Short-course intensity-modulated radiotherapy (70 GY at 2.5 GY per fraction) for localized prostate cancer: preliminary results on late toxicity and quality of life

PURPOSE

To present our preliminary observations on the late toxicity and quality of life (QOL) of patients treated with short-course intensity-modulated radiotherapy (SCIM-RT).

METHODS AND MATERIALS

Fifty-one patients were treated with SCIM-RT at the Cleveland Clinic Foundation between October 1998 and May 1999. The technique consisted of intensity-modulated radiotherapy using 5 static fields (anterior, 2 laterals, and 2 anterior obliques). Inverse plans were generated by the Corvus treatment-planning system. The treatment delivery was performed with a dynamic multileaf collimator. A total of 70.0 Gy was prescribed in all cases at 2.5 Gy per fraction to be delivered in 28 fractions over 5 and a half weeks. The location of the prostate gland was verified and adjusted daily with the BAT transabdominal ultrasound system. The median follow-up was 18 months (range: 11 to 26 months). The Radiation Therapy Oncology Group (RTOG) scales were used to evaluate late toxicity. The Expanded Prostate Cancer Index Composite (EPIC) was used to evaluate QOL. A total of 24 patients completed the EPIC questionnaire at approximately 2 years after therapy (median time from treatment to questionnaire administration: 24 months; range: 21 to 26 months). The results from the EPIC questionnaires were compared to scores from 46 patients treated during the same time period with conformal radiotherapy (CRT) to 78 Gy at 2 Gy per fraction.

RESULTS

The dose was prescribed to an isodose line ranging from 82.0% to 90.0% (mean: 87.2%). The range of the individual prostate mean doses was 73.5 to 78.5 Gy (average: 75.3 Gy). To date, only 1 patient had Grade 1 late urinary toxicity. To date, only 4 patients had Grade 1 late rectal toxicity. No Grade 2 or 3 late urinary or rectal complications have occurred. The actuarial rectal bleeding rate observed at 18 months was 7%. There were no differences in scores from the urinary, bowel, hormonal, and overall QOL domains between SCIM-RT patients and patients treated with CRT. The overall physical and mental QOL scores were also nearly identical to scores reported for the general U.S. population.

CONCLUSION

Preliminary late toxicity results up to 2 years after SCIM-RT are encouraging, with a median follow-up of 18 months (range 11 to 26 months). Late toxicity assessed by the physicians using RTOG late toxicity scores has been excellent. QOL reported by the patients using the EPIC questionnaire reveals no difference between patients treated with high-dose CRT at standard fractionation and patients treated with SCIM-RT. SCIM-RT is an alternative method of dose escalation in the treatment of localized prostate cancer. The proposed schedule significantly increases convenience to patients due to the decrease in overall treatment time.

Locally advanced prostate cancer

Standard therapy for clinically localized prostate cancer includes radical prostatectomy, external beam radiotherapy, or transperineal interstitial brachytherapy. Patients eligible for standard therapy are those with low risk features as defined by various risk group classifications, which generally include clinical stage T1 or T2a, serum prostate-specific antigen (PSA) less than 10 ng/mL, and biopsy Gleason sum of 6 or less. Although there has been important evolution in the performance of these techniques, particularly with respect to functional outcomes, these approaches for low-risk disease are relatively mature, and the cure rates with each of these therapies are similar in this patient population; locally advanced disease is more difficult to cure, however. Biochemical disease-free survival rates in men undergoing radical prostatectomy are clearly related to the pathologic stage. Prognostic groups can be defined based on pathologic stage with increasingly worse outcomes based on extracapsular extension (ECE), margin status, and the status of the lymph nodes and seminal vesicles. In patients with low risk features, the positive margin rate is generally low, making the presence or absence of ECE the dominant variable in predicting the likelihood of treatment failure. These observations suggest that more aggressive therapy is needed to cure those who are likely to have ECE or other adverse histologic features. Several nomograms predicting the likelihood of ECE or 5-year biochemical failure rates are now in routine clinical use, and can be used to select men at high risk of failure with single modality therapy for more aggressive treatment strategies. However, the optimal form of aggressive therapy for these patients is unknown.

SELECT: the next prostate cancer prevention trial. Selenum and Vitamin E Cancer Prevention Trial

PURPOSE

Growing evidence implies that selenium and vitamin E may decrease the risk of prostate cancer. The Selenium and Vitamin E Cancer Prevention Trial (SELECT) is a randomized prospective double-blind study designed to determine whether selenium and vitamin E decrease the risk of prostate cancer in healthy men.

MATERIALS AND METHODS

The preclinical and epidemiological evidence regarding chemoprevention with selenium and vitamin E were reviewed. Secondary analyses from randomized trials of the 2 agents were included in the current analysis. Data from these analyses as well as evidence from the Prostate Cancer Prevention Trial were used to develop the SELECT schema.

RESULTS

Preclinical, epidemiological and phase III data imply that selenium and vitamin E have potential efficacy for prostate cancer prevention. The experience of the Prostate Cancer Prevention Trial shows the interest and dedication of healthy men to long-term studies of cancer prevention. A total of 32,400 men are planned to be randomized in SELECT.

CONCLUSIONS

SELECT is the second large-scale study of chemoprevention for prostate cancer. Enrollment in the study is planned to begin in 2001 with final results anticipated in 2013.

