An Institutional Survey of Early-Onset Breast Cancer in Young Women With Imaging and Molecular Subtype Correlation.

Purpose The burden of breast cancer in young women is high, necessitating an effective breast imaging screening protocol to decrease morbidity and mortality. This is one of the few studies conducted in India on young women with breast cancer, where we present imaging features along with proven molecular subtyping.  Methods This is a retrospective study of 58 young women with biopsy-proven breast cancer between the period of January 2021 to December 2023. All imaging features were analyzed, and histopathological correlation was done. Results In our cohort, the most common age group was between 35 and 40 years. All cases underwent ultrasound, while X-ray and mammography were performed in 20 cases. Among these, three patients underwent contrast-enhanced digital mammography (CEDM), and two underwent MRI. The majority of malignancies were diagnosed as invasive mammary carcinoma. Regarding molecular subtypes, Luminal B was the most prevalent, which was a unique finding in our study, followed by triple-negative breast cancer (TNBC). Lesions with human epidermal growth factor receptor 2 (HER2)-neu and Luminal B subtypes predominantly exhibited indistinct margins, while TNBC cases commonly showed microlobulated margins. Malignant calcifications were most frequently seen in TNBC, followed by Luminal B. A one-way ANOVA demonstrated a statistically significant difference in Ki-67 levels among the subtypes. Tukey's honestly significant difference (HSD) test for multiple comparisons revealed a significant difference between Luminal B and TNBC (p < 0.05), with TNBC showing a higher Ki-67 index. The chi-square test showed a statistically significant association between molecular subtype and the presence of metastases (p < 0.05), with Luminal B more commonly associated with metastatic disease. Pregnancy-associated breast cancer (PABC) was identified in four cases, of which two had metastases, suggesting that delayed presentation is common in PABC. Multicentric malignancies were relatively more frequent in the HER2-neu subtype. Conclusion Our study reflects the increase in breast cancer and metastases in young women. The Luminal B subtype was common in our study, which was different from other studies. Metastases and PABC were higher in Luminal B. Multicentric malignancy was relatively higher in HER2-neu. However, larger multicenter studies are recommended for validating this. These observations mandate an early imaging workup to detect cancer for better survival. We also recommend screening protocols as early as 35 years, as most of the presentations were above this age in our study.