It’s possible that some cancers can be cured in the future, but that’s not how cancers that respond to treatment are described in the present. Cancers can recur, so “cures” are referred to as complete remission or evaluated as “no evidence of disease” (NED).
As treatments evolve and become more sophisticated, some experts believe cancers will one day be eliminated. Others think the ability to control cancer as a chronic disease is more achievable. Either way, it’s important to keep in mind the many types of cancers affecting the unique individuals living with them. There’s no one size fits all.
This article examines the possibility of a future cure for cancer. It explains the complexities of the disease, obstacles that prevent the cure of more cancers, and the ways in which advances in research and treatment may one day deliver success.
Cancer Differences
Speaking of a “cure for cancer” is overly simplistic because there are hundreds of different types of cancer, from the all-too-common but highly treatable non-melanoma skin cancers to the rare and aggressive Merkel cell carcinoma, a different type of skin cancer that’s often fatal.
Even as skin cancers differ from each other, so do the more than 200 cancers that are known to affect the lung, breast, pancreas, bone, and other organs. When two cancers are the same tissue type, subtype, and stage, they may still have significant molecular differences that play a role in treatment options and outcome.
There is no single cure and the science of pharmacogenomics (knowing how a person’s genetic make-up influences how they respond to drugs) is early in its development of personalized medicine. Further, the cancer cells often find ways to escape both treatments and the immune system.
Cancer cells begin as normal cells in the body, making them much more difficult to treat than other microorganisms. Treatments like chemotherapy eliminate cancer cells but also normal cells, leading to side effects of treatment.
Cancer Similarities
Cancer isn’t one disease, but recent scientific advances are exploiting some of the similarities between different cancers in order to treat them. There are changes that transform a normal cell into a cancer cell, and the pathways associated with these changes often overlap.
Early Detection and Cancer
Many cancers can be “cured” if detected early. Stage 0 cancers such as ductal carcinoma in situ (DCIS) are, in theory, cancers that can be cured completely. Small stage 1 tumors can recur but are considered treatable. Five-year survival rates that suggest a more “curable” disease include breast cancer, melanoma, thyroid cancer, and Hodgkin lymphoma, as well as testicular and prostate cancers.
Roughly 90% of cancer-related deaths are due to metastases (original cancers that spread to other parts of the body) and the ways in which errant cells spread to regions where they don’t belong has some commonalities among tumor types.There are changes that transform a normal cell into a cancer cell, and the pathways associated with these changes often overlap.
In one example, cancer cells often lose proteins referred to as adhesion molecules that cause them to stick to nearby cells. This makes the cells more likely to break loose and travel via the blood or lymph fluid to other parts of the body.
Some cancer treatments are based on these similarities and work for more than one cancer type. They include the immunotherapy drug Opdivo (nivolumab) and the targeted therapy drug Vitrakvi (larotrectinib).
Opdivo
This checkpoint inhibitor works to make cancer cells visible to the immune system, eliciting a response to fight them. It is approved for people with cancers including:
- Metastatic non-small cell and small cell lung cancer
- Melanoma skin cancers
- Liver cancer
- Hodgkin lymphoma
- Head and neck cancer
- Kidney cancer
- Certain forms of colorectal or esophageal cancer
Vitraki
This targeted therapy drug works in some people with cancer who test positive for a genetic change called neutrophic receptor kinase (NTRK) gene fusion. It may be used to treat people with:
- Salivary gland tumors
- Sarcomas
- Thyroid cancer
- Colon cancer
- Lung cancer
Obstacles in Curing Cancer
Before discussing a number of obstacles that are preventing the cure and often even control of cancer, it’s important to note that some cancers are highly treatable and appear to go away after treatment.
Oncologists (cancer specialists) often use the terms “no evidence of disease” (NED) or “complete remission” to describe them because they can recur.
With some cancers, such as childhood leukemia and Hodgkin lymphoma, the chance of the cancer returning in adulthood after successful treatment is very low. In this sense, it’s thought that the cancer can be completely cured. Oncologists will refer to someone as “cured,” for example, if they had acute lymphoblastic leukemia as a child.
