Cancer Glossary
Plain-language definitions of medical terms used across HealOnco. Written for patients, caregivers, and families.
62 terms defined
A
Adenocarcinoma
A type of cancer that starts in glandular cells — cells that produce mucus and other fluids. It is the most common type of cancer in the lung, colon, pancreas, and prostate.
Adjuvant Therapy
Treatment given after the primary treatment (usually surgery) to lower the risk of cancer coming back. Common adjuvant therapies include chemotherapy, radiation, and hormonal therapy.
Alopecia
Hair loss, a common side effect of certain chemotherapy drugs. Hair typically grows back after treatment ends.
Anaemia
A condition where you have fewer red blood cells than normal, causing tiredness and breathlessness. Chemotherapy can lower red blood cell counts.
Angiogenesis
The process by which new blood vessels form. Tumours need new blood vessels to grow. Some cancer drugs (anti-angiogenic agents) work by blocking this process.
Ayushman Bharat
India’s national health insurance scheme (also called Pradhan Mantri Jan Arogya Yojana or PMJAY) that covers cancer treatment up to Rs 5 lakh per family per year at empanelled hospitals.
B
Benign
Not cancerous. A benign tumour does not spread to other parts of the body. Compare with malignant.
Biomarker
A measurable substance in the body that can indicate cancer presence, type, or response to treatment. Examples include PSA for prostate cancer and CA-125 for ovarian cancer.
Biopsy
A procedure in which a small sample of tissue is removed and examined under a microscope to check for cancer cells. Types include needle biopsy, core biopsy, and excisional biopsy.
BRCA1 / BRCA2
Genes that normally help repair DNA. Inherited mutations in BRCA1 or BRCA2 significantly increase the risk of breast and ovarian cancer.
C
Carcinoma
Cancer that starts in the skin or in the lining of internal organs. Most cancers are carcinomas.
Chemotherapy
Treatment that uses drugs to kill cancer cells or stop them from growing. Chemotherapy can be given intravenously (IV), orally, or as an injection. At HealOnco, chemotherapy is administered in daycare settings.
Clinical Trial
A research study that tests new treatments or new combinations of treatments in patients. India has several cancer clinical trial centres registered with the CTRI (Clinical Trials Registry of India).
Complete Response (CR)
When all signs of cancer disappear after treatment. Also called complete remission. Does not always mean the cancer is cured.
CT Scan
Computed Tomography scan — an imaging test that uses X-rays taken from different angles to create detailed cross-sectional images of the body. Used for staging and monitoring cancer.
Cytology
The study of cells under a microscope. Pap smear cytology is used to screen for cervical cancer.
D
Daycare Chemotherapy
Chemotherapy administered in an outpatient setting where the patient comes in the morning, receives treatment, and goes home the same day. HealOnco centres operate on this model.
Differentiation
How much cancer cells look like normal cells under a microscope. Well-differentiated cancers look more normal and tend to grow slowly. Poorly differentiated cancers look abnormal and tend to grow faster.
E
ECOG Performance Status
A scale (0-5) used by oncologists to assess how a patient’s disease affects their daily living abilities. ECOG 0 means fully active; ECOG 4 means completely bedridden.
Excision
Surgical removal of tissue, including tumour and a margin of healthy tissue around it.
F
FISH Test
Fluorescence In Situ Hybridisation — a lab test that checks for specific gene changes in cancer cells. Used to test for HER2 amplification in breast cancer.
FNAC
Fine Needle Aspiration Cytology — a biopsy technique using a thin needle to extract cells. Very common in India as a first-line diagnostic for thyroid nodules and breast lumps.
G
Gleason Score
A grading system for prostate cancer, ranging from 6 to 10. A higher Gleason score means the cancer is more aggressive.
Grading
A system for classifying cancer cells based on how abnormal they look under a microscope. Low-grade (Grade 1) cells look more normal; high-grade (Grade 3) cells look very abnormal.
H
HER2
Human Epidermal Growth Factor Receptor 2 — a protein that promotes cell growth. Some cancers (especially breast) have too much HER2, making them HER2-positive. Targeted drugs like trastuzumab treat these cancers.
Hormonal Therapy
Treatment that blocks hormones or lowers hormone levels to slow or stop cancer growth. Used for hormone-receptor-positive breast cancer and prostate cancer.
Hospice Care
End-of-life care focused on comfort and quality of life rather than curing the disease. Kerala’s palliative care model is considered a world leader.
I
Immunotherapy
Treatment that helps the immune system fight cancer. Checkpoint inhibitors like nivolumab and pembrolizumab are the most common type used in India.
Incidence Rate
The number of new cases of a disease per 100,000 people per year. India’s cancer incidence is tracked by the ICMR-NCDIR (National Centre for Disease Informatics and Research).
