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1. Significance Of Oral Field
Cancerization In Management Of
Oral Cancer- A Review
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INDIAN DENTAL ACADEMY
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2. INTRODUCTION
o Worldwide, HNSCC is the sixth most common malignancy in
men and accounts for approximately 5% of malignant tumors
o The concept of “field cancerization” was first introduced by
Slaughter et al. in 1953 when studying the presence of
histologically abnormal tissue surrounding oral squamous cell
carcinoma
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3.  Oral cancer develops in multifocal areas of precancerous change
 Abnormal tissue surrounds the tumor
 Oral cancer often consists of multiple independent lesions that
sometimes coalesce
 The persistence of abnormal tissue after surgery may explain SPT’s
and local recurrences
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4. Characteristics of A genetic field
 Loss of heterozygosity
 Microsatellite alterations
 Chromosomal instability
 Mutations in tp53 gene
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5. Oral field cancerization
“The presence of one or more areas consisting of epithelial cells
that have genetic alterations. A field lesion (or shortly ‘field’)
has a monoclonal origin, and does not show invasive growth
and metastatic behavior, the hallmark criteria of cancer.”
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6. First a patch develops, consisting of a clonal unit of TP53-mutated cells (a stem cell and
daughter cells) as has been described for HNSCC. The next step is the conversion from
patch to a field, an epithelial lesion consisting of cells with cancer-related genetic
alterations, which expands at the expense of normal tissue. During field progression a
number of genetic alterations take place; indicated in the figure are the chromosomal
locations for which LOH has been described. For the progression from field to cancer
the amplification of 11q13 was shown to be important
Proposed model of HNSCC carcinogenesis.
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7. Second primary tumor
Spt’s are the tumors which develop in the oral cavity in
succession to the primary malignant tumors
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8. Theories
Two theories have been implicated to explain the
phenomenon of second primary tumors
Classic view
Alternative view-Micrometastasis
Intraepithelial migration
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9. Classic view-multifocal carcinomas due
to independent mutations
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10. Clonal theory is based on that the multiple lesions arise due to
widespread migration
single cell
clonal expansion
premalignant field
replacement of normal mucosa
separate tumors
2 types of migrations may be involved
 Micrometastasis
 Intraepithelial migration
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11. Clonal theory-explaining ways of migration
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12. secondary tumors when occurs within 6months of
span are termed synchronous primary
And those which occur after 6 months are termed
metachronous primaries
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13. Secondary field cancerization-lesions that are
anatomically distinct but demonstrates genetic
similarities
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14. Investigations
Determining clonality:
 Karyotype analysis
 Detection of p53 mutations
 X chrmosome inactivation
 Microsatellite alterations
Detection of metastatic and second primary tumors:
 Computed tomography
 Magnetic resonance imaging
 Positron emission tomography
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15. Significance in management
 The presence of a field always a risk factor
 Different view on treatment
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16. Treatment
 Current management is often site-specific
 Recurrent premalignant tumors are treated by surgical
excision
 Diffuse high grade premalignant fields are treated by
radiotherapy
 Chemotherapy:
13 cis retinoic acid
 Biochemoprevention –combination of IFN-α,α-tocopherol &
13 cis retinoic acid
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17. Conclusion
Field cancerization is a well known process of malignant
transformation. A good research in this field has a strong potential
to reveal new diagnostic markers for early detection, modalities to
prevent progression, and lastly ways to combat development of
second primary tumor.
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18. References:
o Boudewijn J. M. Braakhuis,2 Maarten P. Tabor, J. Alain Kummer, C.
Rene´ Leemans, and Ruud H. Brakenhoff A Genetic Explanation of
Slaughter’s Concept of Field Cancerization: Evidence and Clinical
Implications journal of cancer research 2003 ;63: 1727–1730.
o Ravi raj jayam oral field cancerization : a review journal of indian
academy of oral medicine and radiology 2010;22(4):201-205
o Raghavendra Kini , Vathsala Naik, Smit Singla Field cancerization of
oral cavit y:A case report and its clinical implications IAJD2011 Vol.
2
o Gabriel D Dakubo, John P Jakupciak2, Mark A Birch-Machin3 and
Ryan L Parr1 Clinical implications and utility of field cancerization
Cancer Cell International 2007, 7:2.
o Anne S. Tsao, MD; Edward S. Kim, MD; Waun Ki Hong, MD Chemoprevention
of Cancer , American Cancer Society, 2004;54:150–180
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