YO29 - Multiple primary cancers (MPC) of breast and lung with primary EGFR T790M mutation Responded to Aumolertinib: A case report

Case summary

Background: The first-line treatment for primary EGFR T790M-mutated NSCLC still lacks standard recommendations, especially in MPC of breast and lung.

Case presentation: A 58-year-old female patient with vaginal bleeding as the initial symptom in August 2022. Previously, in 2021, she underwent a "total hysterectomy" due to cervical CINⅢ involvement of glands. A pathological consultation revealed moderate to poorly differentiated adenocarcinoma in the pelvic mass puncture tissue, with some micropapillary features consistent with metastatic adenocarcinoma. After examination, she was diagnosed with: pulmonary malignant tumor (T4N2M1, stage IV), malignant tumors of the breast (T2N1Mx), and multiple secondary malignant tumors in lymph nodes, bones, adrenal glands, pelvic cavity, lungs and brain.

For lung adenocarcinoma, she commenced treatment with pemetrexed plus carboplatin for 1 cycle, starting in October 2022, in conjunction with fluvestrant. Genetic testing analysis showed that primary T790M mutations and L858R mutation, and was subsequently treated with aumolertinib 110 mg per day orally, which continues to date.

For Breast cancer (cT2N1Mx Luminal B), considering the enlargement of the breast tumor that letrozole therapy previously, she received endocrine therapy with fluvestrant 500mg once every 28 days.

Subsequent assessments showed the disappearance of the lung lesions, hilar and mediastinal lymph nodes, and pelvic soft tissue masses, the reduced left adrenal lesions and shrinking intracranial lesions. The breast ultrasound also showed a reduction in the solid mass in the left upper outer quadrant of breast. The patient's response assessment was evaluated as partial response. Symptomatic treatment such as nourishing myocardium, protecting liver, acid suppression and promoting platelet were provided during the treatment period. As of now, this patient has achieved a PFS of more than 21 months and continues to undergo close follow-up.

Conclusions: This report presents the first case of applying aumolertinib for primary EGFR T790M mutations in patients with MPC of breast and lung, offering a promising treatment approach for the future survival of such patients.

Clinical trial identification

Editorial acknowledgement