Health
Treating metastatic cancer Metastatic cancer may be treated with systemic therapy, for example, chemotherapy, biological therapy, targeted therapy, hormonal therapy; local therapy such as surgery, radiation therapy; or a combination of these treatments. The choice generally depends on the type of primary cancer; the size, location, and number of tumours; the patient’s age and general health; and the types of treatment the patient has had in the past.
Conventionally, metastasis is treated based on the original site of the cancer. For example, if a person has breast cancer and cancer spreads to the liver, it is still treated with the same drugs used for breast cancer because the cancer cells themselves have not changed, they are just living in a new place. Of course, treatment with radiation or
chemotherapy has drawbacks. Radiation can kill healthy cells along with cancer cells. As for chemotherapy, it works by targeting fast-growing cells, like those typically found in rapidly growing tumours. But while chemotherapy can shrink tumours, they often grow back and become resistant, or refractory to the treatment. To combat this resistance, chemotherapy is now often used in combination with other treatments that have different mechanisms for attacking and killing cancer cells. Doctors must be cautious when combining treatments to ensure that the regimen does not become too toxic for patients to tolerate. The goal is to introduce drugs that can be used synergistically with chemotherapy to not only extend life, but to improve quality of life while undergoing treatment.
Most people who die of cancer die of metastatic disease
C
A different approach Oncolytics Biotech in Calgary, Canada, in partnership with the NCIC Clinical Trials Group and the US National Cancer Institute, is developing a different treatment that not only addresses cancers within particular organs but also might help beat the ‘mets’, as metastatic cancers are also known. Our approach involves using certain viruses to infect, multiply within and subsequently destroy cancer cells. Drugs based on such viruses can target the tumour and protect normal tissue,
38 Chemistry&Industry • November 2013
an approach known as virotherapy or oncolytic virus therapy. This involves the conversion of viruses into cancer-fighting agents by reprogramming them to attack cancerous cells, while healthy cells remain relatively undamaged. Several types of these viruses, known as oncolytic viruses, have been developed to date. These include the reovirus, the adenovirus, the Newcastle-disease virus,
and the poxvirus; further types include picornaviruses and vesicular stomatitis virus. It may come as a surprise to some that the cold sore or Herpes simplex virus is also under consideration as an oncolytic virus.
Oncolytics’ investigational drug
treatment, Reolysin, is a proprietary formulation of a virus known as the human reovirus. Reovirus is found
Find C&I online at
www.soci.org/chemistryandindustry
Reovirus replicates in Ras-activated cancer cells, causing virus-mediated cell death
Tumour antigens generated by viral oncolysis may educate the immune system to recognise and kill tumour cells
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64