Molecular epidemiologic studies within the Selenium and Vitamin E Cancer Prevention Trial (SELECT)

OBJECTIVE

To conduct timely epidemiologic investigations of molecular/genetic markers that may contribute to the development of prostate, lung, colorectal, or other cancers within the Selenium and Vitamin E Cancer Prevention Trial (SELECT), and to evaluate interactions between these markers and the study interventions.

METHODS

The epidemiologic studies within SELECT will be based on 32,400 men aged 55 years or older (age 50 or older for the African-American men) enrolled into an intergroup, randomized, placebo-controlled, double-blind, phase III prevention trial of supplemental selenium and vitamin E developed and funded by the National Cancer Institute, and coordinated by the Southwest Oncology Group. During the 12-year study period approximately 1500-2000 cases of prostate cancer, 800 lung cancers, and 500 colon cancers are estimated to be diagnosed, based on data from the ongoing Prostate Cancer Prevention Trial of finasteride. A modified fasting blood sample will be processed to collect plasma for analysis of micronutrients, hormones, cytokines, and other proteins. Buffy-coat derived white blood cells collected at baseline will be used for isolation of DNA and establishment of immortalized cell lines. Red blood cells will be stored for analysis of hemoglobin adducts and other components.

RESULTS

Specific results anticipated from these molecular studies will provide information on factors hypothesized to contribute to prostate cancer risk and that may modify the efficacy of either trial supplement, including: steroid sex hormones and several polymorphic genes that encode proteins affecting androgenic stimulation of the prostate, including the androgen receptor, steroid 5alpha-reductase type II, CYP17, and beta-hydroxysteroid dehydrogenase; polymorphisms of DNA repair genes and carcinogen metabolism genes, including those involved in the activation of chemical carcinogens to reactive intermediates (e.g., CYP1A1) or the detoxification of reactive intermediates (e.g., glutathione S-transferase M1); DNA and protein adducts; and insulin-like growth factors and leptin.

CONCLUSION

SELECT offers an excellent opportunity to conduct molecular epidemiologic investigations to assess gene-environment interactions and their role in prostate, lung, and colon carcinogenesis.

Preliminary observations of single-agent docetaxel as neoadjuvant therapy for locally advanced prostate cancer

Patients with locally advanced prostate cancer present a significant therapeutic dilemma. Despite aggressive local therapies, including radical prostatectomy (RP), these patients are at high risk for biochemical failure. Several research groups have recently demonstrated the feasibility of hormonal and chemohormonal therapy before RP, but limited published data are available regarding the usefulness of chemotherapy without hormonal therapy in the neoadjuvant setting. At Cleveland Clinic Foundation, a phase II trial was initiated to evaluate a 6-week course of docetaxel, 40 mg/m(2) intravenously every 7 days, followed by RP in patients with locally advanced prostate cancer. RP was to be performed within 3 weeks of completion of neoadjuvant chemotherapy. The primary endpoint of this study is pathologic complete response. Preliminary toxicity data suggest that weekly docetaxel is well tolerated and does not increase the risk of perioperative or post operative complications. Reductions in prostate-specific antigen levels were noted in seven of 10 patients who completed the 6-week course of neoadjuvant docetaxel. The neoadjuvant use of investigational cancer therapies may allow for relatively rapid assessment of their antitumor activity.

Radiation dose response in patients with favorable localized prostate cancer (Stage T1-T2, biopsy Gleason < or = 6, and pretreatment prostate-specific antigen < or = 10)

PURPOSE

To study the radiation dose response as determined by biochemical relapse-free survival in patients with favorable localized prostate cancers, i.e., Stage T1-T2, biopsy Gleason score (bGS) < or = 6, and pretreatment prostate-specific antigen (iPSA) < or = 10 ng/mL.

METHODS AND MATERIALS

A total of 292 patients with favorable localized prostate cancer were treated with radiotherapy alone between 1986 and 1999. The median age was 69 years. Sixteen percent of cases (n = 46) were African-American. The distribution by clinical T stage was as follows: T1/T2A, 243 (83%); and T2B/T2C, 49 (17%). The distribution by iPSA was as follows: < or = 4 ng/mL, 49 (17%); and > 4 ng/mL, 243 (83%). The mean iPSA level was 6.2 (median, 6.4). The distribution by bGS was as follows: or = 5 in 89 cases (30%) and 6 in 203 cases (70%). The median radiation dose was 70.0 Gy (range, 63.0-78.0 Gy). Doses of < or = 70.0 Gy were delivered in 175 cases, 70.2-72.0 Gy in 24 cases, 74 Gy in 30 cases, and 78 Gy in 63 cases. For patients receiving < 72 Gy, the median dose was 68 Gy, vs. 78 Gy for patients receiving > or = 72 Gy. A conformal technique was used in 129 (44%) of cases. The median follow-up was 43 months (range, 3-153).

RESULTS

For the entire cohort, the projected 5- and 8-year biochemical relapse-free survival (bRFS) rates were both 81%. For patients receiving > or = 72 Gy, the 5- and 8-year bRFS rates were both 95% vs. only 77% for patients receiving < 72 Gy, p = 0.010. For patients receiving 74 Gy, the 4-year bRFS rate was 94% vs. 96% for patients receiving 78 Gy, p = 0.90. A multivariate analysis for factors affecting bRFS rates using Cox proportional hazards was performed for all cases using the following variables: age (continuous variable), race (black vs. white), iPSA (continuous variable), bGS (< or = 5 vs. 6), Stage (T1-2A vs. T2B-C), radiation dose (continuous variable), and radiation technique (conformal vs. standard). From the multivariate analysis, only iPSA (p = 0.017, chi(2) = 5.7), and radiation dose (p = 0.021, chi(2) = 5.3) were independent predictors of outcome. Age (p = 0.94), race (p = 0.89), stage (p = 0.45), biopsy GS (p = 0.40), and radiation technique (p = 0.45) were not.

