According to WHO estimates, cancer is the second leading cause of death around the world, and the cases are only on the rise. Between 2010 and 2019, there was a 26% rise in global cancer incidence, making it perhaps one of the deadliest and fastest-growing diseases in human history.

While there’s still no cure for it, it’s important to remember that those numbers could be far higher. Thanks to the continuous efforts of scientists, doctors, surgeons, and other specialists working in the field, there have been many breakthrough treatments – like immunotherapy and chemotherapy – that have come together to improve the lives of countless patients around the world. 

10. Halsted’s Mastectomy

Named after its inventor William Stewart Halsted, Halsted’s Mastectomy was developed in the late-19th century. It revolutionized breast cancer treatment, as Halsted’s approach was a radical departure from previous methods. It involved the complete removal of the breast, underlying muscles, and adjacent lymph nodes to ensure the complete removal of the tumor. It was a revolutionary idea at the time, as the procedure didn’t just remove the tumor, but also any remaining cancerous cells that might have spread to nearby lymph nodes. 

By taking this approach, Halsted believed that he could improve long-term outcomes and reduce the risk of disease recurrence. This technique laid the foundation for modern breast cancer surgery, as it focussed on the careful dissection and preservation of healthy tissues. While the procedure has undergone many modern refinements over time, the fundamental principles of Halsted’s Mastectomy remain influential in the field of cancer research.

9. X-Rays And Radiation Therapy

The discovery of X-rays by Wilhelm Conrad Roentgen in 1895 would prove to be a breakthrough event in the field, as it directly led to the development of other modern techniques for cancer treatment. Emil Grubbe, a Chicago chemist and physician, was one of the early pioneers in using X-ray radiation to treat cancer. In 1896, he successfully performed radiation therapy on Rose Lee, a patient suffering from recurrent breast cancer. This was perhaps the first documented instance of using radiation therapy to treat cancer in history, and there would be no looking back.

Grubbe’s experiments had a profound impact on the field of medical radiation therapy. His treatments involved placing lead sheets to shield healthy tissues from the harmful rays, and focusing the X-ray radiation on the tumor site. While these procedures were relatively long by modern standards – each lasting about an hour – they were still a huge leap for the time. Grubbe’s early work with X-rays paved the way for all future research in radiation therapy.

8. Discovery Of Radium

In 1898, Polish physicist and chemist Marie Curie discovered the highly-radioactive element called radium and forever changed the field of cancer treatment as we know it. Early experiments with radium revealed its potential to destroy diseased cells, leading to its widespread use in patients suffering from various types of skin cancers for many years.

Before the discovery of radium, surgical removal of tumors used to be the standard treatment for treating cancer. This approach often proved painful and ineffective, with limited consideration for the rapid growth of new tumors. Radium therapy – also sometimes called ‘Curie Therapy’ after Marie Curie – emerged as a viable alternative, delivering targeted radiation directly to the cancerous cells to eliminate them. 

On the other hand, the introduction of radioactivity to cancer treatment came with its own set of risks, like the absence of proper safety procedures to protect against radiation at that time. There was also a general lack of understanding of radium’s properties, which resulted in health issues like anemia, cataracts, fractured teeth, and even cancer. 

7. Mustard Gas And Chemotherapy

While mustard gas initially came into mass use as a deadly chemical agent during the First World War, it has also played a pivotal role in the larger history of cancer treatment. Researchers in the early 1900s, like Dr. Edward and Helen Krumbhaar, began studying the effects of mustard agents and their potential medical applications. By the 1940s, scientists transformed mustard gas into substances that could be used for cancer chemotherapy, specifically sulfur mustards and nitrogen mustards. 

During World War II, extensive research was done on chemical warfare agents of all kinds, including mustard gas, to better understand their harmful effects and develop countermeasures. The researchers also drew from wartime experience, as accidental exposure to the agent on the frontline revealed its effects on blood cells. Subsequent trials proved the effectiveness of nitrogen mustard in regressing existing tumors, which set the stage for further breakthroughs in chemotherapy in the coming years.

6. Environmental Factors

While we now know that environmental factors can cause cancer, it hasn’t always been common knowledge. The first scientist to link environmental factors with the disease was Percivall Pott, who – in 1775 – wrote a book about how workers in London that were exposed to soot from the chimneys were at a higher risk of scrotal cancer. Pott observed an unusually high incidence of skin sores on the scrotums of chimney sweepers, leading him to identify an environmental factor, soot, as the cancer-causing agent. 

This discovery was a milestone in the history of cancer research, as it not only revealed the role of occupational exposure in carcinogenesis , but also contributed to the understanding of diseases caused by infections like Pott disease. 

