Impact of bladder volume on acute genitourinary toxicity in intensity modulated radiotherapy for localized and locally advanced prostate cancer.

BACKGROUND AND PURPOSE: To evaluate the effect of changes in bladder volume during high-dose intensity-modulated-radiotherapy (IMRT) of prostate cancer on acute genitourinary (GU) toxicity and prospectively evaluate a simple biofeedback technique for reproducible bladder filling with the aim of reducing acute GU toxicity. METHODS: One hundred ninety-three patients were trained via a biofeedback mechanism to maintain a partially filled bladder with a reproducible volume of 200-300 cc at planning CT and subsequently at each fraction of radiotherapy. We prospectively analyzed whether and to what extent the patients' ability to maintain a certain bladder filling influenced the degree of acute GU toxicity and whether cut-off values could be differentiated. RESULTS: We demonstrated that the ability to reach a reproducible bladder volume above a threshold volume of 180 cc and maintain that volume via biofeedback throughout treatment predicts for a decrease in acute GU toxicity during curative high-dose IMRT of the prostate. Patients who were not able to reach a partial bladder filling to that cut-off value and were not able to maintain a partially filled bladder throughout treatment had a significantly higher risk of developing ≥grade 2 GU acute toxicity. CONCLUSION: Our results support the hypothesis that a biofeedback training for the patient is an easy-to-apply, useful, and cost-effective tool for reducing acute GU toxicity in high-dose IMRT of the prostate. Patients who are not able to reach and maintain a certain bladder volume during planning and treatment-two independent risk factors-might need special consideration.

Helical tomotherapy in cervical cancer patients: simultaneous integrated boost concept: technique and acute toxicity.

PURPOSE: To evaluate the acute toxicity of simultaneous integrated boost (SIB) technique for dose escalation with helical tomotherapy (HT) in patients with locally advanced cervical cancer. PATIENTS AND METHODS: 20 patients (FIGO IB1 pN1-IIIB) underwent primary chemoradiation. Prior to chemoradiation, a laparoscopic pelvic and para-aortic lymphadenectomy was performed. A boost region was defined using titanium clips during staging for planning target volume (PTV-B). Patients were treated with five weekly fractions of 1.8 Gy to a total dose of 50.4 Gy to the tumor region and the pelvic (para-aortic) lymph node region (PTV-A), and five weekly fractions of 2.12 Gy to a total dose of 59.36 Gy to the PTV-B. Chemotherapy consisted of weekly cisplatin 40 mg/m(2). 19 patients underwent brachytherapy. Dose-volume histograms were evaluated and acute gastrointestinal (GI), genitourinary (GU), and hematologic toxicity were documented (CTCAE v3.0). RESULTS: Pelvic and para-aortic lymph node metastases were confirmed in nine and four patients, respectively. Five patients refused laparoscopic staging. The mean volume of PTV-A and PTV-B was 1,570 ± 404 cm(3) and 341 ± 125 cm(3), respectively. The mean dose to the bladder, rectum, and small bowel was 47.85 Gy, 45.76 Gy, and 29.71 Gy, respectively. No grade 4/5 toxicity was observed. Grade 2/3 hematologic toxicity occurred in 50% of patients and 5% experienced grade 3 diarrhea. There was no grade 3 GU toxicity. 19 patients underwent curettage 6-9 weeks after chemoradiation without any evidence of tumor. CONCLUSION: The concept of SIB for dose escalation in patients with locally advanced cervical cancer is feasible with a low rate of acute toxicity. Whether dose escalation can translate into improved outcome will be assessed after a longer follow-up.

Intensity-modulated radiotherapy in patients with cervical cancer. An intra-individual comparison of prone and supine positioning.

BACKGROUND: Chemoradiation for cervical cancer patients is associated with considerable gastrointestinal toxicity. Intensity-modulated radiotherapy (IMRT) has demonstrated superiority in terms of target coverage and normal tissue sparing in comparison to conventional 3D planning in gynaecological malignancies. Whether IMRT in prone (PP) or supine position (SP) might be beneficial for cervical cancer patients remains partially unanswered. METHODS: 10 patients on FIGO stage IB-III cervical cancer, 6 patients for definitive and 4 patients for adjuvant external beam pelvic RT, were planned in PP and SP using a 7-field IMRT technique. IMRT plans for PP and SP (mean dose, Dmean 50.4 Gy) were optimized in terms of PTV coverage (1st priority) and small bowel sparing (2nd priority). A comparison of DVH parameters for PTV, small bowel, bladder, and rectum was performed. RESULTS: The comparison showed a similar PTV coverage of 95% of the prescribed dose and for target conformity in IMRT plans (PP, SP). PTV, rectum and bladder volumes were comparable for PP and SP. Significantly larger volumes of small bowel were found in PP (436 cc, + 35%, p = 0.01). PP decreased the volume of small bowel at 20-50.4 Gy (p < 0.05) and increased the rectum volumes covered by doses from 10-40 Gy (p < 0.01), the V50.4 was < 5% in both treatment positions. Bladder sparing was significant better at 50.4 Gy (p = 0.03) for PP. CONCLUSION: In this dosimetric study, we demonstrated that pelvic IMRT in prone position for patients with cervical cancer seems to be beneficial in reducing small bowel volume at doses >or=20 Gy while providing similar target coverage and target conformity. The use of frequent image guidance with KV (kilovolt) or MV (megavolt) computer tomography can reduce set-up deviations, and treatment in prone position can be done with a higher set-up accuracy. Clinical outcome studies are needed to affirm lower toxicity.