Diagnosis and staging:
To determine tumor extension, diagnostic imaging is needed:
-Imaging diagnosis before a biopsy avoids misinterpretation from anatomical distortion.
-Computed tomography (CT scan) and Magnetic Resonance Imaging (MRI sacn) are also used in diagnosis. MRI can be beneficial than CT for evaluating tongue, perineural spread, invasion to skull base and intracranial extension.
-CT of chest is preferred, or X-ray is done in early stages.
-Positron emission tomography-CT (PET-CT) is useful in diagnosis of node and metastases and some primary tumors. It is recommended in patients with stage III and IV disease when definitive treatment is indicated.
-Esophagoscopy is carried out in case of dysphagia.
-Histological evaluation is mandatory by primary tumor biopsy or fine needle aspiration (FNA) of lymph nodes.
-Functional evaluation: actions like chewing, swallowing, breathing, odontology and nutritional status are assessed.
-Special evaluations if needed: psychological and social situation assessmet, cessation of smoking or alcohol dependence10.
The diagnosis of HNSCC can be established by biopsy of the primary tumour. The biopsy method depends upon the location of the tumor. Primary tumours are approached incisional biopsy or excisional biopsy, whereas the suspicious cervical neck mass should be diagnosed with the help of fine needle aspiration (FNA).
A well-differentiated tumour would be similar to the stratified epithelium, with mature-appearing cells organizing into layers with irregular keratinization. A poorly differentiated tumour is characterized by immature cells with nuclear pleomorphism and atypical mitoses, with minimal to no organized keratinization. HPV-negative HNSCCs are moderately or well differentiated, with preservation of stratification and keratinization, whereas HPV-positive HNSCCs are poorly differentiated and even display basaloid morphology on histopathological examination. The histopathological diagnosis of HNSCC can usually be made using haematoxylin and eosin staining. However, in the case of poorly differentiated tumours, immunohistochemistry may be necessary to confirm an epithelial origin11.
TUMOR RESPONSE EVALUATION (RECIST GUIDELINES)
Evaluation of target lesions:
  1. Complete Response (CR): Disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to <10mm.
  2. Partial Response (PR): At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.
  3. Progressive Disease (PD): At least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that is the smallest on study). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. (Note: the appearance of one or more new lesions is also considered progression).
  4. Stable Disease (SD): Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum diameters while on study.
Evaluation of non-target lesions:
  1. Complete Response (CR): Disappearance of all non-target lesions and normalisation of tumour marker level. All lymph nodes must be non-pathological in size (<10mm).
  2. Non-CR/Non-PD: Persistence of one or more non-target lesion(s) and/or maintenance of tumour marker level above the normal limits.
  3. Progressive Disease (PD): Unequivocal progression (see comments below) of existing non-target lesions.
Measurability of tumour:
Measurable Tumour lesions:
Must be accurately measured in at least one dimension (longest diameter in the plane of measurement is to be recorded) with a minimum size of:
• 10 mm by CT scan (CT scan slice thickness no greater than 5 mm
• 10 mm caliper measurement by clinical exam
• 20 mm by chest X-ray.
Malignant lymph nodes:
To be considered pathologically enlarged and measurable, a lymph node must be <15 mm in short axis when assessed by CT scan. At baseline and in follow-up, only the short axis will be measured and followed.
Non-measurable:
All other lesions, including small lesions and non-measurable lesions and these non-measurable include: leptomeningeal disease, ascites, pleural or pericardial effusion, lymphangitic involvement of skin or lung, abdominal masses/abdominal organomegaly identified by physical exam that is not measurable by reproducible imaging techniques.
Special considerations regarding lesion measurability:
Bone lesions.
• Bone scan, PET scan or plain films are not considered adequate imaging techniques to measure bone lesions. However, these techniques can be used to confirm the presence or disappearance of bone lesions.
• Lytic bone lesions or mixed lytic-blastic lesions, with identifiable soft tissue components, that can be evaluated by cross sectional imaging techniques such as CT or MRI can be considered as measurable lesions if the soft tissue component meets the definition of measurability described above.
• Blastic bone lesions are non-measurable.
Cystic lesions:
• Lesions that meet the criteria for radiographically defined simple cysts should not be considered as malignant lesions since they are simple cysts.
• Cystic lesions thought to represent cystic metastases can be considered as measurable lesions. However, if non-cystic lesions are present in the same patient, these are preferred for selection as target lesions.
Lesions with prior local treatment:
• Tumour lesions situated in a previously irradiated area, or in an area subjected to other loco-regional therapy, are usually not considered measurable unless there has been demonstrated progression in the lesion. Study protocols should detail the conditions under which such lesions would be considered measurable.
STAGING OF TUMOR (TNM CLASSIFICATION)
In the TNM system:
When your cancer is described by the TNM system, there will be numbers after each letter that give more details about the cancer, which include:
Primary tumor (T)
Regional lymph nodes (N)
Distant metastasis (M)
TNM classification is grouped into following stages:
TREATMENT AND PHARMACOLOGY:
By the end of the 20th century, radiation had just been discovered, and surgical outcomes were of great use due to the lack of antibiotics and the limitations of anaesthesia. Because of these reasons, radiation therapy (RT) had been used as a primary treatment for the first half of
the century. After few decades, due to treatment failures of early RT techniques, led to the
emergency development of primary surgical treatment for most head and neck cancers. Subsequent advancements in RT improved cure rates and decreased treatment failures.
Today, RT remains an important option in early-stage cancers and plays an
important role in the adjuvant setting. Recently, combinations of chemotherapy and
RT have been used majorly for advanced-stage cancers, both for primary and adjuvant
treatment. Finally, targeted molecular therapies have been developed that bring out new options in managing of HNSCC, which may further improve survival rates12. Figure 2 represents the treatment options involving chemotherapy for locally advanced squamous cell carcinoma of the head and neck.