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5 Facts You May Not Know About Breast Cancer

Updated: Sep 27, 2023

This article has been re-posted from 5 Facts You May Not Know About Breast Cancer - OWise UK.

Breast cancer was the first cancer ever recorded

A manuscript from 3000BC described a “bulging mass in the breast” which was concluded as a grave disease with no available treatment. The notes, thought to be made by the Egyptian Imhotep, were transcribed onto a papyrus scroll bought by Edwin Smith in 1862(1). This is the earliest record of cancer that has been discovered and highlights the progress of breast cancer treatment in terms of screenings, diagnosis, and treatments.

Tamoxifen was originally created as a contraceptive pill

Now a common hormonal treatment, tamoxifen was created for a completely different purpose. Scientists in the 1960’s synthesized the drug hoping it would block estrogen and act as an effective contraceptive. However, during testing, they found that tamoxifen stimulated, rather than suppressed, ovulation in women(2).

This was originally seen as a failure and the development of tamoxifen was almost abandoned. However, the team leader, Arthur Walpole, refused to stop there. He threatened his resignation if the project ceased. They decided to develop tamoxifen as a treatment for breast cancer, which has led to it now being the world’s best-selling hormone therapy for breast cancer.

Chemotherapy was a product of the First World War

"In World War I, chemical warfare began to dominate in the front lines."

The most notorious of these was Mustard Gas, otherwise known as nitrogen mustard. In the 1940’s, two Yale pharmacologists, Alfred Gilman and Louis Goodman noticed that the soldiers affected by mustard gas had a surprisingly low number of immune cells in their blood. They hypothesized that if mustard gas could destroy normal white blood cells, it seemed likely they could also destroy cancerous ones.

In 1942 the first clinical trial was created to test the use of nitrogen mustard in destroying cancer cells. The trial was a success, and further development by Professor Alexander Haddow found the exact molecule within nitrogen mustard that was needed to kill cancer cells, whilst also making the chemical less toxic to normal cells. This signified the birth of chemotherapy, and further developments from the original molecule discovered led to such chemotherapeutic drugs as cyclophosphamide(3).

Breast cancer is more likely to develop in the left breast than the right

Over the past 70 years, several studies have shown that unilateral breast cancer is 5-13% more likely to develop in the left breast than the right(4,5). The reasons why are still unknown. Suggested theories include the left breast being slightly larger than the right(6), breastfeeding being commonly preferred on the right side, which has been suggested as reducing the risk of breast cancer (7), or the more-common right-handed women may check the left breast for lumps more often(8).

However, these explanations have been countered by several findings, including the fact that this asymmetry of breast tumours is also found in men, as well as also being present in breast tumours that stay in the breast or spread to surrounding tissues(5).

Mastectomies date back to the 1800’s

In 1882, a milestone was achieved in breast cancer treatment when a radical mastectomy was performed by William Halsted(9). All the breast tissue was removed, as well as the two muscles behind the breast and the lymph nodes in the armpit. This approach was revolutionary, with previous surgeries resulting in poor long-term results and outlook. They were offered as a one-size-fits-all approach, no matter the woman’s age or tumor type. However, with the subsequent weakening of arm function and lymphoedema, as well as the effect on women’s body image, new options for surgery needed to be explored(10).

Nowadays, a mastectomy is still a common procedure for breast cancer treatment, however the initial radical mastectomy performed by Halsted is rarely used. Instead, a whole range of factors are considered before opting for a mastectomy, and various types of treatment, including breast conserving surgery, are now available.


  1. Hajdu S. (2010) A note from history: Landmarks in history of cancer, part 1. Cancer. 117(5):1097-1102.

  2. Quirke V. (2017) Tamoxifen from Failed Contraceptive Pill to Best-Selling Breast Cancer Medicine: A Case-Study in Pharmaceutical Innovation. Frontiers in Pharmacology. 8.

  3. DeVita V, Chu E. (2008) A History of Cancer Chemotherapy. Cancer Research. 68(21):8643-8653.

  4. Busk T, Clemmesen J. (1947) The Frequencies of Left- and Right-sided Breast Cancer. British Journal of Cancer. 1(4):345-351.

  5. Sughrue T, Brody J. (2014) Breast Tumor Laterality in the United States Depends Upon the Country of Birth, but Not Race. PLoS ONE. 9(8):e103313.

  6. Trichopoulos D, Lipman R. (1992) Mammary Gland Mass and Breast Cancer Risk. Epidemiology. 3(6):523-526.

  7. Ing R, Ho J, Petrakis N. (1977) Unilateral Breast-feeding and Breast Cancer. The Lancet. 310(8029):124-127.

  8. Hartveit F. (1983) The side and size of breast tumours. Clinical Oncology. 9(2):135-142.

  9. Rankin J. William Stewart Halsted. (2006) Annals of Surgery. 243(3):418-425.

  10. Patey D, Dyson W. (1948) The Prognosis of Carcinoma of the Breast in Relation to the Type of Operation Performed. British Journal of Cancer. 2(1):7-13.


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