3D technology gives head and neck cancer patients a chance for the quality of life they had before their diagnosis
“The first thing he wanted to do with his new smile was eat pizza.”
Betsy Davis, DMD, a maxillofacial prosthodontist at the Medical University of South Carolina (MUSC), works with head and neck cancer patients to use 3D printing to build exact replicas of their teeth, nose or ear, offering the best chance to return to the quality of life they had before their diagnosis. By taking precise measurements and scans of unaffected areas, maxillofacial prosthodontists like Davis can build accurate prosthetic replacements that fit together like puzzle pieces.
One of her patients had been diagnosed with a form of head and neck cancer that required surgeons to remove his teeth and part of his jaw. But after treatment with the physician team at the Wellin Head and Neck Tumor Center at MUSC, he received new teeth and part of a jaw, which was planned virtually using 3D-printed parts. This level of attention and precision can give a patient like hers the ability to do the small things they’ve missed—like eating pizza.
A Rising Epidemic
Head and neck cancer starts in the nose, mouth, throat, voice box and sinuses, and treatment may call for partial or complete removal of the affected area, which means that patients are not able to do everyday tasks. And while head and neck cancer comprises only four percent of all cancers, it has a high mortality rate. It is estimated that 64,500 people will be diagnosed with some form of head and neck cancer in 2019, and almost 14,000 people will die from it.1
“Many of us take for granted that we can talk, eat, drink, smile and chew, and even swallow and breathe, without any problems,” explains Terry Day, M.D., endowed chair for the Wendy and Keith Wellin Head and Neck Tumor Center at MUSC. “But if you have an abnormality in those areas, it affects those things we use all the time.”
Most head and neck cancers are classified as squamous cell carcinomas, meaning the disease begins in the flat, scale-like cells that make up the thin layer of skin around the head and neck, as well as the linings of the respiratory and digestive tracts and hollow organs throughout the body. There are five main types of head and neck cancer, named for the areas they affect: laryngeal and hypopharyngeal cancer, nasal cavity and paranasal sinus cancer, nasopharyngeal cancer, oral and oropharyngeal cancer and salivary gland cancer.1
The two biggest risk factors for head and neck cancer in the past have been alcohol and tobacco use, and using these products in conjunction, whether through drinking, cigarettes or smokeless tobacco, also known as “chewing tobacco,” creates an even higher risk.2 But as cigarette use has declined over the last 30 years, so has the prevalence of related oral and oropharyngeal cancers, leaving room for a new risk factor: human papillomavirus (HPV).
HPV is best known for its association with cervical cancer, but HPV-associated head and neck cancers have been cropping up in new cases across the country, with the most common being HPV-associated oropharyngeal cancer. It is estimated that between 70 and 90% of new cases can be linked back to the virus.3
This risk factor change brings a patient demographic change as well as a treatment and prognosis change. Patients with HPV-associated head and neck cancer are more likely to be white males in their 40s and 50s who do not smoke or drink excessive amounts of alcohol. They are almost three times more likely than women to be diagnosed with certain forms of head and neck cancer, like that of the back of the throat.1
While HPV-associated cancers are becoming more common, they are also more responsive to treatment.4 For instance, the overall survival rate for HPV-associated oropharyngeal cancer is 95% after two years, while oropharyngeal cancer not linked to HPV has a survival rate of only 62% after two years.
A team effort
Treatment for head and neck cancer is complicated. The areas it affects are both highly visible and critical to quality of life, so the team of doctors needed covers many specialties. At MUSC, these specialists reside under the same roof, the Wellin Head and Neck Tumor Center, which is critical for ease of travel, treatment and treatment adherence.
From a treatment standpoint, the team consists of a head and neck surgeon, a radiation oncologist, and a medical oncologist, but additional team members are needed to address the quality-of-life perspective, such as a dental expert trained in maxillofacial prosthodontics, speech and swallowing therapists, and a physical therapist. Truly complex cases also require a highly specialized head and neck reconstructive surgeon.
