Hyperthermia in the treatment of prostate cancer

P and N type copper phthalocyanines as effective semiconductors in organic thin-film transistor based DNA biosensors at elevated temperatures

Many health-related diagnostics are expensive, time consuming and invasive. Organic thin film transistor (OTFT) based devices show promise to enable rapid, low cost diagnostics that are an important aspect to enabling increased access and availability to healthcare. Here, we describe OTFTs based upon two structurally similar P (copper phthalocyanine – CuPc) and N (hexdecafluoro copper phthalocyanine – F₁₆-CuPc) type semiconductor materials, and demonstrate their potential for use as both temperature and DNA sensors. Bottom gate bottom contact (BGBC) OTFTs with either CuPc or F₁₆-CuPc semiconducting layers were characterized within a temperature range of 25 °C to 90 °C in both air and under vacuum. CuPc devices showed small positive shifts in threshold voltage (V_T) in air and significant linear increases in mobility with increasing temperature. F₁₆-CuPc devices showed large negative shifts in V_T in air and linear increases in mobility under the same conditions. Similar OTFTs were exposed to DNA in different hybridization states and both series of devices showed positive V_T increases upon DNA exposure, with a larger response to single stranded DNA. The N-type F₁₆-CuPc devices showed a much greater sensing response than the P-type CuPc. These findings illustrate the use of these materials, especially the N-type semiconductor, as both temperature and DNA sensors and further elucidate the mechanism of DNA sensing in OTFTs.

This study illustrates the use of an N-type semiconductor, in both temperature and DNA sensors and further elucidates the mechanism of DNA sensing in OTFTs.

[Local treatment of prostate cancer using thermal-ablative energy]

Thermal and thermal-ablative procedures for treating prostate cancer have been investigated systematically since approximately 1980 (apart from some historical predecessors), and numerous experimental and clinical reports have been published on this subject. Various technologies have been used, including transurethral ablation of prostatic tissue using laser or microwave energy, interstitial application of laser or microwave energy, and inductive heating of previously implanted thermoseeds or injected magnetic nanoparticles in a magnetic field. For all of these procedures, clinical studies with a total of some 350 patients have been performed. However, the results cannot be judged correctly because of a lack of adequate control parameters for the older studies and inadequately short follow-up of all studies. Conclusions regarding treatment-related morbidity seem to be possible, with a generally positive impression and low rates of adverse effects. But before such results can be generalized, patient selection bias and the technology standards that existed when the studies were performed must be taken into consideration. Various papers are reviewed and summarized. In the author's opinion, the different options for thermal and thermal-ablative treatment of prostate cancer are very promising, but in light of the existing standard procedures, feasibility must not overrule reasonableness.

Microwave thermotherapy: historical overview

The application of heat with curative aim is an old and very well-known principle in medicine. A review of the history of heat use in the treatment of prostatic disease is presented. The article is based on bibliographic research (MEDLINE Search and PubMed) and focuses on treatment of benign prostatic hyperplasia (BPH) since the first clinical documentation of transrectal hyperthermia for this condition. Then, in a chronological sequence, not only the evolution toward thermotherapy but also enhancements of the latest techniques are presented. The new advances in the field of patient selection, indications, and outcome predictors, as well as new trends in treatment are briefly considered.

Transrectal microwave hyperthermia for patients with benign prostatic hyperplasia

BACKGROUND

A randomized study evaluated the efficacy of treatment with transrectal microwave hyperthermia (TMH) treatment in patients with benign prostatic hyperplasia (BPH).

METHODS

Eighty BPH patients received TMH therapy and 20 patients were given a sham treatment. TMH was achieved using a prostathermer which includes a microwave transrectal heat generator, a cooling system and a transurethral sensor probe. Patients that received TMH had 5 to 6 sessions of 1 hour each where the prostate was heated to 42 degrees C to 43.5 degrees C. The sham treatment consisted of a single session where the temperature was maintained at 37 degrees C. All patients were evaluated at 3 and 12 months after treatment.

