RADIATION THERAPY FOR HEAD AND NECK CANCERS C. C. WANC, MD*

A general review of the therapeutic experience of the management of carcinoma of the head and neck at the Massachusetts General Hospital and Massachusetts Eye and Ear Infirmary is presented. Early lesions are highly curable by radiation therapy alone; the advanced lesions are preferably treated by com- bined irradiation and surgery, with improved survival rates. Concepts of various approaches are discussed.

Cancer 36:748-751, 1975.

N THE MANAGEMENT OF HEAD AND NECK I cancer, the radiation therapists and sur- geons play an important role either for cure or for palliation. These two methods-radiation therapy and surgery-are not competitive but mutually supportive. The choice of initial method must be the correct one, determined only by what will serve the patient best. When the disease is curable, permanent freedom from local disease is of course the best objective. When both surgery and irradiation can offer ap- proximately equal assurance of cure, the choice of method of treatment is greatly influenced by the cosmetic and functional results to be ob- tained, and by local experience. If, on the other hand, the cancer has progressed to such an ad- vanced stage that cure is highly improbable, pal- liation of symptoms should be the aim.

Experience and sharpened discrimination have clearly established the indications and contra-indications for various treatment meth- ods for head and neck neoplasms. Indis- criminate use of radiation therapy or surgery as the primary method of treatment for far- advanced cancer, with slim hope of obtaining a cure, is seldom successful and is ill advised. For cancer of borderline curability, a program of

Presented at the American Cancer Society-National Cancer Institute National Conference on Advances in Cancer Management, Part 1: Treatment and Rehabilitation, New York, NY, November 25-27, 1974.

From the Department of Radiation Medicine, Mas- sachusetts General Hospital, and the Department of Radia- tion Therapy, Harvard Medical School, Boston, MA.

*Radiotherapist and Head, Division of Clinical Services, Department of Radiation Medicine, Massachusetts General Hospital, and Associate Professor of Radiation Therapy, Harvard Medical School, Boston, MA.

Address for reprints: C. C. Wang, MD, Dept. of Radia- tion Medicine, Massachusetts General Hospital, Boston, MA 021 14.

Received for publication February 15, 1975.

combined irradiation and surgery has proven to be superior to either modality alone.

The radiotherapeutic approach to head and neck carcinomas is based on the following prin- ciples :

1. Most head and neck carcinomas are radioresponsive and require high-dose, small-volume radiotherapeutic techniques for their control.

2. Exophytic and well-oxygenated tumors are more radioresponsive than erosive or hypoxic ones.

3. Carcinomas limited to the mucosa are highly curable by irradiation.

4. Bone and muscle involvement alters the responsiveness of carcinoma and subse- quently decreases the radiocurability.

5 . Cervical lymph node metastases (N,) from well-differentiated carcinomas are better treated by surgical dissection with preoperative radiotherapy than by radia- tion therapy alone.

Owing to the success of treatment directly related to the extent of the lesion, pretreatment workup must be carefully carried out. This in- cludes a careful history, inspection, palpation of the lesion, indirect and direct endoscopy, and plain and contrast radiographic studies of the tumor site. In lesions of the larynx and hypopharynx, laryngograrns and polytomes have been found to be extremely useful in delineating the extent of the disease. Biopsy of the lesion may afford the final microscopic diagnosis.

The radiotherapeutic modalities used for car- 748

No. 2 RADIATION THERAPY FOR HEAD AND NECK CANCERS Wang 749

TABLE I . Results of Early Carcinomas (T,) Treated by Radiation Therapy Alone-3-Year NED MGH Experience

