Cancer spread; do age and tumor type affect the risk?

The authors aimed to determine if there was a link between patient age, tumor type and the spread of cancer. 

Breast cancer metastasis is the spread of the cancer to other parts of the body; following original cancer of the breast. Age at original diagnosis and the area affected by the tumor are just two of the risk factors associated with a breast cancer prognosis (survival outlook).

To date, the influence of age and tumor type on breast cancer metastasis development, time and affected body part has not been well studied. 

The aim of this study was to evaluate the risks of breast cancer metastasis according to age and tumor type.

A total of 9,514 women with early breast cancer were evaluated, of whom 82.3% were estrogen receptor positive (ER+; presence of estrogen receptor proteins on cancer cells), with no previous breast cancer diagnosis.

Overall, 10.4% of the patients developed metastasis; the cancer returned and spread. The most common site was to the skeleton, occurring in 32.5% of those with metastasis. 

Women aged below 50 at cancer diagnosis were 50% more likely to experience metastasis at 2 years after diagnosis than women aged over 50. This risk lowered significantly by 10 years. 

Those with cancer present in the lymph nodes had 2.6 times the risk of developing metastasis compared to those without cancer in the lymph nodes within 10 years of diagnosis. Those with ER- breast cancer (cancer cells that do not  have estrogen receptor proteins) had almost 3 times the risk of developing cancer metastasis within the first two years following treatment compared to those with ER+ disease. If the patient had not developed metastasis by 10 years then the increased risk disappeared. Those with a tumor larger than 20 mm at diagnosis had a 50% increased risk of developing metastasis at 10 years compared to those with smaller tumors. 

Overall, women younger than 50, with ER- cancer that was present in the lymph nodes and a breast cancer tumor that was bigger than 20 mm at diagnosis had a 55% risk of experiencing metastasis by 5 years after diagnosis. Women older than 50, with ER+ cancer that was not present in the lymph nodes and a breast cancer tumor that was smaller than 20 mm at diagnosis had a 3% risk of experiencing metastasis by 5 years. 

The authors concluded that age and tumor type are risk factors of cancer metastasis, and that clinical follow-up may need to continue beyond 5 years in certain subsets of patients. 

Modern cancer treatments may have altered cancer metastasis risks.