CONCLUSION

There is a clear radiation dose response in patients with favorable localized prostate cancers (i.e., Stage T1-T2, biopsy Gleason score < or = 6, and iPSA < or = 10 ng/mL). At least 74 Gy should be delivered to the prostate and periprostatic tissues. With our cohort of patients, longer follow-up will be needed to assess the importance of doses exceeding 74 Gy.

Potential target populations and clinical models for testing chemopreventive agents

Target populations for chemoprevention trials should include those at higher than average risk for the development of prostate cancer as defined by explicit epidemiologic and genetic criteria. Such populations include a "primary prevention" group without histologic or clinical evidence of cancer, and several clinical models of "secondary prevention," including those with clinically evident disease prior to definitive therapy and those at high risk of recurrence after therapy based on histological or biochemical status. Each risk group and clinical model has potential advantages and disadvantages, and the mechanisms that underlie disease development and progression in each group may be unique. These observations give rise to many potential clinical trials of specific agents. These trials should also include collection of data on potentially confounding influences on disease development and progression.

The Prostate Cancer Prevention Trial: Current status and lessons learned

The Prostate Cancer Prevention Trial is the first phase 3 prevention trial for prostate cancer in the United States. The implementation of a large, randomized trial has provided a wealth of information that will aid in future cancer chemopreventive studies in US men. The experience from the implementation of the Prostate Cancer Prevention Trial was reviewed. Lessons learned from the study include: (1) US men are willing to enroll in prevention trials; (2) participants in chemoprevention trials are well educated and healthy; (3) the successful cancer prevention trial is viewed by participants as a "men's health trial"; (4) data management and discipline coordination at participating institutions are critical; (5) study design change is commonly required owing to changes in clinical practice over the course of the trial; and (6) training of institutional staff is essential. With proper design, robust data management, and a flexible staff, large-scale randomized chemoprevention trials can be accomplished in the United States. With the extraordinary number of potential agents, it is expected that much will be accomplished with this strategy in the near future.

Executive Summary of the National Cancer Institute Workshop: Highlights and recommendations

Prostate cancer chemoprevention represents a relatively new and promising strategy for reducing the immense public health burden of this devastating cancer of men in the United States and Western societies. Chemoprevention is defined as the administration of agents (drugs, biologics, and natural products) that modulate (inhibit) one or more steps in the multistage carcinogenesis process culminating in invasive adenocarcinoma of the prostate. In 2000, there were an estimated 170,000 new cases of prostate cancer and 31,000 deaths in the United States. During the past decade, the National Cancer Institute (NCI) organized the chemoprevention research program and began testing the first generation of promising agents (eg, 4-(hydroxy)-fenretinide [4-HPR], difluoromethylornithine [DFMO], antiandrogens) in high-risk cohorts and launched the first-large scale US phase 3 primary prevention trial, known as Prostate Cancer Prevention Trial (PCPT-1), in 18,000 average-risk men (age more than 55 years and prostate-specific antigen [PSA] less than 3 ng/mL) treated for 7 years with finasteride or placebo. In the summer of 1998, the NCI Prostate Cancer Progress Review Group (PRG) Report to the director of NCI was published in response to the leadership of the prostate cancer advocacy community in conjunction with Congress. To further elucidate and address critical issues identified in this report and to develop a research agenda for the newly created Prostate and Urologic Cancer Research Group in the Division of Cancer Prevention at NCI, the NCI organized the workshop "New Clinical Trial Strategies for Prostate Cancer Chemoprevention." The major objectives were to promote understanding and cooperation among the NCI, US Food and Drug Administration (FDA), academia, pharmaceutical industry, and the public regarding new opportunities for clinical prevention trials for prostate cancer. The workshop was divided into three concurrent breakout panels and a fourth joint integrative panel. The workshop addressed multiple key areas identified in the PRG report in the following panels: (1) Molecular Targets and Promising Agents in Clinical Development; (2) Intermediate Endpoint Biomarkers for Prevention Trials; (3) High-Risk Study Populations for Prevention Trials, and (4) Preventive Clinical Trial Designs and Regulatory Issues. Expert panelists were drawn from leading academic, pharmaceutical, and government scientists in basic research and clinical investigation. Key pharmaceutical, biotechnology, academic, and National Institutes of Health scientists presented overviews of their new agents and products in clinical development (representing the next generation of promising agents). Senior FDA physicians from the Center for Drugs and Center for Biologics presented on current standards for new drug and biologic approval for chemoprevention efficacy. Some of the key topics included recent advances in the state of knowledge of promising agents in the clinic based on molecular targets as well as bottlenecks in drug development for pharmaceutical sponsors; strategic modulable biomarkers that can serve as primary endpoints in phase 1/2 trials to assess preventive efficacy; high-risk cohorts with precancer (high-grade prostatic intraepithelial neoplasia) and representative clinical trial designs that are ready for immediate translation into efficient prevention trials, such as Bayesian sequential monitoring for early assessment of biologic activity and factorial designs for assessment of multiagent combinations. Finally, each expert panel generated recommendations for areas of future research emphasizing opportunities and infrastructure needs.

