Proton beam therapy and localised prostate cancer: current status and controversies.

Proton therapy is a promising, but costly, treatment for prostate cancer. Theoretical physical advantages exist; yet to date, it has been shown only to be comparably safe and effective when compared with the alternatives and not necessarily superior. If clinically meaningful benefits do exist for patients, more rigorous study will be needed to detect them and society will require this to justify the investment of time and money. New technical advances in proton beam delivery coupled with shortened overall treatment times and declining device costs have the potential to make this a more cost-effective therapy in the years ahead.

Proton therapy of prostate cancer by anterior-oblique beams: implications of setup and anatomy variations.

Proton therapy of prostate by anterior beams could offer an attractive option for treating patients with hip prosthesis and limiting the high-dose exposure to the rectum. We investigated the impact of setup and anatomy variations on the anterior-oblique (AO) proton plan dose, and strategies to manage these effects via range verification and adaptive delivery. Ten patients treated by bilateral (BL) passive-scattering proton therapy (79.2 Gy in 44 fractions) who underwent weekly verification CT scans were selected. Plans with AO beams were additionally created. To isolate the effect of daily variations, initial AO plans did not include range uncertainty margins. The use of fixed planning margins and adaptive range adjustments to manage these effects was investigated. For each case, the planned dose was recalculated on weekly CTs, and accumulated on the simulation CT using deformable registration to approximate the delivered dose. Planned and accumulated doses were compared for each scenario to quantify dose deviations induced by variations. The possibility of estimating the necessary range adjustments before each treatment was explored by simulating the procedure of a diode-based in vivo range verification technique, which would potentially be used clinically. The average planned rectum, penile bulb and femoral heads mean doses were smaller for initial AO compared to BL plans (by 8.3, 16.1 and 25.9 Gy, respectively). After considering interfractional variations in AO plans, the target coverage was substantially reduced. The maximum reduction of V 79.2/D 95/D mean/EUD for AO (without distal margins) (25.3%/10.7/1.6/4.9 Gy, respectively) was considerably larger than BL plans. The loss of coverage was mainly related to changes in water equivalent path length of the prostate after fiducial-based setup, caused by discrepancies in patient anterior surface and bony-anatomy alignment. Target coverage was recovered partially when using fixed planning margins, and fully when applying adaptive range adjustments. The accumulated organs-at-risk dose for AO beams after range adjustment demonstrated full sparing of femoral heads and superior sparing of penile bulb and rectum compared to the conventional BL cases. Our study indicates that using AO beams makes prostate treatment more susceptible to target underdose induced by interfractional variations. Adaptive range verification/adjustment may facilitate the use of anterior beam approaches, and ensure adequate target coverage in every fraction of the treatment.

Quantitative studies on the transplantability of murine and human tumors into the brain and subcutaneous tissues of NCr/Sed nude mice.

