How would you manage a recurrent cervical cancer previously treated with vaginal cuff brachytherapy and has had a complete response to chemo-immunotherapy?
The paper gives our philosophy in this scenario. The total dose is the function of dose to target and cumulative dose to rectum and bladder. To be able to give a higher dose with brachy, generally would favor around 30.6 Gy with EBRT and then limit the last 14.4 Gy to the pelvic nodal region only for a total of 45 Gy to pelvic node. Brachy in this case can be a multichannel applicator for an additional dose of 30-35 Gy to deliver EQ2 of around 65 Gy or so to target and limiting. Cumulative 2 cc dose to rectum and bladder to <75 and <90 Gy (this includes the contribution from previous adjuvant brachy also).
We have no data suggesting a long-term cure with immunotherapy.
In this unfortunate situation, I would be comfortable going well beyond traditional tolerances. The patient has already locally failed one course of brachytherapy and a lesser dose would unlikely be curative. I would deliver 45 to 50 gray externally with IMRT. I would then likely offer a brachytherapy boost with interstitial or a multi-channel approach (or protons). Bowel and bladder toxicity, while a risk, is much less of a concern than having to perform a surgical exenteration. The risk of rectal bleeding or the future need of a colostomy with a possible cure versus an absolute need for an ostomy and diminished cure.
Unmentioned in the question and certainly important is the age and performance status of the patient.
I agree with the answers above.
I would aim for an EQD2 of 65-70 Gy for this course for the primary tumor. However, would favor 45 Gy to the pelvic nodes.
I would recommend interstitial brachytherapy, especially if the recurrence is 3-4 cm. I often prescribe 6-6.5 Gy x3 fractions with brachytherapy.
To clarify the initial therapy/clinical scenario - a post-op cervical (not uterine) cancer had surgery and then VBT alone, no EBRT? I'm not entirely sure of the rationale behind that thought process as that would not be a routine clinical workflow. Obs or EBRT (or chemoRT) are the mainstays here after surgery.
I'm somewhat similarly confused why disease recurrence limited to the vaginal cuff received presumably 3-4 agent chemo/immuno rather than definitive local salvage.
Regardless, the patient got what the patient got, and now getting to question:
Would still give 45 Gy EBRT to pelvis to treat potential microscopic disease around parametrial beds (assuming radical hysterectomy was done) and intrapelvic without a midline block. I would then follow that with multi-channel cylinder to the vaginal cuff region given there is no 'residual mass' that sounds like it would need interstitial.
If she has truly had a clinical and radiographical complete response on MRI, she no longer has a true 'HR-CTV' of gross disease (for which we'd try to get EQD2 85 Gy) in this clinical scenario. I would probably do something like 3-4 Gy x 5 or equivalent fractionation to get the IR-CTV (initial extent of disease pre-ICI but not necessarily extending up into supravaginal area) to EQD2 a/b 10 of 60-65 Gy.
For a recurrence 3 years from 21 Gy/3 fx, I honestly would not really worry too much about the previous brachy dose. I would try to limit OARs to less than 'traditional' soft constraints per ABS guidelines for intact cervix cancer (Rectum/Sigmoid D2cc < 65, Bladder D2cc < 75, Small bowel D2cc < 60) on the current combined EBRT + MCVCB plan, which should be doable if you're only treating to essentially an IR-CTV. Certainly, ALARA principles given re-irradiation are not unreasonable.