Breast Cancer Incidence Rising In Asian Women At Younger Age: Sunitinib Shows Potential As Treatment For Metastatic Disease

The incidence of breast cancer in parts of Asia is rising steeply and catching up with rates in the western world, Dr Louis Chow, Medical Director of the Comprehensive Centre for Breast Diseases, UNIMED Institute, Hong Kong told oncologists attending the recent 1st Asian Breast Cancer Conference in New Delhi, India, held February 9th and10th. Breast cancer in the west has been linked to obesity , smoking, alcohol consumption, diets high in saturated fat, use of hormone replacement therapy , early onset of menarche and late menopause . The rise observed in Asia is in part attributed to the trend for young Asian women to adopt western lifestyles, he believes.

Unlike the West where women typically present after age 50 with early stage disease, breast cancer in Asian women occurs at a younger age and is usually presented and diagnosed at a later stage of development, he noted. And whilst in Europe and the US, breast cancer mortality is declining, in some areas, notably China, it is rising despite a lower incidence of more aggressive cancers expressing the HER2/neu gene. Clinical trials are less frequently conducted among Asian women and this needed to change, he said.

Clinical experience is variable but also differs from experience with Western women in other ways. For example, docetaxel is associated with little of the toxicity seen in the West, he added. In one recent case, a 63-year-old patient, with controlled high blood pressure , who had previously undergone mastectomy at the age of 38 presented with a recurrence of breast cancer in her remaining breast.

Her cancer was HER2/neu and oestrogen receptor-positive and was treated with the aromatase inhibitor exemestane. She was treated with the chemotherapy gemcitabine until the onset of the common side effect of hand-foot syndrome forced a switch to capecitabine. Initially this controlled symptoms but she went on to develop a pleural effusion and severe shortness of breath after growth of a secondary tumour in the lung obstructed the main right bronchus.

Shortness of breath was relieved and within a week she no longer required oxygen therapy. Unfortunately, a return of hand-foot syndrome necessitated an interruption of sunitinib therapy whereupon shortness of breath returned and within three days the tumour on the right bronchus was visible again on X ray. At this time, her blood pressure was well controlled and the haemorrhage was thought to have resulted from a burst aneurysm , said Dr Chow.

Had this not occurred, the good response her secondary tumour had shown to sunitinib suggested her disease had ceased deteriorating and her quality of life would have improved. About sunitinib Sunitinib is an oral tyrosine kinase inhibitor that targets tyrosine kinases, as well as all known vascular endothelial growth factors, platelet-derived growth factors and other targets associated with poor prognosis. The drug is already approved for metastatic renal cancer, where it has become a treatment of choice, and for gastrointestinal stromal tumours that do not respond to imatinib.

In advanced breast cancer it is in four phase III trials studying its effects when used as first-line therapy in combination with either paclitaxel or docetaxel and is being compared to the existing targeted therapy bevacizumab. Speaking at the same meeting, Professor John Crown of St Vincent’s University Hospital, Dublin, said sunitinib has shown proof of concept in preclinical models of advanced breast cancer and has demonstrated activity as a single agent in clinical studies. The powerful anti-angiogenic effect of a simple small tablet like sunitinib and its impact on breast cancer is generating excitement among oncologists, said Professor Crown.

For doctors of my age in oncology, this really is the most extraordinary and exciting time. Thankfully I have lived long enough to see the development of molecular therapies come to fruition and move into the main frame. The phase III trials will help us quantify sunitinib’s clinical benefit in breast cancer, he commented.