The transplantability of experimental tumors into the brain (i.c.) and s.c. tissues of C3Hf/Sed and athymic NCr/Sed nude mice was examined using quantitative cell transplantation assays. Studies using the immune-competent C3H animals showed that brain is a more favorable site for the transplantation of syngeneic tumor than s.c. tissue and that this is true for nonimmunogenic as well as immunogenic tumors. The capacity of the brain to act as an immunological sanctuary can be overwhelmed by a strong, systemic, secondary immune response such as that evoked by the methylcholanthrene-induced sarcoma FSal. In studies performed using NCr/Sed nude mice, the allogeneic tumor MCaIV was found not to be demonstrably immunogenic. The cell dose required to transplant the tumor into 50% of recipients (TD50) could neither be increased by immunization procedures nor decreased by six Gy whole-body irradiation (WBI) prior to transplantation. Delayed-type hypersensitivity to this tumor was not expressed by nude mice after rechallenge with tumor antigen. The TD50 was again lower for i.c. than s.c. transplantation and the ratio s.c./i.c. was comparable to that found in syngeneic C3Hf/Sed hosts. Three human tumors have been similarly tested. They were: FaDu, a pharyngeal squamous carcinoma; HFSal, a fibrosarcoma; and U87, a malignant glioma. s.c. TD50 values were in all cases significantly higher than those obtained i.c. The ratios TD50 s.c./i.c. ranged from 6.4 to greater than 50 in five studies, substantially higher than those found for transplantation of murine tumors into either the syngeneic or the allogeneic recipients. Six Gy WBI reduced the s.c. TD50 for these tumors, but in each case the value remained significantly higher than that obtained i.c. 19.4 Gy WBI given in 10 equal fractions and followed by i.v. bone marrow rescue reduced further the s.c. TD50 for FaDu. NCr/Sed nude mice demonstrated cross-reacting delayed-type hypersensitivity against FaDu and HFSal. A small proportion of FaDu tumors (less than 2%) displayed a spontaneous halt in growth or even regression. When the host cell infiltrate of these tumors was analyzed, an increase was seen in the proportion of Thy 1.2 and asialo-GM1-positive cells as compared with progressively growing tumors. These data strongly suggest that a residual low level of immune reactivity exists in nude mice against xenotransplanted human tumors. This resistance to s.c. transplantation may be diminished by WBI and is less for intracerebral implantation.

Bladder preservation by combined modality therapy for invasive bladder cancer.

PURPOSE: To update the efficacy of a selective multimodality bladder-preserving approach by transurethral resection (TURBT), systemic chemotherapy, and radiation therapy. PATIENTS AND METHODS: From 1986 through 1993, 106 patients with muscle-invading clinical stage T2 to T4a,Nx,M0 bladder cancer were treated with induction by maximal TURBT and two cycles of chemotherapy (methotrexate, cisplatin, vinblastine [MCV]) followed by 39.6-Gy pelvic irradiation with concomitant cisplatin. Patients with a negative postinduction therapy tumor site biopsy and cytology (a T0 response, 70 patients) plus those with less than a T0 response but medically unfit for cystectomy (six patients), received consolidative chemoradiation to a total of 64.8 Gy. Surgical candidates with less than a T0 response (13 patients) and patients who could not tolerate the chemoradiation (six patients) went to immediate cystectomy. The median follow-up duration is 4.4 years. RESULTS: The 5-year actuarial overall survival and disease-specific survival rates of all patients are 52% and 60%, respectively. For clinical stage T2 patients, the actuarial overall survival rate is 63%, and for T3-4, 45%. Thirty-six patients (34%) underwent cystectomy, all with evidence of tumor activity, including 17 with an invasive recurrence. The 5-year overall survival rate with an intact functioning bladder is 43%. Among 76 patients who completed bladder-preserving therapy, the 5-year rate of freedom from an invasive bladder relapse is 79%. No patient required cystectomy for treatment-related bladder morbidity. CONCLUSION: Combined modality therapy with TURBT, chemotherapy, radiation, and selection for organ-conservation by response has a 52% overall survival rate. This result is similar to cystectomy-based studies for patients of similar age and clinical stages. The majority of the long-term survivors retain fully functional bladders.

Radiation therapy or prostatectomy: an old conflict revisited in the PSA era. A radiation oncologist's viewpoint.

A close examination of the outcomes for the radical treatment of prostate cancer in the prostate-specific antigen (PSA) era shows no clear advantage to radical prostatectomy over external-beam radiation. Both modalities are highly effective against small impalpable tumors of low Gleason grade and with PSA values less than 10 ng/mL. Both modalities struggle against all other stages of prostate cancer. Radiation and surgery are currently in states of rapid evolution, and the results emerging become quickly outdated. It is hoped that the newer, more aggressive approaches will help a significant number of patients, perhaps the majority, not currently being cured by radical therapy.

The life shortening effects of treatment with doxorubicin and/or local irradiation on a cohort of young C3Hf/Sed mice.

