Stereotactic radiosurgery (SRS) - A new normal for small cell lung cancer?

Prophylactic cranial irradiation (PCI), hippocampal avoidance (HA) whole brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS) in small cell lung cancer (SCLC): Where do we stand?

Small cell lung cancer (SCLC) is an aggressive form of lung cancer associated with an increased risk of develping brain metastases (BM), which are a significant cause of morbidity and mortality. Prophylactic cranial irradiation (PCI) was first introduced in the 1970s with the aim of reducing BM incidence and improving survival and quality of life (QoL). Prospective clinical trials and meta-analyses have demonstrated its effectiveness in reducing BM incidence and improving survival, across all stages of the disease following response to induction chemotherapy. Despite its long history, "unknowns" surrounding PCI use still exist and there are particular subgroups of patients for which its use remains controversial. PCI is known to cause neurocognitive toxicity which can have a significant impact on a patient's QoL. Strategies to minimise this, including the use of hippocampal avoidance radiotherapy techniques, neuroprotective drugs and stereotactic radiosurgery in place of whole brain radiotherapy for the treatment of BM, are under evaluation. This review offers a summary of the key PCI trials published to date and the current treatment recommendations based on available evidence. It also discusses the key questions being addressed in ongoing clinical trials and highlights others where there is currently a knowledge gap and therefore where further data are urgently required.

Time management: Improving the timing of post-prostatectomy radiotherapy, clinical trials, and knowledge translation

Background

Management of prostate cancer after surgery is controversial. Past studies on adjuvant radiotherapy (aRT) for higher-risk features have had conflicting results. Through the collaborative conversations of the global radiation oncology Twitter-based journal club (#RadOnc #JC), we explored this complex topic to share recent advances, better understand what the global radiation oncology community felt was important and inspire next steps.

Methods

We selected the recent publication of a landmark international randomized controlled trial (RCT) comparing immediate and salvage radiotherapy for prostate cancer, RADICALS-RT, for discussion over the weekend of January 16 to 17, 2021. Coordination included open access to the article and an asynchronous portion to decrease barriers to participation, cooperation of study authors (CP, MS) who participated to share deeper insights including a live hour, and curation of related resources and tweet content through a blog post and Wakelet journal club summary.

Discussion of Results

Our conversations created 2,370,104 impressions over 599 tweets with 51 participants spanning 11 countries and 5 continents. A quarter of the participants were from the US (13/51) followed by 10% from the UK (5/51). Clinical or Radiation Oncologists comprised 59% of active participants (16/27) with 62% (18/29) reporting giving aRT within the last 5 years. Discussion was interdisciplinary with three urologists (11%), three trainees (11%), and two physiotherapists (7%). Four months after the journal club its article Altmetric score had increased by 7% (214 to 229). Thematic analysis of tweet content suggested participants wanted clarification on definitions of adjuvant (aRT) and salvage radiotherapy (sRT) including indications, timing, and decision-making tools including guidelines; more interdisciplinary and cross-sectoral collaboration including with patients for study design including survivorship and meaningful outcomes; more effective knowledge translation including faster clinical trials; and more data including mature results of current trials, particular high-risk features (Gleason Group 4+, pT4b+, and margin-positive disease), implications of newer technologies such as PSMA-PET and genomic classifiers, and better explanations for practice pattern variations including underutilization of radiotherapy. This was further explored in the context of relevant literature.

Conclusion

Together, this global collaborative review on the postoperative management of prostate cancer suggested a stronger signal for the uptake of early salvage radiation treatment with careful PSA monitoring, more sensitive PSA triggers, and expected access to radiotherapy. Questions still remain on potential exceptions and barriers to use. These require better decision-making tools for all practice settings, consideration of newer technologies, more pragmatic trials, and better use of social media for knowledge translation.