5. P53 Protein

The discovery of the p53 protein in the 1970s revolutionized our understanding of how cancer works. First identified by independent researchers in 1984, p53 is a tumor-suppressor protein found within our cells that plays a crucial role in preventing the development and progression of cancer throughout our lifetimes. It acts as a guardian of the genome, responding to DNA damage – which may lead to cancer – by halting cell growth or inducing cell death. 

Over the years, scientists have uncovered many functions of the p53 protein, describing it instead as a network. In addition to its role in DNA repair and cell death, it’s also involved in processes like metabolism and immunity. Years of better understanding the complex mechanisms driven by p53 has led to many major advancements in cancer research and potential treatments. 

4. Discovery Of The Role Of Viruses

In 1910, Peyton Rous discovered a filterable agent, later named the Rous sarcoma virus, that was causing cancer in chickens. On further experimentation, he found that freezing, drying, or radiation didn’t diminish the virus’s cancer-causing ability, and that the infected chickens produce antibodies, leading him to develop his viral theory of cancer. 

In 1934, Rous also found a virus responsible for warts in jackrabbits that could later develop into cancerous tumors. This newfound focus on viruses as a potential agent of cancer led to further discoveries by him and other researchers in the field. One of them was that certain viruses could permanently alter the DNA of host cells without killing them, resulting in the growth of cancer at a later stage. 

3. Immunotherapy

William Coley is often referred to as the ‘Father of Immunotherapy’ due to his contributions to the field of cancer research in the late 19th century. In 1891, Coley attempted to treat bone cancer by utilizing the immune system. He observed tumor regression in sarcoma patients after infecting them with mixtures of live and inactivated bacteria. 

This new strategy provided early evidence of cancer treatment with the body’s own immune system, and Coley’s work laid the foundation for all future advancements in cancer immunotherapy. Subsequent discoveries in the field, like the discovery of T cells and their role in the immune system, reignited academic interest in using the immune system to fight cancer, leading to further insights and discoveries. 

2. Hormone Therapy

Over the years, hormone therapy has played a major role in cancer research and treatment, particularly in the areas of prostate and breast cancer. It was only made possible after the discoveries of Charles Huggins, a Canadian-born American surgeon and urologist, who was the first researcher to prove the influence of hormones on certain types of cancer. 

Huggins demonstrated that prostate cancer could be affected by hormones, and that inhibiting hormone production through castration or introducing female sex hormones could counteract the disease. This breakthrough led to the rapid adoption of hormone treatment for prostate and other types of cancer, including breast cancer. For his work, Charles Huggins – along with Peyton Rous – received the Nobel Prize for Physiology or Medicine in 1966.

1. Mapping Of The Human Genome

The mapping of the human genome was completed in 2003, giving us – for the first time – access to the entire set of DNA instructions found in a human cell. It was a breakthrough event for the medical world, as doctors and medical researchers now had access to the fundamental knowledge needed to understand genetic mutations and their role in diseases, especially cancer. With this new understanding, personalized therapies could now be developed to target specific genetic changes in cancer cells.

Thanks to the Human Genome Project, researchers discovered that some breast cancer cells had an altered HER-2 gene, which led to the production of a growth-promoting protein. Over the years, similar genetic changes were found in other types of cancer, leading to more advanced targeted therapies and personalized medicine for specific diseases. Unlike traditional chemotherapy and radiation, targeted therapies offer longer-lasting treatment effects with minimal side effects. The ability to sequence the DNA in cancer cells and compare it to the human genome also allowed for a more comprehensive categorization of tumors.

Dogs have an incredible sense of smell. In fact, canines are equipped with over 100 million sensory receptors within their nasal cavity, whereas humans possess about six million. Additionally, dogs also have a second olfactory system that not only allows them to pick up on physical smells but also allows them to detect pheromones, human emotions, and even the presence of storms.

Given their powerful noses, it’s no wonder dogs have been used in hunting, trained to sniff out bombs or drugs, and assisted in search and rescue missions.

However, the 10 dogs on this list were able to accurately detect a much more important, typically undetectable odor in their owners—cancer. And they did so long before their human companions were ever diagnosed by a healthcare professional.

Related: Top 10 Dogs With Unusual Jobs

10 Sierra the Siberian Husky

When Stephanie Herfel’s son left for the Air Force in 2011, she took in his nine-month-old Siberian husky puppy, Sierra. Little did Herfel know what a gift Sierra would truly be.

One day in 2013, Sierra began sniffing and pressing her nose into Herfel’s abdomen. At first, Herfel assumed that perhaps the dog smelled food that she had spilled on her shirt. However, the substance Sierra detected was startling enough to make her roll up into a ball and hide in the closet.