No. NED/ Site No. treated %

Oral cavity 38/50 76 Orop harynx 20/20 71 Supraglottis 16/18 89 Glottis 356/404 88

cinomas of the head and neck are primarily megavoltage radiation with energy at or above 1 MeV, such as a cobalt-60 source or linear ac- celerator with energy ranging from 2-10 MeV. For the oral lesions, interstitial radium or iridium implant has its rightful place and in ex- pert hands has resulted in a high cure rate and excellent cosmetic results. Except in “transoral cone’’ therapy, kilovoltage radiation, as generated by the 200-kV x-ray machine, has no place in the primary management of these dis- eases. Electron-beam therapy is used in selected cases. The radiation dosage is determined by the tumor site, irradiated volume, number of frac- tions, and total elapsed time, as well as by the tolerance of the patient. In general, for oropharyngeal and laryngopharyngeal lesions, external beam therapy is preferred with a dose of 6000 to 6500 rads in 6 to 7 weeks’ time,i.e. 1800 to 1875 ret. For oral lesions, a combination of external-beam therapy and interstitial im- plant with radium needles or iridium wire is effective in delivering high-dose irradiation to a small tumor volume, often resulting in high local control. A dose of 4500 rads external-beam therapy in 4 Vi weeks followed by 3000 rads in- terstitial implant is often carried out for the small oral lesions.

RESULTS OF TREATMENT OF HEAD AND NECK CARCINOMAS BY RADIATION THERAPY

The results reported herein as to various sites are presented according to the classifications as adopted by the American Joint Committee.’ For radiation therapy alone, the cure rates for early carcinomas (T,) arising from the oral cavity, oropharynx, supraglottis, and glottis, for exam- ple, are excellent, with 3-year NED rates rang- ing from 75 to 90%9-e (Table 1). Even for moderately advanced lesions (Tn), approx- imately one out of two patients can be cured by radiation therapy alone (Table 2). These early lesions, i.e. T, and Tn, can therefore be treated satisfactorily by either radiation therapy or sur-

T A ~ L E 2. Results of Moderately Advanced Carcinomas (T4) Treated by Radiation Therapy Alone-3-Year

NED MGH Experience

No. NED/ Site No. treated ?&

Oral cavity 71/l41 50

Supraglottis 23/35 66 Orop harynx 55/100 55

Glottis 88/ 106 83

gery. The choice of treatment modality depends upon a great many factors, of which functional and cosmetic results should play an important role. However, the radiotherapeutic results for advanced lesions, i.e. T, and T,, are less than satisfactory, ranging from 10 to 20% (Table 3).

The complications following radical radiation therapy are closely related to the sites of the tumor and the method and dosage of treatment. For instance, treatment of carcinoma of the floor of the mouth, primarily by interstitial radium implant, tends to be accompanied by a rather high incidence of soft tissue and bone necrosis in the survivors, i.e. 20 to 25%. For the hypopharyngeal and extensive supraglottic le- sions, the incidence of submental and arytenoidal edema following large-field external-beam therapy is high, but generally is clinically asymptomatic. On the other hand, edema of the arytenoid following radical radia- tion therapy for early glottic carcinoma is most uncommon, occurring in less than 1% of the patients. Extensive soft tissue necrosis and os- teoradionecrosis of the mandible following ex- ternal beam therapy generally are the results of high-dose large-field irradiation,n and can be reduced to a minimum if careful radio- therapeutic technique is followed.

COMBINED IRRADIATION AND SURGERY FOR HEAD A N D NECK CARCINOMAS

Treatment of extensive disease, T, and T,, of the head and neck remains a therapeutic chal-

TABLE 3. Results of Advanced Carcinomas (T, and T,) Treated by Radiation Therapy Alone-3-Year NED

MGH Experience

No. NED/ Site No. treated 90

Oral cavity 13/127 10 Oropharynx 12/100 12 Supraglottis 26/117 22 Glottis 13/ 56 23

7 50 CANCER August Supplement 1975 Vol. 36

lenge to both radiation therapists and surgeons. For these extensive lesions, failure from surgical treatment is primarily due to unexpected transection of the periphery of the tumor exten- sion with resultant local marginal recurrences; failures from radiation therapy are primarily due to inability to control the hypoxic tumor core at the primary site. Because of this therapeutic dilemma, a program of combined radiotherapy and surgery, i.e. preoperative or postoperative radiotherapy, has been advocated in the hope of eradicating the radiosensitive peripheral extension of the tumor by irradiation, and removal of the radioresistant central tumor core by surgery, thus reducing marginal or local recurrences. By employing this combined treat- ment, many inoperable lesions have been con- verted into operable ones, with improved therapeutic results. The conditions, among others, in which combined treatment has been found to be useful include carcinoma of the oral cavity, oropharynx, pyriform sinus, and supraglottic larynx.

