Highlights from ASCO 2022: A Look at Key Poster Sessions & Emerging Clinical Data

The American Society of Clinical Oncology’s 2022 Conference has just passed, so let’s take a look at one of the key posters presented at the conference.

Evaluating the efficacy of chemotherapy compared to endocrine therapy

Detecting and treating metastatic breast cancer (MBC) has long been challenging because of the heterogeneity of estrogen receptor (ER) expression. But while ER detection can be challenging, MBC patients with ER uncertainties can now be screened and analyzed using ¹⁸F-fluoroestradiol positron emission tomography/computed tomography (¹⁸F-FES PET/CT).

In a recent study, MBC patients who received ¹⁸F-FES PET/CT were evaluated, and patients with both FES positive (FES+) and negative (FES-) lesions were enrolled. Researchers used the Kaplan-Meier method to measure progression-free survival and compared by log-rank test.

Out of the 635 patients who were screened:

• 75 of 635 (11.8%) patients showed ER uncertainty
• Among them, 20 (39.2%) patients received chemotherapy (CT)
• 21 (41.2%) patients received endocrine-based therapy (ET)
• 10 (19.6%) patients received combined therapy (CT+ET)

According to the results, chemotherapy showed better progression-free survival (PFS) compared to endocrine therapy. On top of that, chemotherapy plus endocrine therapy didn’t improve PFS compared to either chemotherapy or endocrine therapy, alone.

These results show that patients with ER heterogeneity can be identified using ¹⁸F-FES PET/CT, and patients with ER uncertainty showed better sensitivity to chemotherapy rather than endocrine therapy. Treatment outcomes were also not improved with chemotherapy plus endocrine therapy combined therapy.

Exploring targetable genomic mutations in young women with advanced breast cancer

For women younger than 40 years old with advanced breast cancer, clinical data has shown that they’re often faced with a worse prognosis and disease-free survival as compared to women above the age of 40. But as the treatment landscape continues to expand, and with the growing availability of targeted and immune therapies, a recent study aimed to investigate genomic alterations (GA) using comprehensive genomic profiling (CGP) of tumor tissue.

In this study, 2,049 breast cancers were submitted to Foundation Medicine for CGP. Of these patients, 28 (1.37%) were under 30 years of age, 159 (7.76%) were between the ages of 30 and 39 years old, and 1,862 (90.87%) were 40 years old and above. After those breast cancers were submitted, researchers performed a hybrid capture-based CGP to evaluate all classes of GA. breast tissue was used for 69.5% of cases and the remainder of specimens were lymph node, metastatic, or unspecified. This type of genomic profiling was also used to measure tumor mutational burden (TMB), microsatellite instability, and tumor cell PD- L1 expression.

The results showed that breast tumors were less likely to be estrogen receptor-positive in younger women and more likely to be triple-negative. Some of these results include:

• Estrogen receptor-positive breast tumors: 54% of those under 30 years of age, 60% of those between the ages of 30 and 39 years old, 69.4% of those 40 years old and above
• Triple-negative breast tumors: 43% of those under 30 years of age, 33% of those between the ages of 30 and 39 years old, 26.1% of those 40 years old and above

While there was no clear pattern in HER2+ status according to age, the study also found that younger women had higher rates of BRCA1, BRCA2 mutations, RB1 mutations as well as lower rates of CDH1 and PIK3CA mutations. Younger women were also more likely to have PD-L1 expression but had lower frequencies of TMB under 10.

These findings demonstrate that young women with breast cancer have actionable GA and that different mutational profiles may support differential use of targeted and immune therapies. Key differences in genetic mutations can help inform treatment decisions and have a significant impact on the treatment landscape as a whole.