Prophylactic Cranial Irradiation for Patients With Small Cell Lung Cancer

Vinai Gondi, MD, Northwestern Medicine West Region, Warrensville, IL, explores the role of prophylactic cranial irradiation (PCI) for patients with small cell lung cancer (SCLC), a topic he debated at the Great Debates and Updates in Lung Cancer conference in Chicago, Illinois.

Dr Gondi reviewed the recent and upcoming studies evaluating the role of PCI for patients at different stages of SCLC and the potential toxicities that come with this treatment.

Transcript

Hi, my name is Vinai Gondi. I'm the Director of Radiation Oncology in the Western region of Northwestern Medicine, the co-director of the Brain and Spine Tumor Center at Northwestern Medicine Cancer Center in Warrenville, Illinois. My position today was that there is a role for prophylactic cranial radiation for small cell lung cancer. For decades we have understood that prophylactic cranial radiation or PCI has a significant role in the survivorship of our small cell lung cancer patients. Certainly, this was based on, in the limited stage setting, decades old data showing a survival benefit that approximated the survival benefit of adding chemotherapy to thoracic radiotherapy for limited stage small cell lung cancer. But even more recent meta-analysis has shown and confirmed that in modern era there is continued survival benefit with limited stage small cell lung cancer for patients receiving PCI. In the extensive stage setting however, there's been some controversy as a recent Japanese study demonstrated that there may be no survival benefit with the use of PCI for patients with extensive stage small cell lung cancer, so long as that they're surveilled with MRIs. The debate here is to determine whether those results can be extrapolated into the limited stage setting.

Another important consideration for PCI is the potential toxicities that can arise from PCI, specifically with respect to cognition. In the space of therapeutic whole brain radiotherapy for patients who develop brain metastases, we've observed significant benefits in cognitive risk reduction techniques, pharmacologic neuroprotective strategies with the use of memantine, and technologic strategies with the use of hippocampal avoidance. Currently, we are in the process of analyzing an important randomized clinical trial of PCI with or without hippocampal avoidance for patients who had small cell lung cancer with the results expected later this year. Those results are pending.

There's also been some interest in determining whether there is a role for PCI in the setting of any small cell lung cancer patient. That question is being addressed by an ongoing study called the MAVERICK Trial. It's a phase 3 trial of patients with small cell lung cancer randomized to MRI surveillance versus MRI surveillance with prophylactic cranial radiation. Another important consideration is if we consider removing PCI in the upfront setting for small cell lung cancer patients, we are putting our patients at a higher risk of developing brain metastases. In that setting, what is the appropriate treatment for patients who develop brain metastases from small cell lung cancer? Conventional wisdom in practice says that hippocampal avoidant whole brain radiotherapy with memantine is standard of care in that setting. But there's some emerging data that suggests that perhaps radiosurgery could be used. Obviously in the setting of radiosurgery, we are trading one toxicity, the cognitive concerns of whole brain radiotherapy, for another toxicity, potential for symptomatic radiation necrosis, which is why the Energy Oncology CC009 trial currently active is an important trial to address that question. That trial is randomizing patients to radiosurgery versus hippocampal avoidant whole brain radiotherapy for patients who develop brain metastases from small cell lung cancer.

Importantly, several questions need to be addressed in the management of our small cell lung cancer patients, and the best way to do so is enrolling on patients on clinical trials and supporting these trials so we have level 1 evidence to justify our recommendations to our patients. Thank you for your time and attention.

Source:

Gondi, V. “Debate: Prophylactic Cranial Irradiation (PCI) in SCLC - Yes.” Presented at Great Debates & Updates in Lung Cancers. May 4-6, 2023; Chicago, IL