For preoperative radiation therapy, two con- ceptual approaches have emerged.

1. “Conventional” preoperative radiation therapy. The dosage employed in this program is sublethal, ranging from 2000 rads in 1 week to 5000 rads in 5 weeks. Our experience indicates that a dosage of 4000 rads in 4 weeks has resulted in minimal postoperative complications and yet in a significant sterilization rate of the tumors in the resected specimens, and has resulted in improved therapeutic results. After the dose is delivered, this is followed by radical sur- gery in about 4 weeks, encompassing all possible areas of disease just as if radiation therapy had not been given. This program is applicable to medium-sized lesions or le- sions with poor radiotherapeutic or surgical cure rates. The surgical procedure is fol-

TABLE 4. Results of Advanced Carcinomas Treated by Combined Irradiation and Surgery-3-Year NED MGH

Experience

TP T, or T, No. NED/ No. NED/

No. No. Site treated % treated %

Oral cavity 17/28 61 17/32 53 Oropharynx 11 /15 73 13/21 62 Supraglottis 19/24 79 541107 50 Glottis Not indicated Study in progress

lowed by satisfactory functional and cosmetic results. The lesions suitable for this program include carcinomas arising from the supraglottis and pyriform sinus,’ and anterior oral lesions, i.e. carcinoma of the gum, floor of the mouth, oral tongue, and buccal mucosa.a This treatment would not interfere with postoperative rehabilita- tion.

2. Cancerocidal radiation therapy and ex- cision (at times so-called postradiation resection or sequential surgery). The radia- tion dosage used in this program is 6000 rads in 6 to 7 weeks’ time. Contrary to the “conventional” 4000-rads preoperative program, radiation therapy is followed by limited surgical resection in that only the radioresistant nidus of the primary lesion, often in muscle or bone, is excised. The ex- tent of surgery is considerably less than the original lesion, but is adequate for removal of residual disease. This approach is in- tended to preserve vital structures and to avoid excessive functional and cosmetic mutilation by surgery. This method has been found applicable to lesions arising from the tonsil, retromolar trigone, anterior pillar,‘ and base of tongue. Such extensive lesions tend to extend onto the adjacent soft palate, base of tongue, and/or gum, with muscle and bone involvement. Table 4 shows the results of treatment of patients with T, and Ta lesions arising from various sites treated with combined irradiation and surgery. Except for the oropharyngeal group, which received high-dose irradiation and sequential surgery, most patients received low-dose (4000-rads) preoperative radiation therapy and radical resection with or without neck dissection. For those patients suitable for this method of treat- ment, better than 50% have survived 3 or more years without recurrence.

POSTOPERATIVE RADIATION THERAPY

Postoperative radiation therapy is indicated when the tumor is massive, treated primarily by surgery with or without extensive regional lymph node metastases, when the peripheral portion of the tumor is unintentionally transected, or the pathologic specimens show extension to or close to the resection margins. Radiation therapy should be given as soon as the wound is healed, with a dose of 5500 to 6000

No. 2 RADIATION THERAPY FOR HEAD AND NECK CANCERS Wang 751

rads in 6 to 7 weeks’ time. This method has been applied to extensive lesions of the supraglottis and hypopharynx and oral cavity. Although this technique has been used rather extensively in a few centers in this country, we prefer the ap- proach with preoperative radiation therapy in our patients if feasible.

