October 24, 2021 — High-doseradiation therapycan be used to lengthen progression-free survival for people with advancedlung cancer根据一项新的研究，当全身治疗还没有完全停止转移瘤的生长或扩散时。Findings will be presented today at theAmerican Society for Radiation Oncology(ASTRO) Annual Meeting.
This study is the first randomized trial to test the use ofstereotactic body radiation therapy(SBRT) to treat oligoprogressive, metastatic lung and breast cancer. Cancer may be considered oligoprogressive when there is a mixed response to systemic therapy, where some metastatic sites become drugresistant and continue to grow, while other tumors are suppressed by the systemic therapy and remain stable.
The current standard of care for these patients typically is to switch to a different targeted therapy or chemotherapy, but this can cause additional side effects, and an alternate drug is not always available. Adding local therapy like SBRT allows patients to stay on their current therapy by targeting only the drug-resistant lesions. SBRT, which is also known as stereotactic ablative radiotherapy (SABR), delivers precise, high doses of radiation directly to cancer sites, allowing radiation oncologists to treat tumors while sparing surrounding tissue from damage.
“For patients whose cancers appear to be oligoprogressive, stereotactic radiation to progressing sites can help them get more mileage out of their current therapy,” said lead authorC. Jillian Tsai, M.D., Ph.D., a radiation oncologist and director of metastatic disease radiation oncology research atMemorial Sloan Kettering Cancer Centerin New York. “These patients often have gone through multiple lines of systemic therapy before they get to us. Our study shows they don’t have to run out of options. We can use SBRT to selectively treat the sites that are progressing.”
在纳入研究的102名患者中，58名患有非小细胞肺癌(NSCLC)， 44名患有乳腺癌。所有参与试验的患者都有1到5个进展中的转移部位，这些部位对全身治疗没有反应;75%有一个以上的寡进性位点。蔡和她的团队将这些患者随机分成两组:一半的患者在所有进展部位接受SBRT治疗，另一半接受标准治疗，这让医生可以选择是否继续他们目前的全身治疗或切换到另一种药物。
Patients were followed for 51 weeks, by which time 71 had experienced further tumor progression and 30 had died. For patients with NSCLC treated with SBRT, the median progression-free survival was 44 weeks, compared to 9 weeks for those who received standard care (p=0.004). There was no significant 2/4 difference in progression-free survival between the two groups of patients with breast cancer (18 weeks with SBRT vs. 17 weeks with standard care, p>0.05).
“我们发现，对于肺癌患者队列，与标准护理相比，对低进展部位的放疗倾向于帮助他们保持稳定，并保持无进展状态更长时间。然而，对于乳腺癌队列，我们没有看到任何差异。”
Researchers are preparing to close the trial early, after a planned interim analysis established that SBRT could extend the length of time that patients’ tumors remained stable. They are now investigating why people with lung cancer, but not those with breast cancer, responded to radiation.
Tsai said one reason for the different outcomes may be the different systemic therapy agents the patients with lung cancer have received, including immunotherapy. There could be synergy between radiation and specific drugs that enhance the effectiveness of both treatments.
Another reason, she said, could be that participants in the breast cancer cohort had disease that was already too advanced for SBRT to make a difference. “We treated these patients late in their disease trajectory—some patients had undergone nine lines of systemic therapy before coming to us. It’s possible radiation therapy might not be helpful under those circumstances but could be if patients are referred to us before they run out of other options.”
It’s also very likely that breast cancer and lung cancer simply behave differently. “Different cancers have different biology and patterns of progression," said Tsai. "The oligoprogressive state is still a hypothesis. We don’t know if this state exists for all cancers and how long it can exist before further progression occurs.”
Oligoprogresion is an emerging concept in cancer biology, and there is debate whether it exists as a unique state or is a temporary state in which tumors are simply progressing at different rates. Tsai said the research team is currently examining molecular markers to analyze differences.
Find more key studies in the articleRadiation Oncology Research Featured at ASTRO 2021
See photos of some of the latest technologies at ASTRO
For more information:www.astro.org
August 25, 2022
