Brachytherapy in the Treatment of Head and Neck Cancer

Quon and Harrison have performed a considerable serviceto patients with head and neck cancers by reminding the oncology community thata state-of-the-art treatment team must include state-of-the-art brachytherapy.

A fundamental adage in radiotherapy is "If you don’t hit it, you can’tcure it." Modern tools of external-beam radiotherapy, such asintensity-modulated radiation therapy, allow us to tailor radiation dosedistributions (at least on the computer screen) to conform almost as tightly tothe shape of the cancer as brachytherapy. In the head and neck region, however,ensuring that radiation always hits its target is not easy: Accuratelyrepositioning and immobilizing inherently mobile structures such as the tongue,the mandible, and the cervical spine—day after day, week after week—can bequite difficult.

Advantages of Brachytherapy

With brachytherapy, one has the confidence that radiation is always hittingits target because the source of irradiation is located within the target, orright on it, rather than several feet away. Furthermore, the duration of thetreatment, instead of weeks and months, is measured in days (and now, with high-dose-ratebrachytherapy, in minutes). Brachytherapy is, therefore, quite appropriatelydescribed as the ultimate conformal radiotherapy and belongs in thearmamentarium of physicians dealing with patients suffering from head and neckcancers.

Among the frustrations of being a head and neck brachytherapist is seeingpatients after local recurrence and knowing that, if brachytherapy had beenemployed as part of the original planned treatment, the outcome would probablyhave been better. I shall, therefore, take this opportunity to amplify three ofthe issues discussed by Quon and Harrison in their comprehensive review, namely,(1) the role of brachytherapy in nasopharyngeal carcinoma, (2) the role ofbrachytherapy in the postoperative patient, and (3) the role of high-dose-ratebrachytherapy.

Brachytherapy inNasopharyngeal Carcinoma

Adequate external-beam irradiation to the nasopharynx and the retropharyngeallymph nodes is constrained, even in the modern era, by the proximity of thesesites to critical structures such as the brainstem, the optic chiasm, and thespinal cord. In the recent Intergroup study 0099, no brachytherapy was allowed,and as a result, one in three patients (23/69) treated by radiotherapy sufferedlocal recurrence.[1] This was in striking contrast to several reports from theUnited States,[2-4] Europe,[5] and Asia,[6,7] suggesting that adding a plannedbrachytherapy boost to external irradiation led to local recurrences in fewerthan 1 in 10 patients, and was quite safe.

The Postoperative Patient

It is well known that inability to obtain satisfactory margins of resectionleads to local recurrence in most cases if no postoperative irradiation isgiven. What is not as well known is that patients with unsatisfactory surgicalmargins suffer more local recurrences even when postoperative irradiation isadministered.[8-10]

Laramore[11] and Jacobs[12] analyzed a large Intergroup study that involvedthe delivery of 60 Gy by external beam after surgery for locally advanced headand neck cancers. Among patients with unsatisfactory margins, 26% suffered localrecurrences, vs 11% among those with satisfactory margins. Since unsatisfactorymargins reflect a larger residual tumor burden, those patients might benefitfrom a boost dose near the surgical suture line. In our experience,brachytherapy proved to be an excellent means of delivering such a boost, withlittle additional toxicity. Among patients with unsatisfactory margins treatedby a planned brachytherapy boost, only 7% developed a local recurrence.[13,14]

Role of High-Dose-Rate Brachytherapy

The radiation safety problems associated with traditional low-dose-ratetemporary implants in the head and neck region can be onerous, and havediscouraged many radiation oncologists from employing brachytherapy. With high-dose-rateimplants, on the other hand, the patient can stay in a standard room withunrestricted visiting and nursing care. Furthermore, high-dose-ratebrachytherapy offers unprecedented opportunities for dose optimization.

A century’s worth of venerable literature exists regarding traditional low-dose-ratetemporary brachytherapy for head and neck cancers, but in recent years, manystudies and guidelines have strongly supported the notion that high-dose-rateapproaches can be used in its stead for most indications.[15,16] Rare forbrachytherapy, these publications have even included a prospective, randomizedstudy.[17]

We initially employed high-dose-rate brachytherapy in previously treatedpatients.[18] Then, about 7 years ago, we felt comfortable enough with thestrategy that we completely abandoned traditional low dose-rate temporarybrachytherapy in favor of the high-dose-rate approach, and the results havebeen quite gratifying.[19]

References:

1. Al-Sarraf M, LeBlanc M, Giri PG, et al: Chemoradiotherapy versusradiotherapy in patients with advanced nasopharyngeal cancer: Phase IIIrandomized Intergroup study 0099. J Clin Oncol 16:1310-1317, 1998.