Phase II trial of neoadjuvant estramustine and etoposide plus radical prostatectomy for locally advanced prostate cancer

OBJECTIVES

To report the results of a Phase II trial of neoadjuvant estramustine and etoposide before radical prostatectomy in patients with locally advanced disease.

METHODS

Treatment consisted of three cycles of estramustine (10 mg/kg/day) and etoposide (50 mg/m(2)/day) orally on days 1 through 21, repeated every 28 days, followed by radical prostatectomy. The eligibility criteria included locally advanced prostate cancer (clinical Stage T2b/c or T3, prostate-specific antigen [PSA] level of 15 ng/mL or greater, or Gleason score of 8 or higher) without evidence of metastatic disease. The median PSA level was 14 ng/mL (range 5.3 to 50), the median Gleason score was 7 (range 6 to 9), and 44% had Stage T2b/c or T3 disease. The primary endpoint was feasibility of neoadjuvant therapy and radical prostatectomy, including drug and surgery-related toxicities. Secondary endpoints included the pre-prostatectomy PSA level, local response, pathologic outcomes, and time to PSA failure.

RESULTS

Eighteen patients were entered and completed all three cycles of therapy, and 16 (89%) underwent radical prostatectomy. A local response occurred in 15 (94%) of 16 patients with palpable tumors, and the serum PSA reached undetectable levels after therapy and before radical prostatectomy in 9 patients (50%). Five patients (28%) experienced grade 3 toxicity (two with deep venous thrombosis, two with neutropenia, and one with diarrhea) and one (6%) experienced grade 4 toxicity (pulmonary embolus) before surgery. The median operative time was 125 minutes, the mean blood loss was 665 mL, and the mean length of stay was 2.5 nights. Five minor surgical complications occurred in 4 patients. The pathologic analysis demonstrated residual carcinoma with squamous metaplasia and androgen deprivation effect in all patients. Five patients (31%) had organ-confined disease and 9 patients (56%) had specimen-confined disease. All patients achieved an undetectable PSA level postoperatively and at a median follow-up of 14 months (range 5 to 20) and without additional therapy, all 14 patients with negative lymph nodes were disease free.

CONCLUSIONS

This trial confirms the feasibility of radical prostatectomy with acceptable surgical morbidity after neoadjuvant therapy with estramustine and etoposide in patients with locally advanced prostate cancer. However, this regimen is associated with estramustine-induced thromboembolic toxicity. The results of the pathologic analysis suggest a higher than expected rate of organ-confined and specimen-confined disease, but little histologic evidence of antitumor effect beyond that associated with androgen deprivation. Additional study of this paradigm with other drug regimens is warranted.

Localized prostate cancer

Much controversy still surrounds the diagnosis and treatment of localized prostate cancer. Urologists generally believe that early detection and aggressive surgical therapy saves lives despite the absence of confirmatory randomized trials. Furthermore, a recent survey of radiation oncologists and urologists revealed marked polarization toward their own specialties when asked how they would counsel patients on therapy for newly diagnosed localized disease. Some issues are not controversial, however. There is general agreement that pretreatment tumor characteristics, including serum prostate-specific antigen level at diagnosis, tumor grade, and clinical stage as judged by digital rectal examination, are important prognosticators for treatment outcomes independent of the type of treatment. Also, there is sufficient experience with standard therapies (radical prostatectomy and external beam radiotherapy) to counsel patients on the chance for cure and the expected incidence of acute and chronic toxicities. A comparative evaluation of various therapies for prostate cancer should include consideration of cancer control, acute toxicity, treatment-related quality of life issues, salvage of treatment failures, and cost. Within this context, we believe that newly diagnosed patients should be counseled on all available treatment options before embarking on a course of therapy.

SELECT: the Selenium and Vitamin E Cancer Prevention Trial: rationale and design

Prostate cancer is the commonest non-skin malignancy in the United States and has a substantial mortality rate despite the use of PSA-based screening. Furthermore, therapy for prostate cancer by surgery, radiotherapy or hormonal manipulation carries a significant risk of treatment-related morbidity. Recent analysis of secondary endpoints of several large-scale randomized prospective clinical trials for other malignancies has suggested that selenium or vitamin E may result in a decreased incidence and mortality from prostate cancer. In vitro and preclinical studies of these antioxidants support this hypothesis. This review outlines the rationale and design of SELECT, the Selenium and Vitamin E Cancer Prevention Trial, designed to test the hypothesis that selenium or vitamin E alone or in combination can reduce the clinical incidence of prostate cancer in a population-based cohort of men at risk. SELECT is a phase III, randomized, double-blinded, prospective, 2x2 factorial clinical trial which will randomize 32,400 healthy men with normal DRE and serum PSA to one of four study arms: selenium alone, vitamin E alone, selenium+vitamin E, or placebo. Study agents will be taken orally for a minimum of 7 and maximum of 12 y with assessments of general health, incident prostate cancer and toxicity performed at 12 month intervals. Under the assumptions described, the detectable risk reduction is 25% for an effective single agent relative to placebo, with an additional 25% reduction for the combination relative to an effective single agent. The estimated power for the comparison of a single agent vs placebo is 96% and the power for the comparison of an effective single agent vs combination is 89%. Secondary endpoints will include prostate cancer-free survival, all-cause mortality, and the incidence and mortality of other cancers and diseases potentially impacted by the chronic use of selenium and vitamin E. Other trial objectives will include periodic quality of life assessments, assessment of serum micronutrient levels and prostate cancer risk, and studies of the evaluation of biological and genetic markers with the risk of prostate cancer. Prostate Cancer and Prostatic Diseases (2000) 3, 145-151

Laparoscopic radical nephroureterectomy for upper tract transitional cell carcinoma: the Cleveland Clinic experience

PURPOSE

We report our single institutional experience with retroperitoneal laparoscopic radical nephroureterectomy in patients with upper tract transitional cell carcinoma and compare results to those achieved by the open technique.

