O. Chapet
University of Michigan
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by O. Chapet.
Journal of Clinical Oncology | 2006
Jean-Pierre Gérard; Thierry Conroy; Franck Bonnetain; Olivier Bouché; O. Chapet; Marie-Thérèse Closon-Dejardin; Michel Untereiner; Bernard Leduc; Eric Francois; Jean Maurel; Jean-François Seitz; Bruno Buecher; Rémy Mackiewicz; Michel Ducreux; Laurent Bedenne
PURPOSE In 1992, preoperative radiotherapy was considered in France as the standard treatment for T3-4 rectal cancers. The present randomized trial compares preoperative radiotherapy with chemoradiotherapy. PATIENTS AND METHODS Patients were eligible if they presented a resectable T3-4, Nx, M0 rectal adenocarcinoma accessible to digital rectal examination. Preoperative radiotherapy with 45 Gy in 25 fractions during 5 weeks was delivered. Concurrent chemotherapy with fluorouracil 350 mg/m2/d during 5 days, together with leucovorin, was administered during the first and fifth week in the experimental arm. Surgery was planned 3 to 10 weeks after the end of radiotherapy. All patients should receive adjuvant chemotherapy with the same fluorouracil/leucovorin regimen. The primary end point of the trial was overall survival. RESULTS A total of 733 patients were eligible. Grade 3 or 4 acute toxicity was more frequent with chemoradiotherapy (14.6% v 2.7%; P < .05). There was no difference in sphincter preservation. Complete sterilization of the operative specimen was more frequent with chemoradiotherapy (11.4% v 3.6%; P < .05). The 5-year incidence of local recurrence was lower with chemoradiotherapy (8.1% v 16.5%; P < .05). Overall 5-year survival in the two groups did not differ. CONCLUSION Preoperative chemoradiotherapy despite a moderate increase in acute toxicity and no impact on overall survival significantly improves local control and is recommended for T3-4, N0-2, M0 adenocarcinoma of the middle and distal rectum.
Journal of Clinical Oncology | 2004
Jean-Pierre Gérard; O. Chapet; Chantal Nemoz; Johannes Hartweig; Pascale Romestaing; R. Coquard; Nicolas Barbet; Philippe Maingon; Marc Mahe; Jacques Baulieux; Christian Partensky; Marc Papillon; Olivier Glehen; Bruno Crozet; Jean-Paul Grandjean; Patrice Adeleine
PURPOSE The potential advantage of high-dose preoperative radiotherapy to increase tumor response and improve the chance of sphincter preservation for low rectal cancer remains controversial. The aim of this trial was to evaluate the role of escalating the dose of preoperative radiation to increase sphincter-saving procedures. PATIENTS AND METHODS Patients with rectal carcinoma located in the lower rectum, staged T2 or T3, Nx, or M0 with endorectal sonography, and not involving more than two-thirds circumference, were randomly assigned to one of two groups: preoperative external-beam radiotherapy (EBRT; 39 Gy in 13 fractions over 17 days) versus the same EBRT with boost (85 Gy in three fractions) using endocavitary contact x-ray. RESULTS Between 1996 and 2001, 88 patients were enrolled onto the study. A significant improvement was seen in favor of the contact x-ray boost for complete clinical response (24% v 2%) and for a complete or near-complete sterilization of the operative specimen (57% v 34%). A significant increase in sphincter preservation was observed in the boost group (76% v 44%; P =.004). At a median follow-up of 35 months, there was no difference in morbidity, local relapse, and 2-year overall survival. CONCLUSION A dose escalation with endocavitary irradiation provides increased tumor response and sphincter preservation with no detrimental effect on treatment toxicity and early clinical outcome.
