Mistletoe preparations such as Iscador® (Weleda,
Schwäbisch Gmünd, Germany) are commonly used in complementary
and alternative / anthroposophic medicine for many
cancer indications, particularly for solid cancers. Efficacy of this
complementary therapy is still controversial. Objective: Does
long-term therapy with Iscador show any effect on survival,
tumor progression and psychosomatic self-regulation of patients
with breast cancer? Patients and Methods: Prospective
recruitment and long-term follow-up of two controlled cohort
studies: (1) Randomized matched-pair study (38 pairs): breast
cancer patients without any recurrences or metastases and no
mistletoe therapy were matched for prognostic factors. By pairwise
random allocation, one of the patients was suggested
mistletoe therapy to be applied by the attending physician. (2)
Non-randomized matched-pair study (84 pairs): breast cancer
patients without recurrences or metastases that already received
mistletoe therapy were matched to control patients
without Iscador therapy. Results: For overall survival, the nonrandomized
study shows significant effects in favor of Iscador
therapy: hazard ratio HR estimate and 95% confidence interval
CI: 0.43 (0.27-0.68). The effect of long-term Iscador therapy on
tumor progression as measured by the time to local recurrences,
lymphatic or distant metastases in breast cancer patients
without any such events at first diagnosis, is in most
cases significant in favor of the Iscador group, in the randomized
as well as in the non-randomized study. Psychosomatic
self-regulation in the Iscador group improves significantly within
12 months compared with the control group in the randomized
as well as in the non-randomized study: estimate of the
median difference and 95% CI: 0.35 (0.05-0.60), respectively
0.20 (0-0.35). Conclusion: Iscador shows a clinically relevant
effect on breast tumor progression as measured by overall survival
as well as by the time to recurrences, lymphatic or distant
metastases. In the short term, psychosomatic self-regulation increases
more markedly under complementary Iscador therapy
than under conventional therapy alone