2023-10-26 07:32:41
by Health Editorial Staff
An Italian-Spanish study helps to personalize the post-surgical treatment of operable carcinoma. The new technology can identify micro-metastases not visible with the radiological techniques available today
After surgical removal of the tumor, in approximately one third of patients with high-risk stage three and two colon cancer, a micro-metastatic disease remains, which is radiologically invisible, but can be diagnosed with liquid biopsy, a new technology capable of determining the presence of the tumor’s DNA in the patient’s blood is repeatable over time, thus allowing the choice of therapy to be personalized for the individual. This was revealed by the PEGASUS clinical study, presented in Madrid at the annual congress of Esmo, the European Society of Medical Oncology. The results of PEGASUS, promoted by the Institute of Molecular Oncology Foundation (IFOM), also suggest that, in patients with negative liquid biopsy, it is possible to opt for a less intense therapy, reducing toxicity without compromising its effectiveness.
Prevent relapses and avoid unnecessary toxicity
Approximately one in three patients with operable stage III colorectal cancer is at risk of recurrence after surgery due to the presence of micro-metastases which unfortunately the radiological techniques currently available are unable to detect – explains Silvia Marsoni, head of the Research Unit. Precision Oncology at IFOM, creator and coordinator of the PEGASUS study -. To prevent recurrence, almost all patients today undergo chemotherapy after surgery. Not everyone benefits from this strategy and, above all, even patients who do not need it are treated because, until now, an adequate tool to measure residual microscopic disease was not available. This is one of the first prospective studies of liquid biopsy, a new technology capable of detecting the presence of circulating tumor DNA (ctDNA) in the blood of patients after surgery. The objective was therefore to test the feasibility of using this method to follow the course of the disease and guide therapeutic choices.
The experimentation, PEGASUS study
Between July 2020 and July 2022, 135 patients were recruited from 11 Italian and Spanish cancer centers. The post-surgical liquid biopsy was positive in 35 out of 135 patients (26%), of which 12 (34%) had a recurrence, while only in 10% of the remaining 100 patients with negative liquid biopsy, the disease recurred. The data on the negativity of liquid biopsy parameters during and at the end of all treatments administered as part of the protocol suggest an overall effectiveness of the therapy of 40%.
The PEGASUS study involves a post-surgical chemotherapy treatment differentiated based on the results of a liquid biopsy taken approximately four weeks after the surgical removal of the primary tumor – explains the clinical director of the study Sara Lonardi, of the Veneto Oncology Institute IRCCS of Padua , which illustrated the trial in Madrid –. With a positive liquid biopsy, patients receive standard adjuvant chemotherapy (the same used today to treat all high-risk stage III and stage II colon cancers): the so-called CAPOX, which is a regimen based on capecitabine and oxaliplatin very active against colon cancer, but which can cause acute and chronic neurological toxicity in a substantial percentage of cases. With a negative liquid biopsy, however, patients receive a lighter therapy which involves the administration of capecitabine alone for precautionary purposes. The analysis of the liquid biopsy is carried out several times during the treatment and subsequently during the patient’s follow-up, as a tool to reveal any innate resistance of the tumor to therapy and guide the remodulation of the chemotherapy regimen and the use of a more aggressive treatment based on FOLFIRI.
Confirmations and new perspectives
The study, supported by the AIRC Foundation, saw the participation of 11 centers of oncology excellence under the scientific supervision of Salvatore Siena of the Department of Oncology and Hemato-oncology of the University of Milan and Grande Ospedale Metropolitano Niguarda and of Josep Tabernero, director of the Vall d’Hebron Institute of Oncology in Barcelona. If these results are confirmed by those of the various ongoing international studies which also include a direct comparison with standard therapy, they could contribute on the one hand to modifying the guidelines for the treatment of operable colon cancer, reducing or completely eliminating adjuvant therapy in patients with negative liquid biopsy, and on the other to personalize chemotherapy in case of lack of molecular response – concludes Marsoni –. an important contribution to changing the paradigm with a new personalized therapy which will also allow us to explore the biology of micro-metastatic tumors, those for which we need to find new and more effective therapies.
October 26, 2023 (modified October 26, 2023 | 07:32)
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