Biomedical subjects

P Nickers

Publications and source records attributed to P Nickers.

9 recordsLinked to original sources

PubMed2006

[How I treat...fibroproliferative scars].

Following a skin injury like burn, surgery or a trauma, fibroproliferatives scars are responsible of cosmetic, psychologic and symptomatic disorders. Keloids are benign and occur secondary to an imbalance between the synthesis of extracellular matrix and its degradation. There is a lot of therapeutic modalities available. Despite this, recurrence and sometimes increasing lesions are the major complications. Surgery with adjuvant therapy like steroids injections, radiotherapy, silicone materials seems today the best therapeutic choice. A best physiopatholgy's comprehension is at the base of new treatments, but their efficacity still need to be demonstrate in larger studies.

Humans↗

PubMed2006

[Partial breast irradiation: the role of brachytherapy. A new treatment option for early breast cancer].

Early breast cancer can be treated by conservative surgery followed by partial breast irradiation. This recent treatment replaces classical external beam whole breast radiotherapy. Several techniques are available but most experience does exist with interstitial catheter based brachytherapy. This well tolerated treatment shortens the treatment time and offers a good local control and cosmetic outcome, comparable to the best classical treatments, as confirmed by the first published results. These good results can only be obtained by rigorous patient selection and very precise 3D imaging and source implantation techniques.

Brachytherapy↗

PubMed2003

[Prostate brachytherapy: current states and future prospects].

The paper presents the characteristics, the place and the limits of brachytherapy in prostate radiotherapy. While sparing the rectal wall, erectile function as well as urinary continence, I(125) and Pd(103) permanent implants represent interesting approaches for good prognosis tumours in comparison to surgery or conformal external beam radiotherapy with similar cure rates. Overcoming easily the problems of organ motion and patient positioning while allowing doses per fraction as high as 10 Gy, brachytherapy is an excellent boosting method in the treatment of intermediate or unfavourable prognosis tumours of which alpha/beta is 1,5 Gy. Encouraging biological control rates of 80-90% have been published in phase II trials. Compared to external beam radiotherapy, the heterogeneity of irradiation inside the clinical target volume should increase the probability of cure as for a specific dose, a significant part will be overdosed. So far, 120-130% of the prescribed doses are delivered to the peripheral zone at the origin of 70% of tumours. On the opposite, this heterogeneity is inducing an overdosage of the urethral bed at the price of higher toxicity levels in situations of previous obstructive syndrome and urethral stenosis. A better integration of the therapeutic modalities available, brachytherapy included, should increase our curative possibilities in the radiation treatment of prostatic cancer.

Brachytherapy↗

PubMed2001

PSA kinetics after external beam radiotherapy alone or combined with an iridium brachytherapy boost to deliver 85 grays to prostatic adenocarcinoma.

PURPOSE: Increasing the dose to prostatic adenocarcinoma in conformal external beam therapy (EBT) has resulted in increased levels of PSA normalization and increased percentage of biochemical disease-free survival rates. However technical problems due to prostate motion inside the pelvis or patients' set-up make difficult the realization of the EBT boost fields above 72 Gy. Brachytherapy which overcomes these problems was investigated to deliver the boost dose to achieve 85 Gy. PSA nadir which has been identified as the strongest independent predictor of any failure in many studies has been used as the end point for early evaluation of this work. PATIENTS AND METHODS: In a retrospective way we report on 163 patients' PSA kinetics after EBT alone to 68 Gy or EBT first and a brachytherapy boost up to 75 or 85 Gy. RESULTS: At 12 months follow-up, PSA nadirs percentage < or = 0.5 or < or = 1 ng/ml increased from 7.5 and 20.7% after 68 Gy EBT to 49.8 and 71.2% after a brachytherapy boost to deliver 85 Gy (p < 0.0001). In the Cox PH model analysis, the total dose remained the most important factor for predicting PSA normalization. CONCLUSIONS: These results are in accordance with the most recent results published after conformal EBT at the same 80 Gy level of dose. If confirmed on a higher number of patients they could place brachytherapy among the most accurate methods of boosting in the radiation treatment of prostatic carcinoma.

Adenocarcinoma↗

PubMed2000

Feasibility study combining low dose rate (192)Ir brachytherapy and external beam radiotherapy aiming at delivering 80-85 Gy to prostatic adenocarcinoma.

