Local control after radiation for prostatic carcinoma: Significance and assessment

Combined external beam irradiation and external regional hyperthermia for locally advanced adenocarcinoma of the prostate

PURPOSE

To determine the safety and efficacy of combined external beam irradiation and external regional hyperthermia in the treatment of adenocarcinoma of the prostate.

METHODS AND MATERIALS

From 1987 to 1994, 30 patients received combined external beam irradiation and external regional hyperthermia for locally advanced prostate cancer. The results of the 21 patients with newly diagnosed (n = 18) or locally recurrent (n = 3) adenocarcinoma are reported herein. No patient had evidence of distant metastases. Total radiotherapy doses of 65-70 Gy to the prostate were planned using a four-field box technique. Hyperthermia treatments were delivered using an annular phased array microwave device. The treatment goal was to achieve temperatures > or = 42 degrees C in all measured points within the prostate.

RESULTS

Of the newly diagnosed patients, 16 out of 18 (89%) had T3 or T4 tumors, 11 out of 18 (61%) had Gleason scores of 7-9, and the mean pretreatment Prostate Specific Antigen (PSA) was 69 ng/ml. The median follow-up of all 21 patients was 36 months. None of the patients achieved the treatment goal of all intratumoral temperatures > or = 42 degrees C. The mean CEM 43 T90 was 2.34 min. The disease-free survival at 36 months is 25%; 12 out of 18 (67%) of the patients have relapsed. The only significant predictor of relapse was pretreatment PSA. There were no complications > Grade 3.

CONCLUSIONS

In spite of the inability to achieve high tumor temperatures, the relapse-free survival rate in this population of patients with very advanced localized prostate cancer treated with radiation therapy plus hyperthermia compares favorably with most series using radiation therapy alone. Further studies aimed at improving the ability to deliver hyperthermia to the prostate are warranted.

Radiotherapy for localized prostate carcinoma. The correlation of pretreatment prostate specific antigen and nadir prostate specific antigen with outcome as assessed by systematic biopsy and serum prostate specific antigen

BACKGROUND

The objective of this study was to correlate the failure pattern of localized prostate carcinoma after radiotherapy (RT) with pretreatment (preTx) PSA and post-RT nadir PSA, using systematic biopsies and serum PSA in the assessment of outcome.

METHODS

From January 1990 to February 1994, 207 patients treated with external beam RT were followed prospectively with systematic transrectal ultrasound-guided biopsies and measurements of serum PSA levels. Three hundred forty-three biopsies were performed, with 4-7 samples taken per session. The distribution of T classification was as follows: 19 patients had T1b, 15 had T1c, 34 had T2a, 79 had T2b/c, 53 had T3, and 7 had T4. Median follow-up was 36 months (range, 12-70 months). Failures were categorized as biochemical (chemF) (PSA > 2.0 ng/mL and > 1 ng/ mL over nadir), local (LF) (positive biopsy and PSA > 2), and distant (DF). The Cox proportional hazards model was used for multivariate analysis (MVA).

RESULTS

Overall, failures were seen in 68 of 207 patients: 20 LF, 24 DF, 7 LF + DF, and 17 chemF. In univariate analysis, failures correlated significantly with preTx PSA, post-RT nadir PSA, T classification, and Gleason's score (GS). The total failure rate was 12% for T1b, T1c, and T2a; 39% for T2b and T2c; and 60% for T3 and T4 (P < 0.0001). By evaluation with preTx PSA, at 36 months the total failure rate was 3% for preTx PSA < or = 5 ng/mL 16% for 5.1-10 ng/mL, 32% for 10.1-15 ng/mL, 42% for 15.1-20 ng/mL, 63% for 20.1-50 ng/mL, and 88% for > 50 ng/mL (P < 0.0001). By evaluation with post-RT nadir PSA, at 36 months the total failure rate was 4% for nadir PSA < or = 0.5 ng/ mL, 26% for 0.6-1 ng/mL, 33% for 1.1-2 ng/mL, and 92% for > 2 ng/mL (P < 0.0001). In MVA, nadir PSA (P < 0.0001) and T classification (P < 0.0005) were independent predictors for any failure. LF occurred in 13% of patients (27 of 207). For these 27 patients, the categorization of T classification was: T1b/T1c/T2a, 7%; T2b/T2c, 16%; and T3/T4, 15% (P = not significant). In MVA, only nadir PSA (P = 0.0004) predicted for LF. DF occurred in 15% of patients (31 of 207). In MVA, nadir PSA (P < 0.0001) and T classification (P < 0.0001) predicted for DF, with pretreatment PSA of borderline significance (P < 0.05). To assess preTx predictors of outcome, post-RT nadir PSA was removed from the model. PreTx PSA then became the dominant variable to predict any failure (P < 0.0001), LF (P = 0.05), chemF (P = 0.0001), and DF (P < 0.003), while T classification also predicted for any failure (P = 0.03), chemF (P = 0.05), and DF (P < 0.0001).