Journal of Clinical Oncology | 2003
Jean-Pierre Gérard; O. Chapet; Chantal Nemoz; Pascale Romestaing; F. Mornex; R. Coquard; Nicolas Barbet; Dan Atlan; Patrice Adeleine; Gilles Freyer
PURPOSE The combination of radiation, fluorouracil, and oxaliplatin in locally advanced rectal cancer has been shown to be feasible in a phase I trial. The purpose of this phase II trial was to assess tolerance and efficacy of this regimen in a preoperative setting. PATIENTS AND METHODS Between May 2000 and October 2001, 40 operable patients were entered onto the study. Radiotherapy was delivered with a three-field technique to a dose of 50 Gy over 5 weeks with a concomitant boost approach. Two cycles of chemotherapy were given synchronously on weeks 1 and 5, with oxaliplatin 130 mg/m(2) on day 1 followed by 5-day continuous infusion of fluorouracil 350 mg/m(2) and L-folinic acid 100 mg/m(2). Surgery was planned 5 weeks later. RESULTS All patients completed treatment without modification except one who experienced grade 3/4 toxicity. Grade 3 toxicity was seen in seven patients. Surgery was performed in all patients after a mean interval time of 5 weeks. An objective clinical response was seen in 30 patients (75%). Sphincter-saving surgery was possible in 26 patients. No postoperative deaths occurred. In four patients (10%), a reoperation was necessary (anastomotic fistula, n = 2; pelvic abscess, n = 2). In six cases the operative specimen was sterilized (15%), and in 12 cases (30%), only few residual cells were detected. CONCLUSION Such a combined preoperative chemoradiotherapy and oxaliplatin-containing regimen is well tolerated with no increase in surgical toxicity. The good response rate observed warrants its use in further clinical trials.
International Journal of Radiation Oncology Biology Physics | 2002
Jean-Pierre Gérard; O. Chapet; Alain Ramaioli; Pascale Romestaing
PURPOSE To analyze the long-term result of patients presenting with T2-T3 rectal adenocarcinoma treated with curative intent by radiotherapy (RT) alone, using a combination of contact RT, external beam RT, and brachytherapy with an iridium implant. Patients were considered unsuitable for surgery because of the presence of severe comorbidity or because they did not consent to surgery and the possibility of a permanent stoma. METHODS AND MATERIALS Between 1986 and 1998, 63 patients (56 staged with endorectal ultrasonography) were entered into a pilot study. Patients had to have T2-T3, N0-N1, M0 adenocarcinoma of the middle or lower rectum involving less than two-thirds of the circumference. RT began with contact X-rays (80 Gy in 3 fractions for 21 days), followed by external beam RT (39 Gy in 13 fractions for 17 days) with a concomitant boost (4 Gy in 4 fractions). After a 4-6-week interval, an iridium implant delivered a completion dose of 20 Gy to the tumor. No chemotherapy was given. RESULTS The median age of the patients was 72 years. Of the 63 patients, 41 had T2 and 22 had T3 tumors. The mean distance of the tumor from the anal verge was 3.6 cm. All patients completed treatment according to the protocol, except for 7 for whom brachytherapy was not performed. With a median follow-up time of 54 months, the primary local tumor control rate was 63%; after salvage surgery, the ultimate pelvic control was 73% (46 of 63). The 5-year overall survival rate was 64.4%, and for 42 patients aged <80 years, it was 78% with 10 patients alive and well at > or =10 years. No severe Grade 3-4 toxicity was seen. Acute proctitis was seen in most patients but did not require treatment interruption. Late rectal bleeding occurred in 24 patients. Only 1 required blood transfusion. Good anorectal function was maintained in 92% of living patients. The T stage was a strong prognostic factor, with a 5-year overall survival rate of 84% and 53% for T2 and T3 lesions, respectively, in patients <80 years old. CONCLUSION This is the first report of long-term local control and survival for ultrasound-staged T2-T3 rectal adenocarcinoma treated by RT alone, showing that high-dose irradiation to a small volume can provide a high therapeutic ratio for such tumors.
