A comparison of conventional, conformal and intensity-modulated coplanar radiotherapy plans for posterior fossa treatment.

Radiotherapy of the posterior fossa for medulloblastoma treatment can induce ototoxicity, especially when combined with cisplatin chemotherapy. Sensorineural hearing loss can be severe enough to cause permanent disability, which may compromise cognitive development in paediatric patients. This study evaluates the sparing of the cochlea in conventional radiotherapy, three-dimensional conformal radiotherapy (3D-CRT), and intensity-modulated radiotherapy (IMRT). CT scans of three patients were used to plan posterior fossa radiotherapy using coplanar beam arrangements. The posterior fossa and the cochlea were contoured as well as other organs-at-risk (non-posterior fossa brain, lenses, optic nerves, pituitary and cervical spinal cord). Three treatment plans were compared: conventional two-dimensional treatment (parallel-opposed lateral pair); 3D-CRT (two wedged posterior oblique fields); and a four-field coplanar IMRT plan. 3D-CRT and IMRT reduced cochlear doses to less than 70% of the mean target dose. These plans also reduced dose to the non-posterior fossa brain and cervical spinal cord. IMRT showed no advantage over 3D-CRT in sparing the optic nerves and lenses, compared with 3D-CRT. Normal tissue doses were higher in both conformal techniques than in the IMRT plans. Conformal techniques reduced the dose to the cochlea, non-posterior fossa brain and cervical spinal cord. The small size and proximity to the planning target volume (PTV) of the cochlea limited the effectiveness of the IMRT plan. Coplanar 3D-CRT was judged superior to coplanar IMRT, particularly in children, because it achieved adequate sparing of the cochlea and anterior cranial structures, such as the lenses and optic nerves, without compromising the dose to the posterior fossa.

Definitive chemoradiation in patients with inoperable oesophageal carcinoma.

We performed a retrospective study of 90 consecutive cases with inoperable carcinoma of the oesophagus treated with definitive chemoradiation at a single cancer centre between 1995 and 2002. For the last 4 years, 73 patients have received therapy according to an agreed protocol. This outpatient-based regimen involves four cycles of chemotherapy, cycles 3 and 4 given concurrently with 50 Gy external beam radiotherapy (XRT) delivered in 25 fractions over 5 weeks. Cisplatin 60 mg m(-2) day(-1) is given every 3 weeks together with continuous infusional 5-fluorouracil 300 mg m(-2) day(-1), reduced to 225 mg m(-2) day(-1) during the XRT. In all, 45 (50%) patients suffered one or more WHO grade 3/4 toxicity, grade 3 in 93% cases. Patients received more than 90% of the planned chemoradiation schedule. The median overall survival was 26 (15, >96) months, 51% (41, 64) and 26% (13, 52) surviving 2 and 5 years, respectively. Advanced stage, particularly T4 disease, was associated with a worse prognosis. Patients considered not suitable for surgery for reasons other than their disease, mainly co-morbidity, had a significantly better outcome, median survival 40 (26, >96) months, 2- and 5-year survivals 67% (54, 84) and 32% (13, 79), respectively (P<0.001). This schedule is a feasible, tolerable and effective treatment for patients with oesophageal cancer considered unsuitable for surgery.