Do patients with rmHNC treated with checkpoint inhibitors benefit form additional radiotherapy?
Bálint Tamaskovics,
Germany
PO-1076
Abstract
Do patients with rmHNC treated with checkpoint inhibitors benefit form additional radiotherapy?
Authors: Bálint Tamaskovics1, Jan Haussmann1, Danny Jazmati1,2, Judith Neuwahl1, Amir Rezazadeh1, Edwin Bölke1, Wilfried Budach1, Christiane Matuschek1
1Heinrich Heine University, Düsseldorf University Hospital, Dept. of Radiation Oncology, Düsseldorf, Germany; 2West German Proton Therapy Centre Essen (WPE), Dept. of Particle Therapy, Essen, Germany
Show Affiliations
Hide Affiliations
Purpose or Objective
Checkpoint
inhibitors have become the standard of care for recurrent inoperable or
metastatic head and neck cancer (rmHNC). In patients with high disease or
symptom burden, oncologists are inclined to add platinum-based chemotherapy,
despite its high toxicity. Radiation therapy (RT) is established for the
treatment of symptomatic lesions and for tertiary prevention. RT was not
allowed and/or not reported in the pivotal studies. The aim of this study was
to evaluate the combination of checkpoint inhibitors and RT, also in the
non-trial population (multimorbid, elderly and frail patients).
Material and Methods
We identified 83 patients with rmHNC treated
with a programmed cell death protein-1 (PD-1) inhibitor since 2017 in the
electronic medical records of our head and neck cancer center. Retrospectively
collected data (characteristics, therapy, outcome, acute and late toxicity) were
investigated by descriptive statistics and survival analyses using the Kaplan-Meier method, the log-rank test, and the Cox regression model. We performed all
calculations using R version 4.1.1.
Results
Median
age was 64 years (range: 28-92), median Charlson comorbidity index was 8
(range: 3-13). 38.6% of the patents were older than 70 years at the start of therapy.
33.7% had an ECOG performance score ≥2. The median follow-up time was 18.2 months. 63.9%
of the patients received additional RT. The median overall survival (OS) rate was
7.8 months (95% confidence interval [CI]: 5.2-13.9 months). There were no
difference in outcomes among three age subgroups (<60 years, 60-70 years and
70+ years at baseline). We found an overall response rate of 33.8%, with a
median duration of response of 21.4 months. The addition of RT to systemic
treatment was associated with favorable survival: hazard ratio of 0.5 (CI:
0.28-0.87; p=.015). This association was more pronounced, if escalated RT (defined
as >50Gy EQD2 or RT of all lesions) was used. Complete response was seen in 13
patients, seven of them had more than one tumor lesion at baseline. Two of
these seven patients did not receive RT; four of them had a RT of all lesions; so
that we could observe a possible abscopal remission effect in only one case. 21
(25.3%) severe (grade 3-4) immune-mediated adverse events were registered. The
toxicity profile was similar to previous pivotal studies, with the exception of
grade 1 endocrine toxicity, which occurred in 42.2% of patients in our cohort. We
did not observe any severe radiation toxicity.
Conclusion
The combination of PD-1-inhibitor therapy and
RT is feasible according to our study. Despite the absence of the abscopal
effect, RT might have a positive effect on survival rate besides symptom
control. Our findings support the (tailored) therapy of the elderly and frail
patients.