Effect Of Concomitant Chemotherapy Research Articles

The effect of concomitant chemotherapy on parotid gland function following head and neck IMRT

PurposeTo determine whether concomitant chemotherapy increases the incidence of high grade xerostomia following parotid-sparing intensity-modulated radiotherapy (IMRT) in patients with locally advanced head and neck squamous cell cancer. Materials and methodsThe incidence of high grade (⩾G2) acute (CTCAEv3.0) and late (LENTSOMA and RTOG) xerostomia was compared between patients treated with either IMRT or concomitant chemo-IMRT (c-IMRT) in 2 prospective studies. Parotid gland mean tolerance doses (D50) were reported using non-linear logistic regression analysis. ResultsThirty-six patients received IMRT alone and 60 patients received c-IMRT. Patients received 65Gy in 30 daily fractions to the primary site and involved nodal groups and 54Gy in 30 fractions to elective nodal groups, mean doses to the parotid glands were comparable. Concomitant cisplatin 100mg/m2 was administered on days 1 and 29 of IMRT. The incidence of ⩾G2 subjective xerostomia was similar in both groups; acute-64.7% (IMRT) versus 60.3% (c-IMRT), p=0.83; late-43% (IMRT) versus 34% (c-IMRT), p=0.51. Recovery of parotid salivary flow at 1year was higher with IMRT (64% vs 50%), but not statistically significant (p=0.15). D50 for absence of parotid saliva flow at 1year was 23.2Gy (95% CI: 17.7–28.7) for IMRT and 21.1Gy (11.8–30.3) for c-IMRT. ConclusionConcomitant c-IMRT does not increase the incidence of acute or late xerostomia relative to IMRT alone.

Neo-adjuvant chemo-radiation of rectal cancer with Volumetric Modulated Arc Therapy: summary of technical and dosimetric features and early clinical experience

BackgroundTo report about initial technical and clinical experience in preoperative radiation treatment of rectal cancer with volumetric modulated arcs with the RapidArc® (RA) technology.MethodsTwenty-five consecutive patients (pts) were treated with RA. All showed locally advanced rectal adenocarcinoma with stage T2-T4, N0-1. Dose prescription was 44 Gy in 22 fractions (or 45 Gy in 25 fractions). Delivery was performed with single arc with a 6 MV photon beam. Twenty patients were treated preoperatively, five did not receive surgery. Twenty-three patients received concomitant chemotherapy with oral capecitabine. A comparison with a cohort of twenty patients with similar characteristics treated with conformal therapy (3DC) is presented as well.ResultsFrom a dosimetric point of view, RA improved conformality of doses (CI95% = 1.1 vs. 1.4 for RA and 3DC), presented similar target coverage with lower maximum doses, significant sparing of femurs and significant reduction of integral and mean dose to healthy tissue. From the clinical point of view, surgical reports resulted in a down-staging in 41% of cases. Acute toxicity was limited to Grade 1-2 diarrhoea in 40% and Grade 3 in 8% of RA pts, 45% and 5% of 3DC pts, compatible with known effects of concomitant chemotherapy. RA treatments were performed with an average of 2.0 vs. 3.4 min of 3DC.ConclusionRA proved to be a safe, qualitatively advantageous treatment modality for rectal cancer, showing some improved results in dosimetric aspects.

Quantitative Estimates of the Effects of Concomitant Chemotherapy on Acute Dysphagia in Patients Receiving Radical Treatment for Head and Neck Cancer

e22134 Purpose: To generate quantitative parameters describing the effect of concomitant chemotherapy on incidence of grade 3 dysphagia (CTCAE v3.0, assisted feeding) using dose response curves in patients receiving radical treatment for head and neck cancer. Methods: Patients treated at a single centre in prospective phase I and II trials of concomitant chemo-IMRT (CRT) (n=85) and the phase III trial of IMRT vs. conventional radiotherapy (PARSPORT) (n=82) formed the basis of this non-randomized comparison. Patients in the PARSPORT trial received radiation alone (RT). Radiation dose for all patients was radiobiologically equivalent to at least 70Gy in 35 fractions. Concomitant chemotherapy was cisplatin (100 mg/m2) on days 1 and 29. G3 dysphagia was recorded prospectively. Dose volume histograms (DVH) were generated for the pharyngeal mucosa. The mean dose (converted to equivalent dose in 2Gy/fraction, MD2) was used as a univariate descriptor of the DVH, for the generation of the dose response curves. A l...

Quantitative estimates of the effects of concomitant chemotherapy on acute dysphagia in patients receiving radical treatment for head and neck cancer

e22134 Purpose: To generate quantitative parameters describing the effect of concomitant chemotherapy on incidence of grade 3 dysphagia (CTCAE v3.0, assisted feeding) using dose response curves in patients receiving radical treatment for head and neck cancer. Methods: Patients treated at a single centre in prospective phase I and II trials of concomitant chemo-IMRT (CRT) (n=85) and the phase III trial of IMRT vs. conventional radiotherapy (PARSPORT) (n=82) formed the basis of this non-randomized comparison. Patients in the PARSPORT trial received radiation alone (RT). Radiation dose for all patients was radiobiologically equivalent to at least 70Gy in 35 fractions. Concomitant chemotherapy was cisplatin (100 mg/m2) on days 1 and 29. G3 dysphagia was recorded prospectively. Dose volume histograms (DVH) were generated for the pharyngeal mucosa. The mean dose (converted to equivalent dose in 2Gy/fraction, MD2) was used as a univariate descriptor of the DVH, for the generation of the dose response curves. A logistic function of the form p=1/[1+(MD50/D)k] was fitted where, p is the probability of the incidence of toxicity, D is the mean dose, MD50 is the mean dose at which 50% of patients experience toxicity and k describes the increase in incidence with increasing dose. The dose response curves were fitted using non-linear logistic regression. Results: The mean MD2 to the pharyngeal mucosa were 56Gy and 55.8Gy respectively, in the CRT and RT groups. There was a statistically significant difference of 25% (95% CI: 10–38, p=0.002) in the incidence of G3 dysphagia between the CRT (68%) and RT (43%) groups. Fitting dose response curves to the clinical data yielded parameter values (95% CIs) of MD50=46 Gy (42–49), k=4.8 (2.3–7.2) for the CRT group and MD50= 58 Gy (55–61), k=3 (1.6-.45) for RT group. Dose response gradients for CRT and RT showed approximately 1.95% and 1.3% increase (respectively) in probability of G3 dysphagia resulting from an increase in mean dose of 1Gy between doses of 30Gy to 70Gy. Conclusions: Addition of concomitant chemotherapy increases the incidence of G3 dysphagia by 0.65% for every 1 Gy increase in radiation dose. The observed MD50 for G3 dysphagia is lower for RT alone (46 Gy vs. 58 Gy). No significant financial relationships to disclose.