What is Point A and point B Manchester location are important for treatment of_______ cancer. and explain in detail?
Ans. a (Cervix) (Ref. Shaw gynecology 14th/391)RADIOTHERAPY (RT) IN CERVICAL CANCERRadiotherapy (RT) can be used to treat all stages of cervical squamous cell cancer, with cure rates of about 70% for stage I, 60% for stage II, 45% for stage III, and 18% for stage IV.Principles# The radiation treatment plan generally consists of a combination of:- External teletherapy to treat the regional nodes and to shrink the primary tumor and- Intracavitary brachytherapy to boost the central tumor.# For intracavitary insertions, point A, point B, Bladder and rectal points need to be defined with stipulated radiation dose at respective points.# Intracavitary therapy alone may be used in patients with early disease when the incidence of lymph node metastasis is negligible.# Point A:- A point 2 cm above the external os of the cervix and 2 cm lateral to the cervical canal.0- Corresponds to obturator nodes. 0# Point B:- A point 3 cm lateral to point A or 5 cm from the cervical canal.0- Corresponds to iliac crossing. 0# The usual doses delivered are:- 5,000 cGy/rads to point AQ and (Shaw Textbook mentions < 8000 rads)- 2,000 cGy/rads to point B0, (Shaw textbook mentions < 4.500 rads)- Limiting the bladder and rectal dosage to < 6,000 cGy0.# For interstitial implants, prescribed dose, dose rate, agent to be used should be known.Concurrent chemoradiation is very effective in Rx of Ca cervix stage Ilb/IIIa onwards.0Complications following radiation include radiation inflammation of the bladder or bowel, which may lead to pain, bleeding, or, infrequently, fistula formation. The normal cervix is resistant to radiation, and the dose can be as high as 200 to 250 Gy over 2 months. The bladder and rectum can be injured at average dosages in the range of 65 to 70 Gy. Overall moderate to severe radiation complications for treatment of all stages approximate 10%.Radiation complications of the intestine are more frequent than bladder complications. Both tend to occur more than 1 year after therapy.