RESULTS

There was an improvement of subjective obstructive symptoms in 54 patients (75%) after TMH. An evaluation of urodynamic parameters revealed an increase in the maximum flow rate and a decrease of the detrusor opening pressure as well as the detrusor pressure at maximum flow in patients treated with TMH. A significant improvement in the amount of residual urine was seen in all TMH-treated patients (P < 0.0001).

CONCLUSION

Although TMH cannot be considered a superior alternative to open surgical or transurethral excision of the prostate, it is a valid option for patients who have indwelling urethral catheters and for those at high surgical risk.

L'ipertermia transrettale nella prostatite cronica. Esperienza personale

The Authors describe their experience with transrectal prostatic hyperthermia in 88 patients with chronic abacterial prostatitis and pass on to consider the clinical difficulties in effectively tackling these pathologies.

Is there a role for transrectal microwave hyperthermia in the treatment of benign prostatic hyperplasia? A critical review of a six-year experience

We critically reviewed our 6-year experience with transrectal microwave hyperthermia of the prostate for benign prostatic hyperplasia (BPH) in 320 patients either at high surgical risk or refusing surgery. Transrectal prostatic hyperthermia was given in five to ten 60-minute sessions with an intraprostatic temperature ranging from 42 degrees to 43.5 degrees C. Although an amelioration of symptoms and urodynamic measures was seen initially in most patients, only residual urine volume showed a statistically and clinically significant improvement at the long-term follow-up. According to maximum flow nomograms, bladder outlet obstruction was not resolved by the treatment. We conclude that although the transrectal hyperthermia proved to be a safe procedure, it did not cure BPH in the long term. Considering the results seen with newer nonsurgical procedures such as prostatic stents and prostatic lasers, we believe that transrectal hyperthermia should not be recommended to symptomatic BPH patients.

Transurethral microwave thermotherapy of nonbacterial prostatitis and prostatodynia: initial experience

OBJECTIVES

To report our early experience using transurethral microwave thermotherapy (TUMT) to treat patients with nonbacterial prostatitis (NBP) and prostatodynia.

METHODS

Nineteen patients with NBP (symptoms, negative cultures, no response to antibiotics, leukocytosis in expressed prostatitic fluid) and 5 patients with prostatodynia (symptoms, negative cultures, no response to antibiotics, no leukocytosis in expressed prostatitic fluid) were treated with TUMT at interstitial temperatures of 45 degrees to 60 degrees C for 1 hour. Response was assessed by a consistent symptom severity index and global assessment of symptoms.

RESULTS

A marked and significant early (3 months) favorable response was noted in nearly one half of the NBP group but little benefit was found in the prostatodynia group. The treatment was associated with few adverse experiences.

CONCLUSIONS

TUMT appears to be a potentially effective therapy for NBP, but its real efficacy as well as the durability of the response needs to be confirmed with a randomized double-blind sham-controlled trial.

A sham controlled trial of transurethral microwave therapy with subsequent treatment of the control group

To investigate whether there is a significant placebo component to the improvements seen after 1-session transurethral microwave treatment, 40 patients with significant symptoms of prostatism and unequivocally benign glands were recruited to take part in a sham controlled study. After an active treatment the mean American Urological Association symptom scores improved by 63% (19.2 to 7.1) while after a sham treatment symptom scores improved only marginally (18.8 to 16.2, p < 0.001). Residual volumes decreased by 50% (104 to 52 ml.) and flow rates increased by 2.3 ml. per second after an active treatment with no improvement after a sham treatment. There was a consistently greater improvement after an active treatment compared to a sham treatment. Patients who had received a sham treatment were then offered an active treatment and showed improvements similar to those in the original actively treated group and much greater than after the original sham treatment. Mean symptom scores decreased from 16.2 to 9.9 (p < 0.004). Residual volumes decreased from 94 to 40 ml. (p < 0.005) and flow rates increased by 1.6 ml. per second, while these same criteria had deteriorated after a sham treatment. Side effects were mild and short lived, with no patients reporting sexual dysfunction as a consequence of treatment. Transurethral microwave therapy is an effective well tolerated treatment for select patients with benign prostatic hypertrophy and the placebo effect of treatment is minimal.

