MRI-guided brachytherapy in locally advanced cervical cancer: Small bowel and are not predictive of late morbidity

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• 作者：Claire Petit¹ ; ^{claire1.petit@gustaveroussy.fr" class="auth_mail" title="E-mail the corresponding author} ; Isabelle Dumas² ; Cyrus Chargari¹ ; ³ ; Florent Martinetti² ; Pierre Maroun¹ ; Kaya Doyeux² ; Anne Tailleur¹ ; Christine Haie-Meder¹ ; Renaud Mazeron¹ ; ³
• 关键词：Image-guided adaptive brachytherapy ; Cervical cancer ; Dose&ndash ; volume parameters ; Morbidity ; Normal tissue complication probability ; Small bowel
• 刊名：Brachytherapy
• 出版年：2016
• 出版时间：July-August 2016
• 年：2016
• 卷：15
• 期：4
• 页码：463-470
• 全文大小：905 K

文摘

To establish dose–volume effect correlations for late small bowel (SB) toxicities in patients treated for locally advanced cervical cancer with concomitant chemoradiation followed by pulsed-dose rate MRI-guided adaptive brachytherapy.

Methods and Materials

Patients treated with curative intent and followed prospectively were included. The SB loops closed to CTV were delineated, but no specific dose constraint was applied. The dosimetric data, converted in 2-Gy equivalent, were confronted with the occurrence of late morbidity assessed using the CTC-AE 3.0. Dose–effect relationships were assessed using mean-dose comparisons, log-rank tests on event-free periods, and probit analyses.

Results

A total of 115 patients with a median followup of 35.5 months were included. Highest grade per patient was: Grades 0 for 17, 1 for 75, 2 for 20, and 3 for 3. The mean D_2cm³$D_{{2\text{cm}}^3}$ and D_0.1cm³$D_{0.1{\text{cm}}^3}$ were, respectively, 68.7 ± 13.6 Gy and 85.8 ± 33.1 Gy and did not differ according to event severity (p = 0.47 and p = 0.52), even when comparing Grades 0–1 vs. 2–4 events (68.0 ± 12.4 vs. 71.4 ± 17.7 Gy; p = 0.38 and 83.7 ± 26.4 vs. 94.5 ± 51.9 Gy; p   = 0.33). Log-rank tests were performed after splitting the cohort according to four D_2cm³$D_{{2\text{cm}}^3}$ levels: >80 Gy, 70–79 Gy, 60–70 Gy, and <60 Gy. No difference was observed for Grades 1–4, Grades 2–4, or Grades 3–4 (p = 0.21–0.52). Probit analyses showed no correlation between the dosimetric parameters and probability of Grades 1–4, 2–4, or 3–4 events (p = 0.19–0.48).

Conclusion

No significant dose–volume effect relationships were demonstrated between the D_2cm³$D_{{2\text{cm}}^3}$ and D_0.1cm³$D_{0.1{\text{cm}}^3}$ and the probability of late SB morbidity. These parameters should not limit the pulsed-dose rate brachytherapy optimization process.