95 por cento: 7 a 11) no NSABP-31/N9831, 12 (IC 95 por cento: 9 a 18) no HERA, 14 (IC 95 por cento: 11 a 24) no BCIRG/com antraciclinas e 17 (IC 95 por cento: 12 a 34) no BCIRG/sem antraciclinas. O custo para evitar um caso de recidiva seria R$ 418.285,44 com o regime FinHER, R$ 1.716.789,44 no NSABP-31/N9831, R$ 2.481.891,58 no HERA, R$ 2.963.634,62 no BCIRG/com antraciclinas e R$ 3.930.520,43 no BCIRG/sem antraciclinas. CONCLUSÃO: Restringir o uso do trastuzumabe à fase inicial de quimioterapia adjuvante (FinHER) permite beneficiar, do ponto de vista econômico, quatro a nove vezes mais pacientes que a monoterapia adjuvante prolongada como usada nos demais protocolos.
PURPOSE: To examine efficacy figures and drug expenditure for adjuvant chemotherapy in human epidermal growth factor receptor 2 (HER-2) positive breast cancer, in the Brazilian supplemental health insurance market. METHODS: We obtained efficacy data (disease free survival at 3-years) and drug cost estimate for current adjuvant strategies in HER-2 positive breast cancer: Finland Herceptin (FinHER), National Surgical Adjuvant Breast and Bowel Project (NSAPB-31), North Central Cancer Treatment Group (N9831), Herceptin Adjuvant (HERA) and Breast Cancer International Research Group (BCIRG-006). We estimated clinical impact measures - number needed to treat (NNT) and absolute risk reduction (ARR) - and total drug cost by protocol to avoid one single cancer recurrence. RESULTS: The largest ARR was 11.7 percent (95 percent CI: 2.2 percent to 21.2 percent) in the FinHER study, and the smallest in the nonanthracycline arm of the BCIRG trial, 4.9 percent (95 percent CI: 1.8 percent to 8.1 percent). The NNT was 8 (95 percent CI: 3 to 28) in the FinHER, 8 (95 percent CI: 7 to 11) in the NSABP-31/N9831, 12 (95 percent CI: 9 to 18) in the HERA, 14 (95 percent CI: 11 to 24) in the BCIRG/Anthracycline, and 17 (CI 95 percent CI: 12 to 34) in the BCIRG/Nonanthracycline. Drug cost to avoid one single cancer recurrence would be R$ 418,285.44 with the FinHER regimen, R$ 1,716,789.44 with the NSABP-31/N9831, R$ 2,481,891.58 with the HERA, R$ 2,963,634.62 with the BCIRG/Anthracicline, and R$ 3,930,520.43 with the BCIRG/Nonanthracycline (exchange rate: R$ 1.00 = USD 0.56). CONCLUSION: From an economic viewpoint, four to seven times more patients could benefit by using a short-course of trastuzumab at the initial adjuvant chemotherapy cycles (FinHER regimen) than by the prolonged trastuzumab administration as used in other adjuvant schedules.