Short and long-term effects on survival in breast cancer patients treated by primary chemotherapy: an updated analysis of a randomized trial.
A potential advantage of primary over adjuvant chemotherapy in breast cancer survival had been proposed on theoretical grounds. In 1994, early results of the S6-trial comparing primary chemotherapy vs. adjuvant chemotherapy for operable breast cancer in 390 premenopausal patients had shown significant improvement in survival of the primary chemotherapy arm (p = 0.04). An updated analysis conducted in 1995 showed the disappearance of this difference between the two arms (p = 0.18). In the present analysis, we investigated the potential short and long-term benefits attributable to primary chemotherapy by applying weighted logrank tests designed to assess specifically these effects. Results were compared to those obtained with the classical logrank test. At a median follow-up of 105 months, a significant short-term survival benefit (p = 0.02) in favor of the primary chemotherapy has been shown. However, no long-term survival benefit (p = 0.36) could be documented. The classical logrank test had revealed no significant difference (p = 0.24) between the two groups but the proportional hazard assumption being rejected (p = 0.04), the efficiency of this test can be questioned. Results using the present analysis suggested that primary chemotherapy delayed early death rates, without significantly modifying long-term event rates. It emphasizes that a short-term effect which is not necessarily associated with a long-term benefit may be seen at an early evaluation and disappear later on.
Broët
P
P
Department of Biostatistics, Curie Institute, Paris, France.
Scholl
S M
SM
de la Rochefordière
A
A
Fourquet
A
A
Moreau
T
T
De Rycke
Y
Y
Asselain
B
B
Pouillart
P
P
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D005260:Female; D005500:Follow-Up Studies; D005602:France / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D016019:Survival Analysis; D013997:Time Factors
D000970:Antineoplastic Agents