At the Wellin Center, all of these physicians are in one place. They meet weekly at a tumor board meeting to review the CAT scans, PET scans, MRIs and pathology results for each individual patient before any kind of surgery. Then they come to a consensus on the best plan for treatment and work in tandem, both in and out of the operating room, to bring the best results, investing not only in their patient’s cure but also in their life after cure.
“We focus on function, quality of life and cure,” said Davis. “I think those three things are equally weighted in a patient’s mind. And the MUSC head and neck team works together to give them at least a chance at all three. ”
Modern treatment strategies
Each case is unique when it comes to treatment, which is one reason that the tumor boards are so effective. Patients will likely need some combination of radiation therapy, surgery, maxillofacial prosthodontics and physical therapy with voice, speech and swallowing specialists.
For instance, surgeons might need to remove the jawbone along with some teeth and the tongue of a patient with advanced oropharyngeal cancer. In that case, the team may decide to either bring in bone from the fibula to rebuild the jaw or place dental implants to serve as anchors for prosthetic teeth.
If the team decides to use existing bones, they will use the scans and the 3D printer to plan exactly where to cut the bone and how to shape it before the operation. They will then slice the bone into pieces and attach the parts in the proper configuration by use of titanium plates. Joshua Hornig, M.D., a head and neck surgical oncologist at MUSC, said he is always surprised to see how well a patient’s leg recovers after removal of part of the leg bone.
A more cutting-edge method for rebuilding the jaw is to print it out of a plastic called methyl acrylate. Using MUSC’s specially adapted CAT scan machine, physicians can take a scan and convert it into a 3D model that can then be printed.
“We can hold it out to the patient,” said Day. “And we can walk them through their upcoming procedure using a model of their very own jaw.”
In addition to rebuilding the jaw, the team also uses free tissue transfers from muscles of the body to replace the teeth, tongue and lips that were removed, leaving the patient with a quality of life that extends beyond just a cure.
The tumor removal procedure, the surgical reconstruction and the placement of dental implants take place on the same day. With a potential total surgery time of 15 hours or more, Day starts by removing the tumor and any affected area, and Hornig follows with the surgical reconstruction of the fibula while oral surgeons follow with dental implant placement.
Hornig looks at the surgery as more than just a technical feat. “You have to be a great surgeon,” he said. “But you also have to be a fellow human being and listen to them. You have to find out how this is going to impact their life and guide them through these changes.”
Life after plastic
The goal of the team at the Wellin Center is to one day create a living piece of the patient’s bone to implant. Physicians have successfully implanted 3D-printed bladders and kidneys into patients, but they have yet to regrow a mandible or skull from the patient’s own cells.5 That’s where Hornig thinks this field is headed next.
3D printing first made its debut 50 years ago as stereolithography, which allows construction of a 3D model by use of a laser to etch a design into a specific photopolymer.5 Initially used to create industrial prototypes, the technology quickly moved on to large-scale manufacturing and engineering. Next, 3D printing advanced into health care, and its uses have expanded ever since.
MUSC started using 3D printing to assist physicians in reconstructive surgeries 20 years ago, and it continues to advance this practice today. Initially met with skepticism from the medical field, 3D printing is now widely used for this method. Between 2016 and 2019, MUSC produced a total of 57 3D-printed models and prosthetics for patients.
Davis once had a patient who wore his best suit to the hospital on the day he received his prosthesis. He walked in and said, “Today I get my face back.” And Davis thought: a feeling like that is priceless.
References
1. ASCO. Head and neck cancer—statistics. https://www.cancer.net/cancer-types/head-and-neck-cancer/statistics. April 3, 2018.
2. Memorial Sloan Kettering Cancer Center. Prevention, causes, and risk factors for head and neck cancer. https://www.mskcc.org/cancer-care/types/head-neck/risk-prevention-screening.
3. Young D, et al. Oral Oncology. 2015;51(8):727–730. doi:10.1016/j.oraloncology.2015.03.015.
4. National Cancer Institute. Head and neck cancers. https://www.cancer.gov/types/head-and-neck/head-neck-fact-sheet#q2. March 29, 2017.
5. Al’Aref SJ, et al. 3D Printing Applications in Cardiovascular Medicine. Academic Press; 2018.
