Profile of breast cancer in patients with Li-Fraumeni syndrome: An institutional experience.

Abstract

e13042 Background: Li Fraumeni syndrome (LFS) is a rare autosomal dominant syndrome, associated with multisystem cancer predisposition. Considering the rarity of this syndrome, studies are very sparse on survival outcomes of breast cancer with germline TP53 mutation and there exists discrepancy amongst the results. Methods: This retrospective observational study included 17 patients with germline TP53 mutated breast cancer registered at All India Institute of Medical Sciences (AIIMS), New Delhi, India between the period of 1st April 2016 to 31st Dec 2023. Among the 577 high-risk breast cancer patients, who underwent germline mutation testing, 231 (40.03%) cases had pathogenic mutation [145(25.12%) were BRCA mutated,15 (2.59%) were TP53 mutated, and the rest were others pathogenic variant]. All the TP53 mutations were crosschecked via the ClinVar mutation database to be classified as pathogenic. Results: The median age of 15 patients was 31 years (23-55) and 12 (80%) cases were premenopausal. All the patients had breast cancer as the index malignancy. The Stage distribution (AJCC-7th edition) Stage I, 1(6.6%); Stage II, 7 (46.6 %); Stage III, 4 (26.6 %); and Stage IV, 3 (20 %). Eight cases (53.3%) were HER2 positive, 4 (26.6%) were hormone receptor-positive, and 3 (20%) were Triple-negative breast carcinoma (TNBC). Ten (10) patients received neoadjuvant chemotherapy and 6 (60%) had a complete pathological response. Eight cases (53.3%) cases had a significant family history with 9 (60%) of them having at least one first-degree relative with cancer and two had more than one first-degree relative with cancer. One patient had a family history of LFS. The most common familial cancer was breast, followed by lung, GI malignancies, brain tumor, and sarcoma. Synchronous breast cancer was seen in 2 patients, synchronous malignancies were seen in 4 cases (one patient: each with lung adenocarcinoma, periampullary carcinoma, carcinoma colon, and synovial sarcoma, along with breast cancer), Four patients (26.6%) had metachronous cancers: lung cancer, ovarian carcinoma, contralateral breast cancer, and high-grade sarcoma respectively. The most common mutations were point mutations ( n = 11, 73.3%) followed by frameshift mutations ( n = 4, 26.6%). The subtypes of point mutations included missense mutations ( n = 9) and nonsense mutations ( n = 2) with the most common aberration being a replacement of arginine with glycine (c.743G>A, p. Arg248Gln) and locus being exon 7. The median disease-free survival was 41 months and progression-free survival was 15 months. Conclusions: The prevalence of TP53 mutation in our breast cancer patients is 2.5%. With standard treatment protocols, the overall survival of LFS-associated breast cancer is similar to the historic cohort of patients without any germline mutation. Active surveillance of the patient and family screening is imperative, for all positive cases.