Metastasis is the spread of tumorous cells to distant tissues and organs throughout the body. This process occurs in a number of ways – by growing directly through the natural boundaries of an organ and into a neighbouring organ or by spreading via natural cavities, via the lymphatic system or circulatory system.
Opinions have changed over the years regarding this complicated process. In the beginning, cancer was believed to be a local process. As it advances, cells travel to the closest regional lymph nodes and only in the late stages do they tear down this barrier and spread to more distant organs. This understanding justified the extensive resection (surgical removal) of the tumour and regional lymph nodes all at once (during one operation), which was often referred to by the French term – en bloc. Unfortunately, further observation revealed that despite substantial operations, patients were not necessarily protected from the advance of distal metastases. This led to the next hypothesis that tumours were already systemically spread from the beginning or at least with a large potential for spreading beyond their initial locations. This became the foundation of adjuvant or preventative drug therapy. Its goal was to destroy micrometastatic or circulating cancer cells, which definitely continued to circulate in the bodies of patients after operations or radiation. Years passed and this viewpoint also didn’t always justify itself in practice. It turned out that even tumours in one location could be different. For example, those that grow slowly over a long period of time or which don’t even metastasise in distant organs and those which, even at the moment that symptoms first manifest themselves, have already disseminated (spread), such as sarcomas. These aggressive tumours have a tendency to spread far and wide even during adjuvant or preventative therapy or shortly thereafter, ignoring all of the canons of medical science and the achievements of the pharmaceutical industry.
For 30 years – from 1970 to 2000 – the development of tumours was believed to be linked to cell autonomy, the inner workings of the cell itself. Currently the evidence points to a very complex interaction between a cancer cell, its microenvironment and the environment of the body. It’s possible that in the future this will also change the dominant opinion regarding metastasis and how to prevent it.
This is why we can accept the premise that we are dealing with different tumour behaviour patterns. The challenge for the future is to discover the most accurate and reliable indicators that would, from the very beginning, distinguish patients with slow-growing illnesses from patients from whom we can expect dissemination of the tumour in the near future. Identifying these signs will allow us in the future to make more targeted and rational decisions regarding a treatment strategy for each individual case. Today, the widely publicised method of personalised medicine, analysing specific mutations in certain genes, is still just one of these attempts, but it has met with limited success.
For the time being, the main indicators that must be considered when choosing a treatment strategy are tumour cells discovered in the blood vessels (vascular invasion or V+), lymphatic vessels (lymphovascular invasion or L+), along the nerve fibres (perineural invasion or PI+), metastasis in the regional lymph nodes (N+), the tumour’s differentiation grade (poorly differentiated or undifferentiated tumours, meaning how much they resemble the normal cells of respective organ or tissue) and the characteristic indicators of specific tumours. For example, in the case of breast cancer – ER/PR (estrogen and/or progesterone receptors) and HER2 receptors; in the case of prostate cancer – the Gleason index; and in other tumours – specific gene mutations found in the laboratory (KRAS, NRAS, BRAF, etc.).
The apparent pre-metastasis phase, if we can call it that, is only the calm before the storm. Any impulse, which harms the balance of the body (immune, endocrine, psycho-emotional, etc.), whether internal, external or a combination of both, can act as a catalyst that breaks the original peace terms between the body and the tumour.
A number of factors decide if individual cancer cells or a group of them (a tumour embolism) implant themselves in distant organs or tissues. First of all, it depends on the liveliness and mobility of cancer cells that have broken away and their tolerance of external mechanisms and chemical factors, which they meet while travelling to their next locations (sites of metastasis). For example, when entering the blood stream cancer cells are seriously threatened by the turbulence of the bloodstream as well as by attacks from blood cells, which is their natural reaction. The majority of cancer cells are destroyed in the bloodstream. Some attach themselves to the walls of the blood vessels and lay dormant while waiting for more favourable conditions to move on. On the other hand, the strongest (a peculiar version of natural selection!) keep moving until they reach a location which they are happy to accept. Naturally, the body’s overall condition also plays a role, especially immunity, clotting and viscosity factors of the blood, the hormonal environment and the like.
At present, with very few exceptions, a metastasised tumour is not curable, no matter what the pharmaceutical companies promise us. However, all of these tumours are treatable. Even advanced tumours with metastases in several organs can be successfully treated by reducing their size, limiting or slowing their progression, alleviating complaints and symptoms and prolonging life. Patients often have a hard time coming to grips with my prognosis when I tell them that their illness can no longer be completely cured, but that it can be treated and their suffering can be alleviated. When people think of treatment they usually equate it with a complete cure and the elimination of the disease. For the time being this still isn’t possible for malignant tumours. I usually try to explain this in the following way: “Your tumour can’t be completely cured right now, but we have a variety of different methods, which can help. Let’s hope for the best possible outcome, but let’s be ready for the worst case scenario.” There are many chronic illnesses, which can’t be completely cured, but which can be tolerated, such as diabetes. Oncological illnesses are more complicated examples, but in my experience I’ve seen patients who have lived with metastatic cancer for over 10 years. No doctor anywhere in the world can guarantee you eternal life. Moreover, as I mentioned earlier, the balance between the body’s own resistance and the tumour’s aggression is very delicate. By upsetting this balance we’re taking a very big risk. We have to be especially careful and can’t be swayed by the aggressive marketing campaigns of the pharmaceutical industry. The needs of each patient can vary greatly. New drugs can genuinely help one patient, yet be ineffective for another. Yet another patient may enjoy a good quality of life by using symptomatic therapy, adhering to a healthy diet, remaining active or by using other methods (e.g. homeopathy, physical therapy, psychotherapy, etc.).
Once again we’re forced to face a clash between the expectations of the patient and the limitations of contemporary medicine. Metastatic or widespread cancer currently can’t be cured anywhere in the world, not even for huge sums of money. Hoping that money and only money or booking a place at a fancy foreign clinic will solve the problem is simply wishful thinking. This is what we often hear in the media – let’s collect donations to save a life and return a child to its mother or a son to his parents. I don’t discount the possibility that, in rare cases, we can prolong life, perhaps even for years, and that’s already a lot to hope for. On the other hand, by accepting one’s situation and sticking to a regimen of symptomatic treatment, you can live out the time that’s left to you long enough not only to put your affairs in order, but also to accomplish many inspiring things. Remember that every day that you live is a small victory against your illness. Celebrate these small victories and fill your days with something beautiful, meaningful and lasting.