Salvage robot-assisted radical prostatectomy after carbon ion radiotherapy: a case report

Abstract

Salvage radical prostatectomy is a therapeutic option for the biochemical recurrence of prostate cancer after radiotherapy. However, only one case report of salvage radical prostatectomy after carbon ion radiotherapy has been reported. We report a case of salvage robot-assisted radical prostatectomy for local recurrence of prostate cancer after carbon ion radiotherapy with surgical video. Owing to adhesion and degeneration after radiotherapy, difficulties in surgery and post-operative complications have been anticipated. However, surgery was feasible without severe peri- and post-operative complications. Salvage robot-assisted radical prostatectomy after carbon ion radiotherapy may be a reasonable therapeutic option.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13691-020-00464-w.

Introduction

In addition to watchful waiting and androgen-deprivation therapy (ADT), local therapies, such as salvage radical prostatectomy (RP), represent a curative therapeutic option for biochemical recurrence after radiotherapy [1]. However, salvage RP has been underused, where only 1%–2% of patients are estimated to undergo salvage RP because of complex surgery owing to radiation-induced tissue changes making surgical procedures challenging [2]. Thus, classically, salvage RP is associated with a higher incidence of complications, such as rectal injury, anastomotic leaks, and stricture, as well as prolonged urinary incontinence and erectile dysfunction [3]. Salvage RP after local therapies for prostate cancer has been recommended in only high-volume institutions [4]. However, recent studies have reported that robot-assisted radical prostatectomy (RARP) has improved the peri-operative outcome in primary settings as well as salvage settings [5]. Regarding the oncological outcome, promising short- and middle-term cancer controls by salvage RP have been reported that may be comparable to or better than other salvage local treatments, such as brachytherapy, high-intensity focused ultrasound, and cryotherapy [6].

Carbon ion radiotherapy is particle therapy in addition to proton therapy. Carbon ion radiotherapy has several advantages, including excellent dose distribution focused on the target with minimal exposure to surrounding tissues and higher cytotoxic effects on tumor cells than photon radiotherapy or even proton therapy [7]. Carbon ion radiotherapy is anticipated to show greater clinical benefits of better tumor control and less complication. A recent multi-institutional prospective study indicated an excellent oncological outcome of carbon ion radiotherapy in which the five-year biochemical recurrence-free survival rates in low-, intermediate-, and high-risk patients were 92, 89, and 92%, respectively [8]. Nevertheless, the number of institutions that perform carbon ion radiotherapy remains small, and most of them are located in Japan [7]. Thus far, only one case report of salvage RP for biochemical recurrence after carbon ion radiotherapy has been reported, and it does not accompany a video of the intraoperative finding [9]. Here, we report another case of salvage RARP for biochemical recurrence after carbon ion radiotherapy with a surgical video.

Case report

A 72-year-old man was referred to our institution to be treated with salvage therapy for radio-recurrent prostate cancer in 2020. In October 2014, he visited the urologist owing to a high PSA level of 5.79 ng/ml at PSA screening. Subsequently, transperineal prostate biopsy was performed, and adenocarcinoma with the highest Gleason score of 4 + 3 was detected in 10 of 12 cores (bilateral lobes). Computed tomography and bone scan showed no extraprostatic extension or distant metastases, and he was diagnosed with cT2cN0M0 disease. As primary treatment, he chose to undergo carbon ion radiotherapy combined with long-term ADT. Accordingly, from December 2014, leuprolide was administered with bicalutamide (80 mg/day); bicalutamide was stopped after 7 weeks owing to elevated AST and ALT levels. After 6-month neoadjuvant ADT, he had undergone carbon ion radiotherapy [51.6 Gy (RBE)/12 fractions] at the Ion Beam Therapy Center, SAGA HIMAT Foundation (Tosu, Japan). After carbon ion radiotherapy, the PSA level declined to 0.01 ng/ml. The final 3-month leuprolide was administered in April 2017. However, the PSA level gradually increased and reached 2.98 ng/ml in January 2019. Although computed tomography and bone scan still showed no evidence of recurrence, ADT with leuprolide was restarted for biochemical recurrence, and the PSA level declined to 0.14 ng/ml 8 months later. However, despite continuous ADT, the PSA level gradually increased to 0.42 ng/ml in January 2020, and magnetic resonance imaging suggested local recurrence in the left lobe (Fig. 1). In February 2020, he was referred to our department. To confirm local recurrence, we performed transperineal prostate biopsy again, and adenocarcinoma with the highest Gleason score of 4 + 5 was detected in 5 of 13 cores (left lobe).