Treatable vs. Curable
“Treatable” is different than “curable.” For example, breast cancers that are estrogen receptor positive (stage 1 to stage 3) are more likely to recur five to 10 years after diagnosis than in the first five years, and sometimes recur even decades later.These cancers may be more “treatable” as there are more options but they are, in a sense, less “curable” than those that are not hormone receptor positive.
On the other hand, certain cancers are more likely to recur in people who entered remission. They include glioblastoma, which has a five-year survival rate of just 5% even with treatment. Ovarian cancer and peripheral T-cell lymphoma also are more likely to recur.
Cancers Change
There’s a tendency to think of cancer as an unchanging clone of abnormal cells, but that’s not the case at all. Cancer cells are continually changing and acquiring new mutations.
Durable Response
In some cases, the term “durable response” may be used when it appears long-term control of a metastatic cancer is possible or achieved. This is most common in stage 4 cancers that respond to treatments, with immunotherapy drugs appearing to improve the chances of durable response.
These new mutations may give rise to new characteristics of the cancer, such as the ability to spread more freely. Non-genetic cellular changes in cell behavior, called “epigenetic” changes, also occur.
Resistance
Changes in cancer cells mean that a tumor that responded to treatment at first has found ways to resist cancer drugs and continue to grow. A significant amount of cancer research is focused on the growth pathway of specific tumors to identify other targetable places to halt their growth.
Many targeted therapies are able to control the growth of a tumor for a time before resistance develops. In some cases, next-generation drugs are available that allow people to stay ahead of this resistance, but tumors often again change.
Resistance also can transform a tumor into a completely different subtype of cancer. For example, some EGFR positive non-small cell lung cancers may transform to small cell lung cancer, a much more difficult type of cancer to treat.
Cancers Enlist Help From Normal Cells/Tissue Microenvironment
Cancer cells hide and adapt while often enlisting help from normal cells in their surroundings. These nearby cells, such as fibroblasts and macrophages, can be coaxed into helping a tumor grow through blood vessel growth (angiogenesis) to feed the tumor or suppress the immune system.
Their secretions can’t be studied in a lab, adding to the challenge of understanding and treating cancer.
Heterogenicity of Tumors
Another characteristic of cancers is heterogeneity. Not all cancer cells are the same, at the same time. They continually change how they behave and adapt in different parts of a tumor.
Due to these changes, one part of a tumor may be sensitive to a treatment while another part of the tumor (or a metastasis) may be resistant.
Balance: Efficacy vs. Toxicity
Treating cancer means establishing a balance between what’s effective and its side effects. This balance is visible when adding immunotherapy drugs to cancer treatment.
The immune system requires a balance between being overly active and attacking the body’s own tissues, and being underactive such that tumors grow unchecked.
The most common side effects of immunotherapy drugs include inflammatory disorders, while reciprocally, some medications for inflammatory diseases may raise the risk the cancer.
Treatments and Advances Toward a Cure
Progress in curing cancer may seem slow, but several advances in diagnosis and treatment are changing cancer care.
Research Limitations
Most cancer drugs are first studied in the lab and in animal studies. What works in a dish in the lab (in vitro) does not often translate to effectiveness in the human body (in vivo), and cost is always a consideration. According to a 2018 review, it’s thought that roughly 90% of cancer drugs that appear to be effective in lab studies fail to work when studied on humans in clinical trials.
Targeted Therapies
Targeted therapies, while not a cure, can sometimes control a cancer for a significant period of time. Gleevec (imatinib) used to treat leukemia and a few other cancers is a good example.
With second and third generation drugs for some types of cancer, some people—for a time at least— control their cancer as a chronic disease much like high blood pressure or diabetes.
The ability to identify gene mutations and rearrangements is expanding. Tests such as next-generation sequencing allow healthcare providers to examine many genetic alterations that may be treatable.
Immunotherapy
Sometimes a person may experience the spontaneous remission of cancer, even an advanced cancer. It’s now thought that in some cases, the immune system may fight off a cancer.
Immunotherapy drugs known as checkpoint inhibitors make cancer cells visible to the immune system. These drugs can result in durable responses in advanced cancers like melanoma, but they don’t work for everyone. Future research may find ways in which more people will respond.
The immune system knows how to fight cancer with powerful cells such as T cells. Unfortunately, cancer cells have discovered the ability to suppress that immune response so that cancer cells can grow unchecked. Immunotherapy drugs work to empower the immune system instead.