The long-term consequences of treating a cohort of C3Hf/Sed mice in early life with either local-field single dose radiation, systemic doxorubicin, or both, are reported in this study. Significant life shortening was observed in all treatment groups. Median survival times (days) from time of treatment were: control, 690; 35 Gy, 560; 70 Gy, 460; 5 mg/kg doxorubicin, 580; 10 mg/kg doxorubicin, 350; 35 Gy + 5 mg/kg doxorubicin, 510; 70 Gy + 10 mg/kg doxorubicin, 310. Mice receiving hind limb irradiation died principally from induced sarcomas in a dose dependent fashion (80% after 70 Gy and 55% after 35 Gy). Those treated with doxorubicin alone showed an increase in the actuarial incidence of spontaneous malignancies but died mainly from non-malignant causes. Histological examination did not reveal any characteristic cardiac, renal or pulmonary lesions. Doxorubicin did not increase the rate of development of radiation induced sarcomas in mice treated with combined modality.

Conservative surgery, patient selection, and chemoradiation as organ-preserving treatment for muscle-invading bladder cancer.

Multimodality organ-sparing treatment has, during the last decade, become the standard of care for many common malignancies. In appropriately selected patients with muscle-invading bladder cancer, bladder-preserving treatment combining surgical transurethral resection (TUR) with chemoradiation therapy offers a chance for long-term cure and survival equal to cystectomy, while also affording a 60% to 70% chance of maintaining a normally functioning bladder. Selection criteria helpful in determining appropriate patients for bladder preservation include such variables as small tumor size, that a visibly complete TUR is possible, the absence of hydronephrosis and that a complete response (CR) to induction chemoradiotherapy was achieved. Selecting patients based on response to induction therapy allows for prompt cystectomy if residual disease is found or for prompt consolidation chemoradiotherapy if a CR with induction therapy is achieved. Bladder-preserving treatment usually results in a normally functioning bladder without incontinence or hematuria for stage T2 and T3a patients. Stage T3b-T4 patients are locally controlled less frequently using these techniques. However, no data exist to suggest that patients with more advanced disease are in any way disadvantaged by preoperative chemoradiotherapy as an attempt at bladder conservation. Patients require close urological surveillance as do any patients with superficial bladder cancer who are being treated conservatively. As studies addressing the possibility of organ preservation continue to show positive results, more patients will become informed about and will be offered selective bladder-sparing approaches as one-treatment option.

The combination of cis-platin based chemotherapy and radiation in the treatment of muscle-invading transitional cell cancer of the bladder.

Radical cystectomy is the standard of care for patients with muscle-invading transitional cell carcinoma of the bladder. More limited surgery is only useful in highly selected patients and radiation therapy alone gives overall local-control rates under 40%. Phase II studies have shown that when radiation and trans-urethral surgery are combined with cis-platin based chemotherapy local-control rates increase such that the majority of patients preserve a tumor-free functional bladder. Up to 85% of patients selected for bladder sparing therapy on the basis of their initial response to chemo-radiation may keep their bladders. This figure could increase further when other powerful prognostic factors such as the presence of hydronephrosis, the presence of carcinoma in situ, and DNA ploidy are also taken into account in initial patient selection. The activity of cisplatin combinations in metastatic disease is not in doubt with up to 50% response rates generally reported. The hope that this will translate into the eradication of micrometastatic disease (known to be present in up to 40% of patients at diagnosis) has yet to be borne out. Those randomized trials so far reported have not shown any survival advantage when combined-modality therapy is compared to radiation alone. The addition of combination chemotherapy to radiation does not increase bladder morbidity but carries a considerable systemic penalty. Thus, despite promising Phase II studies, until local control and survival benefit is proven in a randomized trial it should continue to be regarded as experimental.

The long-term effect on PSA values of incidental prostatic irradiation in patients with pelvic malignancies other than prostate cancer.

