Restarting hormone therapy leads to increased progression-free survival

This study examined the effect that restarting hormone treatment, as compared to stopping it, had on progression-free survival. It found that restarting treatment led to increased progression-free survival. 

Breast cancer is classified into different subtypes depending on the prescence or absence of certain receptors (proteins found on the surface of the cancer cells). These subtypes influence treatment options, and also directly affect disease prognosis. Hormone receptor positive cancer grows in response to female hormones such as estrogen.

Breast cancer patients with hormone receptor postive cancers commonly receive hormone treatment after inital surgery or radiotherapy. This treatment can include tamoxifen (Nolvadex) or aromatase inhibitors (for example, letrozole [Femara]). Some patients stop treatment and it is unclear what effect this has on their progression-free survival. 

This study examined the effect that stopping treatment had on progression-free survival. This study included 3071 patients. 1,607 patients had continued hormone therapy. 953 patients had stopped but restarted. 511 stopped treatment and did not restart. All patients filled out a questionnaire.

Some factors that led to patients stopping treatment were a higher amount of side effects and a good prognosis (small tumor, no lymph node involvement). Disease-free survival (time from treatment until disease return) at eight years was 89.8% for restarters and 82% for nonrestarters. 

This study concluded that restarting hormone treatment leads to increased progression-free survival.

This is an observational study so other factors the authors were not aware of could have impacted on the results.