Lancet Oncology | 2003
Jean-Pierre Gérard; Pascale Romestaing; O. Chapet
Surgery is the standard treatment for rectal adenocarcinoma. The tumour is resistant to radiation; doses above 80 Gy are necessary and have to be delivered by endocavitary irradiation. Contact radiotherapy is a basic method of delivering a high dose in a small volume. Brachytherapy can be used to deliver a boost of radiation into a residual lesion. External-beam radiotherapy can be used to supplement the dose to the deep part of the primary tumour and to the perirectal lymph nodes. T1N0 tumours have been treated by contact radiotherapy, and local control was achieved in 85-90% of patients with no severe toxic effects. Combined endocavitary irradiation and external-beam irradiation can achieve local control in 80% of patients with T2 tumours and 60% of patients with T3 tumours with only moderate toxic effects and a 60% 5-year overall survival. Radiotherapy alone is suitable for patients with T1N0 lesions (contact radiotherapy) or patients with T2-3 (combined endocavitary and external-beam radiotherapy) who cannot undergo surgery. For T2 or early T3 tumours of the lower rectum requiring surgery and a permanent colostomy, combined irradiation can be used as a first-line treatment in an attempt to avoid abdominoperineal amputation.
International Journal of Radiation Oncology Biology Physics | 2012
Cécile Ortholan; Pascale Romestaing; O. Chapet; Jean Pierre Gerard
PURPOSE To investigate, in rectal cancer, the benefit of a neoadjuvant radiation dose escalation with endocavitary contact radiotherapy (CXRT) in addition to external beam radiotherapy (EBRT). This article provides an update of the Lyon R96-02 Phase III trial. METHODS AND MATERIALS A total of 88 patients with T2 to T3 carcinoma of the lower rectum were randomly assigned to neoadjuvant EBRT 39 Gy in 13 fractions (43 patients) vs. the same EBRT with CXRT boost, 85 Gy in three fractions (45 patients). Median follow-up was 132 months. RESULTS The 10-year cumulated rate of permanent colostomy (CRPC) was 63% in the EBRT group vs. 29% in the EBRT+CXRT group (p < 0.001). The 10-year rate of local recurrence was 15% vs. 10% (p = 0.69); 10-year disease-free survival was 54% vs. 53% (p = 0.99); and 10-year overall survival was 56% vs. 55% (p = 0.85). Data of clinical response (CR) were available for 78 patients (36 in the EBRT group and 42 in the EBRT+CXRT group): 12 patients were in complete CR (1 patient vs. 11 patients), 53 patients had a CR ≥ 50% (24 patients vs. 29 patients), and 13 patients had a CR <50% (11 patients vs. 2 patients) (p < 0.001). Of the 65 patients with CR ≥ 50%, 9 had an organ preservation procedure (meaning no rectal resection) taking advantage of major CR. The 10-year CRPC was 17% for patients with complete CR, 42% for patients with CR ≥ 50%, and 77% for patients with CR <50% (p = 0.014). CONCLUSION In cancer of the lower rectum, CXRT increases the complete CR, turning in a significantly higher rate of long-term permanent sphincter and organ preservation.
