HISTOPATHOLOGICAL EFFECT OF NONCONTACT LASER TREATMENT ON HUMAN PROSTATE 1535 thermocoagulation, when predominantly glandular, without risk of injury to surrounding structures. Based on this obser- vation, we extended the indications for noncontact laser pros- tatectomy to include patients with large middle lobe BPH.28

In conclusion, ou r findings indicate that the reported clin- ical results with the currently recommended 4-quadrant la- ser prostatectomy at 50 watts (60 wat t s at the laser console) for 60 seconds could be improved by modifying the laser regimen (that is rate of tissue heating) a n d the spatial dis- tribution of lesions. Furthermore, our results suggest that laser prostatectomy is a safe procedure.

REFERENCES

1. McCullough, D. L.: Transurethral laser treatment of benign prostatic hyperplasia. J. Urol., 1 4 6 1126, 1991.

2. Costello, A. J., Bowher, W. G., Bolton, D. M., Braslis, K. G. and Burt, J.: Laser ablation of the prostate in patients with benign prostatic hypertrophy. Brit. J. Urol., 6 9 603, 1992.

3. Kabalin, J. N.: Laser prostatectomy performed with a right angle firing neodymium:YAG laser fiber at 40 watts power setting. J . Urol., 1 5 0 95, 1993.

4. Marks, L. S.: Serial endoscopy following visual laser ablation of prostate (VLAP). Urology, 42: 66, 1993.

5. Dixon, C., Machi, G., Theune, C. and Lepor, H.: A prospective, double-blind, randomized study comparing laser ablation of the prostate and transurethral prostatectomy for the treat- ment of BPH. J . Urol., part 2, 1 4 9 215A, abstract 6, 1993.

6. Kabalin, J. N.: Urolase laser prostatectomy. Monogr. Urol., 14: 23, 1993.

7 . Johnson, D. E., Levinson, A. K., Greskovich, F. J., Cromeens, D. M., Ro, J. Y., Costello, A. J. and Wishnow, K. I.: Transure- thral laser prostatectomy using a right-angle laser delivery system. SPIE Proc., 1421: 36, 1991.

8. Johnson, D. E., Price, R. E. and Cromeens, D. M.: Pathologic changes occurring in the prostate following transurethral la- ser prostatectomy. Lasers Surg. Med., 1 2 254, 1992.

9. Anvari, B., Motamedi, M., Pow-Sang, M., LaHaye, M., Orihuela, E., Jacques, S. L. and Rastegar, S.: Application of a high power diode laser (810 nm) for treatment of benign prostatic hyper- plasia: theoretical and experimental analysis. SPIE Proc. La- sers Urol., 2129 76, 1994.

10. Orihuela, E., Motamedi, M., Pow-Sang, M., Cammack, T. and Warren, M.: Nd:YAG laser thermal effect in the prostate: application to laser treatment of benign prostatic hyperplasia. SPIE Proc. Lasers Urol., 2129 19, abstract, 1994.

11. Orihuela, E., Motamedi, M., Cammack, T., Torres, J., Pow-Sang, M., LaHaye, M., Cowan, D. and Warren, M.: Comparison of

12.

13.

14.

15.

16.

17

18

thermoco&ulation effects of low power-slow heating vs high power-rapid heating neodymium:YAG laser regimens in a canine prostate model. J . Urol., 153: 196, 1995.

Kabalin, J. N. and Grill, H. S.: Dosimetry studies utilizing the Urolase right angle firing neodymium:YAG laser fiber. Lasers Surg. Med., 1 4 145, 1994.

Costello, A. J. , Bolton, D. M., Ellis, D. and Crowe, H.: His- topathological changes in human prostatic adenoma following Nd:YAG laser ablation therapy. J. Urol., 152: 1526, 1994.

Orihuela, E., LaHaye, M., Pow-Sang, M., Motameh, M., Cowan, D., Tbakhi, A. and Warren, M.: Histopathological evaluation of the laser effect on human prostate cancer. J. Urol., part 2,151: 436A, abstract 836, 1994.

