For the age group 50–54 y, adjuvant trastuzumab resulted in 0.74 (for the ER+/PR+ [best prognosis] subtype) to 1.72 (for the ER−/PR− [worst prognosis] subtype) QALYsDW gained per patient treated (Table 3); patients with ER−/PR− cancer benefited from 2.33 (95% CI 2.29–2.37) times greater QALY gains than ER+/PR+ patients. This evidence concerns the gene ESR1 and cancer.