Breast Cancer: Whether it has crossed the basement membrane is the key to distinguishing invasive breast cancer

While breast cancer is considered one of the most feared diseases among women, vague anxiety can be reduced if the progression process and examination systems are accurately understood. Professor Kim Hyeong-seok of the Department of Surgery at Hanyang University Guri Hospital recently explained the core details from diagnosis to treatment of breast cancer through 'Uihak Channel Biondwi'.

Classification of Breast Cancer and Survival Rates According to Whether the Basement Membrane is Crossed

The breast consists of mammary ducts that gather at the nipple and lobules that produce milk. Most breast cancers start in the epithelial cells of these ducts or lobules. A state where cancer cells stay without crossing the 'basement membrane', which is the boundary of the duct, is called 'non-invasive breast cancer (carcinoma in situ)', and in this case, metastasis to other organs is extremely rare. On the other hand, from the moment cancer cells penetrate the basement membrane and spread to surrounding tissues, they are classified as 'invasive breast cancer', and from this point, the possibility of metastasis to lymph nodes or other organs arises. Invasive breast cancer is diagnosed from stage 1 to stage 4 depending on the stage.

Looking at the current status of breast cancer occurrence in South Korea, as of 2023, approximately 30,000 patients were newly diagnosed annually, and it is frequent enough to rank first in female cancer occurrence. In particular, unlike the West, it has the characteristic of having many patients in their 40s, so regular checkups are essential from the 40s. Fortunately, due to the advancement of medical technology, the 5-year relative survival rate of breast cancer has significantly improved from 79.3% in the early 1990s to 94.7% recently. This is thanks to early detection through regular checkups, advancements in surgery and radiation therapy, and the development of drug therapies tailored to the characteristics of the cancer. In particular, the survival rate when confined within the breast reaches 99.2%, while it is 93.6% for locally advanced cases where surrounding tissues or lymph nodes are invaded, and 55.4% for distant metastasis where it has spread to other organs, showing that early detection plays a decisive role in survival rates and the possibility of breast preservation.

Breast Cancer Risk Factors and Management Through Lifestyle Habits

The risk factors for breast cancer are largely divided into uncontrollable factors and controllable factors. Age, family history and genetic mutations (such as BRCA1/2, etc.), the duration of exposure to female hormones (early menarche, late menopause, experience of childbirth and age of first childbirth, etc.), dense breasts, and a history of atypical hyperplasia or lobular carcinoma in situ are factors that are difficult to control. Additionally, a history of receiving chest radiation therapy at a young age can also increase the risk.

On the other hand, it is possible to lower the risk through lifestyle choices. Since alcohol consumption increases cancer risk, it is recommended to reduce or avoid it if possible. Consistent exercise and maintaining an appropriate weight after menopause are helpful. However, in the case of hormone therapy experienced during menopause, rather than unconditionally avoiding it or stopping it arbitrarily, it should be decided after consulting with medical staff regarding the severity of symptoms and individual risk levels.

The Role and Differences Between Imaging Tests and Biopsies

Finding abnormal findings in screening results does not always mean cancer. Imaging tests are the stage for judging the degree of suspicion of cancer, and confirming cancer is only possible through a 'biopsy'. Each imaging test has a complementary role.

• Mammography: The basis of regular checkups, it is advantageous for checking microcalcifications or structural changes.
• Breast Ultrasound: Used complementarily when it is difficult to confirm with mammography alone in the case of dense breasts, and is suitable for looking closely at the interior and boundaries of a lump.
• Breast MRI: Uses contrast agents to most sensitively evaluate the extent and size of a lesion, and is useful for high-risk patients or confirming lesions after a cancer diagnosis.

The most common biopsy method is 'Core Needle Biopsy', where the location is confirmed with ultrasound and then tissue is collected with a thick needle. In addition, if more tissue is needed, 'Vacuum-Assisted Biopsy' is performed, and 'Fine Needle Aspiration Test' is performed for evaluating lymph nodes or cysts. Professor Kim Hyeong-seok explained that the concern patients often have, that 'cancer spreads because of needle biopsy', lacks medical evidence, so they can proceed with peace of mind.

Pain and Lumps: What Symptoms Should Be Watched For

Breast pain is a symptom reported by many patients, but there is no need to suspect cancer from pain alone. Most are periodic pain before and after menstruation, muscle pain, costochondral pain, or pain caused by external stimulation after wearing incorrect underwear or exercising. However, if the following symptoms appear, you must seek medical attention from a specialist.

The most common cancer symptom is a 'painless lump'. In addition to this, if a new lump is felt in the breast or armpit, if the skin changes like an orange peel or becomes indented, if the nipple is retracted, if bloody discharge comes from the nipple, if the size or shape of one breast changes rapidly, or if the breast is red, swollen, and hot, you must undergo an examination immediately.

If cancer is confirmed by biopsy, the 'subtype' is determined by checking levels such as ER (Estrogen Receptor), PR (Progesterone Receptor), and HER2 (Human Epidermal Growth Factor Receptor 2). If ER or PR is positive, it is defined as hormone receptor-positive breast cancer, and if the HER2 protein is expressed, it is defined as HER2-positive breast cancer. These subtypes are the most important clues in establishing a customized treatment plan for each individual patient.