Principal Director & Unit Head - Medical Oncology, Fortis Hospital, Shalimar Bagh, New Delhi, India
Part 4 of 18 in Cancer: Myths Facts and Advances
Does a Healthy Lifestyle or Family History Prevent Cancer? Myths Explained
August 7, 2026
A healthy lifestyle does not guarantee that a person will never develop cancer, and most cancers are not directly inherited, which makes both of these common assumptions about cancer myths rather than facts. Understanding what genetics can and cannot explain is an important first step before considering cancer treatment in India.
Can Someone Who Has Never Been Unwell Still Get Cancer?
Dr. Mohit Agarwal of Fortis Hospital, Shalimar Bagh, explains that good general health and strong immunity reduce the risk of many illnesses, but this does not mean a person cannot develop cancer. Patients are often surprised by a cancer diagnosis precisely because they assumed a healthy life offered complete protection, but no lifestyle can guarantee immunity from cancer.
Is Cancer Usually Passed Down Through Families?
Only around 5 to 10 percent of cancers are actually carried in the genes, with another 5 to 10 percent showing familial clustering. The great majority of cancer cases are sporadic, meaning they arise without any identifiable genetic predisposition running in the family. A parent's cancer diagnosis does not mean a child is destined to develop the same cancer.
When Should Genetic Testing Be Considered for Cancer?
Genetic testing becomes relevant when two or more generations of a family are affected by cancer, when a patient develops breast, ovarian or colon cancer before the age of 30, when a male develops breast cancer, or when the same individual develops two related cancers, such as breast and ovarian cancer or colon and ovarian cancer. These specific patterns, rather than a single relative's cancer diagnosis, are what actually guide the decision to pursue genetic testing.
Series index | Smoking and Cancer: Why It Remains the Biggest Preventable Risk →
This article is based on a Jivo Masterclass session conducted by Dr. Mohit Agarwal, Principal Director and Unit Head, Medical Oncology, Fortis Hospital, Shalimar Bagh, New Delhi, India. The article has been summarised with the assistance of an AI tool from the original masterclass recording. Watch the full Masterclass recording
This guide is based on a live Jivo Masterclass — Dr. Mohit Agarwal taught doctors across Africa on September 7, 2025.
FROM THE LIVE Q&A
Dr. Remigius Thadeo Mushi (Tanzania)
Could you elaborate more on the next generation sequencing (NGS) you mentioned?
Dr. Mohit Agarwal
We take the biopsy specimen and extract the DNA from the cancer cell, then sequence it to identify where something has gone wrong in the DNA or RNA, which tells us why that individual developed the cancer. Through this we identify specific mutations that may be the probable reason. Research is ongoing to counteract every change found on NGS, but currently we have a few drugs available for certain specific mutations — if we find one of those, we give that specific drug and the patient benefits.
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Frequently Asked Questions
Doctors practising in Africa face the challenge of exact diagnosis in the absence of PET-CT scan machines, which are not available in most countries, forcing guesswork. If the protocol decided in the home country is chemotherapy, what is the difference between chemotherapy administered in a country like Nigeria or Ethiopia compared to an advanced centre like Fortis Shalimar Bagh, and how can that gap be filled?▼
If you don't have a PET-CT, the second-best modality is a CT scan of the probable areas — chest, abdomen, and maybe head and neck depending on the cancer — which will give some answers on staging. As for treatment: chemotherapy is calculated as per the height, weight and profile of the patient, not given as a simple fixed dose. There are specific mixing criteria — it cannot be mixed like an antibiotic — and India has specific mixing units where care is taken over contamination and dosing. Drugs also have to be given over an appropriate infusion time, since infusing over the wrong duration causes more side effects. We also have monitoring systems running during chemotherapy to catch problems early, and targeted therapies and immunotherapies have specific temperature and light-sensitivity handling requirements that are important to follow correctly.