MATERIALS AND METHODS

A total of 77 patients underwent radical nephroureterectomy for pathologically confirmed upper tract transitional cell carcinoma. Of these patients 42 underwent laparoscopic nephroureterectomy from September 1997 through January 2000 and 35 underwent open surgery. All specimens were extracted intact. Of the laparoscopic group the juxtavesical ureter and bladder cuff were excised by our novel transvesical needlescopic technique in 27 and radical nephrectomy was performed retroperitoneoscopically in all 42. Data were compared retrospectively with 35 patients undergoing open radical nephroureterectomy from February 1991 through December 1999.

RESULTS

Laparoscopy was superior in regard to surgical time (3.7 versus 4.7 hours, p = 0.003), blood loss (242 versus 696 cc, p <0. 0001), specimen weight (559 versus 388 gm., p = 0.04), resumption of oral intake (1.6 versus 3.2 days, p = 0.0004), narcotic analgesia requirements (26 versus 228 mg., p <0.0001), hospital stay (2.3 versus 6.6 days, p <0.0001), normal activities (4.7 versus 8.2 weeks, p = 0.002) and convalescence (8 versus 14.1 weeks, p = 0.007). Complications occurred in 5 patients (12%) in the laparoscopic group, including open conversions in 2, and in 10 (29%) in the open group (p = 0.07). Followup was shorter in the laparoscopic group (11.1 versus 34.4 months, p <0.0001). The 2 groups were similar in regard to bladder recurrence (23% versus 37%, p = 0.42), local retroperitoneal or port site recurrence (0% versus 0%) and metastatic disease (8.6% versus 13%, p = 1.00). Mortality occurred in 2 patients (6%) in the laparoscopic group and 9 (30%) in the open group. Cancer specific survival (97% versus 87%) and crude survival (97% versus 94%) were similar between both groups (p = 0.59).

CONCLUSIONS

In patients with upper tract transitional cell carcinoma who are candidates for radical nephroureterectomy the retroperitoneal laparoscopic approach satisfactorily duplicates established technical principles of traditional open oncological surgery, while significantly decreasing morbidity from this major procedure. Short-term oncological and survival data of the laparoscopic technique are comparable to open surgery. Although long-term followup data are not yet available, it appears that laparoscopic radical nephroureterectomy may supplant open surgery as the standard of care in patients with muscle invasive or high grade upper tract transitional cell carcinoma.

Dosimetric comparison of pre-planned and or-planned prostate seed brachytherapy

PURPOSE

To compare the dosimetry of the traditional two step procedure (volume study + treatment planning several weeks later) with that of an OR-based single procedure in which these two steps follow one another immediately. Computer generated treatment plans were used in both procedures.

METHODS AND MATERIALS

Several dosimetric parameters relating to target coverage were obtained from dose volume histograms of CT-based evaluation plans developed either 1 or 3 days following seed implantation. A total of 113 patients with early stage (T1C, T2A) prostate cancer were used for this retrospective study.

RESULTS

The fraction of target (prostate) covered by the prescription dose (144 Gy), 90% of the prescription dose (115 Gy), and the dose encompassing 90% of the target in the evaluation plan were all statistically significantly improved for OR-based plans compared to pre-planned cases.

CONCLUSION

In our hands, there is a small but significant improvement in dose coverage of the prostate when the ultrasound volume study and treatment planning are combined into a single procedure.

Replication linkage study for prostate cancer susceptibility genes

BACKGROUND

Since the publication of the first genome screen for prostate cancer (CaP) 5 years ago, over a dozen linkage studies have appeared. Most attention has been directed to chromosome 1, where two separate regions have been identified as harboring a prostate cancer susceptibility locus: HPC1 in the 1q24-25 interval and PCaP in the 1q42.2-43 interval. Linkage analysis of chromosome 16 has also provided evidence of harboring two loci predisposing to CaP.

METHODS

We report on a replication linkage study of chromosomes 1 and 16 in 45 new and 4 expanded multiplex CaP families. Multipoint Z-scores were obtained for 30 highly polymorphic short-sequence tandem repeat markers spanning chromosome 1, and 22 markers spanning chromosome 16.

RESULTS

The replication sample gave no evidence for a CaP susceptibility locus in the 1q24-25 interval and equivocal evidence for such a locus at 1q42.2-43. With respect to chromosome 16, positive Z-scores were obtained over a contiguous interval covering the entire p arm and the proximal half of the q arm.

CONCLUSIONS

The linkage analysis of our replication sample does not support the existence of HPC1, and the evidence for the existence of PCaP remains equivocal. Evidence of a susceptibility locus on 16p remains strong, but the evidence for a susceptibility locus on 16q is weakened.

