A mathematical model of axillary lymph node involvement considering lymph node size in patients with breast cancer

Early detection of metastatic disease in asymptomatic breast cancer patients with whole-body imaging and defined tumour marker increase

BACKGROUND

Follow-up care in breast cancer is still an issue of debate. Diagnostic methods are more sensitive, and more effective therapeutic options are now available. The risk of recurrence is not only influenced by tumour stage but also by the different molecular subtypes. This study was performed to evaluate the use of whole-body imaging combined with tumour marker monitoring for the early detection of asymptomatic metastatic breast cancer (MBC).

METHODS

This analysis was performed as part of a follow-up study evaluating 813 patients with a median follow-up of 63 months. After primary therapy, all patients underwent tumour marker monitoring for CEA, CA 15-3 and CA 125 at 6-week intervals within an intensified diagnostic aftercare algorithm. A reproducible previously defined increase was considered as a strong indicator of MBC. From 2007 to 2010, 44 patients with tumour marker increase underwent whole-body magnetic resonance imaging and/or an FDG-PET/CT scan. Histological clarification and/or imaging follow-up were done.

RESULTS

Metastases were detected in 65.9% (29/44) of patients, 13.6% (6/44) had secondary malignancies besides breast cancer and 20.5% (9/44) had no detectable malignancy. Limited disease was found in 24.1% (7/29) of patients. Median progression-free survival of MBC was 9.2 months and median overall survival was 41.1 months. The 3- and 5-year survival rates were 64.2% and 40.0%, respectively.

CONCLUSIONS

A reproducible tumour marker increase followed by whole-body imaging is highly effective for early detection. By consequence, patients might benefit from earlier detection and improved therapeutic options with a prolonged survival.

Diagnostic efficacy of whole-body diffusion-weighted imaging in the detection of tumour recurrence and metastasis by comparison with 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography or computed tomography in patients with gastrointestinal cancer

Objective: The primary aim of this study was to assess the efficacy of whole-body diffusion-weighted imaging (WB-DWI) in detecting tumour recurrence and metastasis of gastrointestinal cancers by comparison with 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography or computed tomography (¹⁸F-FDG-PET/CT). A secondary aim was to evaluate the change of apparent diffusion coefficient (ADC) value between metastases and normal tissues.

Methods: Twenty-eight previously confirmed gastrointestinal cancer patients with suspected tumour recurrence or metastasis were recruited. WB-DWI and PET/CT images were evaluated by two radiologists and a nuclear medicine physician. Agreement between WB-DWI and PET/CT for detective efficacy was compared using kappa statistics. Additionally, diagnostic accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were also statistically analysed. ADC values between metastatic and normal tissues were compared.

Results: There was no statistically significant difference (P > 0.05) in the overall diagnostic performances of PET/CT (accuracy 98.9%; sensitivity 95.2%; specificity 99.8%; PPV 98.9%; NPV 98.9%) and WB-DWI (accuracy 95.9%; sensitivity 81.7%; specificity 99.1%; PPV 95.0%; NPV 96.1%). WB-DWI showed agreement with PET/CT (κ = 0.877) for detecting recurrence and distant metastases. A statistically significant difference in ADC value was observed between tissues of normal healthy volunteers and metastases in lymph nodes, liver and bones (P < 0.05).

Conclusions: WB-DWI is reliable in detecting tumour recurrence and metastasis of colorectal cancer and offers the same diagnostic performance as ¹⁸F-PET/CT without ionizing radiation. The quantitative value of ADC provides extra information to determine cancer metastasis.

Dynamics of metastasis suppressor gene inactivation

For most cancer cell types, the acquisition of metastatic ability leads to clinically incurable disease. Twelve metastasis suppressor genes (MSGs) have been identified that reduce the metastatic propensity of cancer cells. If these genes are inactivated in both alleles, metastatic ability is promoted. Here, we develop a mathematical model of the dynamics of MSG inactivation and calculate the expected number of metastases formed by a tumor. We analyse the effects of increased mutation rates and different fitness values of cells with one or two inactivated alleles on the ability of a tumor to form metastases. We find that mutations that are negatively selected in the main tumor are unlikely to be responsible for the majority of metastases produced by a tumor. Most metastases-causing mutations will be present in all (or most) cells in the main tumor.

Stochastic dynamics of metastasis formation

Tumor metastasis accounts for the majority of deaths in cancer patients. The metastatic behavior of cancer cells is promoted by mutations in many genes, including activation of oncogenes such as RAS and MYC. Here, we develop a mathematical framework to analyse the dynamics of mutations enabling cells to metastasize. We consider situations in which one mutation is necessary to confer metastatic ability to the cell. We study different population sizes of the main tumor and different somatic fitness values of metastatic cells. We compare mutations that are positively selected in the main tumor with those that are neutral or negatively selected, but faster at forming metastases. We study whether metastatic potential is the property of all (or the majority of) cells in the main tumor or only the property of a small subset. Our theory shows how to calculate the expected number of metastases that are formed by a tumor.

Magnetic resonance axillography for preoperative diagnosis of the axillopectoral muscle (Langer's axillary arch): a case report

The axillary arch of Langer is the most common muscular variation in the axilla. Recognition of anatomic variations is important for surgeons to perform safe axillary surgery. We describe a case of a woman with breast cancer, in whom sentinel lymph node biopsy was successfully performed and the presence of this anomaly preoperatively diagnosed by magnetic resonance axillography.