PURPOSE: To determine the effect of external beam radiation therapy on serum prostate-specific antigen (PSA) production by the benign prostate. METHODS AND MATERIALS: We studied a cohort of 24 men receiving treatment for cancer of the bladder or rectum. The radiation fields in all cases encompassed the prostate gland, and none of the patients were known to have prostate cancer. All patients had 2 or more PSA estimations obtained in the years following their radiation treatment. A second group of 46 patients who had undergone radical external beam radiation therapy for prostate cancer and who were clinically disease free 8-22 years later were also observed, with a median of 5.8 years of PSA observations. RESULTS: Only 3 of the 24 patients in the first group showed a significant rise of > 0.2 ng/ml in their serum PSA levels, with a median of 3.3 years follow-up from the first PSA test. Seven of 24 showed progressive declines, and 14 of 24 showed steady levels. The median PSA for this group was < or = 0.5 ng/ml. Only 6 of the 46 in the second group showed a PSA rise of > 0.2 ng/ml. Thirty-four had stable values, and 6 had further declines. Again, the median PSA for the entire group was < or = 0.5 ng/ml. CONCLUSION: Recovery of prostatic secretory function is an uncommon event after external beam radiation. The concern that this might significantly confound new definitions of biochemical failure after radical radiation for prostate cancer that are based on progressively rising PSA values thus appears to be unfounded.

The treatment of prostate cancer by conventional radiation therapy: an analysis of long-term outcome.

PURPOSE: To assess the long-term outcome of conventional external beam radiation therapy in the management of clinically confined prostate cancer and to examine the proposition that radiation accelerates tumor growth in those who fail treatment. METHODS AND MATERIALS: One thousand and forty-four men with T1-4NxM0 prostate cancer treated by conventional external beam radiation therapy at the Massachusetts General Hospital between 1977 and 1991 were analyzed. Median follow-up was 49 months. Failure was defined as: two sequential rises in serum prostate specific antigen (PSA) level; or a PSA > 1 ng/ml 2 or more years after radiation; or any clinical failure. Kaplan-Meir actuarial analyses were used to assess outcome. RESULTS: At 10 years only 40% of the T1-2 group remained disease free. When subdivided by grade, the well-differentiated tumors (Gleason 1-2) exhibited a 53% actuarial 10-year disease-free survival, moderately differentiated (Gleason 3) 42%, and poorly differentiated (Gleason 4-5) 20%. The corresponding values for the T3-4 men were 33% for Gleason 1-2, 20% for Gleason 3, and 10% for Gleason 4-5. Overall the value for T3-4 tumors was 18% at 10 years. On relapse the median PSA doubling times for the T1-2 patients were predicted by histology: 18.8 months for Gleason 1-2 patients; 11.1 months for Gleason 3; and 9.6 months for Gleason 5. Significant differences were found between the Gleason 3 and the Gleason 4-5 groups (p = 0.04) and the Gleason 1-2 and the Gleason 4-5 groups (p = 0.03). A wide range of doubling times was seen within each grade group. When compared with recently reported data on selected T1-2 patients who were managed by expectant observation there was no advantage over the first decade (and certainly no disadvantage) in terms of metastasis-free survival or disease-specific survival for the irradiated Gleason 1-3 patients. However, a gain was seen for those with Gleason 4-5 tumors. CONCLUSION: Less than half of the T1-2NxM0 and less than one-fifth of the T3-4NxM0 patients receiving conventional radiation therapy were biochemically disease free at 10 years. The PSA doubling times on relapse show a wide variation. Grade was important in determining the rate of relapse suggesting that radiation does not induce a homogeneous acceleration of prostate tumors. A metastasis-free and disease-specific survival advantage was found for the poorly differentiated tumors when compared with similar patients reported in the literature who were managed initially by observation.

Androgen deprivation and radiation therapy: sequencing studies using the Shionogi in vivo tumor system.