While Herfel had previously experienced pain in her abdomen, she was advised by an ER physician that she had an ovarian cyst and was sent home with pain medication. Given Sierra’s reaction, Herfel made an appointment with her gynecologist. On November 11, 2013, her doctor confirmed that she had stage 3 ovarian cancer.

Herfel had a full hysterectomy, lost her spleen, and continued chemotherapy until April 2014. Unfortunately, in 2015, Sierra again exhibited the same behavior as in 2013 when she “smelled” Herfel’s cancer. Sierra was right again—the cancer had returned—but this time in Herfel’s liver. Sierra also confirmed a third recurrence of cancer in 2016.

Sadly, Herfel passed away on July 8, 2021, at 54, after an eight-year battle with ovarian cancer and acute myeloid leukemia. However, had it not been for Sierra’s keen sense of smell, Herfel may not have had the additional eight years with her family.^[1]

9 Heidi the German Shepherd-Lab Mix

Anne Wills’s dog Heidi, a German shepherd-lab mix, worked as a search and rescue dog. While Heidi had saved thousands of lives, Wills could never have imagined that Heidi would also save her life.

In February 2015, Heidi began exhibiting strange behaviors each time Wills would sit down—refusing to let Wills up, scratching her arm, and panting excessively, almost as if in a panic. From there, Heidi began pressing her nose into Wills’s chest, taking deep breaths.

Assuming something was wrong with her canine companion, Wills took Heidi to the vet. However, after Heidi received a clean bill of health, Wills realized that Heidi might, in fact, be sensing something was wrong with her instead.

Wills made an appointment to see her doctor, and after being sent for a CAT scan, she was informed that she had lung cancer. She underwent surgery along with intensive chemotherapy and radiation treatments with Heidi by her side every step of the way. Sadly, Heidi passed away from cancer on December 24, 2015.^[2]

8 Victoria the Treeing Walker Coonhound

Lauren Gauthier of Buffalo, New York, is the founder of Magic’s Mission Beagle and Hound Rescue, an animal rescue organization that saves dogs from abusive and neglectful situations.

In 2017, Gauthier took in Victoria, a treeing walker coonhound with an infected eye, who had been surrendered by a hunter. Gauthier never realized that not only was she saving Victoria but that Victoria would also save her.

In the spring of 2017, Victoria began staring at Gauthier’s face and putting her nose directly on an area that Gauthier had assumed was simply a pimple or blemish. Victoria would repeatedly touch Gauthier’s nose, look at her, and then smell the area again. When Victoria’s behavior persisted, Gauthier decided to see a doctor.

Gauthier had a biopsy, revealing that the “dot” on her face was actually a basal cell carcinoma. However, thanks to Victoria’s heightened senses and persistence with her owner, Gauthier was able to catch the skin cancer in the early stages and undergo surgery to have it removed.^[3]

7 Troy the Doberman Pinscher

Diane Papazian and her husband Harry already owned a fox terrier. However, in 2011, Harry insisted they add Troy, a four-month-old Doberman pinscher, to their family. Given Papazian’s allergies, she was a bit hesitant, but she and her husband ended up bringing Troy into the family… a month earlier than expected. What Papazian did not yet understand was that Troy was meant to come into her life at the time he did.

As the tiny pup was lying in bed with the couple, Troy continued to nuzzle against Papazian’s left side, which caused an allergic reaction to her skin. As Papazian began scratching, she noticed a lump in her left breast.

Papazian had undergone a routine mammogram six months prior, and the results were normal, but after feeling the mass, she got in touch with her doctor. That lump turned out to be stage 2 breast cancer. Papazian had a double mastectomy, started chemotherapy treatments, and was later deemed cancer free, all thanks to their new pup.^[4]

6 Daisy-May the West Highland Terrier

In April 2017, 68-year-old Thelly Price’s west highland terrier, Daisy-May, began constantly sniffing around Price’s neck and throat. At first, Price couldn’t see or feel anything that would contribute to Daisy-May’s strange behavior. However, Daisy-May’s nose was spot on.

On May 17, 2017, Price went to the doctor after noticing a lump in the exact area that Daisy-May had been sniffing. Her doctor assumed she had a fatty lump, but after being referred to an ear, nose, and throat clinic for further evaluation, Price was diagnosed with non-Hodgkin’s lymphoma.

