The Stages of Cancer
Understanding cancer stages is vital for NPs to ensure high-quality, informed, and comprehensive care for patients with cancer, fulfilling their roles in clinical decision-making, patient education, and inter-professional collaboration. This knowledge is rightly considered essential for NP boards and likely to show up in the exams.
What is Cancer
Cancer is a disease in which some cells grow uncontrollably and spread to other body parts1. It's caused by DNA changes due to various factors, including gene mutations, exposure to radiation and cancer-causing chemicals like smoking and asbestos, obesity, hormonal imbalances, and chronic inflammation.
Types of Cancer
Cancer can affect virtually any body part, and there are many types. The most common types of cancer are:
Breast: It primarily affects women but can also occur in men. There are different sub-types of breast cancer, depending on which cells in the breast turn into cancer.
Lung: This includes two main sub-types: small cell and non-small cell lung cancer. It's strongly associated with smoking, although non-smokers can also develop lung cancer.
Colorectal: This includes cancers of the colon or rectum, which are parts of the large intestine. Screening tests like colonoscopies can help detect this cancer early when it's more treatable.
Prostate: This is a common cancer in men and occurs in the prostate, a small walnut-shaped gland that produces seminal fluid. It's often a slow-growing cancer and may not need immediate treatment in its early stages.
Skin: The most common types are basal and squamous cell carcinoma, usually caused by sun exposure. Melanoma is less common but more dangerous.
Worldwide Cancer Statistics2
| Incidence | Deaths |
|---|---|
| breast (2.26 million cases) | lung (1.80 million deaths) |
| lung (2.21 million cases) | colon and rectum (916 000 deaths) |
| colon and rectum (1.93 million cases) | liver (830 000 deaths) |
| prostate (1.41 million cases) | stomach (769 000 deaths) |
| skin [non-melanoma] (1.20 million cases) | breast (685 000 deaths) |
| stomach (1.09 million cases) |
As you can see, there are many types of cancers, some are blood cancers also known as hematologic cancers (leukemia, multiple myeloma), while others are solid tumor cancers (breast cancer, colorectal cancer). This blog focuses on solid cancers staging.
Cancer Stages
Cancer staging is the process of determining how much cancer there is within the body and if it has spread. This information can aid in treatment and prognosis.
Number Staging (0-4)
Cancer staging for solid tumors includes 4 stages:
- Stage 0 = no cancer
- Stage 1 = localized
- Stage 2 = early locally advanced
- Stage 3 = late locally advanced
- Stage 4 = metastasized
Cancer treatment and prognosis vary significantly based on its diagnosed stage. Cancers diagnosed in stages 1 to 3 could be treatable and curable with a combination of therapies such as surgery (resection) and chemotherapy. These early to intermediate stages usually indicate that the cancer is localized or has limited spread. However, stage 4 cancer, characterized by more extensive spread or metastasis to distant organs, is generally not considered curable. In these cases, the treatment focus shifts towards managing symptoms, slowing the progression of the disease, and maintaining the best possible quality of life for the patient.
The TNM Staging System
The TNM staging system is a standardized method used for classifying the stage of cancer. It provides important information about the size and extent of the tumor, whether the cancer has spread to nearby lymph nodes, and if it has metastasized to other parts of the body3.
- T (Tumor): This letter indicates the size and extent of the primary tumor. It ranges from T0 (no evidence of tumor) to T4 (a larger or more invasive tumor).
- N (Node): The N category describes whether the cancer has spread to nearby lymph nodes. It ranges from N0 (no lymph node involvement) to N3 (distant lymph node involvement).
- M (Metastasis): The M category identifies whether the cancer has spread to distant organs or tissues. It is classified as M0 (no distant metastasis) or M1 (presence of distant metastasis).
By combining the T, N, and M categories, the TNM staging system assigns a specific stage to the cancer, which helps determine its prognosis and guide treatment decisions. Please note that the TNM staging system can vary slightly depending on the type of cancer being evaluated, as different cancer types may have specific criteria for staging.
Two examples of how TNM staging in practice:
- Breast Cancer: If the tumor is small and confined to the breast (T1), no lymph nodes are involved (N0), and there is no evidence of distant metastasis (M0), the cancer may be classified as stage I or II.
- Lung Cancer: If the primary tumor is relatively large and has invaded nearby structures (T3), nearby lymph nodes are affected (N2), and there is no evidence of distant metastasis (M0), the cancer may be categorized as stage III.
In both examples, the TNM staging system helps healthcare providers assess the extent of the cancer, plan treatment strategies, and communicate the stage of the disease to the patient.
For NP board exams, be ready to identify what the letters represent in the TNM staging system. You will not be asked to stage a cancer.
There are also some less common staging systems such as:
- Ann Arbor: It is a staging system used to classify the spread of Hodgkin's Lymphoma and non-Hodgkin's Lymphoma. This system is based on the size and location of the lymph nodes involved and the extent of the disease beyond the lymph nodes4.
- Dukes': This system is primarily used for staging colorectal cancer. It is based on the extent of tumor invasion, the involvement of lymph nodes, and the presence of metastasis5.
- Clark and Breslow: This system classifies the spread of melanoma, based on the depth of tumor invasion5. This system is helpful in the surgical treatment of melanoma6.
Final Thoughts
It is crucial for NPs to understand the interpretation of tumor staging, including the TNM system, as it will equip them with the basic tools to comprehend cancer terminology better. Remember that various staging tools are available depending on the type of cancer, such as blood versus solid tumors or specific cancers. This blog aims to review the fundamental principles of cancer staging to help NPs better understand it for the NP board exams.
On a personal note, I can say that working with cancer patients has been a challenging and enriching journey in my career. Each day presents new opportunities to make a tangible difference in people’s lives, navigating through their most challenging times with compassion and care. This path, while demanding, is one I wholeheartedly recommend for its profound ability to impact lives positively. The resilience, courage, and strength I witness in my patients continually inspire me, reminding me of the power of the human spirit and hope.
And to all those affected by cancer, know that you are not alone. Your journey is one of immense courage, and there is a community ready to support, uplift, and walk with you every step of the way. We have included some resources below.
Please feel free to leave us a comment below and share this blog with anyone who would benefit from it.
“What Is Cancer?” National Cancer Institute, 11 Oct. 2021, www.cancer.gov/about-cancer/understanding/what-is-cancer.
World Health Organization: WHO. Cancer. 3 Feb. 2022, www.who.int/news-room/fact-sheets/detail/cancer.
“Cancer Staging.” National Cancer Institute, 14 Oct. 2022, www.cancer.gov/about-cancer/diagnosis-staging/staging.
“Hodgkin Lymphoma Stages | Hodgkin Disease Stages.” American Cancer Society, www.cancer.org/cancer/types/hodgkin-lymphoma/detection-diagnosis-staging/staging.html.
Dukes’ Staging of Colorectal Cancer | SEER Training. training.seer.cancer.gov/staging/systems/schemes/duke.html.
“Clark and Breslow Staging.” Melanoma Skin Cancer | Cancer Research UK, www.cancerresearchuk.org/about-cancer/melanoma/stages-types/clark-breslow-staging.
- “Breast Cancer Information, Support and Donations - National Breast Cancer Foundation.” National Breast Cancer Foundation, 14 Dec. 2023, www.nationalbreastcancer.org.
- “Find Support Programs and Services in Your Area.” American Cancer Society, www.cancer.org/support-programs-and-services.html.