Identification and fine mapping of a region showing a high frequency of allelic imbalance on chromosome 16q23.2 that corresponds to a prostate cancer susceptibility locus

Linkage to a prostate cancer susceptibility locus was recently reported on chromosome 16q23. We now report a region exhibiting a high frequency of allelic imbalance (AI) corresponding to this locus in tumors from 51 men diagnosed with prostate cancer using the same linked markers. The highest frequency of AI was found at markers D16S3096 (45%) and D16S516 (53%) that map to chromosome 16q23.2. In addition, 19 of the 51 (37%) prostate tumors showed interstitial AI involving one or both of these markers. This result strongly suggests that a candidate prostate cancer tumor suppressor gene maps between markers D16S3096 and D16S516. We estimate that the distance between these markers is approximately 118 kb using a Stanford radiation hybrid panel. We observed a positive association with family history (P = 0.048) when comparing those men showing interstitial AI at markers D16S3096 and/or D16S516 with those without any imbalance at these two markers. Taken together, these data suggest that we have precisely localized a region of chromosome 16q23.2 that may harbor a prostate cancer tumor suppressor gene implicated in the development of non-familial and possibly familial forms of prostate cancer.

No difference in biochemical failure rates with or without pelvic lymph node dissection during radical prostatectomy in low-risk patients

OBJECTIVES

To detect the short-term differences in biochemical relapse-free rates between patients with and without pelvic lymph node dissection (PLND). Recently, a trend has begun to omit PLND in patients undergoing radical prostatectomy considered at low risk of pelvic lymph node metastases.

METHODS

The records of 1152 consecutive radical prostatectomy cases were reviewed. A total of 575 patients with favorable tumor characteristics (prostate-specific antigen [PSA] 10 ng/mL or less, Gleason score 6 or less, and clinical Stage T1 or T2) who were not receiving adjuvant or neoadjuvant therapy were divided into two groups according to whether PLND was performed (PLND group, n = 372) or omitted (no PLND group, n = 203). Proportional hazards were used to analyze the effect of age, race, family history, stage, biopsy Gleason score, initial PSA, PLND, and pathologic findings on the likelihood of biochemical failure. Biochemical failure-free survival for each group was estimated by Kaplan-Meier analysis. The mean follow-up was 38 months (range 1 to 141).

RESULTS

The actuarial 4-year biochemical relapse-free rate for the PLND versus no PLND groups was 91% and 97%, respectively (P = 0.16). On multivariate analysis, PLND was not an independent predictor of outcome (P = 0.24).

CONCLUSIONS

The results of our study indicate that the omission of PLND in patients with favorable tumor characteristics does not adversely affect biochemical relapse rates.

Laparoscopic radical cystoprostatectomy with ileal conduit performed completely intracorporeally: the initial 2 cases

OBJECTIVES

To present the initial 2 patients who underwent laparoscopic radical cystoprostatectomy, bilateral pelvic lymphadenectomy, and ileal conduit urinary diversion, with the entire procedure performed exclusively by intracorporeal laparoscopic techniques.

METHODS

Two male patients, 78 and 70 years old, with muscle-invasive, organ-confined, transitional cell carcinoma of the urinary bladder underwent the procedure. The entire procedure, including radical cystoprostatectomy, pelvic node dissection, isolation of the ileal loop, restoration of bowel continuity with stapled side-to-side ileoileal anastomosis, retroperitoneal transfer of the left ureter to the right side, and bilateral stented ileoureteral anastomoses were all performed exclusively by intracorporeal laparoscopic techniques. Free-hand laparoscopic suturing and in situ knot-tying techniques were used exclusively.

RESULTS

The surgical time was 11.5 hours in the first patient and 10 hours in the second. The respective blood loss was 1200 mL and 1000 mL. In both patients, ambulation resumed on postoperative day 2, bowel sounds on day 3, and oral intake on day 4; the hospital stay was 6 days. Narcotic analgesia comprised 108.3 mg and 16.5 mg of morphine sulfate equivalent, respectively. Pathologic examination revealed pT4N0M0 (prostate) and pT2bN0M0 transitional cell carcinoma of the bladder with the surgical margins negative for cancer in both patients. No intraoperative or postoperative complications occurred in either patient.

CONCLUSIONS

To our knowledge, this is the initial report of laparoscopic radical cystoprostatectomy with intracorporeal ileal conduit urinary diversion. We believe that with further experience and refinement in the operative technique, laparoscopic radical cystoprostatectomy with ileal conduit urinary diversion may become an attractive treatment option for selected candidates with localized muscle-invasive bladder cancer.

Retroperitoneal laparoscopic radical nephrectomy: the Cleveland clinic experience

PURPOSE

Laparoscopic radical nephrectomy is usually performed by the transperitoneal approach. At our institution the retroperitoneoscopic approach is preferred. We confirm the technical feasibility of retroperitoneoscopic radical nephrectomy, even for large specimens, and compare its results with open surgery in a contemporary cohort.

MATERIALS AND METHODS

A total of 47 patients underwent 53 retroperitoneoscopic radical nephrectomies. Data from the most recent 34 laparoscopic cases were retrospectively compared with 34 contemporary cases treated with open radical nephrectomy.