Motamedi, M., Pow-Sang, M., Orihuela, E., Johnson, S., Bhattacharya, A,, Rastegar, S., LaHaye, M. and Warren, M.: Changes in prostatic tissue temperature during laser irradia- tion. Read at annual meeting of South Central Section, Amer- ican Urological Association, Vancouver, British Columbia, Canada, August 27-31, abstract 13, p. 90, 1994.

Orihuela, E., Pow-Sang, M., LaHaye, M., Anvari, B., Motamedi, M. and Warren, M.: Influence of the temperature of irrigation fluid in the depth of coagulation necrosis in canine prostate treated with Nd:YAG laser. J. Endourol., 7: S89, P.IV-12, 1993.

Smith, J. A,, J r . and Dixon, J. A.: Tissue effects of lasers in the genitourinary system. In: Lasers in Urologic Surgery. Chicago: Year Book Medical Publishers, Inc. chapt. 2, pp. 16-31, 1985.

Mostofi, F. K. and Price, E. B.: Hyperplasia of the prostate. In: Tumors of the Male Genital System. Washington, D. C.:

19.

20.

21.

22.

23.

24

25

26

Armed Forces Institute of Pathology, fasc. 8, pp. 182-194, 1973.

Orihuela, E., Motamedi, M., Pow-Sang, M., LaHaye, M. and Warren, M.: Low-power laser radiation for the treatment of benign prostatic hyperplasia: initial clinical experience. J. En- dourol., 8: 301, 1994.

Orihuela, E., Pow-Sang, M., Motamedi, M., LaHaye, M., Cowan, D. and Warren, M.: Histopathological correlation and random- ized clinical trial comparing low power versus high power laser regimens in the human prostate. J. Urol., part 2, 151: 332A, abstract 418, 1994.

McCullough, D. L.: Minimally invasive management of benign prostatic hyperplasia. In: Campbell’s Urology, 6th ed. Ed- ited by P. C. Walsh, A. B. Retik, T. A. Stamey and E. D. Vaughan, J r . Philadelphia: W. B. Saunders Co., update 8, pp. 1-12, 1993.

Shanberg, A. M., Lee, I. S., Tansey, L. A. and Sawyer, D. E.: Extensive neodymium:YAG photoirradiation of the prostate in men with obstructive prostatism. Urology, 43: 467, 1994.

Bolton, D. M. and Costello, A. J.: Management of benign pros- tatic hyperplasia by transurethral laser ablation in patients treated with warfarin anticoagulation. J . Urol., 151: 79, 1994.

Leach, G. E., Sirls, L., Ganabathi, K, Roskamp, D. and Dmochowski, R.: Outpatient visual laser-assisted prostatec- tomy under local anesthesia. Urology, 4 3 149, 1994.

Childs, S. J. : Problems and complications. In: Laser-Assisted Transurethral Resection of the Prostate (TURP). Baltimore: Williams & Wilkins, chapt. 8, pp. 67-71, 1993.

Watson, G. and Anson, K: Comparison between sidefire and contact laser prostatectomy. SPIE Proc. Lasers Urol., 2129 15. 1994.

27. Narayan, P., Leidich, R., Fournier, G., Shinohara, K., Indudhara, R. and Ingerman, A,: Transurethral evaporation of prostate (TUEP) with Nd:YAG laser using a contact free beam technique: results in 61 patients with benign prostatic hyper- plasia. Urology, 4 3 813, 1994.

28. LaHaye, M., Pow-Sang, M., Orihuela, E., Motamedi, M. and Warren, M.: Could laser therapy be an alternative treatment to open prostatectomy for benign prostatic hyperplasia? Read at annual meeting of South Central Section, American Uro- logical Association, Vancouver, British Columbia, Canada, Au- gust 27-31, abstract 14, p. 91, 1994.

