Breast Cancers Behave Differently Before And After The Age Of 70

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Breast Cancers Behave Differently Before And After The Age Of 70: Could

Immune Defense Mechanisms Play A Role?

http://www.medicalnewstoday.com/articles/104610.php

Article Date: 18 Apr 2008 - 7:00 PDT

Researchers in Belgium have discovered that increasing age affects the way

breast cancer behaves. As women approach the age of 70, they become less likely

to be diagnosed with aggressive tumors that have spread to the lymph nodes.

But after 70, the cancer is increasingly likely to spread, particularly if the

tumors are small.

Until now, there has been conflicting evidence on aging and lymph node

involvement and this study is the first to show clearly how the link between the

two

changes before and after the age of 70.

Professor Hans Wildiers told the 6th European Breast Cancer Conference

(EBCC-6) in Berlin today (Friday), that he suspects that women older than 70

have

decreased immune defence mechanisms, which are less able to deal with tumors

that are likely to metastasize to other sites in the body.

" The effect of age of lymph node positivity is not straightforward. There

seems to be a different effect between women aged up to 70 years and women older

than 70. For the younger group of women, age appears to have a negative effect

on lymph node status - the older they become, the less likely the cancer is

to have spread to the lymph nodes. For the older group of women (aged over 70),

age appears to influence lymph node status in the opposite way - the older

they become, the more likely they are to have cancer cells in the lymph nodes if

the tumor is small, " said Prof Wildiers, who is adjunct head of clinic in the

department of general medical oncology at the Multidisciplinary Breast

Centre, University Hospitals Leuven, Belgium.

" There is an interaction between age and tumor size, suggesting that, up to

the age of 70, age mainly has a positive effect on lymph node status for older

women with small tumors. A likely explanation is that breast tumors

metastasize less frequently to lymph nodes with increasing age due to the

decreased

biological aggressiveness in these tumors. On the other hand, over the age of

70,

if the tumors have the potential to metastasize to lymph nodes, this occurs

more rapidly in smaller tumors and this might be related to decreased immune

defence mechanisms in elderly patients. "

Prof Wildiers and his colleagues investigated 2,227 women who had been

treated for breast cancer between 2000 and 2006 at the University Hospitals

Leuven.

Then they compared the results with a separate database of over 11,000 breast

cancer patients on the Eindhoven Cancer Registry.

They found that for women aged 70 or younger, increasing age was associated

with a decreased prevalence of cancer spreading to the lymph nodes. The women's

risk of having positive lymph nodes decreased by 13% for every decade they

aged, up to age 70.

Once aged 70 and over, the odds of lymph node involvement doubled with every

10-year increase in age for women who had tumors that were no bigger than 15mm

across. If the tumors were larger than 42-43 mm, then risk of lymph node

involvement continued to decrease.

Prof Wildiers said: " We know that the elderly have depressed immune defences,

and, therefore, it is possible that these decreased defences are unable to

prevent invasion of the lymph nodes by metastases in a subset of breast tumors

in elderly women. Although breast cancer survival in older women appears to be

similar to survival in the general population irrespective of disease status,

it might well be that there is a balance in the elderly between, on the one

hand, a less aggressive type of tumour, and, on the other hand, their decreased

immunological defences. "

He said the findings supported the idea that there are two types of tumor in

elderly women: ones that are slow-growing and don't invade the lymph nodes

even if the tumors are larger, and ones that are aggressive and metastasize very

early to the lymph nodes. Women with slow-growing tumors might benefit from

less aggressive treatment, while the smaller tumors in the women aged over 70

might need to be treated more aggressively.

" Further research now needs to be conducted into the role the immune system

plays in lymph node invasion, " he concluded.

6th European Breast Cancer Conference (EBCC 6)

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