Receiving a cancer diagnosis can be emotionally overwhelming, especially with the introduction of unfamiliar medical terminology that may heighten your fears. However, gaining an understanding of these terms can empower you in managing your health. One such term is “in situ,” which indicates that the cancerous cells are contained in the location where they first appeared, without having spread to nearby tissues or other regions of the body.
Generally speaking, this is positive news. Cancers in situ are often highly treatable and can usually be completely removed, typically via surgery. Medically, this is classified as stage 0 cancer. It’s also referred to as noninvasive or preinvasive cancer. (Discover the truth about common cancer and food myths here.)
The term “curable” is often used for in situ cancers, as no further treatment is typically required. As noted by the American Cancer Society, doctors prefer the term “in remission” instead of cured, due to the possibility, however small, of cancer returning.
One of the major advantages of regular screening, especially for breast, colon, and skin cancers, is the early detection of cancer while it’s still in situ. This early detection significantly increases the likelihood of successful treatment.
In situ cancers are often detected through screening
According to the Breast Cancer Research Foundation, ductal carcinoma in situ (DCIS) comprises up to 25% of breast cancer diagnoses. While DCIS can increase the risk of more invasive breast cancer, it is not deemed life-threatening. The cancerous cells originate and typically remain in the milk ducts, rarely spreading to surrounding breast tissue. Often, a lump isn’t felt, so this type of cancer is usually detected via mammogram and confirmed through a biopsy. The tumor is generally removed through a lumpectomy, preserving the surrounding breast tissue, and radiation therapy may be recommended to target any remaining cancerous cells.
Most skin cancer cases are either basal cell carcinoma or squamous cell carcinoma, but the rarer and more hazardous melanoma can also be in situ. Depending on your health and the melanoma’s location, surgery is often the first treatment option. If surgery isn’t viable, a cream called imiquimod may be used to stimulate the immune system to combat the cancer, as outlined by Cancer Research UK.
Colon cancer often doesn’t present noticeable symptoms until later stages, according to the Moffitt Cancer Center. Hence, regular screening, such as a colonoscopy, is vital for early detection. If colon cancer is found in situ, the abnormal cells are confined to the innermost layer of the colon wall. These cells can typically be removed during a colonoscopy using a surgical scope, preventing further cancer progression.
Why in situ cancers still require serious attention
Even with an in situ cancer diagnosis, it’s crucial not to take it lightly. Per the Breast Cancer Research Foundation, up to 50% of untreated DCIS cases can evolve into more invasive breast cancer. Encouragingly, treatment for DCIS results in a 98% survival rate over 10 years.
An in situ skin carcinoma indicates that abnormal cells are limited to the upper skin layers. However, if untreated, these cancers can become dangerous. Melanoma, for instance, can be life-threatening if not addressed promptly due to its rapid spread. As noted by Westlake Dermatology, untreated melanoma can be fatal within just four weeks. It’s also vital to take squamous cell carcinoma seriously, as they can still be deadly if ignored, despite not spreading as swiftly as melanoma.
Colon cancer typically grows slower than other cancer types. A colon polyp can take up to a decade to develop into cancer, according to the Cleveland Clinic. Nevertheless, this doesn’t justify delaying colon cancer screenings. The National Cancer Institute projects that over 154,000 individuals in the U.S. will be diagnosed with colorectal cancer in 2025, ranking it as the fourth most common cancer after breast, prostate, and lung cancer. It is also anticipated to be the second leading cause of cancer-related deaths, following lung cancer.
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