Told you, I’m going to post more regularly now. Also, it seems natural to have these little pre-article sentences now, so I may as well carry on.
Credit: Institute of Cancer Research
Cancer diagnosis is a life changing event. The knowledge that a random mutation has caused uncontrollable cell growth, leading to a potentially fatal condition is something that is difficult to fathom and, to some, inconceivable. It’s rare, if not impossible, that anything positive arises from cancer. One man’s condition, however, has resulted in the first precise tracing of a cancer’s evolution. Scientists from the Institute of Cancer Research, London, and collaborators were able to effectively “carbon date” the different stages of the cancer’s progression, from a bundle of cells to the tumours that ultimately caused his death.
The study, published in Annuals of Oncology, gives an indication as to what may cause cancers to rapidly spread, potentially aiding doctors in gauging a tumour’s response to therapy.
You can read more about what metastasis is here (credit: National Cancer Institute).
The patient in question was diagnosed with bowel cancer in 2008, which then metastasised to other areas of the body. Upon removal of the primary cancer, Nicola Valeri (Institute of Cancer Research) discovered a nodule in the patient’s lung. Though he suspected it may be cancerous, he decided to monitor the nodule before performing further surgery. Then, in 2011, a piece of the nodule was analysed after needle extraction and it was indeed a secondary tumour, which was then removed.
Unfortunately, the biopsy left some residue in its wake. As the needle was removed, it left behind a string of tumour cells, a rare side effect of the procedure. These cells subsequently developed into another secondary tumour, this time located in the patient’s chest wall.
The tumour was discovered in 2013, some two years after the extraction, located in the exact area of the needle’s trajectory thus it must have originated on the day of the biopsy. The rarity provided Valeri and co. with a time marker, a point of reference – the exact moment when a few cells began their two-year evolution into another tumour.
This was used to figure out how the cancer had progressed over his lifetime. Knowing the exact time when the chest wall tumour emerged allowed Valeri and his team to calculate how many mutations it had undergone during the two years from inception to discovery. They could then extrapolate the rate of change to follow its progression in time back to its origin.
Study co-leader Dr Andrea Sottoriva (Chris Rokos Fellow in Evolution & Cancer and Evolutionary Genomics & Modelling Team Leader, ICR) elaborated on the technique, saying “The mathematical techniques we borrowed for our study were originally developed to measure the time when new species of plants and animals arose during evolution. Our research was able not only to track the genetic evolution of the cancer, but also to put precise timings on each stage in a cancer’s progression.”
The primary colon cancer actually emerged 5 – 8 years prior to diagnosis. A year or so later, this metastasised to the lung and thyroid. The thyroid tumour was discovered in 2012 and the patient eventually passed away in 2015 from new kidney metastasis.
The chronology of the patient’s cancer development (Credit: Valeri et al., 2017)
According to Valeri, the huge surprise was simply how little time it took for the cancer to metastasise from the bowel to the lung and thyroid, as well as the fact that they all remained dormant for years instead of continued growth and spread. The results suggest that, in some cases, there may be a large lagging period in which cancer can be diagnosed and its metastasis impeded through treatment. Valeri added “It means there might be periods of years where we could intervene.”
The unfortunate yet unique turn of events that led to this research discovery is more proof that cancer is a condition of sheer complexity. There is an abundance of details that are yet to be discovered but it bodes well for the future, where scientists and doctors can theoretically diagnose early and prevent such rapid metastasis, saving lives in the process.