Is the Improvement of Prognosis of Patients With Metastatic Pulmonary Adenocarcinoma Treated With TCM Herbal Medicine due to Lag Time to Treatment Bias?

Abstract

BACKGROUND. Traditional Chinese herbal medicine was associated with improved prognosis in patients with performance score 0-1 at the time of diagnosis of stage IV pulmonary adenocarcinoma (PAC) treated with platinum-based chemotherapy (PBT). OBJECTIVE. The authors investigated the effect of 1- to 4-month lag time to traditional Chinese medicine (TCM) treatment on the median and 1-year survival of PBT-PAC patients. The median lag time to treatment was 3 months. In the first 3 months, about 35% of the patients died, but thereafter the survival curve flattened off and the death of the next 35% to 40% of patients took 9 months. Leaving out patients with lag time up to 3 months therefore would be a reasonable choice. To be on the safe side, the effects of leaving out patients up to 4 months were investigated. The Kaplan-Meier survival curves were used. The median and 1-year survival of the PBT-PAC patients was 5.0 months and 27%, respectively. Leaving out patients with 0-1 month follow-up, 0-2, 0-3, and 0-4 months follow-up changed the median and 1-year survival, respectively, to 5.5 months and 32%, 6.5 months and 36%, 9.0 months and 43%, and 10.0 months and 52%. The median survival of PBT + TCM in PAC patients was 22.6 months and 78%. Median lag time to TCM treatment was 3.0 months. With up to 4 months lag time to treatment due to combined patients' and TCM doctor's waiting time, the improved survival of PBT + TCM performance score 0-1 (fully ambulant) patients at the time of diagnosis still is significant (P < .01, hazard ratio = 0.51). Moreover, the survival of patients treated by TCM doctors with little or more months lag time to treatment was not different (P = .79). Increasing lag time to treatment up to 4 months improves the median and 1-year survival of PBT patients without TCM but is unlikely to explain the greatly improved prognosis of PBT + TCM treated patients with fully ambulant stage IV PAC.