Thankfully, due to Daisy-May’s keen sense of smell and early detection, Price was able to undergo surgery without the need for radiation or chemotherapy.^[5]

5 Kransky the Miniature Dachsund

As Claire Seeber was curled up on the couch talking to her mother shortly after the Christmas of 2019, her “mini-sausage dog,” Kransky, began incessantly sniffing a mole on her right calf. While Seeber laughed at the tickling sensation, what Kransky discovered was no laughing matter.

Seeber explained her laughter to her mother and what was going on during their call. Given Kransky’s behavior, her mother urged her to get checked out. However, Seeber brushed off Kransky’s actions and her mother’s advice as simple paranoia. Nevertheless, Seeber’s mother wouldn’t back down, so she finally gave in and made an appointment.

As soon as her doctor took one look at the mole, he insisted that it needed to be removed and sent for biopsy. A few days later, Seeber’s doctor confirmed that she had a cancerous melanoma.

Seeber was scheduled for surgery to remove the surrounding cells and ensure that all of the cancer was gone. Thankfully, the surgery was a success which meant Seeber would not need any radiation or chemotherapy treatments, and best of all, Kransky was by her side the entire time.^[6]

4 Lola the Chihuahua

Approximately 10 days before Christmas 2020, 41-year-old Tess Robison’s chihuahua, Lola, began acting incredibly strange—smelling Tess’s breath, staring at her, and acting more needy than usual. Then, in a desperate attempt to get Robison’s attention, Lola jumped on her stomach. Two days later, a lump appeared.

Robison immediately made an appointment with her doctor, but it was uncertain what the mass was. Robison was then referred to several different hospitals before being diagnosed with stage 3 low-grade serous carcinoma, a rare form of ovarian cancer, in January 2021.

In March 2021, Robison underwent a 12-hour surgery in which a full hysterectomy was done. However, during the operation, doctors also discovered that cancer had spread to Robison’s bowels. Between the surgery and regular chemotherapy treatments, Robinson is now on the road to recovery.^[7]

3 Broady the Newfoundland

Forty-five-year-old Lucy Gies of Didcot, Oxfordshire, adopted Broady, a 154-pound (11-stone) Newfoundland in July of 2021 when his previous family was no longer able to care for him. Unbeknownst to Giles, the “gentle giant” would be more of a blessing than she would ever realize.

By September 2021, Broady began acting strange, and each time Giles would sit down, he would sniff and nuzzle her right armpit. Initially, Giles assumed Broady simply wanted extra attention. However, one morning as Giles was taking a shower, she decided to do a breast exam. That’s when she felt a lump in her right armpit.

Giles’s doctor believed that the lump was hormone related, but when weeks passed with no change, Giles was sent to the hospital for testing. Giles was diagnosed with HER-2 positive breast cancer and was told she also had cancer cells in her lymph nodes.

In October 2021, Giles began six rounds of chemotherapy, then had a lumpectomy followed by radiation treatment. Giles is currently still going through chemotherapy.^[8]

2 Bessie the Cairn Terrier

Ron Wain and his partner of Newhall, Yorkshire, rescued their Cairn terrier, Bessie, when she was only 10 months old. However, in 2018, after spending 12 years with the couple, Bessie exhibited behavior that was out of character, such as constantly watching Wain’s every move, following him around, and laying on his chest.

Around the same time Bessie began behaving strangely, Wain noticed he was having to make more trips to the restroom than normal. In light of Bessie’s odd behavior and his increased restroom visits, Wain decided to bring the issue to his doctor’s attention. Wain was then diagnosed with bladder cancer.

Unfortunately, Wain’s first operation was unsuccessful in removing all the cancer, so he opted for a bacterial treatment, which uses a strain of tuberculosis called bacillus Calmette-Guerin (BCG) to treat non-invasive bladder cancers. Once Wain was at the end of his treatment, he was told his cancer had cleared. Bessie, too, stopped following Wain around and went back to her normal behavior.^[9]

1 Buster the Jack Russell Terrier

In the spring of 2014, Mike Wagner of Deering, New Hampshire, was lying in bed without a shirt when his dog Buster, a Jack Russell terrier, laid his head on Wagner’s chest and began nudging him. It was then that Wagner noticed a lump on his chest.

Wagner didn’t think too much of the lump and continued his work as a logger for the next few months. However, he began to notice that while he was working and pulling wood, every time he moved his arm, he got an odd feeling in his chest.

Wagner then made an appointment to get checked out. He was referred to a breast cancer center where a biopsy was done, and he was diagnosed with breast cancer. Wagner underwent surgery to remove the cancer, but during the procedure, the doctor realized it had also spread into Wagner’s lymph nodes.

In an attempt to rid his body of cancer, Wagner then went through five months of chemotherapy and six months of radiation. He officially had his last treatment on October 2, 2015.^[10]