Preliminary results of a hyperfractionated dose escalation study for locally advanced adenocarcinoma of the prostate

The objective of this study was to build on our experience with 3-D conformal radiotherapy (CRT) by using a hyperfractionated dose escalation scheme to maximize the therapeutic ratio between improved local control and reduced morbidity in patients with locally advanced prostate cancer. Twenty patients with locally advanced (T3, T4) adenocarcinoma of the prostate were treated with a hyperfractionated radiotherapy schedule. All fields were designed with a conformal therapy based beam's eye view, 3-D planning system. The pelvic lymph nodes received 1.8 Gy/day to a total dose of 45 Gy in 5 weeks. Using partial transmission blocks, the prostate and periprostatic tissues received 1.3 Gy twice daily (minimum interval of 6 h) to a total dose of 78 Gy in 6 weeks. The dose was chosen by calculating the biologically effective dose (BED) which would produce the same effect in late reacting tissue but an increase for the tumor as our standard dose of 69 Gy delivered in 1.8-2.0 Gy fractions. The alpha/beta chosen for late damage was 3 Gy and 10 Gy was used for the tumor. All 20 patients completed the planned course of treatment. Although an increase in the tumor BED would be expected to result in increased acute effects, no significant worsening of acute side-effects was observed compared with standard treatment. All patients had only mild (Grade 1) rectal or bladder toxicity during treatment. One patient had an exacerbation of diverticulitis during treatment requiring hospitalization for antibiotics but completed treatment on schedule.(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency of residual neoplasm in the prostate following three-dimensional conformal radiotherapy

The incidence of residual neoplastic cells on prostatic biopsy following conventional external beam radiotherapy is reported to range from 40-90%. As a result, it has been stated that current modalities of radiotherapy may carry an unacceptable local failure rate even in patients irradiated for low stage disease. In order to assess the potential benefits of three-dimensional (3-D) treatment planning, an unselected, consecutive group of patients with localized adenocarcinoma of the prostate was evaluated. This study was designed to determine the frequency of residual cancer in the prostate two years following definitive external beam radiotherapy designed, using a 3-D planning system. Between February 1988 and February 1989, 30 consecutive patients with localized (Stage T1-T3NxMo) adenocarcinoma of the prostate received definitive external beam radiotherapy. All treatment fields were designed with a computed tomography (CT)-based 3-D treatment planning system, resulting in a static conformal radiotherapy plan. The minimum dose delivered to the target volume, which included the prostate, periprostatic tissues, and a 1 cm margin, was between 65 and 69 cGy. Twenty-six patients had Stage T1, T2NxMo primary tumors and four were T3NxMo. Two years following the completion of treatment, all patients underwent digital rectal examination, transrectal ultrasound examination of the prostate with multiple biopsies, bone scan, and serum prostate specific antigen (PSA) determinations. Residual prostate cancer was proven by biopsy in six of 30 patients (20%). Four of 26 (15%) with Stage T1 and T2 tumors had a positive biopsy. However, two of the four Stage T3 tumors had postradiation biopsies positive for cancer (50%). Only one patient with a positive biopsy had an abnormal rectal examination. Five of the eight patients with elevated serum PSA levels after two years had residual neoplasia identified on biopsy. One of six patients with an abnormal postradiation ultrasound had residual tumor. Only one of the 22 patients (5%) with a normal serum PSA at two years had a positive postradiation biopsy. In patients with localized prostate cancer, the use of 3-D static conformal radiotherapy followed by multiple ultrasound guided biopsies confirmed the efficacy of external beam radiotherapy in low stage disease. We believe that the low incidence of positive biopsies in this study resulted from the benefits of 3-D treatment planning as well as the fact that all patients were evaluated, whereas past studies have been in selected patient groups when suspicion of residual disease existed prior to biopsy.(ABSTRACT TRUNCATED AT 400 WORDS)

