Farnham, 73, has a music career that began in the late 1960s and has continued to flourish ever since. In the 1980s, his album "Whispering Jack" sold "over a million copies" according to Yahoo Entertainment. The hit single, "You're the Voice," helped cement Farnham as a fixture among Australia's music greats. He performed often with the late Olivia Newton-John, who died of breast cancer last year, and other stars like Lionel Richie.

“John Farnham: Finding the Voice” details Farnham's life from childhood to becoming a teen music heartthrob and all the highs and lows of his career and personal life. The documentary film premiers May 18.

Despite his multi-decade-long career full of accolades, Farnham's cancer diagnosis last year reminded him and his family that the disease can impact anyone, no matter who you are.

"It's cruel and brutal but they're the cards you're dealt in life and cancer doesn't care who you are," Rob Farnham said.

Farnham's family revealed he was battling cancer in August 2022. The legendary singer spent nearly 12 hours in surgery to remove a tumor from his mouth.

Before treating the tumor, Farnham's sons told "The Sydney Morning Herald", their father was experiencing some symptoms signaling something wasn't quite right.

"He was having trouble sleeping. He likes to sleep on his side and he had a lump on his cheek," James Farhnam said.

"He just thought it was an ulcer and it turned out to be cancerous," Rob Farhnam added.

"The cancer tumor was located in his mouth and it has been successfully removed," John's wife, Jill Farnham said according to the Australian news outlet 9 News.

"There is still a long road of recovery and healing ahead of us, but we know John is up for that task," she added.

Last month, Farnham's son revealed he also suffered a lung infection and was hospitalized.

"He is currently being treated for a respiratory infection in the hospital, but he is comfortable and receiving the very best care," Farnham's family said in a statement to the U.K.-based news outlet The Daily Mail.

Despite Farnham's ongoing journey to a full recovery, his family said his bravery while fighting is inspiring.

"He's inspiring us every day, but then again, he always has," Rob Farnham said.

Understanding Mouth Cancer

While John Farnham's family has kept some elements of his cancer battle private, here’s what we do know about mouth cancer.

Mouth cancer, also called oral cancer, is cancer that forms in the mouth according to Mayo Clinic. Mouth cancer can occur in the following areas:

• Lips
• Gums
• Tongue
• The inner lining of the cheeks
• The roof of the mouth
• The floor of the mouth

Symptoms and Risk Factors for Mouth Cancer

With April being Oral, Head and Neck Cancer Awareness Month, John Farnham’s story is an important reminder to know the risk factors and symptoms.

Risk factors for developing mouth cancer may include tobacco and heavy alcohol use, excessive sun exposure to your lips, human papillomavirus (HPV), or a weakened immune system.

Some possible signs of mouth cancer may include:

• A lip or mouth sore that doesn’t heal
• A white or reddish patch on the inside of your mouth
• Loose teeth
• A growth or lump inside your mouth
• Mouth pain
• Ear pain
• Difficult or painful swallowing

While these symptoms may not mean you definitely have mouth cancer, it’s important to take note of any changes to your body or health, and to discuss them with your doctor.

WATCH: The human papillomavirus HPV can cause anal, oral, and penile cancers. 

How Are Mouth Cancers Treated?

Your doctor will work with you to determine the best treatment option, depending on where the cancer is located within your mouth and your overall health. Treatment options typically include:

• Surgery
• Radiation therapy
• Chemotherapy
• Targeted drug therapy
• Immunotherapy

Coping With a Cancer Diagnosis

Farnham's mouth cancer diagnosis seemed to have an impact on his entire family, but luckily, the pop star had his wife and sons by his side as he battled his mouth cancer and throughout his recovery.

Coping with a health diagnosis can be challenging for anyone no matter who you are. Often, cancer warriors and their families experience a series of emotions as they grow to understand what their cancer battle will look like.

Psychiatrist Dr. Lori Plutchik told SurvivorNet that the patient or person going through a stressful event should accept that emotions will be fluid. You may feel fine one day and then feel a massive wave of stress the next.

It's also important for those you look to for support whether that's a therapist, friends, and family, or both to understand the fluidity of stress-related emotions.

Sometimes it's worth seeking mental health help from a therapist, and this goes for both cancer warriors and their caregivers who also bear a huge burden caring for their beloved cancer warrior.

"Caregiving is a huge job. It's going to impact your health and your physical well-being. It will impact your finances, your social life, your emotions, and your mental energy," Amy Brown, nurse manager of Gynecologic/Oncology at Johns Hopkins Hospital in Baltimore, Maryland, told SurvivorNet.

Though caregiving can be a difficult and sometimes thankless job, it can be very rewarding as well.

"Even though this is not what you signed up for, this is not how you planned your life, and this may be the biggest crisis of your life that you didn't see coming, it has the potential to be incredibly meaningful," Brown said.

Learn more about SurvivorNet's rigorous medical review process.

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