Isn't the next generation sequencing procedure going to take a long time before giving the patient medication? How many days does it take to get the precise DNA gene mutation result and start the exact medication?▼
Previously it used to take 30 days, and it still does in most institutes, but with the advanced machines we now have, our turnaround time is only about five to six working days — even including a Sunday, a comprehensive NGS report is usually ready by about the seventh day.
Can you give an approximate idea of the cost range for cancer treatment, since doctors often get asked this even before a formal case file is created?▼
The cost is very different for every cancer and every stage — it can vary from a few thousand rupees to a million rupees. The good news is that targeted therapy and immunotherapy drugs, which used to be very costly, now have more reasonable generic alternatives. For example, a drug that used to cost about $5,000 for a single dose as immunotherapy now costs just around $1,000 for a single dose. We also try to provide assistance programmes through indications approved by the companies that manufacture these drugs, to help patients financially.
Do we have targeted therapy and immunotherapy for all forms of cancer, or only for a few?▼
It is not available for everyone blanketly — you first need to identify the target on the cell, which is where NGS and special staining come in. Not every individual harbours those targets, but many do, and we then use specific targeted drugs. Immunotherapy is not available for all cancers either, but with present indications it is available for the majority of advanced cancers — about 70% of advanced cancers would be candidates for some form of immunotherapy. There are specific criteria that must be met; giving it without meeting those criteria would not help the patient and would just be a financial waste.
What investigations help us identify targets on cancer cells?▼
We take a biopsy from the specimen, cut it into sections, make blocks, and apply immunohistochemistry staining, which lets us identify targets on the cells. We then do mutation testing to see what mutations are present in the genes, to identify further targets we can address. We also do PD-L1 testing, which tells us whether the patient can receive immunotherapy. It is a combination of these staining protocols along with NGS that tells us the best way forward for the patient.
Can someone who has always been healthy still develop cancer?▼
Yes. Good general health and strong immunity reduce the risk of many illnesses, but this does not mean a person cannot develop cancer; no lifestyle can guarantee immunity from it.
What percentage of cancers are actually inherited?▼
Only around 5 to 10 percent of cancers are carried directly in the genes, with another 5 to 10 percent showing familial clustering; the great majority of cases are sporadic, arising without any identifiable genetic predisposition.
When should genetic testing be considered for cancer risk?▼
When two or more generations of a family are affected by cancer, when a patient develops breast, ovarian or colon cancer before the age of 30, when a male develops breast cancer, or when the same individual develops two related cancers such as breast and ovarian cancer.
In This Series: Cancer: Myths Facts and Advances
- 1.Cancer Myths, Facts and Advances
- 2.Breast Cancer Surgery: Lumpectomy Versus Mastectomy
- 3.Does a Biopsy Spread Cancer? Diagnosis Myths Explained
- 4.Does a Healthy Lifestyle or Family History Prevent Cancer? Myths Explained
- 5.What Are the Risk Factors for Cancer Beyond Smoking?
- 6.Cancer Screening Guidelines: Breast, Cervical, Prostate and Lung Cancer
- 7.Why Cancer Staging Matters Before Treatment Begins
- 8.Is Surgery Always Necessary for Cancer? Myths About Surgical Treatment
- 9.The Cervical Cancer Vaccine: Who Should Get It and Why
- 10.Chemotherapy Myths: Pain, Hair Loss and Daily Life
- 11.The Cost of Cancer Treatment in India and How International Patients Are Supported
- 12.How Does Immunotherapy Treat Cancer?
- 13.Personalised Cancer Treatment and Next Generation Sequencing Explained
- 14.Radiation Therapy for Cancer: Separating Fear From Fact
- 15.Secondhand Smoke and Cancer Risk to Family Members
- 16.Smoking and Cancer: Why It Remains the Biggest Preventable Risk
- 17.What Is Targeted Therapy for Cancer and How Does It Work?
- 18.Warning Signs of Cancer: When to See a Doctor