What threshold for adjuvant therapy in older breast cancer patients?

Purpose: To consider the question of when to prescribe adjuvant treatment f or elderly breast cancer patients, particularly when comorbidities are pres ent. Knowledge of the threshold relapse risks above which adjuvant treatmen t is worth prescribing would enhance decision making. Patients and Methods: A Markov analysis of delta from the medical literatur e was conducted. Patients aged 65 to 85 years were considered, along with t hree levels of comorbidity. The threshold risk of relapse at 10 years (RR10 ), at which time treatment provides absolute reduction or reduction of an a bsolute 1% in relapse or mortality, was evaluated. Results: The threshold RR10 for an absolute reduction in mortality risk by adjuvant treatment was low through the age of 85 years. However, for an abs olute 1% reduction, the effect of treatment on relapse and the effect of tr eatment on mortality increasingly diverged. The threshold RR10 for an absol ute 1% reduction in relapse risk remained fairly low (5% to 6% for tamoxife n, 12% to 19% for chemotherapy). The threshold RR10 for an absolute 1% redu ction in mortality risk, although starting close to the RR10 for an absolut e 1% reduction in relapse risk, rose sharply. For tamoxifen, the difference between the two was 4% for an average 65-year-old, 6% at the age of 75 yea rs, and 15% at the age of 85 years, Far chemotherapy, the differences were 6%, 12%, and 30%, respectively. Similarly, thresholds increased with increa sing comorbidity, In older and sicker patients, the maximum benefit Was rea ched after 5 years rather than 10 years. Conclusion: Older breast cancer patients can expect a reduction in relapse that is fairly similar to that of younger patients. However, the effect on mortality diverges markedly, and attention should be paid to this differenc e in clinical decision making. Comorbidity should be considered in recommen dations for adjuvant treatment, including clinical practice guidelines. J Clin Oncol 18:1709-1717. (C) 2000 by American Society of Clinical Oncolog y.