Concomitant administration of chemotherapy and tamoxifen is as effective as sequential administration in women with endocrine-responsive breast cancer and comment that it might be even more effective than sequential therapy in patients aged less than or equal to 40 years.

In women in early or later middle age, outcome in ER-poor breast cancer was significantly improved by treatment with polychemotherapy and was not affected by inclusion of tamoxifen in the regimen.

A study of ovarian cancer patients undergoing chemotherapy determined that individuals with a mutant, nonfunctional version of the tumor-suppressing gene p53 had a survival rate more than twice as high as counterparts with a properly functioning gene. This, despite the fact that the gene in question is, under normal circumstances, essential for preventing cancer in the first place.