A coaxial microwave applicator for transurethral hyperthermia of the prostate

Benign prostatic hyperplasia (BPH) is a common disease of elderly men. The current definitive treatment for urinary obstruction caused by this disease is surgery (transurethral resection of the prostate, or TURP). Recent evidence suggests that hyperthermia may be a useful nonsurgical alternative for treatment of symptomatic BPH. A transurethral microwave applicator has been designed around a Foley catheter for delivery of local hyperthermia to the prostate. The Foley balloon is used to maintain the antenna position within the prostatic urethra. The Foley catheter also features an antenna choke to confine power deposition to the intended region. The antenna is a coaxial dipole designed to operate at 915 MHz. Qualitative and quantitative specific absorption rate (SAR) patterns are shown for this antenna. In vivo experiments in dog prostate demonstrate that temperatures > 42 degrees C can be obtained > 1 cm away from the catheter, while maintaining a maximum urethral temperature of 47 degrees C to 48 degrees C. Histology obtained acutely after the hyperthermia treatments showed minimal damage to the periurethral tissues. We conclude from these studies that this microwave applicator is capable of providing local hyperthermia to the prostatic tissues with a predictable and well-circumscribed thermal distribution.

Is there a role for transrectal microwave hyperthermia of the prostate in the treatment of abacterial prostatitis and prostatodynia?

Transrectal microwave hyperthermia of the prostate was administered to 54 patients with chronic abacterial prostatitis or prostatodynia, who failed to respond to several courses of conventional therapies. Hyperthermia was delivered in 60-min long sessions with three randomly chosen regimens (1 session/week for 4 weeks; 1 session/week for 6 weeks; 2 sessions/week for 3 weeks). A prostatic temperature of 42.5 +/- 0.5 degrees C was maintained throughout the entire duration of each session. Patients were assessed pre- and postoperatively by scoring of subjective symptoms, uroflowmetry with flow nomograms, determination of residual urine volume, and transrectal ultrasonography of the prostate. At the long-term follow-up, the subjective symptom score was significantly improved in all patients. Fifty percent of the patients also reported an improvement of life quality, 47% reported their condition unchanged, and 3% reported deterioration, despite therapy. Urodynamic parameters improved but did not reach statistical significance. No major complications were encountered. Our preliminary data indicate that transrectal microwave hyperthermia of the prostate is a safe therapy that can be beneficial as a second line treatment in selected patients with recurring symptoms of abacterial prostatitis or prostatodynia, which do not respond to medical therapy.

Transrectal microwave hyperthermia for advanced prostate cancer: long-term clinical results

Transrectal microwave hyperthermia was applied to 46 stages D1 and D2 prostate cancer patients to treat urinary symptoms and local pain unrelieved by total androgen ablation therapy. Hyperthermia was administered in 10, 60-minute sessions twice a week for 5 weeks. A calculated intraprostatic temperature of 43.5 +/- 0.5C was maintained throughout the treatment. At 2 years the mean residual urine volume was significantly decreased (p less than 0.05), while the mean peak flow rate and maximum flow nomogram were improved but not significantly. The majority of patients reported a notable amelioration of subjective symptoms and quality of life. The only complication was a prostatorectal fistula that was cured by leaving a urethral catheter in place for 4 weeks. Prostatic hyperthermia is a safe and effective palliative procedure for bladder outlet obstruction due to advanced prostate cancer.

Effect of radiation combined with hyperthermia on human prostatic carcinoma cell lines in culture

The effect of radiation combined with heat on three human prostatic carcinoma cell lines growing in vitro was investigated. Cells were exposed to different radiation doses followed by heat treatment at 43 degrees C for one hour. Heat treatment, given ten minutes after radiation, significantly enhanced the radiation response of all the cell lines studied. The combined effect of radiation and heat produced greater cytotoxicity than predicted from the additive effects of the two individual treatment modalities alone. These results indicate that a combined treatment regimen of radiation plus hyperthermia (43 degrees, 1 hr) might be an important tool in maintaining a better local control of prostatic cancer.

