Ga PET-CT scan radiomics model helps identify prostate cancer

24th October 2022

A Ga PET-CT scan radiomics model distinguished between benign and prostate cancer more successfully than nuclear medicine radiologists

A gallium positron emission tomography/computed tomography (Ga PET-CT) scan-based radiomics model was better able to distinguish between benign prostate disease and prostate cancer than radiologists according to a retrospective study by Chinese researchers.

Prostate cancer is the 2nd most commonly occurring cancer in men and the 4th most common cancer overall with more than 1.4 million new cases reported in 2020 cancer and 375,304 recorded deaths. Prostate specific membrane antigen (PSMA) is a transmembrane protein that is expressed by virtually all prostate cancers and molecules targeting PSMA can be labelled with radionuclides to become both diagnostic and/or therapeutic agents. Gallium-68 prostate-specific membrane antigen (PSMA) positron emission tomography (PET) has increasingly been utilised globally to assess the local and metastatic burden of prostate cancer. Moreover, a meta-analysis of 37 studies concluded that Ga-68-PSMA PET improves detection of metastases with biochemical recurrence, particularly at low pre-PET PSA levels. A Ga PET-CT scan is normally interpreted by nuclear medicine specialists although there is some evidence to suggest that lesions can be missed. The use of radiomics focuses on improvements in image analysis, using an automated high-throughput extraction of large amounts (200+) of quantitative features of medical images. To date however, the predictive value of a Ga PET-CT scan radiomics model has not been explored for patients with prostate cancer and was the subject of the present study.

The Chinese team retrospectively examined patients who underwent a Ga PET-CT scan and who had pathologically proven prostate cancer or biopsy benign prostate disease. Radiomics prostate cancer features were extracted from the scans and a model created and the ability of the model to differentiate between prostate cancer and benign disease tested. The sensitivity, specificity, positive and negative predictive values of the model were calculated and compared with those of two radiologists who visually inspected the scans.

Ga PET-CT scan radiomics model performance

A total of 125 patients were included and split into a training set (87) and a test set (38). All patients underwent biopsy or surgery and their pathological examination results were assessed.

On the test set, the radiomics model had a sensitivity of 84%, specificity of 77% and and a positive predictive value of 88% for distinguishing between cancer and benign disease.

The agreement between the two radiologists for visual inspection of the scans were very close (kappa = 0.81). However, the corresponding sensitivity for the radiologists on the test set were 74% and specificity was 55% and both were significantly different to the radiomics model (p = 0.036 and 0.002 respectively).

The authors concluded that they had successfully developed and validated a radiomics model based on data extracted from a Ga PET-CT scan and that this non-invasive model was able to predict intraprostatic lesions in men with prostate cancer.

Citation
Zang S et al. Development and validation of 68Ga-PSMA-11 PET/CT-based radiomics model to detect primary prostate cancer EJNMMI Res 2022

Dense breasts and benign disease on mammography linked to higher risk of future breast cancer in Korean study

1st June 2022

Women found to have dense breasts and benign breast cancer upon mammography screening have an increased risk of future breast cancer, according to a recent Korean study

The presence of fatty or dense breasts and benign breast cancer seen on mammography screening in Korean women is associated with a more than two-fold higher risk of future breast cancer. This was the main finding of a retrospective analysis by a team of Korean researchers.

The World Health Organization has reported on how in 2020, there were an estimated 2.3 million women diagnosed with breast cancer which resulted in 685 000 global deaths.

Several factors have been identified as being associated with an increased risk for breast cancer in women which include increasing age, genetics, a family history of the cancer and prior treatment with radiation therapy.

Another factor is the presence of dense breasts upon mammography and one meta-analysis has suggested that the percentage dense area seen on mammography is a strong breast cancer risk factor.

A future factor associated with a higher breast cancer risk is the presence on screening, of both proliferative or non-proliferative benign breast disease, regardless of a family history of breast cancer.

To date, there are limited data on the combined impact of both dense breasts (based on the Breast Imaging Reporting and Data-System (BI-RADS) and the presence of benign breast cancer. One study has indicated that women with benign breast disease and dense breasts are at high risk for future breast cancer.

However, the study was undertaken largely in Westernised populations and there is little information on how the combination of dense breasts and benign breast cancer affect the risk among Asian women, especially given how Asian women have a higher percent breast density compared to Caucasian women.

In the present study, the Korean team retrospectively examined results from a breast screening mammography programme conducted in the Korean population among women 40 years of age and older. These women were followed until the data of their breast cancer diagnosis although individuals with a prior history of breast cancer were excluded.

Breast density was categorised using BI-RADS from A to D based on increasing levels of breast density. The primary outcome of interest was breast cancer and the results were adjusted for several factors such as a family history of the disease, age at menarche, number of children etc.

Dense breasts and breast cancer development

The analysis included 3,911,348 women in whom 58,321 breast cancers developed in women with a mean age of 51.8 years during a median follow-up of 10.6 years.

Breast cancer developed in women with both a higher level of benign breast cancer (18.4% vs 13.3%, p < 0.01) and more dense breasts (55.4% vs 38.4%, p < 0.01) at baseline.

When comparing the different BI-RADs categories, there was an increasing risk of breast cancer with higher breast densities in women who had benign breast cancer.

For example, in women with BI-RADS category A, there was a 49% higher risk of breast cancer in those identified with benign breast cancer (hazard ratio, HR = 1.49, 95% CI 1.40 – 1.58) compared to those in BI-RADS category A but without benign breast cancer.

This risk more than doubled for women with the highest category (BI-RADS D) and benign breast cancer (HR = 2.75, 95% CI 2.63 – 2.88).

The authors concluded that both higher breast density and the presence of benign breast cancer are linked to a higher risk of subsequent breast cancer.

Citation
Kin S et al. Mammographic Breast Density, Benign Breast Disease, and Subsequent Breast Cancer Risk in 3.9 Million Korean Women Radiology 2022