Stereotactic ablation radiotherapy (SABR) is a method of highly precise external irradiation, which involves the concentration of an increased dose of radiation at the level of the tumor tissue, with its limitation in the neighboring organs. It has become the treatment of choice for many volume-limited lung tumors where surgical approach is not indicated. It is a non-invasive method, comfortable for the patient, with increased effectiveness. These can be major advantages compared to other therapy modalities, but there may be a risk of severe toxicity in some patients, by affecting central structures.
Results of a non-randomized controlled trial published in JAMA Network, suggest that SABR customized according to tumor volume, location and histopathological type in the treatment of lung tumors can minimize the treatment dose, improving therapeutic outcomes, with low occurrence of severe toxic effects and very good local disease control. Retrospective data suggest that small tumors, up to 10 cm3 in volume, can be effectively controlled with an effective biological dose of less than 100 Gy.
A customized dose of SABR resulted in no tumor recurrence at 1 year locally 94% to 97%, and at 5 years it varied between 83% and 93%, depending on staging and degree of metastasis at diagnosis.
The study shows that the level of toxicity decreased significantly, only one patient of those included in the study had a possible grade 5 adverse reaction related to the treatment.
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The controlled multicenter phase 2 iSABR study enrolled 217 patients diagnosed with 285 lung tumors at two academic centers in the US and Japan. The objective was to determine whether an individualized dose of SABR can decrease the rate of toxicity, resulting in better disease control.
The patients were divided into 3 categories, depending on the type of cancer, staging and histopathological result:
Group 1: those with non-small cell lung cancer (NSCLC) stages T1-3N0M0 Group 2: stages T1-3N0M0 with newly diagnosed primary NSCLC but with a history of single/multiple NSCLC in the past Group 3: lung metastases from NSCLC or other solid tumor
SABR dose and fractionation were individualized according to tumor size, location, and history, with the most commonly used being 25 Gy in a single session, with a median follow-up of 33 months and median overall survival of 59 months.
The results were promising, with a decrease in adverse effects in patients, 5% of those included in the study having grade 5 toxic effects, and the recurrence rate decreased significantly both at 1 year post-therapy and at 5 years.
The study represents an important step towards bringing the approach into medical practice.
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2023-12-02 08:33:27
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