RESULTS

For the 53 retroperitoneoscopic radical nephrectomies mean tumor size was 4.6 cm. (range 2 to 12), surgical time was 2.9 hours (range 1.2 to 4.5) and blood loss was 128 cc. Mean specimen weight was 484 gm. (range 52 to 1,328), and concomitant adrenalectomy was performed in 72% of patients. Mean analgesic requirement was 31 mg. morphine sulfate equivalent. Average hospital stay was 1.6 days, with 68% of patients discharged from the hospital within 23 hours of the procedure. Minor complications occurred in 8 patients (17%) and major complications occurred in 2 (4%) who required conversion to open surgery. Various parameters, including patient age, body mass index, American Society of Anesthesiologists status, tumor size (5 versus 6.1 cm.), specimen weight (605 versus 638 gm.) and surgical time (3.1 versus 3.1 hours), were comparable between patients undergoing laparoscopic (34) and open (34) radical nephrectomy. However, laparoscopy resulted in decreased blood loss (p <0.001), hospital stay (p <0.001), analgesic requirements (p <0.001) and convalescence (p = 0.005). Complications occurred in 13% of patients in the laparoscopic group and 24% in the open group.

CONCLUSIONS

Retroperitoneoscopy is a reliable, effective and, in our hands, the preferred technique of laparoscopic radical nephrectomy. At our institution retroperitoneoscopy has emerged as an attractive alternative to open radical nephrectomy in patients with T1-T2N0M0 renal tumors.

Defective DNA repair genes in a primary culture of human renal cell carcinoma

PURPOSE

Genomic stability is maintained by error-free DNA replication, repair, and recombination. To determine if repair genes contribute to genomic instability, we used a newly established cell line RCC-AJR (from clear-cell renal cell carcinoma) to examine hMSH2 (a mismatch-repair gene) and the gene encoding DNA beta polymerase (polbeta; a known contributor to base-excision repair).

METHODS

Coding sequences of hMSH2 and polbeta were amplified by the polymerase chain reaction (PCR) using RNA from RCC-AJR cells and matched normal kidney (NK) cells from the same patient. Nucleotide sequences of the PCR products were determined by the dideoxy-DNA method and direct sequencing. Expressions of repair genes were assayed by Western blotting. Microsatellite stability in RCC-AJR cells was assayed by alteration in (CA)n repeats.

RESULTS

In the RCC-AJR cells, we detected (a) a deletion of 1476 bp encoding 492 amino acids of hMSH2 cDNA, (b) an 87-bp deletion in the polbeta coding sequence, (c) truncated forms of hMSH2 and polbeta proteins, and (d) microsatellite instability.

CONCLUSIONS

This study provides evidence of alterations in hMSH2 and polbeta in the homogeneous cell population of an RCC-AJR tumor culture. The data indicate that repair genes may help preserve genomic stability in this cell line. We believe that this new primary RCC-AJR cell line will prove a useful model for investigating the cascade of genetic events in renal cells that leads to renal carcinogenesis.

Extent of extracapsular extension in localized prostate cancer

OBJECTIVES

To measure the radial extent of extracapsular penetration by tumor cells, thereby providing estimates of the margins needed around target volumes. New radiotherapeutic techniques, like brachytherapy and conformal radiotherapy, irradiate small volumes and reduce the dose to periprostatic tissues. Even in the early stages of localized prostate cancer, extracapsular extension (ECE) is commonly seen.

METHODS

Two hundred sixty-five consecutive radical prostatectomy specimens were analyzed for the presence of ECE. ECE was found in 92 of all cases (35%); measurements were performed in 79 of the 92 cases. A total of 98 ECE sites were evaluated in the 79 cases. The distance of tumor outside the capsule was measured in millimeters. Extension less than 0.1 mm was considered as "focal".

RESULTS

The site of ECE was posterolateral in 53% of cases, lateral in 24%, posterior in 13%, and at the base in 10%. The median amount of ECE at all sites was 1. 1 mm (mean 1.7). However, the range was wide; the minimum measurable extent was 0.1 mm and the maximum 10.0 mm. The extent was within 3.8 mm for 90% of all cases. By stratifying cases with favorable and unfavorable tumors, the 90th percentiles of ECE were as follows: 3.3 mm for favorable tumors (clinical Stage T1-2, initial prostate-specific antigen 10 ng/mL or less, and biopsy Gleason score 6 or less) and 3.9 mm for unfavorable tumors (clinical Stage T3, initial prostate-specific antigen greater than 10 ng/mL, or biopsy Gleason score 7 or greater).

CONCLUSIONS

Most of the ECE was at posterolateral sites. The extent of disease outside the prostate was within 4 mm in 90% of cases. Since ECE was observed in 30% to 60% of all patients with clinical Stage T1-2 prostate cancer, only 3% to 7% of all such cases would have disease extent exceeding 4 mm. The present study provides useful estimates of the amount of ECE. These estimates could be potentially used in planning the target volumes for treatment of prostate cancer with either conformal radiotherapy or brachytherapy.

Higher than standard radiation doses (> or =72 Gy) with or without androgen deprivation in the treatment of localized prostate cancer

PURPOSE

To study the effect on biochemical relapse-free survival (bRFS) and clinical disease-free survival of radiation doses delivered to the prostate and periprostatic tissues for localized prostate cancer.