Chronic abacterial prostatitis and hyperthermia. A possible new treatment?

A group of 45 patients with chronic abacterial prostatitis or prostatodynia underwent 6 weekly, 1-hour sessions of local deep microwave hyperthermia (42.5 +/- 0.5 degrees C) to the prostate. All patients had a long history of symptoms typical of the condition. They all failed to respond to a variety of conventional treatments administered over several years by various specialists. Each patient served as his own control before and after the hyperthermic treatment. The results of this study are encouraging: 25% showed a sustained and complete loss of symptoms and 50% had a partial response; the remaining 25% reported no improvement. These results open up new possibilities in the treatment of this condition, which has so far responded poorly to conventional therapy.

Histological effects of local microwave hyperthermia in prostatic cancer

Recent investigations have shown that hyperthermia can reduce the volume of the prostate and improve local symptoms in patients with carcinoma of the prostate. Histological examinations of the effect of hyperthermia on prostatic cancer tissue, however, have not been performed systematically until now. Thus, we initiated a study to investigate the effects of heat on prostatic cancer as a prerequisite for further clinical trials on hyperthermia as treatment for prostatic cancer. Twenty patients with untreated prostatic cancer underwent local hyperthermia (915 MHz), each receiving four sessions of 60 min each. The intraprostatic temperature was 42-43 degrees C. Histological specimens of the prostate were taken before the treatment and 1-2 weeks after the last hyperthermia session. Hyperthermia produced hyperaemic alterations of the prostatic stroma and a diffuse oedema with interstitial lymphoplasmacellular infiltration. Definite signs of tumour cell necrosis, however, could not be seen in any of the patients. Hence the shrinkage of prostatic tumours described earlier cannot be explained by histologically proven tumour cell destruction. Thus hyperthermia is not adequate as a single treatment for prostatic cancer. Hyperthermia may, however, be useful as part of integrated therapy regimens together with cytostatic or hormonal agents and radiotherapy because of hyperaemic, chemo- and radiosensitizing effects.

Side-effects of local hyperthermia: results of a prospectively randomized clinical study

In 1986, 25 patients with stage II and III carcinoma of the cervix were treated by a combination of radiation and local hyperthermia using an endotract intravaginal applicator. Another 25 patients were treated with radiation alone. Both groups were followed up for a minimum period of 18 months. The acute and long-term toxicity of local hyperthermia was closely monitored. Our study shows that whereas local hyperthermia adds significantly to the local control achieved with radiation alone, it is not in any way associated with any significant short- or long-term toxicity, and does not enhance the radiation reactions.

Locoregional prostatic cancer. Advances in management

Conceptual advances include attempts to achieve uniformity among systems for characterizing and reporting experiences with prostatic cancer, better understanding of the zonal anatomy of the prostate, and recognition of probable precursor lesions to prostatic cancer. Prostatic-specific antigen, transrectal ultrasonography, and fine-needle aspiration biopsy are major innovations in diagnosis and staging of prostatic cancer. The varied and unpredictable behavior of prostatic cancer has stimulated the search for reliable indicators of the biologic potential of the disease. Management of localized prostatic cancer remains controversial. A nerve-sparing technique of radical retropubic prostatectomy accomplishes total removal of the prostate with possible preservation of sexual potency. Linear accelerator irradiation is an acceptable alternative treatment. Interstitial irradiation with a variety of radionuclides remains under investigation using ultrasound to enhance distribution of radiation sources. Endocrine therapy may prove especially advantageous if administered before development of bone metastasis.

