As every year, World Cancer Day is celebrated on 4 February. Cancer is one of the main causes of morbidity and mortality across the globe. In 2018, 18 million new cases of cancer were diagnosed worldwide and the estimates are that in 20 years there will be 30 million new cases each year. Advances in diagnosis and treatment, as well as the implementation of screening programmes have made it possible to reduce the mortality associated with different types of cancer.
How have the diagnosis and treatment of the disease advanced in recent years?
Improvements in early detection and treatment, as well as new treatments and their combinations have led to a drop in cancer mortality, especially in lung, bowel and breast cancer. Recent data reveal that the rate of decline in cancer mortality has accelerated slowly, from approximately 1% per year during the 1990s to 1.5% per year during the 2000s, and 2% per year since 2015.
We have two ways to improve the control of cancer: prevention and research. Prevention through population screening programmes and the reduction of risk factors such as tobacco. It should be noted that one in three deaths from cancer is attributable to five avoidable risk factors: tobacco, alcohol, sedentary lifestyle, infections and poor diet.
The second way is to advance in research, in all diagnostic and therapeutic areas.
How do you approach cancer patients at the Hospital Clínic?
Cancer is a very complex disease that requires the intervention of many specialists, both for its detection and its diagnosis and treatment.
Ideally, it should be diagnosed as early as possible in order to find the cancer at a localized stage, which is where we have the most effective treatments with the highest survival rates. That is why, for some tumours, we have population screening programmes. At the Hospital Clínic, we carry out the screening of the bowel and breast cancer referral area and we are going to start to screen for cervical cancer. The aim is to find the disease before it produces symptoms.
It is also very important to detect warning signs. In Catalonia, because of the way in which the health system is structured, in basic health areas and referral hospitals, this is done by family doctors: when a warning sign is detected, a rapid diagnosis is activated.
The patient can then be referred to the Hospital Clínic, where the hospital is divided up into different units or committees for each tumour. This is a basic part of the approach to cancer patients, because it is where the oncology strategy is defined in a multidisciplinary way and where comprehensive and personalized cancer treatment is guaranteed for each patient.
There has been a revolution in cancer treatments in what is known as the era of precision medicine.
How do you decide which treatment is best?
We decide this in the tumour committee, made up of a multidisciplinary team of specialists for each tumour. In this committee, all the cases are presented in order to decide on the best oncology strategy. Each specialist provides precise information on the case (radiologist, pathologist, nuclear medicine, etc.), thereby classifying the cancer as accurately as possible. It is like a puzzle in which each piece is made up of information from a different specialist and, when you have all the pieces, you can name the type of cancer and define the best treatment, which is based on the combination of systemic treatment (chemotherapy, targeted therapies, hormonal treatments and/or immunotherapy) and local treatments such as surgery and radiotherapy.
There has been a revolution in all these treatments in what is known as the era of precision medicine, from minimally invasive surgery to targeted molecular therapy and image-guided radiation therapy.
What role does radiation oncology play in the treatment of cancer?
Approximately 40% of the patients who are cured of cancer have received radiotherapy as part of their overall treatment. And 60% of cancer patients will need radiotherapy during their treatment, as a curative or palliative measure. Moreover, it is estimated that the need for radiotherapy treatment will rise by 16% in the next few years, both due to the increase in incidence and to new indications.
What does radiotherapy consist of?
Radiotherapy mainly uses very high-energy ionizing radiation in order to destroy tumour cells by preventing their accelerated division. The tumour’s healthy tissues can also be affected by the radiotherapy but, unlike the cancer cells, they are able to repair the damage caused by the treatment within a few weeks of its completion.
So, the amount of radiation received by healthy tissues must be reduced.
Minimizing the dose received by healthy tissues is one of the main goals of any radiotherapy treatment. This reduction in dose can currently be achieved by using high-precision techniques such as intensity-modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT), or a respiratory movement control and synchronization technique (respiratory gating), which enables the monitoring and synchronization of respiratory movements with the administration of the treatment.
All these technological advances allow for better local control of the disease with minimum side effects. They also allow us to combine them with drugs in order to be more effective.
Another type of radiotherapy treatment that has allowed us to advance in precision medicine is proton therapy, and in the next few years we shall have a centre in Catalonia. This type of treatment is especially indicated in paediatric tumours and tumours located next to critical organs, mainly the base of the skull and the spinal cord, since the radiation is absorbed by the tumour and there is no exit dose.
The technological advances in radiotherapy allow us to provide more intensive treatments in less time.
The aforementioned technological advances allow us to provide more intensive treatments in less time, since we minimize the toxicity. Thus, treatments that used to last 6-7 weeks can now be carried out in 3-4 weeks, for example in breast cancer and prostate cancer.
We have new treatments such as stereotactic ablative radiotherapy (SABR), where high radiation doses are administered for 1-5 days, achieving very good results in tumour control, both in localized and oligometastatic disease. It is an excellent technique for localized tumours and for combining with systemic treatments.
The synergies in the combination of radiotherapy and systemic treatment, especially immunotherapy and molecular therapy, constitute a very promising scenario for the coming years, using radiotherapy to activate the immune system.
We can also expect more personalized radiotherapy, by advancing in the study of predictive/prognostic markers of the benefits of radiotherapy in the local control of each tumour subtype, as is already done for some chemotherapy treatments.
What are the latest advances in research?
We have advanced and we are advancing in all areas. Possibly, the progress in the molecular characterization of tumours that has enabled the development of new drugs, as well as the better understanding of the immune system, have allowed us to improve in advanced stages of the disease where we had the worst results. The use of prognostic markers, predictors of the toxicity or efficiency of local or systemic treatment has allowed us to adapt the treatment in a more personalized manner.
Speaking of prevention, what can we do to improve detection or to detect tumours earlier?
We have three main objectives in the fight against cancer:
- To reduce the incidence: ensuring people avoid risk factors, adopt a healthy diet, practise sport, etc.
- To increase adherence to screening programmes in order to improve early detection. We have a lot of work to do here. The population has to be aware of the importance of attending invitations to undergo screening tests, such as faecal occult blood tests or mammograms, and we have to make the population understand the importance of these programmes for their health.
- To make the disease chronic: Incorporating technological and therapeutic innovations, training and research. Carrying out more and better research.
What has been the effect of the pandemic? Has activity recovered compared with last year?
The data show a slight recovery in the number of cancer diagnoses, especially from July 2020 on, and this fortunately continued throughout 2021. Nevertheless, the real impact of the diagnostic delay caused by the pandemic will not be felt for several years.