International Journal of Radiation Oncology Biology Physics | 2009
Mira Maalouf; Gersende Alphonse; Anthony Colliaux; Michael Beuve; Selena Trajkovic-Bodennec; Priscillia Battiston-Montagne; Isabelle Testard; O. Chapet; Marcel Bajard; Gisela Taucher-Scholz; Claudia Fournier; Claire Rodriguez-Lafrasse
PURPOSE We initiated studies on the mechanisms of cell death in head and neck squamous cell carcinoma cell lines (HNSCC) since recent clinical trials have shown that local treatment of HNSCC by carbon hadrontherapy is less efficient than it is in other radioresistant cancers. METHODS AND MATERIALS Two p53-mutated HNSCC cell lines displaying opposite radiosensitivity were used. Different types of cell death were determined after exposure to carbon ions (33.6 and 184 keV/microm) or X-rays. RESULTS Exposure to radiation with high linear energy transfer (LET) induced clonogenic cell death for SCC61 (radiosensitive) and SQ20B (radioresistant) cells, the latter systematically showing less sensitivity. Activation of an early p53-independent apoptotic process occurred in SCC61 cells after both types of irradiation, which increased with time, dose and LET. In contrast, SQ20B cells underwent G2/M arrest associated with Chk1 activation and Cdc2 phosphorylation. This inhibition was transient after X-rays, compared with a more prolonged and LET-dependent accumulation after carbon irradiation. After release, a LET-dependent increase of polyploid and multinucleated cells, both typical signs of mitotic catastrophe, was identified. However, a subpopulation of SQ20B cells was able to escape mitotic catastrophe and continue to proliferate. CONCLUSIONS High LET irradiation induced distinct types of cell death in HNSCC cell lines and showed an increased effectiveness compared with X-rays. However, the reproliferation of SQ20B may explain the potential locoregional recurrence observed among some HNSCC patients treated by hadrontherapy. An adjuvant treatment forcing the tumor cells to enter apoptosis may therefore be necessary to improve the outcome of radiotherapy.
Cancer Radiotherapie | 2014
G. Créhange; Mack Roach; Etienne Martin; Luc Cormier; D. Peiffert; Alexandre Cochet; O. Chapet; S. Supiot; Jean-Marc Cosset; Michel Bolla; H.T. Chung
Even in the current era of dose-escalated radiotherapy for prostate cancer, biochemical recurrence is not uncommon. Furthermore, biochemical failure is not specific to the site of recurrence. One of the major challenges in the management of prostate cancer patients with biochemical failure after radiotherapy is the early discrimination between those with locoregional recurrence only and those with metastatic disease. While the latter are generally considered incurable, patients with locoregional disease may benefit from emerging treatment options. Ultimately, the objective of salvage therapy is to control disease while ensuring minimal collateral damage, thereby optimizing both cancer and toxicity outcomes. Advances in functional imaging, including multiparametric prostate MRI, abdominopelvic lymphangio-MRI, sentinel node SPECT-CT and/or whole-body PET/CT have paved the way for salvage radiotherapy in patients with local recurrence, microscopic nodal disease limited to the pelvis or oligometastatic disease. These patients may be considered for salvage reirradiation using different techniques: prostate low-dose or high-dose rate brachytherapy, pelvic and/or lomboaortic image-guided radiotherapy with elective nodal irradiation, focal nodal or bone stereotactic body radiation therapy (SBRT). An individualized approach is recommended. The decision about which treatment, if any, to use will be based on the initial characteristics of the disease, relapse patterns and the natural history of the rising prostate specific antigen (PSA). Preliminary results suggest that more than 50% of patients who have undergone salvage reirradiation are biochemically relapse-free with very low rates of severe toxicity. Large prospective studies with a longer follow-up are needed to confirm the promising benefit/risk ratio observed with salvage brachytherapy and or salvage nodal radiotherapy and/or bone oligometastatic SBRT when compared with life-long palliative hormones.
