Throat Cancers

Determining the Grade of the Tumor

Pathologists will typically report on the grade of the tumor. This is a qualitative interpretation by the pathologist of how much the cancerous cells resemble normal tissue from that site. There are a number of different grading systems that might be used. The most common is as follows:

  • GX: Grade cannot be assessed
  • G1: Well differentiated
  • G2: Moderately differentiated
  • G3: Poorly differentiated
  • G4: Undifferentiated

Differentiation refers to how closely the cells taken from a tumor or lesion resemble normal cells from the healthy tissue surrounding the tumor. “Well differentiated” means that the cells look similar to normal cells in that area. “Undifferentiated” means the cells look nothing like normal cells in that area.

While it is important to report the tumor’s grade, few doctors use this information to make decisions regarding treatment or prognosis for this particular cancer type.


1 Moore C. Smoking and cancer of the mouth, pharynx, and larynx. JAMA: the journal of the American Medical Association. Jan 25 1965;191(4):283-286.

2 Pelucchi C, Gallus S, Garavello W, Bosetti C, La Vecchia C. Cancer risk associated with alcohol and tobacco use: focus on upper aero-digestive tract and liver. Alcohol research & health: the journal of the National Institute on Alcohol Abuse and Alcoholism. 2006;29(3):193-198.

3 Little MP. Cancer after exposure to radiation in the course of treatment for benign and malignant disease. The lancet oncology. Apr 2001;2(4):212-220.

4 D'Souza G, Kreimer AR, Viscidi R, et al. Case-control study of human papillomavirus and oropharyngeal cancer. The New England journal of medicine. May 10 2007;356(19):1944-1956.

5 Hildesheim A, Berrington de Gonzalez A. Etiology and prevention of cervical adenocarcinomas. Journal of the National Cancer Institute. Mar 1 2006;98(5):292-293.

6 Armstrong RW, Armstrong MJ, Yu MC, Henderson BE. Salted fish and inhalants as risk factors for nasopharyngeal carcinoma in Malaysian Chinese. Cancer research. Jun 1983;43(6):2967-2970.

7 Larsson LG, Sandstrom A, Westling P. Relationship of Plummer-Vinson disease to cancer of the upper alimentary tract in Sweden. Cancer research. Nov 1975;35(11 Pt. 2):3308-3316.

8 El-Serag HB, Hepworth EJ, Lee P, Sonnenberg A. Gastroesophageal reflux disease is a risk factor for laryngeal and pharyngeal cancer. Am J Gastroenterol. Jul 2001;96(7):2013-8.

9 Vaezi MF, Qadeer MA, Lopez R, Colabianchi N. Laryngeal cancer and gastroesophageal reflux disease: a case-control study. Am J Med. Sep 2006;119(9):768-76.

10 Wei WI, Sham JS. Nasopharyngeal carcinoma. Lancet. Jun 11-17 2005;365(9476):2041-2054.

11 Hoare TJ, Thomson HG, Proops DW. Detection of laryngeal cancer--the case for early specialist assessment. Journal of the Royal Society of Medicine. Jul 1993;86(7):390-392.

12 Referenced with permission from The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Head and Neck Cancers V.2.2016. © National Comprehensive Cancer Network, Inc 2016. All rights reserved. Accessed December 7, 2016. To view the most recent and complete version of the guideline, go online to