Conducting Clinical Trials in Rare Oncology

Rare oncology is a subset of oncology that encompasses those cancers with the rarest incidence. They may be a common type like cervical cancer that presents differently, such as small cell cervical cancer. This would mean that even though the tumor affects an area of the body commonly impacted by cancer, the treatment of this more rare presentation will require a different approach. Alternatively, rare oncology can refer to a tumor or malignancy that impacts a part of the body that infrequently gets cancer.

Understanding Rare Cancers

What makes a cancer rare is its frequency. A cancer is said to be rare if it impacts a small percentage of the population. However, experts disagree as to whether that figure should be 2 in 100,000 or 6 in 100,000 (The National Cancer Institute puts the threshold at 15 in 100,000). In any case, a little over 20% of people who are diagnosed with cancer each year have a rare type, although some research puts the number closer to 33%. Childhood cancer is also rare. Then, amongst those who get rare cancers, the five-year survival rate (47%) is significantly lower than that of more common cancers (65%).

With such a low incidence, developing rare oncology treatments is challenging. Rare cancers tend to be diagnosed late, after more common issues are ruled out, and then the treatment itself can be complicated. In some cases, the survival rate is so low at that point that treatments are not pursued or patients drop out of clinical trials. In other instances, the issue is securing treatment (e.g., insurance coverage, age requirements at treatment centers).

Rare Cancer Care Initiatives

Treating patients with rare cancers is challenging. In a survey of 420 oncologists, almost two-thirds of respondents blame a lack of personal experience or existing guidelines within their clinical practice. Another 40% credit the fact that there are few treatment options, while almost 45% say that reimbursement issues make treating rare cancers cumbersome. Current initiatives towards improving rare oncology center on developing more straightforward practice guidelines, improving reimbursement, and developing a national registry of people with rare cancer.

Many Rare Cancers No Longer Rare

In the past few years, less common cancers have started to receive more attention. According to the Evaluate Pharma Orphan Drug Report 2020, “orphan drug sales are forecast to increase from $119bn in 2018 to $217bn in 2024,” and historically, the top-performing orphan drugs are in oncology. Going forward, that trend is expected to continue thanks to advances in genome sequencing. As researchers have been able to understand more about molecular profiles, they have been able to develop impactful treatments for many rare cancers. Basket trials in particular (also called histology-agnostic) have highlighted this and fueled the development of tumor-agnostic treatments. In other words, they are treating the mutations that create tumors at a molecular level, so it doesn’t necessarily matter what type of cancer, just that the genetic mutation is the same.

In essence, rare oncology is evolving. Next week, we will explore the rare cancer landscape in scope and practice. Stay tuned!


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