Local hyperthermia to canine prostate. A pilot study

Repeated treatments of localized deep microwave hyperthermia were given to a series of dogs by means of a 915 MHz, water-cooled skirt-type applicator. The applicator was inserted into the rectum and directed toward the prostate in order to heat it by means of the absorbed microwaves while keeping the rectal wall at a lower temperature by surface cooling of the applicator itself. Sessions were given for different lengths of time ranging between ninety minutes and five hours, during which the prostate temperature was kept at 42.5 degrees C (+/- 0.5 degrees C) or 44.5 degrees C (+/- 0.5 degrees C). Three-dimensional temperature distributions in the prostate were measured accurately and verified by a Luxtron Fluoroptic Unit. Temperatures were constantly monitored in the rectal wall and in the prostatic urethra. Thorough and systemic follow-up was done before, during, and after each treatment, and the observations are reported. Two interesting preliminary observations were made: (1) differential blood counts showed significantly monocytosis following the treatments and lasted for at least one week, and (2) values of creatinine phosphokinase (CPK) and serum glutamic oxaloacetic transaminase (SGOT) were found to rise irreversibly in those animals which were later found to have definite histopathologic evidence of localized necrotic damage.

The effect of hyperthermia on human prostatic carcinoma cell lines: evaluation in vitro

The effect of hyperthermia on established human prostate carcinoma cell lines (PC-3, DU-145) and related sublines (1-LN, 125-1L) was investigated in vitro. Cells were exposed to heat treatment at 43C or 37C for varying time intervals, (one hr or two hrs) and cell survival was evaluated by the colony formation assay and by measurement of cellular growth rate. While one hr exposure at 43C did show a mean inhibition of colony formation, ranging from 29 to 41%, a statistically significant increase in inhibition rate (p less than 0.001) was observed at two hr exposure, ranging from 57 to 92%. This study is a report of the cytotoxic effect of hyperthermia on established human prostatic tumor cell lines. These in vitro results indicate that hyperthermia may become a potentially useful form of adjunctive therapy for local control of prostatic cancer. However, the temperature and exposure time may have an important impact on cell kill when this new modality for cancer treatment is proposed for a clinical trial.

Diseases of prostate treated by local microwave hyperthermia

A new method is described for the treatment of diseases of the prostate with local hyperthermia applied transrectally by microwaves. A series of 500 treatment sessions given to 74 patients with 14 controls, is reported. Thirty patients had advanced cancer of the prostate, 37 had benign hyperplasia and were unsuitable for surgery, and 21 had chronic prostatitis. Marked objective and subjective improvement was noted in the majority in twenty-four months of follow-up.

Current conflicts in the management of prostatic cancer

In summary, 5-, 10-, and 15-year actuarial survival can be achieved in 81, 60, and 35% of patients with disease limited to the prostate and in 61, 36, and 18% of those with extracapsular extension. In various subgroups of patients with nodular disease who were selected by the same criteria applied in the selection for surgical resection, survival of 60% can be achieved. Conversely, local control may not be achieved following irradiation because of cell survival within the target volume. More sophisticated boost therapy using interstitial implants, high energy particles, radiosensitizers, and/or hyperthermia may improve local control and hence longer term survival. Local control may not be achieved following surgical resection because of transection of tumor at the surgical margin. Case selection for surgery might be improved by pre-operative transrectal ultrasonography or MRI examination. In situations in which pathologic examination demonstrates frank tumor transection, local control still may be achieved by prompt and judicious salvage by X-ray therapy.

Histopathological observations in the canine prostate treated by local microwave hyperthermia

A large series of repeated experiments were performed applying localized microwave hyperthermia to the prostate in dogs using a new water-cooled skirt-type antenna [1], operating at 915 MHz, as part of a new hyperthermia apparatus being developed for the treatment of the prostate in humans. The prostate gland of 20 male dogs was heated repeatedly under general anesthesia, at temperatures between 40 degrees C and 47 degrees C, and for different lengths of time up to 10 h. The prostate and other tissues were evaluated histopathologically following treatments. Invariably, all treatments by hyperthermia of the prostate caused a mononuclear inflammatory infiltration in the interstitium and polymorphonuclear infiltration in the glandular elements. Permanent tissue damage was found to be time-and temperature-dependent. Heating at 42.5 degrees C (+/- 0.5 degrees 5C) for up to 1.5 h was found to be harmless and could be safely repeated with our equipment. This study was part of a preclinical evaluation of a new antenna and apparatus.