A group of researchers have claimed to have taken the 1st step on the path to treat radiotherapy dosage to individual patients via their genetic characteristics. This was mentioned by a radiation oncologist in Berlin at Europe’s ECCO-15 – ESMO 34 Cancer Congress. He mentioned that his team’s work might supply the foundation for personalized radiotherapy in which, with a simple blood test, doctors may be able to choose the optimal radiation dose for a certain patient.
The researchers from Netherlands, Belgium, Germany, and Canada apparently examined a group of patients with hypersensitivity to radiation therapy. About more than 8000 European patients were apparently incorporated in the database.
Professor Dirk de Ruysscher, Maastricht University Medical Centre, Maastricht, The Netherlands, commented, “Part of this project is the establishment of a sub-database in which very rare patient characteristics are brought together with the hypothesis that their genetic traits will enable the characterization of molecular pathways related to radio-sensitivity. Major problem for radiation oncologists at present is that we are bound by the need to avoid damage to normal tissues. This means that the dose of radiation generally used is governed by the response of the most radiosensitive patients, and this may lead to many patients receiving lower than optimal doses, hence affecting the ability to deliver a higher dose that may result in better local tumor control.”
A tissue bank may incorporate skin fibroblasts, whole blood, lymphocytes, plasma, and lymphoblastic cell lines from patients who were identified to be oversensitive to radiation. This theory was apparently determined from patients in Europe and Canada.
As opposed to the control group, the hypersensitive patients apparently demonstrated either severe side effects which may take place at extremely low radiation levels, or severe side effects which could last for more than around four weeks post radiotherapy and/or may need surgery. Severe late side effects could also arise or may continue for more than about 90 days after the end of radiotherapy.
About 33 such patients and in those roughly 10 were males and around 23 were females, of whom approximately 11 i.e. two males and nine females eventually turned out to be really hypersensitive to radiation, which may emphasize the scarcity of this condition. Their mean age is said to be 61.6 ± 8.5 years which may range from 49 – 74 years. One patient apparently had non-small cell lung cancer, about six had breast cancer, two apparently had head and neck cancer and one had lymphoma. The radiation doses, the by and large treatment times and the follow-up times all apparently fell within the standard guidelines.
Professor de Ruysscher, mentioned, “The severe side effects included acute skin reactions, extreme skin thickening or fibrosis, lung tissue inflammation and blindness due to optical nerve damage. Although radiotherapy is a highly effective way of treating cancer, it is important that we are able to identify the patients who will react badly to it and adjust their dosage accordingly.”
He further remarked, “We hope that the EU will fund a successor project to elucidate genetic pathways in combination with other patient data so that we can make predictive models that can be implemented in standard clinical practice. We believe that, if we can understand what it is going on at a molecular level, we may be able to develop a blood test that will allow us to know precisely how an individual patient will react to radiotherapy, and to target the dose accordingly. Such personalized treatment will be a major advance, allowing us to minimize both radiotherapy doses and unpleasant side effects, while treating the tumor in the most effective way possible. Perhaps even more importantly, it will enable us to give higher doses to many patients and hence improve control of their tumors.”
Radiotherapy apparently functions properly by causing DNA damage in cells in a certain region so that they may kill themselves. As cancer cells may reproduce more and could be undifferentiated which means that it may not have the capability to become a more specific cell type, they may not be able to mend the damage properly which is supposed to be caused by radiotherapy as compared to discriminated, usual cells which may generally fix themselves. Though, few of the normal cells enclosing the treatment site may also be damaged throughout radiotherapy. And it is this damage that may result in side effects.
The finding that people as well as tumors, may respond in a different way to radiotherapy may allow doctors in the future to aim doses even more cautiously, by taking into account not just the radiosensitivity of the tumor type but also the probable response of any patient to treatment.