Immunotherapy with SRS does NOT increase risk of radiation necrosis in melanoma brain mets!!!

We already know that folks who get immunotherapy WITH (or as soon as possible relative to) SRS [stereotactic radiation] therapy for brain mets do best.  Here's a post with multiple links that covers that and then some: Anti-PD-1 works best with SRS for brain mets in melanoma, Don't wait to add anti-PD-1 to SRS for brain mets, etc, etc!!!!!

Yet, patients are STILL being advised BY THEIR ONCOLOGISTS, "Oh, my goodness, no!!  We can't do both immunotherapy and SRS to brain mets at the same time.!  It would be too toxic.  It would increase the risk of radiation necrosis!"

Now, radiation necrosis is a real problem.  It is a complication that arises for far too many.  However, combining radiation with immunotherapy does NOT increase the risk!  Check out this review of 137 patients and their 1,094 brain lesions:

Radiation necrosis with stereotactic radiosurgery combined with CTLA-4 blockade and PD-1 inhibition for treatment of intracranial disease in metastatic melanoma. Fang, Jiang, Allen, et al.  J Neurooncol. 2017 May 12.  

Immune checkpoint inhibitors have demonstrated remarkable benefits in cancer patients. However, concern regarding toxicity in the setting of stereotactic radiosurgery (SRS) is often raised. In this study, we characterize radiation necrosis (RN) following immunotherapy and SRS. Melanoma patients treated with SRS and anti-CTLA-4 and/or anti-PD-1 at our institution from January 2006 to December 2015 were retrospectively reviewed. Overall survival (OS) and time to RN were assessed using Kaplan-Meier analysis. Logistic regression and Cox proportional hazards analyses were performed to identify predictors of radiation necrosis-free survival (RNFS) and RN risk. One-hundred thirty-seven patients with 1094 treated lesions over 296 SRS sessions were analyzed. Median follow-up was 9.8 months from SRS. Rate of RN was 27% of patients with median time to RN of 6 months. Median OS from SRS treatment was 16.9 months. RNFS at 6 months, 1 and 2 years was 92.7, 83.0, and 81.2%. Treatment with chemotherapy within 6 months of SRS was associated with worse RNFS at 1 year. On multivariate analysis, chemotherapy within 6 months and increased number of lesions treated were predictive of increased RN risk, whereas immunotherapy type and targeted therapy were not predictive. Median target volume of lesions that developed RN was greater than that of lesions that did not. Concurrent treatment with chemotherapy, larger size and number of lesions treated were predictive of RN. Immunotherapy type and timing proximity to SRS were not associated with RN risk.

So, this review of real ratties demonstrates that having chemo (OMG????!!!!), larger sized brain lesions, and a greater number of lesions treated DOES increase the risk of radiation necrosis - giving immunotherapy (ipi or anti-PD-1) and timing proximity to SRS treatment does NOT!!!!!

Could we get some nit-wit oncologists/radiation oncologist to read their own professional journals....or this blog?  Well, if you get told something similar to the little talk outlined above....PRINT and DELIVER this report to them! Hang tough, dear ratties! - c