One notable finding is that the diversity of gut bacteria (the gut microbiome) relates to how well checkpoint inhibitors work. Research into ways to increase diversity of the gut microbiome (probiotics didn’t do it) is needed to see if these drugs can be effective for more people.
Nanotechnology
Nanotechnology is a way of detecting and treating cancer at the molecular level using nanoscale devices. These devices are very small, between 100 and 10,000 times smaller than a human cell.
Adjunct Therapy Using Immunotherapy
Immunotherapy in combination with radiation treatment can sometimes improve control due to the “abscopal effect.” Cell death from radiation activates immune cells that then attack tumor cells far away from the site where radiation was delivered.These combined therapies with an added (adjunct) treatment may improve outcomes.
Scientists hope one day these tiny devices will be used to detect cancer at the earliest possible stage. Nanoscale devices can also be used to deliver targeted therapies directly to cancer cells and to help guide surgeons during tumor removal.
Cancer Vaccines
The same mRNA technology that was used to create COVID-19 vaccines is also being tested for cancer treatment. An mRNA cancer vaccine could target specific proteins found in cancer cells and could be individualized for a person’s specific type of cancer.
These vaccines will be able to help the immune system learn to recognize the cancer cells as invaders so they can be eliminated.This technology has been used in clinical trials with mixed and sometimes disappointing results.
More than 20 mRNA-based vaccines had entered clinical trials by 2021, with some promising outcomes in treating solid tumors.
Treatment of Oligometastases
As noted earlier, metastases are responsible for most cancer deaths. Sometimes a metastatic cancer may be reasonably controlled by treatment, but a new metastasis starts or continues to grow (a “rogue” tumor).
Treatment of these areas with methods such as stereotactic body radiotherapy (SBRT) with a curative intent may sometimes eradicate these rogue tumors, allowing a cancer to again be controlled.
The Future of Finding a Cancer Cure
There are many approaches both already available and in the works that promise to improve cancer care and perhaps, one day, a cure. For example, some people respond particularly well to certain treatments.
Researchers want to know why a rare person might respond to a treatment. One example is the EGFR inhibitor Iressa (gefitinib), which was limited 20 years ago to only people with non-small cell lung cancer who responded well.
The evolving understanding of the role of EGFR mutations in some lung cancers (between 10% and 20% of non-small cell lung cancers) led to expanded drug approval in 2015, for people with specific EGFR-related changes.
While two main types of EGFR changes account for 85% of those identified, researchers continue to work on more rare types, like EGFR exon 20 insertion mutations.
Other research priorities that may change the way “cure for cancer” is understood include:
- Understanding recurrence, or how and why cancer cells may hide and return
- Understanding metastases, which can lead to new treatments like bisphosphonates in breast cancer
- Liquid biopsies, which can offer new insights into tumor resistance
New genetic discoveries also may lead to prevention or early detection of cancers, as well as treatment options. Genome-wide association studies are studies that look at people with and without a disease and then look for changes (called single nucleotide polymorphisms) in the entire genome that may be associated with the disease.
Summary
While cancer can’t be cured, that’s not how oncologists and cancer experts think about a successful treatment. They refer to it as complete remission, allowing for the fact that cancers can recur. They also describe it as “no evidence of disease” that, in some cases, may prove permanent.
What About CRISPR?
Gene editing (CRISPR-Cas9) is certainly advancing the science that could aid in treatments, but it’s unlikely that gene editing alone could be a cure in the near future. More potential could be seen in the use of CRISPR to edit cells in the immune system to better fight cancer as with strategies like CAR-T immunotherapy.
Advances in cancer treatment aren’t the same as a cure but they are helping people to live longer with a cancer diagnosis, sometimes even with the hope of managing it as a chronic disease. Evolving research continues to deliver more personalized care, including immunotherapy and targeted therapy drugs.
It’s unlikely that a single, one size fits all treatment will ever be effective for all cancers. Yet new understanding about cancer and its treatment already informs cancer care and offers options that weren’t possible even a few years ago.
A Word From Verywell
One in two men and one in three women are expected to develop cancer during their lifetime, and far too many people still succumb to the disease.So hope for a cure is important, but so are quality of life and survivorship, whatever advances the future may hold. Your healthcare team can help you to find support during your cancer journey.
