Safe use of intravesical bacillus Calmette-Guérin immunotherapy for bladder cancer during breastfeeding: a case report.

Bacillus Calmette-Guérin (BCG) is tuberculosis vaccine. It contains live but attenuated tubercle bacillus. It is also used for bladder cancer treatment, where it is directly instilled into the bladder. BCG activates the local immune response within the bladder to fight cancer cells. The issue of whether BCG instillations into the bladder cause the bacillus to be excreted in breast milk in a lactating woman remains unknown. The US FDA suggests discontinuing breastfeeding when undergoing treatment with BCG due to potential adverse reactions. The authors report on a breastfeeding woman with bladder cancer who elected to receive BCG immunotherapy. The baby received a precautionary dermal BCG vaccination 2 weeks before the patient's treatment. Ultimately, she was able to complete her treatment while breastfeeding her child without any negative effects on the infant or herself. To the best of the authors' knowledge, this is the first article showing that breastfeeding may be safe during BCG treatment for bladder cancer.