Rare Cancers in the United States

According to the World Cancer Research Fund International, the United States has the seventh highest prevalence of cancer in the world, in comparison with 49 other countries. The data states that 318 Americans per 100,000 are diagnosed with cancer in 2012. The study took into consideration the fact that developed nations (such as the United States) have better diagnostic tools and methods that could detect the cancers at earlier rates.

However, what many do not consider is the fact that the number of rare cancers in the United States is more significant than what most would think. The American Cancer Society (ACS) recently released a report indicating that one in five cancer diagnosis in the country is a rare form of the disease. This means that 20% of the diagnosed cancer patients in the United States is suffering from a form of rare cancer. If the rate of rare cancer is that high, how “rare” is it, really, and what are the consequences?

What is a rare cancer?

The ACS says in a different report, “There is no universally adopted definition for rare cancers. The National Cancer Institute definition is fewer than 15 cases per 100,000 people per year. More recently, a consortium from the European Union (RARECARE) 2 defined rare cancers as those with fewer than 6 cases per 100,000 people per year, which is the definition we use in this report.” How few is 6 cases per 100,000? Well to put that into perspective, the same source goes on to say that the incidence rate for breast cancer is at 123 cases per 100,000.  

These are the cancers that are not as widespread as the others. However, the same source also says that “Nearly 13% (1 in 8) of all cancers diagnosed in adults ages 20 and older are rare based on our definition, the equivalent of approximately 208,000 new cases in 2017.”

This is alarming on so many levels, particularly since many rare forms of cancers have low survival rate. How so? Rare forms of cancer lack the same level of scrutiny given to more known forms of cancer, simply because fewer people have it. According to the article The burden of rare cancers in the United States, as published by the ACS, “Reasons for poorer survival for rare cancers include lack of effective treatments and standard treatment guidelines as well as delays in diagnosis.” The same source goes on to add, “Poor survival for some rare cancers, such as those that are more prevalent among adolescents and young adults, may also in part reflect differences in tumor biology.”

In this regard, this means that some forms of rare cancers have poor survival rates because they are diagnosed later, there is a lack of effective treatment, as well as standard treatment guidelines.

Where are rare cancers found?

The ACS reveals that rare cancers of the oral cavity and pharynx comprise 15.4% of rare cancers in adults in the United States. This is followed by genitourinary system cancers at 13.8%. Other rare forms of cancer that are too diverse to be clustered are at 10%, while digestive system cancers are at 8.6%. Lastly, respiratory system cancers comprise 1.1% of the statistic.

When it comes to the digestive system, the most common of the rare cancers in the area is the cancer of the small intestine. This is followed by anus, anal canal, and anorectum cancers; gallbladder cancers; peritoneum, omentum, and mesentery cancers; and retroperitoneum cancers.

For the oral cavity and pharynx, the most common kind of rare cancer is found on the tongue. This is followed by tonsil rare cancers; gum and other mouth cancers; salivary gland cancers; hypopharynx cancers; lip and floor of mouth cancers; and nasopharynx and oropharynx cancers.

Meanwhile, the bulk of rare cancers in the respiratory system are found in the larynx. This is followed by the nose, nasal cavity & middle ear cancers, and cancers of the trachea and mediastinum.

On the other segment of rare cancers, soft tissue cancer, including the heart, ranks the highest. This is followed by male breast cancer, mesothelioma, bones and joints, eye and orbit, and Kaposi sarcoma cancers.

Lastly, rare cancers of the testis rank the highest for rare cancers of the genitourinary system. This is followed by cancers of the vulva, penis, vagina, and ureter, respectively.

What happens next?

It is expected that 208,000 rare cancers will be diagnosed among adults in the US this year, not including the diagnosis of rare subtypes of more common forms of cancer. while there may be less interest in rare cancers decades ago, today more and more organizations are coming together to challenge these rare diseases.

For instance, Europe’s RARECARE project is instrumental in providing information on rare cancers for professionals, as well as for patients. Patients are also directed to different patient organizations that will help them find a support system, as well as other people who are suffering from the diseases. There is a handy list of treatment centers, common indicators of rare cancers, and an updated cancer list. The list goes on and on. Essentially, the RARECARE project is quickly becoming as one of the authorities when it comes to facilitating an information network on rare cancers.

Researchers for rare cancers are also ongoing. Just this May, there was a very successful drug that showed patients with bile duct cancer who took the clinical trial drug lived for a year and a half longer than those who did not have the drug. The BILCAP trial is instrumental in showing that there are still medical advancements that are targeted towards rare cancers. The study also raised the fact that it is difficult to recruit enough patients for the clinical trials, giving that it is a rare form of cancer.

Overall, there is still hope that rare forms of cancers are being given the same amount of attention by health experts, particularly when it comes to better diagnosis and better treatment options for patients. In time, the mortality rates associated with rare cancers may be as manageable as more common forms of cancers, with ample research and development.