COMPLICATIONS OF COMBINED TREATMENT

Because of combination of radiation therapy and surgery, postoperative complications are ex- pected, but may be minimized by observing careful radiotherapeutic and surgical technique. This generally occurs after high-dose irradia- tion, i.e. 6000 to 6500 rads followed by massive resection of extensive disease requiring partial glossectomy and/or mandibulectomy and neck dissection, and consists of soft tissue ulceration, osteoradionecrosis of the mandible, oropharyngo- cutaneous fistulae, sloughing of skin flap, poor wound healing, and occasionally carotid blow- out, etc. A complication rate as high as 15 to 20% occurred in these patient^.^ O n the other hand, patients receiving high-dose irradiation and limited surgery (nidusectomy) and conven- tional preoperative radiation therapy, i.e. 4000 rads in 4 weeks, and/or modest postoperative radiation therapy, have complication rates of less than 5%.

NECK NODES

For the management of nodal disease, not fix- ed, NI, from a well-differentiated carcinoma of the head and neck region, radical neck dissec- tion remains the treatment of choice. It has been found that preoperative radiation therapy ap- plied to the nodal areas has reduced the in- cidence of local recurrence. A dosage of 4500 rads in 4% weeks is planned. For patients with extensive nodal disease, treated primarily by

radical neck dissection, without the benefit of preoperative irradiation, postoperative radiation therapy should be given to avoid local recur- rence. For metastatic nodes from poorly differentiated carcinomas arising from the nasopharynx, faucial tonsil and base of the tongue, i.e. Waldeyer’s ring, radical radiation therapy is the treatment of choice, and surgery is reserved for removal of residual nodes postradia- tion.

DISCUSSION

Carcinomas arising from the head and neck region are curable malignant tumors. When the lesion is small, TI and T2, and treated properly, the cure rate by surgery or by radiation therapy is high. The choice of therapeutic modality for such lesions is complex and depends upon the site of origin, presence or absence of metastatic nodal disease, age, physical status of the patient, and skill of the surgeon or radiation therapist. In general, radiation therapy is highly effective for the control of mucosal lesions, TI and T2, with resultant excellent functional and cosmetic results. Radical surgery is reserved for radiation failures in this group of patients. The extensive disease, T8 and TI, often associated with bone and muscle involvement and cervical lymph node metastases, is rarely considered operable by previous standards and/or is often incurable by radiation therapy alone; such lesions are presently treated by combined irradiation and surgery, either preoperative or postoperative radiation therapy, with promising results. For the obviously incurable, advanced lesions, with or without distant metastases, radiation therapy and/or chemotherapy may offer some degree of palliation. For the patients afflicted with head and neck cancer, successful treatment often rests on full cooperation and interaction between the surgeon and radiotherapist.

REFERENCES

1 . American Joint Committee for Cancer Staging and End Results Reporting: Clinical Staging System for Car- cinoma of the Oral Cavity (1967), Hypopharynx (1965). and Larynx (1972). Chicago, American Joint Committee for Cancer Staging and End Results Reporting.

2 . Cheng, V. S. T., and Wang, C. C . : Osteoradionecrosis of the mandible resulting from external megavoltage radia- tion therapy. Radiology 112:685-689, 1974.

3. Wang, C. C. : Role of radiation therapy in the manage- ment of carcinoma of the oral cavity. Otolaryngol. Clin. North Am. 5:357-363, 1972.

4. Wang, C. C. : Management and prognosis of squamous

cell carcinoma of the tonsillar region. Radiology 104:667-671, 1972.

5 . Wang, C. C . : Megavoltage radiation therapy for supraglottic carcinoma-Results of treatment. Radiology 109: 183-1 86, 1973.

6. Wang, C. C.: Treatment of glottic carcinoma by megavoltage radiation therapy and results. Am. J . Romtgcnol. 120:157-163, 1974.

7. Wang, C. C., Schulz, M. D., and Miller, D.: Combined radiation therapy and surgery for carcinoma of the supraglottis and pyriform sinus. Am. J. Surg. 124:551-554, 1972.