INR
Indian Rupee — the currency in which all treatment costs on HealOnco are listed.
L
Lymph Node
Small, bean-shaped organs that filter lymph fluid and contain immune cells. Cancer often spreads to nearby lymph nodes first before reaching distant organs.
Lymphoma
Cancer that starts in the lymphatic system. The two main types are Hodgkin lymphoma and non-Hodgkin lymphoma.
M
Malignant
Cancerous. Malignant cells can invade nearby tissues and spread to other parts of the body. Compare with benign.
Mastectomy
Surgery to remove the entire breast. A modified radical mastectomy also removes some lymph nodes under the arm.
Metastasis
The spread of cancer from its original site to other parts of the body through the blood or lymph system. Stage IV cancer typically means metastatic disease.
MRI
Magnetic Resonance Imaging — an imaging test that uses magnets and radio waves to create detailed pictures of organs and tissues. Useful for brain, breast, and soft tissue cancers.
Mucositis
Inflammation and ulceration of the mucous membranes lining the mouth and throat, a common side effect of chemotherapy and radiation.
N
NCCN Guidelines
Treatment guidelines published by the National Comprehensive Cancer Network, an alliance of leading US cancer centres. Widely followed by Indian oncologists.
Neoadjuvant Therapy
Treatment given before the primary treatment (usually surgery) to shrink the tumour. Common in breast cancer and locally advanced cancers.
Neutropenia
An abnormally low count of neutrophils (a type of white blood cell), making the patient more vulnerable to infections. A common and serious side effect of chemotherapy.
O
Oncologist
A doctor who specialises in treating cancer. Medical oncologists prescribe chemotherapy and other drugs; surgical oncologists operate; radiation oncologists use radiation therapy.
P
Palliative Care
Care focused on relieving symptoms and improving quality of life, given alongside active treatment or when curative treatment is no longer an option.
Partial Response (PR)
When a tumour shrinks by at least 30% in response to treatment but does not disappear completely.
Pathology Report
A medical report from a pathologist describing what was found when tissue or cells were examined under a microscope. It includes tumour type, grade, margins, and biomarker status.
PET-CT Scan
Positron Emission Tomography combined with CT — an imaging test that shows metabolically active areas in the body. Used for cancer staging and to check if treatment is working.
PMJAY
Pradhan Mantri Jan Arogya Yojana — see Ayushman Bharat.
Prognosis
The likely course and outcome of a disease. Prognosis depends on cancer type, stage, grade, and the patient’s overall health.
Protocol
A detailed plan for a course of treatment, including drug names, doses, schedule, and duration. Also called a regimen.
R
Radiation Therapy
Treatment that uses high-energy beams (X-rays, protons) to kill cancer cells. Can be given externally (EBRT) or internally (brachytherapy).
Recurrence
When cancer comes back after a period of remission. Can be local (same site), regional (nearby lymph nodes), or distant (metastatic).
Remission
A decrease or disappearance of signs and symptoms of cancer. Can be partial or complete.
Resection
Surgical removal of part or all of an organ or tissue that contains cancer.
S
Sarcoma
Cancer that starts in bone, muscle, fat, cartilage, or other connective tissues. Less common than carcinoma.
Staging
The process of determining how much cancer is in the body and where it is located. The TNM system (Tumour, Nodes, Metastasis) is most commonly used. Stages range from I (early) to IV (advanced).
Survival Rate
The percentage of patients who are alive a certain number of years (usually 5) after diagnosis. It is a statistical average and does not predict what will happen to any individual patient.
T
Targeted Therapy
Drugs that target specific proteins or genes that help cancer cells grow. Unlike chemotherapy, targeted therapy aims to spare normal cells. Examples include imatinib for CML and erlotinib for lung cancer.
Thrombocytopenia
An abnormally low platelet count, which can cause easy bruising and bleeding. Can be a side effect of chemotherapy.
TNM Staging
A system that describes cancer size (T = Tumour), lymph node involvement (N = Nodes), and whether cancer has spread (M = Metastasis). Combined into an overall stage (I through IV).
Tumour Board
A group of doctors from different specialties (medical oncology, surgical oncology, radiation oncology, pathology, radiology) who meet to discuss individual patient cases and recommend treatment plans.
Tumour Marker
A substance found in blood, urine, or tissue that can indicate cancer. Examples: CEA (colon), AFP (liver), CA 19-9 (pancreas), PSA (prostate).
U
Ultrasound
An imaging test that uses sound waves to create pictures of internal organs. Commonly used for initial evaluation of breast, thyroid, and abdominal cancers.
W
WHO Pain Ladder
A three-step approach to cancer pain management recommended by the World Health Organization: Step 1 (non-opioid like paracetamol), Step 2 (weak opioid like tramadol), Step 3 (strong opioid like morphine).