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New drug to aid SA fight against asbestos-linked cancer
May 31, 2006 - In response to an urgent need to improve local treatment for anexcruciating form of asbestos-related cancer, international corpo-ration Lilly has recently released a drug that promises to ease its symptoms when other treatments fall short.
Alimta (Pemetrexed), when used with cisplatin – another widely used chemotherapy drug – is the first and only drug to be approved by the Food and Drug Association for the treatment of patients with mesothelioma when surgery is not an option. Treatments such as this one are highly relevant in South Africa, where asbestos-related illnesses are painfully prevalent.
“Control has come from thebottom up, with protests by unions and workers on the painful effects of mesothelioma. This has brought attention to the disease in South Africa,” said Prof Raymond Abratt, head of the oncology department at Grootte Schuur Hospital in Cape Town, speaking at a media con-ference on treatment options formesothelioma. Resistant to fire and heat and imbued with strength and flexibility, asbestos is a remarkable material that found many uses duringthe industrial era.
With deposits located primarilyin the Northern Cape, the North West province, Limpopo province and Mpumalanga, asbestos miningin South Africa began in earnest in the 1930s and during the following decades attracted a multitude of companies. This has left alegacy of individuals sufferingasbestos-related illnesses, one of which is mesothelioma. Working with asbestos constitutes a major risk factor for mesothelioma,with a history of work with asbestosreported in up to 80% of all cases. The risk of asbestos-related diseaseincreases with heavier exposure to asbestos and longer exposure time. Mesothelioma is cancer of the mesothelium, a membrane that coversand protects most of the internalorgans of the body. This lethal form of cancer causes the cells of the mesothelium to become abnormal and divide without control or order. These cells can invade and damagenearby tissues and organs. The cancercells can also spread from their original site to other parts of the body. Malignant mesothelioma moves through four stages, each one more severe than the next, culminating in cancer spreading into the chest wall, centre of the chest, diaphragm or stomach. As a result of the sheer volume of asbestos mined in South Africa, the incidence of mesothelioma in the country is among the highest in the world, and six times higher than the UK. The male:female ratio is 2,5: 1 and incidence increases with age from the fifth decade onwards, peaking after the age of 70. “The most curious thing about this illness is the length of time that can elapse between exposure and manifestation,” says Prof. Hilary Calvert, professor of medicaloncology for the Northern Institute for Cancer Research.
Mesothelioma can develop 20 or more years after the first exposure, while the peak incidence is between 35 and 45 years after exposure. The production of crocidolite, also known as blue asbestos, peaked in 1977.
Therefore, all those exposed during the 1970s and 1980s will be approaching the peak in their occurrence of malignant mesothelioma. It is expected that the incidence of mesothelioma will continue at least for the lifetime of those largenumbers of people exposed to crocido-lite in mining and in industry. Therefore, not only the miners, but their families and those exposed to asbestos through other means have a chance of developing the disease. “In our country, we had a patient who developed mesothelioma at 32. The reason for this was that, when she was young, one asbestos factory allowed peopleto obtain free materials for theirgardens from their grounds. Herparents had used this material, and the woman had been exposed by playing in the garden as a young girl,” states Prof Johan Vansteenkiste of the respiratory oncology unit of the University Hospital Gasthuisberg, in Belgium. There is debate over how much exposure is needed to develop mesothelioma. There have been cases reported where exposure has been as short as a few months. Mesothelioma has also been reported in some individuals without any known exposure to asbestos.
Treatment of the disease depends on the location of the cancer, the stage of the disease, and the patient’s age and general health. However, the nature of the disease is such that by the time it has been diagnosed, it is often in its advanced stages and beyond complete surgical excision and possible cure. These options include surgery, radiation therapy and chemotherapy either administered singularly or combined. Alimta is used alongside chemotherapy treatments that use drugs to destroy cancer cells throughout the body.
It works by interfering with a crucial process that allows cancercells to reproduce and spread. Speci-fically, Alimta works by stopping theproduction of three enzymes thatare required to feed the cancer cell. To date, Lilly’s drug has found success in a number of patients who underwent the treatment. Dr Daniel Osei-fofie, a medical doctor practising in Kimberly, told the meeting that he started trial treatments with Alimta in February 2005.
The new drug was used on a 54-year old man, who worked on a Northern Cape asbestos-mine for six years. He reported that the patient had returned to work in February this year after five treatments. “Previously, we could not offer much to these patients,” he said.
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