The Periodic Table turns 150!

It was 1869 when Russian chemist Dmitry Mendeleev first organised the chemical elements into the grid-like structure which is so well recognised today. At the time, only 63 elements were known, but many of the additional elements discovered in the intervening years have largely fit into the organisational structure that Mendeleev created. In celebration of this significant achievement, UNESCO has designated 2019 the International Year of the Periodic Table of Elements.

As of today, there are 118 known elements in the periodic table. The modern periodic table is still widely used across a number of branches of science including chemistry and nuclear physics. In this blog, we’ll take a look at how the developing periodic table has contributed to our understanding and treatment of cancer.

Perhaps one of the most famous links between cancer treatment and the periodic table is the discovery of radium by Marie and Pierre Curie at the end of the 19th century. This discovery formed the basis for the development of radiation therapy. Of course, this technique has moved on greatly in terms of both efficiency and safety since the late 1800s, and radiotherapy is now a commonly used treatment for cancer. In modern medicine, a mildly radioactive form of the metal (Radium-223) is used as internal radiotherapy treatment for cancers of the bone that have spread from the prostate.

But radium isn’t the only element that has been useful for radiotherapy. For example, iodine-131 given as capsules or in a drink can be effective as an internal radiotherapy for thyroid cancer. Gamma rays from the Cobalt-60 isotope were also widely used in external radiotherapy before more modern technologies were developed. Radiotherapy methods continue to advance and in 2018 the first proton beam centre in the UK was opened in Newport, Wales. Proton beam therapy is a type of highly targeted radiotherapy that can more accurately treat hard to reach tumours whilst minimizing damage to surrounding tissues. Recent studies also suggest that using helium ions may improve this type of therapy, so the periodic table of elements can be found once again at the cutting edge of cancer research and treatment.

There are also important applications of the periodic table of elements in chemotherapy. Arsenic trioxide, for example, can be given as a treatment for leukaemia. Although this element has long been associated with toxicity and poison, the medicinal properties of arsenic mean that is has been used therapeutically for over 2000 years. The specific anti-leukemic properties of arsenic were first described in the late 1800’s, and the arsenic trioxide agent Trisenox is now used for the treatment of an aggressive type of leukaemia known as acute promyelocytic leukaemia (APL).

Another well-known example comes in the form of ‘platins’, which is an informal name for a group of chemotherapy drugs based on the element platinum. Perhaps the most famous of these is Cisplatin, which was approved as a cancer treatment in the 1970s, and is still used to treat a number of cancers, including testicular and ovarian cancer. Cisplatin works by entering cancerous cells and forming cross-links in the DNA to make the code unreadable – and so the cell dies because it can no longer read its DNA code. Platinum-based chemotherapies continue to show great promise, with a number of new compounds currently under development. These new generation drugs are expected to have less toxicity and fewer side effects than those which have come before them.

So from ancient medicine to the modern day, the periodic table of elements has played a pivotal role in the development of cancer treatments. With the most recently discovered elements only officially taking their place on the table in 2016, it is likely that Mendeleev’s periodic law will continue to inform the development of new and better cancer treatments for many years to come.

 

Blog written by: Dr Beth Routley