Description of Event or Problem · 1
THIS LITERATURE REPORT FROM A PHYSICIAN IN (B)(6) CONCERNS A (B)(6) MALE WHO DEVELOPED SECONDARY SARCOMA OF BONE 6 YEARS AFTER PERMANENT I-125 IMPLANT FOR INTERMEDIATE-RISK PROSTATE CANCER. ON AN UNREPORTED DATE THE PATIENT PRESENTED WITH A T2B NX MX GLEASON 3+4 ADENOCARCINOMA OF THE PROSTATE, SCREEN DETECTED WITH AN INITIAL PROSTATE-SPECIFIC ANTIGEN (IPSA) OF 5.7. HIS ONLY MEDICAL COMORBIDITIES WERE DIABETES, HYPERTENSION AND REFLUX. THE PATIENT OPTED FOR BRACHYTHERAPY. NEOADJUVANT ANDROGEN DEPRIVATION THERAPY WAS GIVEN TO DECREASE PROSTATE SIZE. HE REC'D A TRANSPERINEAL IODINE-125 IMPLANT IN 2006. A TOTAL OF 120 SOURCES EACH CONTAINING ABOUT 0.33 MCI OF I-125 WERE PLACED AT PRE-PLANNED COORDINATES. AT PLANNING, THE PROSTATE VOLUME WAS 43 ML, AND THE PLANNING TARGET VOLUME WAS 59 ML. THE PLANNING TARGET VOLUME WAS DEFINED AS THE PROSTATE PLUS A SUPERIOR 5 MM, LATERAL 3 TO 5 MM AND ANTERIOR 0 TO 3 MM MARGIN. THE PRESCRIPTION DOSE WAS 144 GY, WITH A D90% OF 160 GY. POST-IMPLANT, DOSIMETRY SHOWED ACCEPTABLE V100, V150 AND V200 OF 100%, 59.4% AND 21.3%, RESPECTIVELY. IN ROUTINE F/U, HIS PSA FELL TO A NADIR OF 0.06 IN (B)(6) 2012. SIX YEARS AFTER BT IMPLANTATION, HE DEVELOPED LEFT LOWER BACK, HIP AND THIGH PAIN. INVESTIGATION REVEALED A 9 X 7 X 7 CM SOFT TISSUE MASS CENTERED ON THE LEFT INFERIOR PUBIC RAMUS, CLOSELY ASSOCIATED WITH THE PROSTATE AND WITHIN THE LOW DOSE REGION OF THE BRACHYTHERAPY IMPLANT. STAGING COMPUTED TOMOGRAPHY (CT) SCAN OF THE CHEST, ABDOMEN AND PELVIS DID NOT REVEAL ANY OTHER LESIONS. CT-GUIDED CORE NEEDLE BIOPSY REVEALED A HIGH-GRADE UNDIFFERENTIATED SARCOMA OF BONE. A MULTIDISCIPLINARY DISCUSSION, A RECOMMENDATION FOR NEOADJUVANT CHEMOTHERAPY AND SURGICAL RESECTION WAS MADE. THREE CYCLES OF DOXORUBICIN 75 MG/M2 AND CISPLATIN 100 MG/M2 EVERY 21 DAYS WERE PLANNED. THE TUMOUR DECREASED (8.4 X 5.4 X 6.8 CM) ON POSTCHEMOTHERAPY MAGNETIC RESONANCE IMAGE AND SYSTEMIC IMAGING SHOWED NO EVIDENCE OF DISTANT METASTATIC DISEASE. HE UNDERWENT RESECTION OF THE LEFT ANTERIOR HEMI-PELVIS USING COMPUTER NAVIGATION TO PRESERVE THE HIP JOINT LATERALLY. PATHOLOGY REVEALED A HIGH-GRADE PLEOMORPHIC SPINDLE CELL SARCOMA WITH A FASCICULAR STORIFORM GROWTH PATTERN AND SCLEROTIC MATRIX. IT WAS UNDIFFERENTIATED WITH NO OSTEOID OR CHONDROID MATRIX IDENTIFIED. THE TUMOUR WAS 95% NECROTIC AND WHILE THE OSTEOTOMY MARGIN WAS NEGATIVE, THERE WAS A HIGHLY INFILTRATIVE GROWTH PATTERN WITH FOCALLY POSITIVE AND CLOSE SOFT TISSUE MARGINS. THE POSTOPERATIVE COURSE WAS COMPLICATED BY INFECTION REQUIRING PERCUTANEOUS DRAINAGE AND LONG-TERM ERTAPENEM AND VANCOMYCIN. THIS RESULTED IN A DELAY TO THE INITIAL PLAN FOR 3 FURTHER CYCLES OF ADJUVANT CHEMOTHERAPY. A DISCUSSION ABOUT THE RISKS AND BENEFITS OF CHEMOTHERAPY WAS HELD 12 WEEKS POSTOPERATIVELY, AND THE PATIENT REFUSED THIS OPTION. THIRTEEN WEEKS AFTER SURGERY, RADIATION THERAPY WAS DELIVERED WITH A VOLUME MODULATED ARC THERAPY (VMAT) TECHNIQUE. THE PRESCRIPTION DOSE WAS 50.4 GY IN 28 FRACTIONS WITH AN ADD'L BOOST OF 6 GY IN 3 FRACTIONS TO A SMALLER VOLUME. F/U IMAGING UP TO 12 MONTHS POST-RADIATION THERAPY SHOWED NO SIGNS OF LOCALLY RECURRENT DISEASE. THIS CASE MEETS THE CRITERIA FOR RADIATION-INDUCED SARCOMA (PRIMARY AND SECONDARY NEOPLASM OF DIFFERENT HISTOLOGY, ARISING WITHIN THE IRRADIATED REGION, WITH A LATENCY PERIOD OF 6 YEARS). HOWEVER, GIVEN THE OVERALL LOW RATES OF SARCOMA POST-RADIATION (ESTIMATED AT (B)(6)), THE POSSIBILITY OF AN UNRELATED MALIGNANCY REMAINS. ALLISON Y. YE, JESSICA CONWAY, MICHAEL PEACOCK, PAUL W. CLARKSON, CHENG-HAN LEE, CHRISTINE SIMMONS, LORNA WEIR, MICHAEL MCKENZIE. SECONDARY SARCOMA OF BONE POST-PROSTATE BRACHYTHERAPY: A CASE REPORT. CAN UROL ASSOC J 2014; 8 (5-6): E468-470.