2. Wang CC: Improved local control of nasopharyngeal carcinoma afterintracavitary brachytherapy boost. Am J Clin Oncol 14:5-8,1991.

3. Vikram B, Mishra S: Permanent iodine-125 (I-125) boost implants afterexternal radiation therapy in nasopharyngeal cancer. Int J Radiat Oncol BiolPhys 28:699-701, 1994.

4. Vikram B: Permanent iodine-125 (I-125) boost after teletherapy in primarycancers of the nasopharynx is safe and highly effective: long-term results. IntJ Radiat Oncol Biol Phys 15:1140, 1997.

5. Levendag PC, Schmitz PI, Jansen PP, et al: Fractionated high-dose-ratebrachytherapy in primary carcinoma of the nasopharynx. J Clin Oncol16:2213-2220,1998.

6. Teo PM, Leung SF, Fowler J, et al: Improved local control for earlyT-stage nasopharyngeal carcinoma—a tale of two hospitals. Radiother Oncol57:155-166, 2000.

7. Leung TW, Tung SY, Sze WK, et al: Salvage brachytherapy for patients withlocally persistent nasopharyngeal carcinoma. Int J Radiat Oncol Biol Phys47:405-412, 2000.

8. Vikram B, Strong EW, Shah JP, et al: Failure at the primary site followingmultimodality treatment in advanced head and neck cancer. Head Neck Surg6:720-723, 1984.

9. Parsons JT, Mendenhall WM, Stringer SP, et al: An analysis of factorsinfluencing the outcome of postoperative irradiation for squamous cell carcinomaof the oral cavity. Int J Radiat Oncol Biol Phys 39:137-148, 1997.

10. Huang D, Johnson CR, Schmidt-Ullrich RK, et al: Incompletely resectedadvanced squamous cell carcinoma of the head and neck: The effectiveness ofadjuvant vs salvage radiotherapy. Radiother Oncol 24:87-93, 1992.

11. Laramore GE, Scott CB, al-Sarraf M, et al: Adjuvant chemotherapy forresectable squamous cell carcinomas of the head and neck: Report on IntergroupStudy 0034. Int J Radiat Oncol Biol Phys 23:705-713, 1992.

12. Jacobs JR, Ahmad K, Casiano R, et al: Implications of positive surgicalmargins. Laryngoscope 103:64-68, 1993.

13. Vikram B, Mishra S: Permanent iodine-125 implants in postoperativeradiotherapy for head and neck cancer with positive surgical margins. Head Neck16:155-157, 1994.

14. Beitler JJ, Smith RV, Silver CE, et al: Close or positive margins aftersurgical resection for the head and neck cancer patient: The addition ofbrachytherapy improves local control. Int J Radiat Oncol Biol Phys 40:313-317,1998.

15. Nag S, Cano ER, Demanes DJ, et al: The American Brachytherapy Societyrecommendations for high-dose-rate brachytherapy for head-and-neck carcinoma.Int J Radiat Oncol Biol Phys 50:1190-8, 2001.

16. Nag S (ed): High Dose Rate Brachytherapy: A Textbook. Armonk, NY, FuturaPublishing Co, 1994.

17. Inoue T, Inoue T, Yoshida K, et al: Phase III trial of high- vs.low-dose-rate interstitial radiotherapy for early mobile tongue cancer. Int JRadiat Oncol Biol Phys 51:171-175, 2001.

18. Yu L, Vikram B, Chadha M, et al: High dose rate interstitialbrachytherapy in patients with cancers of the head and neck. EndocurietherapyHyperthermia Oncology 12:1-6, 1996.

19. Vikram B, Beitler JJ, Sood B, et al: High dose rate brachytherapy inpatients with previously untreated cancers of the head and neck. J BrachytherInt 16:95-101, 2000.