1304P - A structured multidisciplinary approach for diagnosing immune-related pneumonitis in patients undergoing adjuvant durvalumab for stage III non-small cell lung cancer

Background

In inoperable stage III NSCLC, the standard of care is chemoradiotherapy and adjuvant durvalumab (IO) for 12 months. Pneumonitis is the commonest toxicity leading to IO discontinuation. Failure to distinguish between radiation-induced changes, IO pneumonitis and infection can lead to unnecessary IO discontinuation. We investigated use of a structured multidisciplinary review of CT-scans, radiation dose distributions and clinical symptoms for the diagnosis of IO pneumonitis.

Methods

An ethics-approved retrospective study was conducted at an academic medical center for stage III NSCLC patients treated with chemoradiotherapy and adjuvant IO between 2018-2021. A thoracic radiologist reviewed baseline and follow-up chest CT-scans, systematically scored radiological features suspected for pneumonitis using a published classification system ( Veiga C, Radioth Onc 2018 ), and had access to the radiation dose distributions. Next, two thoracic oncologists reviewed each patients’ case record, CT-scans and radiation fields. A final consensus diagnosis incorporating views of expert clinicians and the radiologist was made. IO pneumonitis was diagnosed only when both the radiologist and pulmonologists were in agreement.

Results

Among the 45 included patients, 14/45 (31.1%) had a pneumonitis scored in patient records. IO was discontinued in 11/45 cases (24.4%). Review by the radiologist led to a diagnosis of IO pneumonitis only in 6/45 patients (13.3%). Review by thoracic oncologists led to a diagnosis of IO pneumonitis in only 4/45 patients (8.9%). In addition, a suspicion of an immune-related pneumonitis was rejected in 3 separate patients (6.7%), after the thoracic oncologists had reviewed the patient's radiation fields.

Conclusions

In patients treated using the PACIFIC regimen, multidisciplinary assessment of CT-scans, radiation doses and patient symptoms, resulted in fewer diagnoses of immune-related pneumonitis (8.9%). In contrast, routine clinical assessment by treating pulmonary oncologists led to discontinuation of IO in 24.4% of patients. This highlights the need for multidisciplinary review in order to avoid inappropriate cessation of adjuvant IO.

Clinical trial identification

IRB00002991.

Editorial acknowledgement

Legal entity responsible for the study

Suresh Senan.

Funding

Has not received any funding.

Disclosure

I. Bahce: Financial Interests, Institutional, Advisory Board: BMS, Boehringer Ingelheim, AstraZeneca, Roche, Pfizer, Takeda, MSD; Financial Interests, Institutional, Research Grant: BMS, Boehringer Ingelheim, AstraZeneca. S. Senan: Financial Interests, Personal, Advisory Board, Ad boards on SCLC and NSCLC: AstraZeneca; Financial Interests, Personal, Advisory Board, Panel to assess treatment toxicity: MSD; Financial Interests, Personal, Advisory Board, NSCLC presentation: Jansen; Financial Interests, Personal, Advisory Board, Adjudication of lung toxicity in non-metastatic lung cancer: MSD; Financial Interests, Personal, Advisory Board, Advisory board: Roche; Financial Interests, Institutional, Research Grant, Funded PhD studentship to study patterns of care in early-stage lung cancer: AstraZeneca; Financial Interests, Institutional, Funding, Funded trials evaluating in preoperative chemo-immune-radiotherapy and in radio-immunotherapy in stage IV NSCLC: BMS; Financial Interests, Institutional, Funding, Co-PI of an institutional trial evaluating a palliative radiotherapy workflow: Varian Medical Systems; Financial Interests, Institutional, Funding, Co-PI of an institutional trial evaluating immune effects of ablative radiotherapy of adrenal metastases: ViewRay Inc; Non-Financial Interests, Leadership Role, Co-investigator for a phase III trial evaluating adjuvant immunotherapy in SCLC: AstraZeneca. All other authors have declared no conflicts of interest.