CONCLUSIONS

Systematic prostate biopsies, performed as part of the rigorous followup of prostate carcinoma after RT, define the patterns of failure and confirm the prognostic value of preTx PSA, post-RT nadir PSA, and T classification. Prior to treatment, preTx PSA is the overwhelming independent predictor of failure, but it is surpassed by post-RT nadir PSA when this is added to the model.

Routine prostate biopsies following radiotherapy for prostate cancer: results for 226 patients

OBJECTIVES

To determine the time course of histologic resolution of prostate cancer following radiotherapy (RT) and to correlate biopsy results with clinical outcome.

METHODS

Since July 1990, all patients treated with radical external beam RT for prostate cancer at the General Division of the Ottawa Regional Cancer Centre have had systematic transrectal ultrasound (TRUS) and TRUS-guided biopsies beginning 12 months after RT and then every 6 months until negative or until clinical failure. Thus, 226 patients have had 375 TRUS with four to seven specimens per examination. Stage distribution was T1b: 32, T1c: 11, T2a: 45, T2b: 82, T3: 50, and T4: 6. Median follow-up was 33 months.

RESULTS

Biopsy results were negative in 69.5% of patients by 30 months of follow-up. Thirty-two (14%) had local failure (T1b: 12.5%, T1c: 0%, T2a: 11%, T2b: 15%, T3: 18%, T4: 33%). Seven (3%) had chemical failure, and 47 (21%) had biopsy-only failure. Median follow-up for the biopsy-only failure group is only 19.5 months and mean prostate-specific antigen (PSA) is 1.0 ng/mL. Thirty-nine patients, initially with biopsy-only failure, have converted to negative biopsies at a median of 26 months. Nadir PSA for patients with local failure was 3.9 ng/mL at 14 months versus 0.7 ng/mL at 23 months for those without failure. Patients with late conversion to negative biopsy results had a later nadir PSA of 1.3 ng/mL at 27.3 months.

CONCLUSIONS

Routine prostate biopsy specimens after RT in an unselected population show tumor clearance that is in agreement with long-term clinical follow-up, although tumor may take more than 30 months to resolve. Nadir PSA can be used to predict outcome.

Proliferative cell nuclear antigen in postradiotherapy prostate biopsies

PURPOSE

To determine if staining for proliferative cell nuclear antigen (PCNA) can distinguish between biologically active and inactive "residual tumor" in postradiotherapy prostate biopsies by correlating PCNA staining with clinical outcome.

METHODS AND MATERIALS

Since July 1990 all patients treated at the General Division of the Ottawa Regional Cancer Center with radical external beam radiotherapy for prostate cancer have had systematic transrectal ultrasound and transrectal ultrasound-guided biopsies beginning 12 months postradiotherapy. One hundred sixty-two patients have had 278 transrectal ultrasounds with four to seven biopsy specimens per examination. All biopsies were stained for prostate specific antigen and prostatic acid phosphatase. Keratin 903 was used to distinguish radiation atypia in benign glands from residual cancer. PCNA staining was done on all suspicious biopsies. Stage distribution was 31 T1b, 35 T2a, 61 T2b, and 35 T3-4. Median follow-up was 32 months (range 13-74).

RESULTS

Negative biopsies have been obtained in 83% of T1b and T2a tumors and 70% of T2b and T3-4. Twenty-six tumors have recurred locally (T1b: 10%, T2a: 3%, T2b: 21%, T3-4: 26%), six with concurrent distant metastases. Of these 26 local failures, 23 had positive PCNA (mean 15.4 nuclei per 100) and three could not be determined (insufficient tissue). In 34 patients showing residual carcinoma at the first postradiotherapy biopsy, subsequent negative biopsies were obtained at a median of 25 months. Proliferative cell nuclear antigen staining could be performed in 23 of these 34 patients. Sixty-five percent (15/23) were negative on the first biopsy, indicating a nonproliferative state. In those with PCNA positive residual on initial biopsy, none retained PCNA staining on subsequent negative biopsies. One patient with an initial PCNA negative biopsy has failed locally.

CONCLUSION

Proliferative cell nuclear antigen staining is useful in postradiotherapy prostate biopsies. Negative PCNA in a positive biopsy predicts (83-97%) for eventual resolution of tumor. Positive PCNA correlates with local failure (49-79%), but when present in an early biopsy (12-18 months), may still disappear.