Bladder Cancer

Authors: Meghana Pandit, Akhil Gajjala, and Dr. Lopamudra Das Roy

Published 2022

Introduction

Bladder cancer is the rapid development of tumor cells within the bladder, which is an organ in the urinary system responsible for storing urine. The bladder may be the organ in question, but it is included in the urinary system, which consists of many other organs such as the kidneys, the urethra, and the uterus and prostate, which are equally susceptible to a tumor given the fact that it becomes metastatic. There are many different types and stages of bladder cancer as well.

Types

The most common type of bladder cancer is urothelial or transitional cell carcinoma. The tumor begins to develop in the innermost tissue layer of the bladder (urothelial cells). As the ureters and urethra are also lined with these cells, the entire urinary tract must be examined for tumors as well, as it is quite possible the tumor could have spread into those organs. Just like many other cancers, there are also two additional types of transitional cell carcinoma: low-grade and high-grade. [1]

The second most common type of bladder cancer is squamous cell carcinoma, which accounts for 1% to 2% of all cases. It begins in the squamous cells, which are thin, flat cells that line the inside of the bladder. This type is likely to occur after a long-term infection or irritation. Next is adenocarcinoma, which accounts for 1% of all bladder cancers and begins in the glandular cells that produce mucus in the bladder. [1] Less than 1% of bladder cancers are caused by small cell carcinoma. It begins in the neuroendocrine cells, which are small and nerve-like, where it creates and releases hormones and other substances. Some people, very rarely, develop cancer of the bladder muscle or other structural tissues rather than the bladder lining. This specific type of cancer is called a sarcoma. [2]

Causes and Risk Factors

The biggest cause and risk factor for bladder cancer is smoking. Other risk factors include increasing age, being male, exposure to certain chemicals, previous cancer treatment, chronic bladder inflammation, personal or family history of cancer, second hand smoke. Gene mutations can potentially be a cause of bladder cancer as well. Somatic mutations, or mutations after conception, are common in bladder cancer cases. [1,3]

Symptoms

Symptoms of bladder cancer include hematuria (blood in the urine), which is the first sign of bladder cancer in most cases, having to urinate more often than usual, pain or burning during urination, feeling as if you need to go right away, even when your bladder isn't full, having trouble urinating or having a weak urine stream, and/or having to get up to urinate many times during the night. Symptoms of advanced bladder cancer include being unable to urinate, lower back pain on one side, loss of appetite and weight loss, feeling tired or weak, swelling in the feet, and/or bone pain. [1]

Prevention

The biggest way one can prevent bladder cancer is by not smoking or being overly exposed to secondhand smoke. As a result, the cancer-causing chemicals found in smoke won't be able to accumulate in your bladder. Another prevention method is to be cautious around chemicals. Keep all safety rules in mind when working with or around chemicals. By drinking water, harmful substances may be diluted and flushed out of your bladder more quickly. Lastly, increase your intake of fruits, vegetables, nuts, fish, and lean protein; reduce fat and red meat consumption. [1,4]

Staging

Just like other cancers, bladder cancer stages are also determined through TNM staging.

The “T” in TNM stands for tumor, which is the step when doctors look at the size of the tumor. There are multiple T stages. CIS, or Tis, denotes the presence of very early, high-grade cancer cells in the bladder lining's innermost layer. Ta indicates that the cancer is only in the urothelial cells. T1 indicates that the cancer has spread to the connective tissue beneath the lining. T2 indicates that the cancer has spread through the connective tissue into the muscle. It is classified as T2a and T2b. T2a indicates that the cancer has spread to the superficial muscle. T2b indicates that the cancer has spread to deeper muscles. T3 indicates that the cancer has spread through the muscle and into the fat layer. It is also divided into two parts: T3a and T3b. T3a indicates that the cancer in the fat layer is only visible under a microscope (microscopic invasion). T3b indicates that the cancer in the fat layer can be seen on tests or felt by your doctor during an anesthetic examination (macroscopic invasion). T4 indicates that the cancer has spread beyond the bladder. Basically, it is divided into two parts: T4a and T4b. T4a indicates that the cancer has spread to the prostate, uterus, or vagina. T4b indicates that the cancer has spread to the pelvic or abdominal wall. [5]

The “N” in TNM stands for nodes. During this step in the staging process, doctors examine your lymph nodes, which are a network of glands located throughout the body. They are located in areas such as the armpits, neck, and groin. Some of the main functions of the lymph nodes include draining waste fluid, waste products, and damaged cells, as well as containing cells that fight infection. There are 4 “N” stages: N0, N1, N2, and N3. N0 indicates that there are no cancer cells in any of the lymph nodes, N1 indicates the presence of cancer cells in one lymph node in the pelvis (between your hip bones), N2 indicates that cancer cells have been found in more than one lymph node in the pelvis, and N3 indicates the presence of cancer cells in one or more lymph nodes located just outside the pelvis. [5]

