Simultaneous modulated accelerated radiotherapy in cervical cancer with retroperitoneal lymph node metastasis after radical hysterectomy and pelvic lymphadenectomy.

Objective: To compare the dosimetry, toxicity, and efficacy of simultaneous modulated accelerated radiotherapy (SMART) with 3-dimensional conformal radiotherapy (3DCRT) in cervical cancer with retroperitoneal lymph node metastasis after radical hysterectomy and pelvic lymphadenectomy.

Methods: Total 32 patients who underwent SMART were retrospectively evaluated. Daily fractions of 2.2 to 2.4 Gy and 1.8 to 2 Gy were prescribed and delivered to gross tumor volume and clinical target volume to a total dose of 63.8 and 52.2 Gy, respectively. A 3DCRT plan was designed for the SMART group and planned to deliver the same prescribed dose. The doses of organs at risk (OARs) were compared. Thirty-six patients who received 3DCRT were used to compare the target dose, toxicities, and efficacy with 32 cases who received SMART.

Results: The mean doses delivered to gross tumor volume and clinical target volume were significantly higher in the SMART group than in the 3DCRT group (63.8 vs 55.2 Gy [P < 0.01] and 52.5 vs 48.6 Gy [P < 0.01], respectively). For SMART plan, the doses of OARs were significantly lower than that of 3DCRT plans (small intestine: 25.1 vs 30.9 Gy [P < 0.01], bladder: 35.3 vs 46.3 [P < 0.01], and rectum: 31.7 vs 43.7 [P = 0.002], respectively). The patients experienced less acute and late toxicities in the SMART group (acute toxicities: enteroproctitis, P = 0.019; cystitis, P = 0.013; leukopenia, P = 0.025; late toxicities: enteroproctitis, P = 0.007; and cystitis, P = 0.026, respectively). No significant difference was found for 1-year survival (78.7% vs 67.7%, P = 0.222), but SMART group had a higher 2-year survival rate (2-year: 63.1% vs 39.1%, P = 0.029).

Conclusions: Simultaneous modulated accelerated radiotherapy plans yielded higher dose to the targets and better sparing of OARs than did 3DCRT in cervical cancer with retroperitoneal lymph node metastasis after radical hysterectomy and pelvic lymphadenectomy. Simultaneous modulated accelerated radiotherapy provided better clinical outcomes than did 3DCRT. Long-term follow-up and studies involving more patients are needed to confirm our results.