PURPOSE: To test the relative effect of neoadjuvant and adjuvant androgen deprivation on the radiation response of an androgen dependent tumor. METHODS AND MATERIALS: The transplantable, androgen dependent, Shionogi adenocarcinoma was grown as allografts in the hind limbs of NCr/Sed (nu/nu) athymic nude mice. Bilateral orchiectomy was the chosen form of androgen deprivation. Groups of tumors were irradiated to graded tumor doses and then studied for durable tumor control. The radiation response was expressed as the radiation dose required to control 50% of the tumors (TCD50). The sequence of radiation and orchiectomy was studied. RESULTS: When radiation was combined with orchiectomy the Shionogi tumor was significantly more likely to be controlled than when radiation was used alone. Orchiectomy 12 days prior to radiation (neoadjuvant therapy) produced a significantly greater decline in the TCD50 than when orchiectomy was used 1 day or 12 days after radiation (adjuvant therapy). If, before radiation, tumors were allowed to regrow after orchiectomy to their original size in an androgen independent fashion then the advantage was largely lost. Those tumors responding well to neoadjuvant orchiectomy (>50% volume decrease) were significantly more likely to be eradicated by radiation than those with a lesser response. CONCLUSION: When using combinations of androgen deprivation and radiation in the treatment of the Shionogi tumor, sequence and timing of the therapies are crucial to maximize the effect.

Invasive bladder cancer: treatment strategies using transurethral surgery, chemotherapy and radiation therapy with selection for bladder conservation.

PURPOSE: Combined modality therapy has become the standard oncologic approach to achieve organ preservation in many malignancies. METHODS AND MATERIALS: Although radical cystectomy has been considered as standard treatment for invasive bladder carcinoma in the United States, good results have been recently reported from several centers using multimodality treatment, particularly in patients with clinical T2 and T3a disease who do not have a ureter obstructed by tumor. RESULTS: The components of the combined treatment are usually transurethral resection of the bladder tumor (TURBT) followed by concurrent chemotherapy and radiation therapy. Following an induction course of therapy a histologic response is evaluated by cystoscopy and rebiopsy. Clinical "complete responders" (tumor site rebiopsy negative and urine cytology with no tumor cells present) continue with a consolidation course of concurrent chemotherapy and radiation. Those patients not achieving a clinical complete response are recommended to have an immediate cystectomy. Individually the local monotherapies of radiation, TURBT, or multidrug chemotherapy each achieve a local control rate of the primary tumor of from 20 to 40%. When these are combined, clinical complete response rates of from 65 to 80% can be achieved. Seventy-five to 85% of the clinical complete responders will remain with bladders free of recurrence of an invasive tumor. CONCLUSIONS: Bladder conservation trials using combined modality treatment approaches with selection for organ conservation by response of the tumor to initial treatment report overall 5-year survival rates of approximately 50%, and a 40-45% 5-year survival rate with the bladder intact. These modern multimodality bladder conservation approaches offer survival rates similar to radical cystectomy for patients of similar clinical stage and age. Bladder-conserving therapy should be offered to patients with invasive bladder carcinoma as a realistic alternative to radical cystectomy by experienced multimodality teams of urologic oncologists.

The response of two human tumor xenografts to fractionated irradiation. The derivation of alpha/beta ratios from growth delay, tumor control, and in vitro cell survival assays.

A series of growth delay experiments was performed to derive alpha/beta ratios for two human neoplasms growing as xenografts in the hind limbs of NCr/Sed nude mice. The tumors were irradiated at 6 mm mean diameter under clamp-hypoxic conditions in one, two, four, or eight fractions, 2 fractions per day with a minimum intertreatment interval of 4 hr and a maximum overall treatment time of 3 days. The alpha/beta ratios derived for the high grade glioma U87 and the pharyngeal squamous carcinoma FaDu were 38 and 20 Gy, respectively. Comparably high values were derived from the same two tumors in a reanalysis of fractionated TCD50 data. The alpha/beta ratios were similarly high whether the TCD50 data were analyzed using the Full Effect plot or the Direct Method. For comparison, cell survival assays were performed on U87 and FaDu irradiated in vitro under plateau-phase, aerobic conditions. The alpha/beta ratios obtained were 9.2 and 15.0 Gy, respectively. Such high alpha/beta values suggest a therapeutic gain could result from the use of small doses per fraction.