Lastly, the “M” in TNM stands for Metastasis. This step allows doctors to determine whether the tumor is metastatic, meaning it has spread, or non-metastatic. There are two large M stages: M0, which means the tumor is not metastatic, and M1, which means the tumor has metastatic spread. Furthermore, M1 is divided into M1a and M1b. M1a means your cancer has spread to the lymph nodes outside the pelvis, and M1b means your cancer has spread to other parts of the body, like the bones, lungs, and liver. [5]

Screening and Diagnosis

There are multiple different screening for bladder cancer which include physical exams, biopsies, image scans, CT scans (CAT Scans), MRI (magnetic resonance imaging), PET Scan (positron emission tomography scan), chest X-Rays, bone scans, a cystoscopy, which is when doctors pass a tiny, narrow tube into your urethra called a cystoscope (doctors can use the lens on the device to look for cancerous symptoms inside your bladder), a urinalysis, which is a quick test that looks for the presence of blood and other materials in your urine. [5]

Global Scenario

In the world, 1 out of 27 men get bladder cancer and 1 out of 89 women get bladder cancer. [6] Food, exercise, smoking, and other potentially modifiable lifestyle choices and health behaviors have all been linked to bladder cancer carcinogenesis to varied degrees. One of the key dietary and lifestyle factors that contributes to bladder cancer is smoking. Leaving aside racial and ethnic discrimination, human behavior can be harmful. One such type of cancer that can be mostly avoided by leading a very healthy lifestyle is bladder cancer. [7,8]

When it comes to bladder cancer statistics worldwide, there are roughly 81,180 cases of the disease each year. Divvying this up by gender reveals that in the US, bladder cancer affects 61,700 males and 19,480 women. After years of rise, the number of bladder cancer cases in the US gradually fell from 2009 to 2018 by about 1% annually. Men are four times as likely to get a diagnosis than women are. Additionally, White males experience twice as many incidents as Black men. Bladder cancer commonly strikes older people. Patients with bladder cancer make up 90% of those over 55. The average age of discovery of bladder cancer is 73. It has been proven through various studies that this specific type of cancer is found more frequently in Southern/Western Europe and North America as well. Greece has the highest rate of cancer in men, while Lebanon has the highest rate of cancer in women. While bladder cancer was more common in affluent nations and some regions of Africa, North Africa and the Middle East had the highest fatality rates. In addition, the socioeconomic status of bladder cancer basically consists of the fact that men are much more likely than women to develop this particular type, and they also have higher death rates when compared to all other natural deaths worldwide. [7]

Socioeconomic Factors

Finding statistics on the socioeconomic situation for bladder cancer was a struggle. We weren’t able to find many sources, and the one source we found dated all the way back to 2005 which is extremely out of date. This is a serious problem and more people need to begin finding data about this not only for bladder cancer, but for all cancer. In the article from 2005, the author demonstrates that socioeconomic situations and underdeveloped countries are the most at risk for bladder cancer. Cost for treatment is a big issue. Those who are in a lower socioeconomic status (SES) may struggle with being able to gain access to effectively treat bladder cancer as well as have medical insurance to help cover the costs for treatment. Even more important, SES also plays a role in prevention of bladder cancer. Hygiene is a huge part of preventing such a cancer as unhygienic restroom areas could lead to a fungal infection or bacteria entering the urethra and then spreading to the uterus, bladder, other parts of the urinary system, and even other organs. If these infections become too frequent, one would be at a high risk for bladder cancer. When considering the extremes of the SES groups, 5.0% of patients in the highest SES group had confined cancer, as opposed to 7.4% of patients in the lowest SES group. Additionally, 52.2% of patients in the highest SES group had high-grade disease compared to 52.8% of those in the lowest SES group. Patients from the lowest SES group were more likely to have higher-staged tumors and slightly higher-grade disease than the highest SES group [9].

References:

[1] https://www.mayoclinic.org/diseases-conditions/bladder-cancer/symptoms-causes/syc-20356104

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2963788/

[3] https://consultqd.clevelandclinic.org/altered-gene-expression-initiates-promotes-bladder-cancer/

[4] https://health.clevelandclinic.org/bladder-cancer-your-personal-risk-and-how-to-reduce-it-2/

[5] https://my.clevelandclinic.org/health/diseases/14326-bladder-cancer

[6] https://www.cancer.org/cancer/bladder-cancer/about/key-statistics.html#:~:text=Risk%20of%20bladder%20cancer&text=The%20average%20age%20of%20people,is%20about%201%20in%2089.

[7] https://www.cdc.gov/cancer/bladder/index.htm

[8] https://www.cancer.org/cancer/bladder-cancer/about/key-statistics.html#:~:text=About%2081%2C180%20new%20cases%20of,men%20and%204%2C980%20in%20women)

[9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821748/

Lopamudra Das RoyNovember 15, 2022