How effective is routine treatment with trastuzumab in early breast cancer?

This study investigated the role of trastuzumab (Herceptin) as part of standard care in patients with human epidermal growth factor receptor-2 positive (HER2+) early breast cancer (BC). The study conclude that trastuzumab was effective in general practice, including patients not often included in clinical trials (such as the elderly).

Trastuzumab is a treatment that targets the human epidermal growth factor receptor 2 (HER2), which can lead to cancer growth. Trastuzumab is part of the standard care for HER2+ breast cancer patients. The studies which led to the prominent role of trastuzumab often excluded elderly patients or those with existing conditions that may complicate treatment. Therefore, it was not known if the same results would be seen in more diverse patients.

This study examined the use of trastuzumab in patient groups that are underrepresented in clinical trials in order to assess whether this standard treatment is effective across a wide variety of patients.

This study included 3,940 HER+ early BC patients treated with trastuzumab as part of routine practice.  These patients were monitored for an average of 39 months. 26% were older than 65 years of age. More than half of patients had a tumor stage of pN0, meaning no regional lymph node metastasis (spread) was found. 94% received chemotherapy, with 14% as primary treatment, 78% as secondary therapy after initial treatment, and 2% as both.

90% of patients were recurrence free after 3 years. 82.8% were recurrence free after 5 years. Hormone receptor status, primary tumor size and lymph node involvement were found to have the greatest influence over the risk of recurrence. Age did not significantly affect results.

Overall survival (time from treatment until death from any cause) was 96.8% after 3 years and 90% after 5 years. Serious adverse drug reactions were reported in 1% of patients, with 18% experiencing cardiac toxicity at least once during the observation time.

The study concluded that trastuzumab was effective in treating localized disease in a wide range of patient groups.

As the study was non-interventional; no control group was present in the analysis. Further, patients who had HER+ tumors but were not treated with traztuzumab were not included in the analysis. 

Discuss with your doctor whether traztuzumab treatment is an option for you.