Adjuvant and salvage irradiation following radical prostatectomy for prostate cancer.

PURPOSE: We performed a retrospective analysis to assess the durability of benefit derived from irradiation after prostatectomy for pT3N0 disease, and the possibility of cure. METHODS AND MATERIALS: We studied 88 patients who were irradiated after prostatectomy and had available prostate specific antigen (PSA) data, no known nodal or metastatic disease, no hormonal treatment, and follow-up of at least 12 months from surgery. Forty patients received adjuvant therapy for a high risk of local failure with undetectable PSA. Forty-eight patients received salvage therapy for elevated PSA levels. Mean follow up was 44 months from date of surgery and 31 months from irradiation. Biochemical failure was strictly defined as a confirmed rise in PSA of >10%, or as the ability to detect a previously undetectable PSA value. RESULTS: After salvage irradiation, 69% of patients attained an undetectable PSA. Eighty-eight percent of adjuvant patients were biochemically and clinically free of disease (bNED) at 3 years from prostatectomy. Sixty-eight percent of those receiving salvage irradiation were bNED 3 years after surgery. On univariate analysis, treatment group (adjuvant or salvage), pre-operative PSA, and the status of seminal vesicles were significant prognostic factors. The extent of PSA elevation in the salvage group was also significant. We did not demonstrate a significant difference between those salvage patients referred for persistently elevated PSA as compared to those with a late rise in PSA. On multivariate analysis, the only significant predictor of outcome was treatment group, with adjuvant irradiation having better outcome than salvage. CONCLUSION: More than two-thirds of this group of patients remain biochemically disease free at 3 years following irradiation, attesting to a number of potential cures. For patients with stage pT3N0 prostate cancer following radical prostatectomy, our data support the use of either routine postoperative adjuvant irradiation or close PSA follow-up with early salvage treatment.

Acute and late toxicity of patients with inflammatory bowel disease undergoing irradiation for abdominal and pelvic neoplasms.

PURPOSE: Little data exists in the medical literature describing the response of patients with inflammatory bowel disease (IBD) to abdominal and pelvic irradiation. To clarify the use of this modality in this setting, this study assesses the short- and long-term tolerance of 28 patients with IBD to abdominal and pelvic irradiation. METHODS AND MATERIALS: From 1970 to 1999, 28 patients with IBD (10 patients-Crohn's disease, 18 patients-ulcerative colitis) were identified and underwent external beam abdominal or pelvic irradiation. Mean follow-up time after radiation therapy was 32 months. Patients were treated either by specialized techniques (16 patients) to minimize small and large bowel irradiation or by more conventional approaches (12 patients). Acute and late toxicity was scored. RESULTS: The overall incidence of severe toxicity was 46% (13/28 patients). Six of 28 patients (21%) experienced severe acute toxicity necessitating cessation of radiation therapy. Late toxicity requiring hospitalization or surgical intervention was observed in 8 of 28 patients (29%). One patient experienced both an acute as well as late toxicity. For patients undergoing radiation therapy by conventional approaches, the 5-year actuarial rate of late toxicity was 73%. This figure was 23% for patients treated by specialized techniques (p = 0.02). CONCLUSIONS: Because of the potentially severe toxicity experienced by patients with IBD undergoing abdominal and pelvic irradiation, judicious use of this modality must be employed. Definition of IBD location and activity as well as careful attention to irradiation technique may allow treatment of these patients with acceptable rates of morbidity.

Flow cytometric analysis of DNA ploidy, percent S-phase fraction, and total proliferative fraction as prognostic indicators of local control and survival following radiation therapy for prostate carcinoma.