International Journal of Radiation Oncology Biology Physics | 2001
Claire Mauduit; Ahmed Siah; Marie Foch; O. Chapet; Sébastien Clippe; Jean-Pierre Gérard; Mohamed Benahmed
PURPOSE By using as an experimental model the male mouse gonad, which contains both radiosensitive (germ) and radioresistant (somatic) cells, we have studied the growth factor (and/or receptor) expression of transforming growth factor-beta receptor (TGFbeta RI), stem cell factor (SCF), c-kit, Fas-L, Fas, tumor necrosis factor receptor (TNF R55), and leukemia inhibiting factor receptor (LIF-R) after local irradiation. METHODS AND MATERIALS Adult male mice were locally irradiated on the testes. Induction of apoptosis in the different testicular cell types following X-ray radiation was identified by the TdT-mediated dUTP Nick End Labeling (TUNEL) approach. Growth factor expression was evidenced by semiquantitative RT-PCR and Western blot analyses. RESULTS Apoptosis, identified through the TUNEL approach, occurred in radiosensitive testicular (premeotic) germ cells with the following kinetics: the number of apoptotic cells increased after 24 h (p < 0.001) and was maximal 48 h after a 2-Gy ionizing radiation (p < 0.001). Apoptotic cells were no longer observed 72 h after a 2-Gy irradiation. The number of apoptotic cells increased with the dose of irradiation (1-4 Gy). In the seminiferous tubules, the growth factor expression in premeiotic radiosensitive germ cells was modulated by irradiation. Indeed Fas, c-kit, and LIF-R expression, which occurs in (radiosensitive) germ cells, decreased 24 h after a 2-Gy irradiation, and the maximal decrease was observed with a 4-Gy irradiation. The decrease in Stra8 expression occurred earlier, at 4 h after a 2-Gy irradiation. In addition, a significant (p < 0.03) decrease in Stra8 mRNA levels was observed at the lowest dose used (0.5 Gy, 48 h). Moreover, concerning a growth factor receptor, such as TGFbeta RI, which is expressed both in radiosensitive and radioresistant cells, we observed a differential expression depending on the cell radiosensitivity after irradiation. Indeed, TGFbeta RI expression was increased after irradiation in interstitial radioresistant testicular cells in a dose- and time-dependent manner, while it decreased in seminiferous radiosensitive (germ cells) testicular cells. Such a differential expression between radioresistant and radiosensitive cells in TGFbeta RI levels was observed in terms of both mRNA and protein. In contrast, the growth factors specifically expressed in the somatic radioresistant (Sertoli) cells in the seminiferous tubules (SCF, Fas-L, TNF R55) were not affected by ionizing radiation (up to 4 Gy, 72 h). CONCLUSION Growth factor expression decreased in the radiosensitive testicular cells after irradiation. Such a decrease occurred before the detection of apoptosis using the TUNEL approach. TGFbeta RI mRNA levels decreased in the radiosensitive cells, whereas it increased in the radioresistant cells, suggesting that TGFbeta RI may represent a biomarker of the intrinsic radiosensitivity of cells.
International Journal of Colorectal Disease | 2006
O. Chapet; Jean-Pierre Gérard; F. Mornex; Silvia Goncalves-Tavan; Jean-Michel Ardiet; Anne d’Hombres; Véronique Favrel; Pascale Romestaing
BackgroundTo report our patient experience with squamous cell carcinoma of the anal margin and to evaluate the prognostic factors influencing outcome.Materials and methodsBetween 1980 and 2001, 26 patients with anal margin squamous cell carcinoma were treated in Lyon-Sud: 7 T1, 14 T2, 4 T3, and 1 T4 with 20 N0, 3 N1, and 3 N2. The anal canal was invaded in five patients. Treatment consisted of definitive external irradiation in 14 patients and adjuvant irradiation (after a local excision) in 12 patients. External irradiation was combined with chemotherapy in seven patients, brachytherapy in four patients, and both brachytherapy and chemotherapy in one patient.ResultsThe local control rate was initially 61.4%, and it was 80.8% after salvage treatment. The 5-year overall and specific survival rates were 71 and 88.3%, respectively. Three factors correlated with specific survival: cell differentiation (P=0.038) and T (P=0.001) and N category (P=0.0005). A salvage abdominoperineal resection was successfully employed in five of seven local recurrences. Four grade 3 and two grade 4 toxicities were observed. Sphincter preservation was possible in 66% of alive patients.ConclusionOur results confirm the dominating place of definitive irradiation and radiochemotherapy in the treatment of anal margin squamous cell carcinoma. The indications for abdominoperineal resection must be limited to local relapse. The prognosis of squamous cell carcinoma is correlated to T and N staging and cell differentiation.