I would like to discuss my fathers case and would appreciate your opinion on it.
My father was diagnosed with squamous cell carcinoma of the lower buccal mucosa of the left cheek last year in July and was operated for the same. The operation involved wide excision left cheek lesion+radical neck dissection+reconstruction of palatial flap. The lesion was excised with clear margins of 2 cm.The dissected tissue was sent for histopathology testing. Sections from the tumour showed features of well differentiated squamous cell carcinoma. All the resection margins were free from the tumour. 3 out of the 13 dissected lymph node showed tumour deposits (2 level 1b lymph nodes and 1 level 3 lymph node).
He subsequently received radio an chemotherapy six weeks after the operation for 6 weeks i.e 5 chemo cycles and 30 radio cycles.
The patient was normal after that but noticed a small growth in his front of his left ear (parotid region swelling) in december which gradually progressed to grow in size and became painful. Following this FNAC was performed which showed atypical pyknotic squamous cells suspicious of metastatic squamous cell carcinoma.
For confirmation PET-CT SCAN was performed which showed focal abnormal increased FDG uptake in the enlarged lymph node in the superficial lobe of left parotid.
Now the physician has suggested to do superficial parotidectomy.
But I would like to know
1. Is metastasis to parotid gland common in lower buccal carcinomas?
2.Before giving radiotherapy PET -planning was done
And it showed no areas of neoplastic lesion. So how did it reccur?
3. What should be done further to prevent such recurrences?

Sadly there is no way to prevent a recurrence. Nutrition, surgeon, hospital, overall health, age, lifestyle habits, treatment and initial dx all play a role.

What I can tell you is that cancer can spread anywhere once it hits the nodes. The location of the primary tumor can lead to different locations. For distant metastasis most oral cancer likes to make the hike to the lungs as a next stop - however - I've known people with it in their hips, vertebrae, colon, ribs, and yes... glands etc.. (though that is more local that distant) Its odd - on a local level - tongue cancer tends to move around the tongue, nodes base of tongue floor of mouth salivary glands. Oral mucosa cancer - like cheek - seems to hop around the gums, cheek and into the jaw area so yes the parotid is a possibility simply based on its location in conjunction to the original tumor. The standard treatment for your dad's cancer was removal of the nodes and primary tumor which they did with clear margins... but because cancer moves on a cellular level (microscopic) there is always the potential for it to still exist and NOT be picked up on a scan until it is a fair size.

Radiation and chemo would normally take care of residual cells but that depends on where the radiation was aimed (did they include the parotid in the radiation field? Spare it all together - or simply paint it with a low dose) and if they spared it then can they do rads to the area again after the parotid is removed? If they did hit it with rads can they give him more?

Remember more radiation will cause more issues. Based on the location of the parotid, he could end up with trismus (difficulty opening his mouth) ear troubles, skull/jaw bone issues as well.

If you trust your dr. and you are at a CCC - then do what the dr. says. If you are not at a CCC I would ask for a second opinion, though this treatment you described seems very much on par with what should be done.

At this point I would call it salvage surgery. I would hope they plan to maybe follow it up with something else though since it seems persistent.

To help him I would recommend proper nutrition including high protein and lots of fluids. hugs. and welcome and sorry about the recurrence. Unfortunately is a little like playing craps - very unpredictable.

Thank you for your reply.
They did involve the parotid region in radiation. And the same dose of radition was given to it as the other areas. Now the doctor has suggested to do a superficial parotidectomy and subsequent treatment would depend on the histopathology report of the dissected tissue.
At the moment he's said that chemotherapy will be given after surgery as radiation has already been given quite recently