PURPOSE: Treatment recommendations for localized prostate cancer may be improved by the identification of tumor factors prognostic for local control and survival. In this retrospective study, flow cytometric deoxyribonucleic acid (DNA) ploidy analysis and cell cycle analysis were performed on paraffin-embedded biopsy material to determine if additional prognostic factors could be identified in patients treated with radiation therapy. METHODS AND MATERIALS: Seventy patients with T1-4NxM0 tumors were identified in whom the primary treatment had been radical radiation therapy with no prior or concurrent endocrine therapy and in whom sufficient prostatic tissue was available for flow cytometric analysis. There were 40 diploid, 26 aneuploid, and 4 multiploid cases. Aneuploid and multiploid cases were combined for analysis. Cell cycle data were obtained on all diploid and 10 aneuploid cases. RESULTS: The histologic differentiation of the tumor (well or moderate vs. poor) was an independent predictor of overall survival and disease-free survival (p = 0.05 and 0.01, respectively). Local control was worse in the poorly differentiated patients, although this was not statistically significant in a multivariate analysis (p = 0.08). Neither T-stage, deoxyribonucleic acid ploidy (diploid vs. nondiploid), percent S-phase fraction, nor total proliferative fraction (S-phase fraction + G2M) significantly predicted for any of these endpoints. Within the diploid and well or moderately differentiated subgroup (n = 25), S-phase (< 4.2 vs. > or = 4.2) was a significant predictor of local control (100% vs. 51%, p = 0.03). A comparable distinction could be made using total proliferative fraction (< 10% vs. > or = 10%) with local control rates of 100% vs. 56% (p = 0.05). Among the poorly differentiated tumors, no similarly favorable subgroup was identified. CONCLUSIONS: This retrospective and multivariate analysis identifies both histology and percent S-phase or total proliferative fraction as predictors of local control following irradiation, and confirms that histology, but not DNA ploidy, is significant for overall survival. If these previously unreported findings are confirmed by prospective studies, S-phase should be added to histology as a parameter in the evaluation of clinical trials.

Advanced prostate cancer: the results of a randomized comparative trial of high dose irradiation boosting with conformal protons compared with conventional dose irradiation using photons alone.

PURPOSE: Following a thorough Phase I/II study, we evaluated by a Phase III trial high versus conventional dose external beam irradiation as mono-therapy for patients with Stage T3-T4 prostate cancer. Patient outcome following standard dose radiotherapy or following a 12.5% increase in total dose to 75.6 Cobalt Gray Equivalent (CGE) using a conformal perineal proton boost was compared for local tumor control, disease-free survival, and overall survival. METHODS AND MATERIALS: Stage T3-T4, Nx, N0-2, M0 patients received 50.4 Gy by four-field photons and were randomized to receive either an additional 25.2 CGE by conformal protons (arm 1--the high dose arm, 103 patients, total dose 75.6 CGE) or an additional 16.8 Gy by photons (arm 2--the conventional dose arm, 99 patients, total dose 67.2 Gy). Actuarial overall survival (OS), disease-specific survival (DSS), total recurrence-free survival (TRFS), (clinically free, prostate specific antigen (PSA) less than 4ng/ml and a negative prostate rebiopsy, done in 38 patients without evidence of disease) and local control (digital rectal exam and rebiopsy negative) were evaluated. RESULTS: The protocol completion rate was 90% for arm 1 and 97% for arm 2. With a median follow-up of 61 months (range 3 to 139 months) 135 patients are alive and 67 have died, 20 from causes other than prostate cancer. We found no significant differences in OS, DSS, TRFS or local control between the two arms. Among those completing randomized treatment (93 in arm 1 and 96 in arm 2), the local control at 5 and 8 years for arm 1 is 92% and 77%, respectively and is 80% and 60%, respectively for arm 2 (p = .089) and there are no significant differences in OS, DSS, and TRFS. The local control for the 57 patients with poorly differentiated (Gleason 4 or 5 of 5) tumors at 5 and 8 years for arm 1 is 94% and 84% and is 64% and 19% on arm 2 (p = 0.0014). In patients whose digital rectal exam had normalized following treatment and underwent prostate rebiopsy there was a lower positive rebiopsy rate for arm 1 versus arm 2 patients (28 vs. 45%) and also for those with well and moderately differentiated tumors versus poorly differentiated tumors (32 and 50%). These differences were not statistically significant. Grade 1 and 2 rectal bleeding is higher (32 vs. 12%, p = 0.002) as may be urethral stricture (19 vs. 8%, p = 0.07) in the arm 1 versus arm 2. CONCLUSIONS: An increase in prostate tumor dose by external beam of 12.5% to 75.6 CGE by a conformal proton boost compared to a conventional dose of 67.2 Gy by a photon boost significantly improved local control only in patients with poorly differentiated tumors. It has increased late radiation sequelae, and as yet, has not increased overall survival, disease-specific survival, or total recurrence-free survival in any subgroup. These results have led us to test by a subsequent Phase III trial the potential beneficial effect on local control and disease-specific survival of a 12.5% increase in total dose relative to conventional dose in patients with T1, T2a, and T2b tumors.

