BREAST CANCER PART-11
Welcome to part 11 of educational series on breast cancer. In tenth part, we learned about management of locally advanced breast cancer with preoperative chemotherapy, surgery, postoperative chemotherapy and radiotherapy. Also, we learned about definition of LABC.
Question: Now Dr. Shah, it seems that even in LABC good results are possible, with addition of preoperative chemotherapy. However, Her-2 test has been mentioned few times in this series, and also you mentioned Herceptin in tenth part. Can you tell us somewhat more about that?
Answer: As we discussed last time, breast cancer can be treated with chemotherapy, hormonal therapy, and these newer so called TARGETED therapies. These are so called as they have a more focused action on specific part of cancer cells, unlike chemotherapy which acts on several aspects of cell functioning, and hence has more side effects.
Her-2 receptor on breast cancer cell surface provides these cells ability to grow much faster, and survive in body longer. This knowledge led to development of a drug directly attacking this receptor i.e. Herceptin(Trastuzumab). It is the first such drug in breast cancer. About 25% patients have cancers that test positive for Her-2. Only these patients benefit from use of this drug.
Que: That sounds exciting. Do you mean to say that this drug has no side effects? Do we need chemotherapy then?
Ans:. I definitely share your excitement. This drug has improved results remarkably for patients with Her-2 positive disease, who otherwise had a poor prognosis. In fact, results are so good that it can be used alone without chemotherapy to treat patients with very advanced cancers.
However, in stage 1-3, it has to be combined with chemotherapy to achieve the best results. In stage 3 for example, when added to preoperative chemotherapy, many cancers are not found at time of surgery i.e. a very high rate of pathologic CR is seen, and this translates into good chance of cure. In other stages, it is given after surgery, initially with chemotherapy, and then for a long period after chemotherapy is over. In these studies, it reduces risk of relapse by 50%, which is very good by any standards, and very few drugs in oncology give such results.
With regard to side effects, it is extremely well tolerated, and can be easily given to even patients with significant weakness. Few specific precautions are required.
Que: Why don’t we have more such TARGETED therapies?
Ans: Actually we do, but it is a recent development, with difficult technology and the drugs are still expensive. Another target is VEGF which provides tumors with extra blood supply which they need to grow big. Avastin (Bevacizumab) is a drug which blocks action of VEGF and shrinks tumors. It is used in several cancers now, including breast, lung, colorectal, liver, kidney and others. Also, just like Her-2, there is a Her-1 receptor. Lapatinib is a drug that blocks both these receptors, and is in tablet form.
Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA),
Diplomate American Board of Oncology and Hematology.
Shyam Hem-Onc Clinic. 402 Galaxy, Near Shivranjani, Opp Jhansi ki Rani BRTS, Ahmedabad. 079 26754001 www.shyamhemoncclinic.com