BACKGROUND: Increasing the radiation dose to prostatic adenocarcinoma has provided higher local control rates. A total of 80 Gy seem necessary to achieve this goal but patient set-up and prostate motion remain difficult problems to solve in conformal radiotherapy. Brachytherapy which overcomes these points could be an alternative way to external beam boost fields. We wanted to transpose the irradiation models largely used in cervix cancer treatment combining external beam radiotherapy and low dose rate brachytherapy. MATERIALS AND METHODS: In 71 patients with 19.5 and 13 ng/ml mean and median PSA levels, respectively, a dose escalation from 74 to 85 Gy was performed in four groups. RESULTS: Shifting from intraoperative placement of sources vectors (Group I) to positioning under ultrasound controls (groups II-IV), improving the implantation shape and optimizing radiation delivery to urethral bed have reduced the total dose to rectal wall under 65 Gy and to urethra under 100 Gy. Rectal/prostate dose ratio was lowered from 0.7 (Groups I-II) to 0.58 (Groups III-IV) while avoiding problems resulting from pelvic bone arch interference, prostate volume or seminal vesicles location. The mean and median follow-up periods are 28 and 18 months. In Groups III and IV 85% of patients without hormonotherapy treated with 80-85 Gy normalized PSA under 1 ng/ml within 6 months. No severe late effect has been noted for patients implanted under echographic control. CONCLUSIONS: The method described allows to deliver 85 Gy. Longer follow-up is however needed but the levels of dose delivered are not expected to induce prohibitive side effects.

Adenocarcinoma↗

PubMed1997

Modern brachytherapy: current state and future prospects.

This article reviews the current trends and future developments in brachytherapy. Established techniques including interstitial and high-dose rate brachytherapy are discussed with particular reference to lung, oesophageal, cervical and endometrial cancer. Intra-operative high-dose rate brachytherapy and other new techniques are also mentioned.

Brachytherapy↗

PubMed1988

Correlation between size and external temperature in four rat tumours after treatment with cytostatic agents.

The reduction in size of four experimental tumours (ISIS 130 and ISIS 208 immunocytomas, S 437 mammary adenocarcinoma, S 447 colon adenocarcinoma) was investigated in LOU rats under the influence of cytostatic agents belonging to different classes (5-fluorouracil, methotrexate, vinblastine, cisplatin, doxorubicin, cyclophosphamide). External tumour and rectal temperatures were measured at the same time, twice daily, during the whole experiment. With the rectal temperature of the rats kept constant, the reduction in tumour dimensions following chemotherapy correlated via a linear relationship with the duration and degree of tumour hypothermia for the three tumours S 437, ISIS 208, ISIS 130. However, for the same reduction in tumour volume following chemotherapy, the duration and degree of transient tumour hypothermia varied according to the type of tumour and cytostatic agent studied. There was not correlation between the decrease in size of S 447 and external tumour hypothermia. Even when the reduction in tumour size was statistically significant, the hypothermic tumour phase after drug administration was not sufficient to be significant, except for vinblastine. However, the temperature of this slowly growing tumour before chemotherapy was particularly low. The measurement of the degree and duration of external tumour hypothermia of tumours following chemotherapy would represent a new physiological technique for measuring the efficacy and duration of action of cytostatic agents.

Animals↗

PubMed1986

Effect of chemotherapy on tumor temperature in rats.

Two transplanted rat immunocytomas with different degrees of sensitivity to single injection of cyclophosphamide (CY) were used to assess the reliability of recording of the tumoral and rectal temperatures may be useful to evaluate the efficacy of cytostatic drugs against experimental rat tumors. With the highly sensitive tumor (ISIS 130), 25 mg/m2 of CY resulted in a pronounced tumor inhibition (Treated/Control tumors = 28%); with the less sensitive (ISIS 208), a CY dose of 320 mg/m2 was necessary to inhibit tumor growth to the same extent. The more important the decrease in tumor size was, after the administration of the drug, the larger the decrease was in tumoral temperature. Since the rectal temperature remained fairly stable, there was an increase of the difference between the tumoral and rectal temperatures. From the comparison between the results obtained for the two tumors with a wide range of CY doses, it appeared that the decrease in tumoral temperature did not correlate with the drug dose itself, but with the actual antitumor efficacy of the drug in each particular case.

Animals↗

PubMed1986

Correlation between size and external temperature of the ISIS 130 tumour after treatment with cytostatic agents.

The reduction in size of the experimental ISIS 130 tumour has been investigated in LOU rats under the influence of increasing doses of cytostatic agents belonging to different classes. External temperatures of tumours as well as rectal temperatures have been measured at the same time, twice daily, during the whole experiment. The greater the decrease in the tumour size after drug administration, the larger was the decrease in external temperature of tumour. The rectal temperatures remained fairly stable, thus differences between the tumour and rectal temperatures increased. A possible correlation between the reduction of tumour size and the decrease of external temperature of tumour has been traced for every cytostatic agent, and the same linear relationship has been found to link these two parameters. The decrease in external temperature of tumour may, moreover, predict the decrease in tumour size within a term of 1-2 days. Measurement of the magnitude of the transient tumour hypothermia of ISIS 130, following chemotherapy, would represent a new method for measuring the efficiency and duration of action of cytostatic agents.

Animals↗