Cervix Flashcards

Question

Which patients get adjuvant radiation after surgery? Which patients get adjuvant chemoradiation?

Answer 1

``` Radiation: Sedlis criteria per GOG 92 Patients with IM factors were randomized to RT vs obs. There was improvement in PFS with RT. The study was not powered to detect a difference in OS. +LVSI, superficial DOI, >5cm +LVSI, middle DOI, >2cm +LVSI, deep DOI, any size -LVSI, middle/deep DOI, >4cm ``` ``` cisRT: Peters criteria per GOG 109 Patients with HR factors randomized to RT vs cis/5FU-RT. There was improvement in PFS and OS. HR was 2 for both metrics. +margins +parametria +LN ```

Answer 2

GOG 263 is currently studying this. Randomized trial of IM factor patients after surgery, randomized to cisRT vs RT The OUTBACK trial is studying patients that are HR and randomizing them to cisRT vs cisRT+carbo/taxol x 4

Answer 3

1. Inhibits sublethal repair 2. Synchronizes cell populations 3. Induces proliferation in non-proliferating cells 4. Reduces fraction of hypoxic cells 5. Increases apoptosis

Answer 4

Gross target volume = actual tumor as determined clinically and radiographically Clinical target volume = an area that has high likelihood of harboring malignancy Planned target volume = added margin to account for motion and daily set up error

Answer 5

``` GTV = 80-90Gy CTV = 45-54Gy ```

Answer 6

Ionizing radiation induces cell DNA damage, which results in cell death.

Answer 7

Oxygen fixation hypothesis: oxygen is known to chemically modify radiation-included DNA damage making it irreparable.

Answer 8

Sensitive: M phase Resistant: S phase

Answer 9

Linear accelerator. The principles behind this involve accelerating electrons across a variable electric field. The gantry is the portion which emits radiation. Multileaf collimators control the shape of the of the radiation beam before it reaches the patient.

Answer 10

IMRT is an improvement over 3D. 3D: uses fewer fields. At each gantry angle, the radiation is either hitting the target or not. IMRT: with IM, can use same angles but create more complex dose distribution. It is of particular use when normal tissues and target tissues are in close proximity, or in varying proximity across a field and gantry angles.

Answer 11

Image-guided radiation therapy. Historically treatment setups were verified with radiographs, and treatment fields by x-rays superimposed on the patient. Modern linacs have on-board imaging that allows fields to be recorded electronically at every treatment step. By comparing computer generated radiographs and actual patient images, discrepancies in field shape and patient set up can be corrected before treatment is delivered. - Allows for treatment shape to change throughout course of treatment (ie, as tumors shrinks) - CT scanners have been added to linacs

Answer 12

The dose delivered to the target is inversely proportional to the square of the distance to the target. *So if you double the distance, the dose is reduced by a factor of 4.

Answer 13

2cm lateral to the central canal of the uterus and 2cm from the lateral fornix in the axis of the uterus. Where the uterine artery crosses the ureter. Correlates to the paracervical triangle.

Answer 14

3cm lateral to Point A. Correlates to the obturator nodes.

Answer 15

85Gy to Point A 60Gy to Point B when combining EBRT and brachytherapy.

Answer 16

Use largest size possible, and position as far laterally and cephalad as possible, in order to given the highest tumor dose at depth for a given mucosal dose.

Answer 17

Tandem in the axis of the pelvis, equidistant from the sacral promontory, pubis and lateral pelvic walls. Tandem should bisect the ovoids in AP films, and bisect their heights in lateral films.

Answer 18

Vaginal: <140 Gy (average 120-140) Bladder: should be <75-80 (average 68) Rectum: should be <70-75 (average 70)

Cervix Flashcards

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