One for the Boys: Male breast Cancer Incidence, Mortality and Survival Rates
Whilst researching for our new, updated posts on female breast cancer survival rates, it became apparent that there is not a lot of information in one place about male breast cancer.
In this post we will be looking at all the latest information on male breast cancer incidence, mortality and survival rates.
Male breast cancer Incidence Rates
The American Cancer Society estimates that in the year 2017 2,470 men will have a breast cancer diagnosis. This is in comparison to a whopping 252,710 American women estimated to be diagnosed with breast cancer in 2017.
Indeed, breast cancer is around 100 times less common in men than in women. The American Cancer Society predicts that the lifetime risk for breast cancer in males is around 1 in 1,000.
Male breast cancer is very rare, of all breast cancers less than 1% occur in men.
Because of the relative rarity of male breast cancer, medical studies and statistics are of small samples. There is, obviously, nowhere near the amount of research studies and information for male breast cancer as there is for female breast cancer.
However, it is known that incidence rates of male breast cancer were on the increase between the years of 1973 and 1988. One medical study used the SEER database to examine male breast cancer incidence rates. Indeed, between 1973 and 1988 male breast cancer increased from 0.86 to 1.08 per 100,000.
However, according to the breast cancer.org, the incidence rates of breast cancer in men have been fairly stable over the last 30 years.
Survival Rates for Male Breast Cancer
For reasons not fully understood yet, male breast cancer patients have a poorer outcome compared with female patients when matched with stage at diagnosis.
One 2013 medical study examined 150 operable male cancer patients and compared them to female breast cancer cases between 1980 and 2012.
The results were:-
- The 5 year disease free survival rate for men was 65.6%
- 5 year disease free survival rate for women was 72.9%
- The 10-year disease free survival rate for men was 40.1%
- 10 year disease free survival rate was 51.5% for women
- The 5 year overall survival rate was 72.9% for men and 83.2% for women
- 10 year overall survival rate was 53.9% for men and 68.5% for women
What are the reasons for the difference in survival rates for men and women
As mentioned, due to the rarity of breast cancer in men, extensive, large sample size studies are few and far between.
However, there are some differences in some of the main prognostic factors for breast cancer.
According to one study, that analysed SEER statistics between the years of 1973 and 1998, there are several factors in male breast cancer cases that differed from women:-
This study found that men:-
- Had a higher mean age at diagnosis
- Were more likely to have lymph node involvement
- Had a more advanced stage of breast cancer at diagnosis
- Were more likely to have hormone receptor positive status (ER+ and PR+) tumors
- Larger tumor size at diagnosis
Male Breast Cancer Survival Rates by Stage
Female Breast Cancer Survival Rates by Stage
We can see from the above 2 graphs for male and female breast cancer survival rates by stage, that the figures are fairly similar. Furthermore, for ductal carcinoma in-Situ, survival rates for both sexes tends to be excellent.
Statistical Note: Expect the female survival rates to be slightly better than the above graph shows. This is because these figures were taken from 2012 available SEER statistics, whereas the male graph data is from 2017.
Age at diagnosis in Male Breast Cancer
Similarly to women, the age at diagnosis does affect prognosis and risk factor in male breast cancer. It is medically well established that incidence rates rise steadily with age.
The average age of diagnosis for male breast cancer is 67.68 years. This is 5 to 10 years older than for female breast cancer patients in the USA. However, age at diagnosis varies geographically. For example, in the Middle East and South Asia, the age gap is much narrower between men and women.
Male Breast Cancer, Family History and Genetics.
According to a 2016 medical paper, one of the main predisposing factors for male breast cancer is a positive family history.
Indeed, men with a first degree relative with breast cancer have a 2 time greater risk than those with no family history. This risk can increase up to 5 times greater with more affected relatives. It is estimated that up to 10% of male breast cancers are hereditary types.
This suggests that genetic factors play an important role in male breast cancer. Two important gene mutations BRCA1 and BRCA2 play a role in male breast cancer with BRCA2 carrying a higher risk.
A 2016 medical study found that the lifetime risk for males developing breast cancer is 1.5% for BRCA1 gene mutation and 5-10% for BRCA2 mutation carriers. This compares to a 0.1% risk factor for the general male population.
It has been suggested by medical research that BRCA2 breast cancers in men more closely resemble post-menopausal female breast cancer. However, these male breast cancers tend to be of a high grade.
Types of male breast cancer.
Ductal carcinoma in situ accounts for only around 10% of male breast cancers. Ductal-carcinoma in-Situ (DCIS) is a very early form of breast cancer and usually presents as low grade. As for women, prognosis for DCIS is excellent.
The most common type of male breast cancer is invasive ductal carcinoma. Indeed, one research study looked at data from SEER of over 2,000 male patients and found that 93.7% are ductal or unclassified cancers. Papillary cancers account for 2.6% of male breast cancer cases, 1.8% are mucinous and only 1.5% are lobular.
Male breast cancers tend to have higher rates of hormone receptive positive tumors. Around 90% of male breast cancers are estrogen receptor positive (ER+) and 81% progesterone positive (PR+).
Furthermore, a study of HER2 tumors found that only 5% of male breast tumors were positive. High expression of androgen protein was also associated with lymph node spread and a poorer prognosis for male breast cancer.
Also younger black men had a lower survival rate than younger white men. This may be due to socio-economic factors.
Other Risk Factors for Male Breast Cancer
We have already looked at some of the risk factors associated with male cancer of the breast, including getting older and family history. However, let’s have a look at some other factors.
High Estrogen Levels
As we have seen, a large percentage of male breast tumors are estrogen receptor positive and breast cell growth (including tumor growth) is stimulated by high levels of estrogen.
So, why would men have high Estrogen Levels?
- Hormonal Therapy: Sometime female hormones (estrogen and progesterone) are prescribed to men for the treatment of testicular cancer, prostate enlargement and aromatase deficiency.
- Obesity: Obesity, at present is not considered an established risk factor for male breast cancer but some medical studies have shown an increased incidence amongst obese men. However, it is known that being overweight increases estrogen levels.
- Liver Disease: Liver disease may alter the body’s ability to regulate estrogen levels in the blood. Hence, excessive alcohol intake is known to damage the liver and may be linked to male breast cancer although more research is needed in this area.
- Klinefelter Syndrome. Around 1 in 1,000 men are affected by this congenital disease whereby men have at least two ‘X’ chromosomes, rather than the traditional one. With this condition men have higher levels of estrogen and lower levels of male hormones.
- Gynecomastia: Benign condition of the breast that causes breast swelling in males. Gynecomastia can be caused by an imbalance of male and female hormones. However, a 2014 study by the National Cancer Institute confirms that gyncomastia carries a 10-fold risk for male breast cancer.
- Environmental factors: Exposure to radiation or female hormones in foods
- Ruddy KJ, Winer EP. (2013) Male breast cancer: risk factors, biology, diagnosis, treatment, and survivorship. Ann Oncol (2013) 24 (6): 1434-1443. https://academic.oup.com/annonc/article/24/6/1434/179450/Male-breast-cancer-risk-factors-biology-diagnosis
- Sanguinetti A, Polistena A, Lucchini R, Monacelli M, S. Galasse S, (et al). (2015) Male breast cancer, clinical presentation, diagnosis and treatment: Twenty years of experience in our Breast Unit Int J Surg Case Rep. 2016; 20(Suppl): 8–11.