Use of PSA nadir to predict subsequent biochemical outcome following external beam radiation therapy for T1-2 adenocarcinoma of the prostate.

PURPOSE: This study assessed the ability of nadir prostate-specific antigen (PSA) to act as an early surrogate for subsequent freedom from biochemical failure following radiation therapy for T1-2 prostatic adenocarcinoma. METHODS AND MATERIALS: A retrospective analysis was performed on the biochemical outcome of 314 consecutive men with T1-2 disease treated by conventional external beam radiation at the Massachusetts General Hospital. Minimum follow up was 2 years, and failure was defined as three successive rises in serum PSA of greater than 10%. Kaplan-Meier actuarial analysis of outcome was employed. RESULTS: The overall 5-year freedom from biochemical progression was 63%. For those who achieved a PSA nadir of < or = 0.5 ng/ml (n = 123) it was 90%, for 0.6-1.0 ng/ml (n = 103) it was 55%, and for > 1.0 ng/ml (n = 88) it was 34%. Multivariate analysis showed an undetectable PSA nadir to be independent of Gleason grade and initial PSA in predicting subsequent outcome (P < 0.05). The likelihood of achieving an undetectable PSA nadir correlated strongly with the pretreatment value: 74% if this was below 4 ng/ml; 42% for those between 4.1 and 10 ng/ml; and 32% for those above 10 ng/ml. CONCLUSION: A PSA nadir of < or = 0.5 ng/ml represents an early endpoint strongly predictive of a favorable outcome following radiation therapy which may be used for the rapid assessment of new radiation strategies.

Adjuvant irradiation after radical prostatectomy for adenocarcinoma of prostate: analysis of freedom from PSA failure.

A total of 84 consecutive men with extracapsular disease after radical prostatectomy who received postoperative irradiation and no adjuvant endocrine therapy were analyzed. Failure was defined as the development of clinical disease recurrence either locally or at a distant site, the development of detectable prostate-specific antigen (PSA) when postoperatively it had been undetectable, or any rise in PSA when postoperatively it still had been detectable. Sixteen of the 84 men had nodal disease. Overall, five-year actuarial freedom from relapse was 60 percent. For node-negative men, it was 64 percent and for node-positive men 43 percent. For the 68 men with pathologic Stage T3N0 disease, five-year freedom from relapse was 73 percent when seminal vesicles were negative and 43 percent when involved. Tumor grade also predicted the likelihood of recurrence. In a multivariate analysis the time interval from surgery to radiation and the level of postoperative PSA (detectable versus undetectable) did not influence the likelihood of relapse nor the median time to relapse. Fourteen separate patients treated with radiation alone for palpable tumor recurrence were also analyzed. Fewer than 40 percent were disease-free only two years after irradiation. We conclude that when treatment failure is defined in biochemical as well as clinical terms postoperative irradiation reduces the rate of relapse at five years relative to recently reported series in which adjuvant irradiation was not given. The additional morbidity is low. Whether or not this will translate into an overall cause-specific survival gain is currently unclear.