METHODS AND MATERIALS

A total of 1041 consecutive localized prostate cancer cases treated with external beam radiotherapy (RT) at our institution between 7/86 and 2/99 were reviewed. All cases had available pretreatment parameters including pretreatment prostate-specific antigen (iPSA), biopsy Gleason score (bGS), and clinical T stage. The median age was 69 years. Twenty-three percent of cases (n = 238) were African-American. The distribution by clinical T stage was as follows: T1 in 365 cases (35%), T2 in 562 cases (54%), and T3 in 114 cases (11%). The median iPSA level was 10.1 ng/ml (range: 0.4-692.9). The distribution by biopsy Gleason score (bGS) was as follows: < or =6 in 580 cases (56%) and > or =7 in 461 cases (44%). Androgen deprivation (AD) in the adjuvant or neoadjuvant setting was given in 303 cases (29%). The mean RT dose was 71.9 Gy (range: 57.6-78.0 Gy). The median RT dose was 70.2 Gy, with 458 cases (44%) receiving at least 72.0 Gy. The average dose in patients receiving <72 Gy was 68.3 Gy (median 68.4) versus 76.5 Gy (median 78.0) for patients receiving > or =72 Gy. The mean follow-up was 38 months (median 33 months). The number of follow-up prostate-specific antigen (PSA) levels available was 5998.

RESULTS

The 5- and 8-year bRFS rates were 61% (95% CI 55-65%) and 58% (95% CI 51-65%), respectively. The 5-year bRFS rates for patients receiving radiation doses > or =72 Gy versus <72 Gy were 87% (95% CI 82-92%) and 55% (95% CI 49-60%), respectively. The 8-year bRFS rates for patients receiving radiation doses > or =72 Gy versus <72 Gy were 87% (95% CI 82-92%) and 51% (95% CI 44-58%), respectively (p < 0.001). A multivariate analysis of factors affecting bRFS was performed using the following parameters: age (continuous variable), race, T-stage (T1-T2 vs. T3), iPSA (continuous variable), bGS (< or =6 vs. > or =7), use of AD (yes vs. no), radiation technique (conformal versus standard), and radiation dose (continuous variable). T-stage (p < 0.001), iPSA (p < 0.001), bGS (p < 0.001), and RT dose (p < 0.001) were independent predictors of outcome. Age (p = 0.74), race (p = 0.96), radiation technique (p = 0.15), and use of AD (p = 0.31) were not. We observed 11% clinical failures (local, distant, or both) at 5 years and 15% at 8 years for the entire cohort. There was a statistically significant improvement with higher radiation doses (p = 0.032). The 5-year clinical relapse rates for patients receiving > or =72 Gy versus <72 Gy were 5% and 12%, respectively. The 8-year clinical relapse rates for patients receiving radiation doses > or =72 Gy versus <72 Gy were 5% and 17%, respectively (p = 0.026).

CONCLUSION

Patients receiving radiation doses exceeding 72 Gy had significantly better bRFS and clinical disease-free survival rates. Although results need to be confirmed with longer follow-up, these preliminary results are extremely encouraging. If these results are confirmed by other institutions and by longer follow-up, RT doses exceeding 72 Gy should be considered as standard of care.

Role of Viagra after radical prostatectomy

OBJECTIVES

To determine whether the response to sildenafil citrate (Viagra) in patients with erectile dysfunction after radical prostatectomy was influenced by the presence or absence of neurovascular bundles, the interval from surgery to the initiation of drug therapy, and the dose of the drug.

METHODS

Baseline and follow-up data from 91 patients presenting with erectile dysfunction after radical prostatectomy were obtained. The patients were stratified according to the type of nerve-sparing (NS) procedure: bilateral NS, unilateral NS, and non-NS. They were interviewed using the Cleveland Clinic Post Prostatectomy (CCPP) questionnaire and the International Index of Erectile Function (IIEF) questionnaire.

RESULTS

The presence or absence of the neurovascular bundles influenced the ability to achieve vaginal intercourse. In the patients who had undergone bilateral NS, 71.7% (38 of 53) responded; in those with unilateral NS, 50% (6 of 12) responded; and in those with non-NS, 15.4% (4 of 26) responded. The IIEF questionnaire confirmed the quality of the positive responses, with significant improvements in response to question 3 (frequency of penetration), question 4 (frequency of maintenance of erection), and question 7 (satisfaction with intercourse). The magnitude of improvement in responses was higher in the bilateral NS group than in the unilateral NS and non-NS groups (P <0.05). When the data of the 48 positive responders were analyzed, no difference in the response rate was found when the interval from surgery to drug therapy was stratified by the following three intervals: 0 to 6 months (44%), 6 to 12 months (55%), and greater than 12 months (53%). Of the positive responders, 14 (29.1%) required the 50-mg dose, and 34 (70.9%) required the 100-mg dose. The most common side effects were transient headaches (28.6%), flushing (21.9%), dizziness (8.8%), dyspepsia (6.5%), and nasal congestion (5.4%), with an increase in the incidence of headaches seen at the higher dose (P = 0.04).

CONCLUSIONS

Successful treatment of erectile dysfunction with sildenafil citrate after radical prostatectomy depends on the presence of the neurovascular bundles. Our data suggest that the response to sildenafil is not related to the interval between the surgery and initiation of drug therapy but is related to the dose.

Initial release of the lateral pelvic fascia

Initial incision of the lateral pelvic fascia before division of the dorsal vein complex allows posterior displacement of the neurovascular bundles and development of the proper prostatorectal plane. This technique may decrease positive surgical margins while preserving the neurovascular bundles. This technique also completely preserves the posterior attachments to the urethra, allowing preservation of maximal urethral length.