Fig. 1.

Magnetic resonance imaging with each parameter as indicated below of figures suggested local recurrence in the left lobe

In April 2020, salvage RARP with lymph node dissection of the external iliac, obturator, and external iliac regions was performed using the da Vinci Xi system (Supplementary video). Before surgery, we performed full-bowel preparation and consulted the gastroenterological surgeon in the case of rectal injury. The transperitoneal approach with 6 ports in 23 degrees of the Trendelenburg position was used. Because he had a history of appendectomy for acute appendicitis at 33 years of age, extensive adhesion of the intestinal tract was observed at the site after appendicitis, and exfoliation was required. During bilateral lymph node dissection, modest adhesion was observed between vessels and surrounding tissues. After lymph node dissection, Retzius’ cavity was opened, and the bilateral endopelvic fascia was dissected, where adhesion was more apparent at the apex lesion of the prostate. Bladder neck dissection was performed using an anterior approach. However, the correct dissection line was vague owing to fibrosis, resulting in minor bladder injury in the trigone during dissection that was repaired instantly; the procedure was converted to a lateral approach. The Denonvilliers’ fascia was incised and exfoliated to the apex of the prostate with caution, although adhesion was modest. The dorsal vein complex was dissected with no ligation and was sutured. The urethra was dissected, and the prostate was excised without nerve preservation. Careful observation after prostate removal revealed no rectal injury. Vesico-urethral anastomosis was performed after Rocco’s stitches. The total operation time was 5 h 2 min: the console time was 2 h 58 min, which was longer mostly owing to post-appendicitis extensive adhesion of the intestinal tract and partially owing to the post-radiation effect. Blood loss was less than measurable, and no peri-operative complication was detected. Cystography was performed 7 days after the operation, revealing no leakage from the vesico-urethral anastomosis, and the urethral catheter was removed. He had no post-operative complication and was discharged 10 days after the operation.

The pathological finding showed adenocarcinoma with a Gleason score of 4 + 4 and tertiary pattern 5, located only in the left lobe with extracapsular extension (T3a) and showing a tumor location consistent with the finding of magnetic resonance imaging (Fig. 2). The surgical margin status and lymph node metastasis among 14 nodes were negative. The PSA level at 7 month after surgery declined to less than 0.006 ng/ml even after ADT was terminated. Although continence recovery was slower than usual, urinary incontinence was improved to 1-pad use per day.

Fig. 2.

Macroscopic and microscopic findings of the prostate specimen obtained from salvage robot-assisted radical prostatectomy. Each figure shows haematoxylin and eosin staining with magnification power as indicated below of figures

Discussion

We reported a case of salvage RARP for the local recurrence of prostate cancer after carbon ion radiotherapy. In countries with institutions that perform carbon ion radiotherapy, surgery after carbon ion radiotherapy is important. This case showed the feasibility of salvage RARP after carbon ion radiotherapy, although various difficulties may be accompanied depending on the case. Additionally, we learned that the lateral approach might be better during bladder neck dissection in surgery to see correct dissection line.

Because carbon ion radiotherapy can reduce the dose distribution to the surrounding tissues of target organs, changes in surrounding tissues might be less than those for other radiotherapies. Thus far, several cases of salvage surgery after carbon ion radiotherapy in lung cancer, osteosarcoma, and malignant melanoma have been reported, indicating the feasibility of operation, but increased difficulties exist in the peri-operative period [10]. Thus, salvage surgery, even after carbon ion radiotherapy, is a therapeutic option for radio-recurrent prostate cancer. However, the patient selection for salvage local therapy is a key issue that may be improved by next-generation imaging modalities, such as positron emission tomography, using prostate-specific membrane antigen.

Conclusion

We report a case of salvage RARP after carbon ion radiotherapy that indicates the feasibility of surgery.

Supplementary Information

Below is the link to the electronic supplementary material.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.