EDITORIAL COMMENT

Congratulations to the authors who have made a serious attempt to determine if the low wattage, longer time concept is a better form of neodymium:YAG laser therapy of human prostatic tissue than higher wattage, shorter time. There are several drawbacks to the study, which are real and unavoidable but must be carefully weighed when examining the data. Six patients had prostate cancer; cancer is not BPH. The other 4 men did not have significant BPH. One should be most cautious in transferring the conclusions drawn to the typical BPH patient seeking invasive therapy.

The authors did not detect nonconfluent coagulation necrosis when lesions were created at the traditional 2 , 4 , 8 and 10 o’clock positions with the 15 watts for 180 seconds treatment but this was seen in 2 of 4 cases treated with 50 watts for 60 seconds. When 6 or 8 lesions were created in a single transverse plane, there was always conflu- ent coagulation necrosis with either technique, slightly deeper with 15 watts for 180 seconds but not definitely statistically different than 50 watts for 60 seconds. The point is that these prostates were examined acutely within several hours of treatment. Would the 2 ,4 , 8 and 10 lesions have become confluent if examined 2 or 3 days later?

Removing the laser fiber and re-equilibrating it after each treat- ment allowed the prostate to cool off and may have significantly affected the results. This scenario is not usually present when one performs laser irradiation and proceeds from 1 treatment site imme- diately to an adjacent site when treating BPH patients.

It is comforting to know that the prostates treated were not frac- tured and the peripheral zone was not destroyed. This is important from a potential damage to adjacent tissue standpoint, especially considering rectal injury. If one treated a 30 gm. prostate as de- scribed in figure 6, A with 8 treatments (8 X 180 seconds) or 24 minutes a t 3 separate locations 13 X 24 minutes), this would take 72 minutes of laser therapy to treat a 30 gm. gland, which is considerably longer than transurethral resection of the prostate would take.

1536 HISTOPATHOLOGICAL EFFECT OF NONCONTACT LASER TREATMENT ON HUMAN PROSTATE

From the data presented I cannot conclude that 15 watts for 180 seconds is superior to 50 watts for 60 seconds regimen. Taking 3 times as long to treat the disease using the 15 watts for 180 seconds regimen does not seem worth the extra time. The authors present a strong argument to treat sites closer together with either technique, that is 1, 3, 5, 7, 9 and 11 versus 2,4, 8 and 12 o’clock positions. The authors seemingly concur with the higher wattage, shorter time concept because they state that they are treating larger glands with the high power, shorter time technique. If one is to treat smaller glands with the low wattage, longer time technique, why not just use a contact probe and instantly vaporize the tissue within an equiva- lent total treatment time?

In terms of considering effective laser techniques, my personal bias is that creating an 8 mm. wide trough of vaporized prostatic tissue down to the circular bladder neck fibers and extending from the bladder neck to the proximal verumontanum, much as one does with conventional transurethral resection of the prostate, is an ef- fective strategy to combine with either vaporization or coagulation necrosis techniques as described in this study. For those who prefer not to have retrograde ejaculation, the trough can be omitted.

Whether vaporization techniques are superior to coagulation ne-

crosis techniques as described are still unanswered. One fact is still certain, that is both techniques can safely and effectively treat BPH with minimal morbidity. The authors are to be congratulated in their efforts to bring to our attention carefully made scientific observa- tions on human prostates. The ideal model to study the techniques as described in humans would be to treat BPH containing glands with the laser in patients who were scheduled for cystoprostatectomy several days to weeks later. The ethical aspects of such a study would be tenuous with no benefit to the patient other than a greater understanding of laser treatment of BPH.

David L. McCullough Department of Urology Bowman Gray School of Medicine Winston-Salem, North Carolina

REPLY BY AUTHORS All of the comments by Doctor McCullough were fully addressed in

the Discussion of our article except those related to the use of contact laser therapy and bladder neck incision.