Vaginal dose de-escalation in image guided adaptive brachytherapy for locally advanced cervical cancer

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• 作者：Sandy Mohamed^a ; ^b ; ^{sandy.mohamed@nci.cu.edu.eg" class="auth_mail" title="E-mail the corresponding author} ; Jacob Christian Lindegaard^a ; Astrid A.C. de Leeuw^c ; Ina Jü ; rgenliemk-Schulz^c ; Kathrin Kirchheiner^d ; Christian Kirisits^d ; Richard Pö ; tter^d ; Kari Tanderup^e
• 关键词：Cervical cancer ; Brachytherapy ; MRI guided ; Radiation dose ; Vaginal dose ; Dose de escalation
• 刊名：Radiotherapy and Oncology
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：120
• 期：3
• 页码：480-485
• 全文大小：987 K

文摘

Vaginal stenosis is a major problem following radiotherapy in cervical cancer. We investigated a new dose planning strategy for vaginal dose de-escalation (VDD).

Materials and methods

Fifty consecutive locally advanced cervical cancer patients without lower or middle vaginal involvement at diagnosis from 3 institutions were analysed. External beam radiotherapy was combined with MRI-guided brachytherapy. VDD was obtained by decreasing dwell times in ovoid/ring and increasing dwell times in tandem/needles. The aim was to maintain the target dose (D90 of HR-CTV ⩾ 85 Gy EQD2) while reducing the dose to the surface of the vagina to <140% of the physical fractional brachytherapy dose corresponding to a total EQD2 of 85 Gy.

Results

The mean vaginal loading (ovoid/ring) was reduced from 51% to 33% of the total loading with VDD, which significantly reduced the dose to the vaginal dose points (p < 0.001) without compromising the target dose. The dose to the ICRU recto-vaginal point was reduced by a mean of 4 ± 4 Gy EQD2 (p < 0.001), while doses to bladder and rectum (D_2cm³) were reduced by 2 ± 2 Gy and 3 ± 2 Gy, respectively (p < 0.001).

Conclusions

VDD significantly reduces dose to the upper vagina which is expected to result in reduction of vaginal stenosis.