Trastuzumab for breast cancer - weighing the benefits versus heart risks

The most commonly diagnosed cancer amongst women is breast cancer. There are various types of breast cancers, for instance, HER2-positive cancer in which the tumor's cells produce excess quantities of HER2, a particular protein called the human epidermal growth factor, whilst those with normal production are called HER2-negative. According to a systematic review in The Cochrane Library, women with HER2-positive breast cancer have a substantially higher chance of prolonging life and reducing the risk of cancer recurrence after completion of therapy if they add trastuzumab (Herceptin) to their standard treatment. Trastuzumab is a new-generation antibody based medicine that inhibits the receptor and stops it from initiating excessive cell growth, which causes tumors. About one-fifth of women with early breast cancer have HER2-positive tumors, which are linked to a worse outlook than HER2-negative tumors if left untreated. However, trastuzumab is also linked to an increased risk of experiencing cardiac problems. A team of Italian researchers decided to examine accurate evidence of trastuzumab's harms and benefits by reviewing clinical trial data and found eight trials with 11,991 HER2-positive women who had operable breast cancer and who were either assigned to randomly receive trastuzumab in addition to other treatments, or not. The average follow-up time was three years. Overall, the findings revealed that the combination of drugs decreased breast cancer mortality by one-third, however, the risk of heart toxicity increased by five times in women who received trastuzumab compared with those who received standard therapy alone. This translates into a survival rate of 900 from 1,000 women on standard therapy alone after three years, compared with 933 survivors from 1,000 women in the same time period, who received standard chemotherapy and trastuzumab for one year. Leading researcher Lorenzo Moja, who works in the Department of Public Health at the University of Milan comments: "This means that for every 1000 women treated with trastuzumab, 33 more women will have their lives prolonged." And also that around 95 additional women will remain disease-free once they completed their therapy. The findings did show, however, that trastuzumab has serious adverse effects, with around 26 in 1,000 women experiencing serious heart toxicity, which is 21 more women when compared with the chemotherapy alone group. Moya says: "These heart toxicities are often reversible if the treatment is stopped straight away." The researchers conclude from their findings that trastuzumab's benefits outweigh its risks in women with a higher risk of recurrence and no signs of a weak heart. However, the benefit to risk balance is less clear in those with a lower recurrence risk and women with a higher risk of cardiac complications, and must therefore be carefully evaluated. According to Roberto D'Amico, senior scientist at the Clinical Trial Unit of the Department of Oncology of the University of Modena in Italy: