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© 2000 American Society for Clinical Oncology Is Radiation Therapy a Preferred Alternative to Surgery for Squamous Cell Carcinoma of the Base of Tongue?From the Departments of Radiation Oncology and Otolaryngology, University of Florida College of Medicine, Gainesville, FL. Address reprint requests to William M. Mendenhall, MD, Department of Radiation Oncology, University of Florida Health Science Center, PO Box 100385, Gainesville, FL 32610-0385; email mendewil@ shands.ufl.edu.
PURPOSE: To evaluate irradiation alone for treatment of base-of-tongue cancer.
PATIENTS AND METHODS: Two hundred seventeen patients with squamous cell carcinoma of the base of tongue were treated with radiation alone and had follow-up for RESULTS: Local control rates at 5 years were as follows: T1, 96%; T2, 91%; T3, 81%; and T4, 38%. Multivariate analysis revealed that T stage (P = .0001) and overall treatment time (P = .0006) significantly influenced local control. The 5-year rates of local-regional control were as follows: I, 100%; II, 100%; III, 83%; IVA, 64%; and IVB, 65%. Multivariate analysis revealed that the following parameters significantly affect the probability of this end point: T stage (P = .0001), overall treatment time (P = .0001), overall stage (P = .0131), and addition of a neck dissection (P = .0021). The rates of absolute and cause-specific survival at 5 years were as follows: I, 50% and 100%; II, 81% and 100%; III, 65% and 76%; IVA, 42% and 56%; and IVB, 44% and 52%. Severe radiation complications developed in eight patients (4%). CONCLUSION: The likelihood of cure after external-beam irradiation was related to stage, overall treatment time, and addition of a planned neck dissection. The local-regional control rates and survival rates after radiation therapy were comparable to those after surgery, and the morbidity associated with irradiation was less.
THE MANAGEMENT of base-of-tongue squamous cell carcinoma is controversial. The major treatment options are radiation therapy and surgery, alone or combined with adjuvant irradiation. There is considerable debate about whether surgery produces better end results than irradiation, particularly for advanced tumors. There are no randomized data to address this question.1-8 Other contentious issues for patients treated with primary radiation therapy include boost technique (external beam v interstitial implantation),9-15 planned postradiotherapy neck dissection,16-18 altered fractionation,19-21 and adjuvant chemotherapy.22-24 The purpose of this article is to review our experience with external-beam irradiation, alone or followed by a planned neck dissection, for patients with squamous cell carcinoma of the base of tongue and to compare our experience with the pertinent literature.
Two hundred seventeen patients with previously untreated squamous cell carcinoma of the base of tongue were treated with external-beam irradiation alone with curative intent at the University of Florida between October 1964 and December 1996. Because the policy at the University of Florida during this time was to treat essentially all patients with squamous cell carcinomas of the base of tongue with primary radiotherapy, this is an unselected series of patients. All patients had follow-up for at least 2 years; 171 (79%) had follow-up for  5 years. All patients had follow-up until death or within approximately 1 year of the date of analysis; no patient was lost to follow-up. One hundred seventy-one patients (79%) were male; the median age was 60 years (range, 28 to 87 years). Patients were staged according to the 1998 American Joint Committee on Cancer (AJCC) staging system.25 The distribution of primary tumor stage was as follows: T1, 29 patients (14%); T2, 76 patients (35%); T3, 70 patients (32%); and T4, 42 patients (19%). Patients were staged as having T4 cancers if there was trismus, bone invasion, tongue fixation, or extension of the primary tumor into the soft tissues of the neck. Invasion of the deep muscles of the tongue, which is subjective and could be present in a T2 or T3 lesion, was not grounds for staging in the T4 category. Similarly, invasion of adjacent sites such as the lateral pharyngeal wall or larynx did not result in staging in the T4 category. The distribution of patients according to N stage was as follows: N0, 34 patients (16%); N1, 35 patients (16%); N2A, 17 patients (8%); N2B, 43 patients (20%); N2C, 63 patients (29%); and N3, 25 patients (11%). Overall AJCC stage distribution was as follows: I, two patients (1%); II, 16 patients (18%); III, 43 patients (20%); IVA, 131 patients (60%); and IVB, 25 patients (11%). One hundred thirty-one patients (60%) had cancers that were well to moderately differentiated or not specified, and 86 patients (40%) had poorly differentiated malignancies. Seven patients (3%) had synchronous squamous cell carcinoma of the head and neck (excluding skin cancers) when base-of-tongue cancer was diagnosed. All patients received continuous-course external-beam radiation therapy alone to the primary cancer with once-daily (68 patients, 31%) or twice-daily (149 patients, 69%) fractionation. Patients treated with the planned split-course technique (38 patients) and those who received an interstitial boost (32 patients) were excluded.3 These techniques were used early in our experience at the University of Florida and have been abandoned because of poor results compared with our current treatment techniques.7,26 Twice-daily fractionation has been used in patients with advanced tumors since 1978; for the past 10 to 15 years, it has been used for essentially all patients with base-of-tongue carcinoma who can come for treatment twice a day. The median total dose was 70.1 Gy (range, 56.58 to 80 Gy) for patients treated once daily (usually at 1.8 to 2 Gy per fraction) and 76.8 Gy (range, 70.8 to 81.6 Gy) for patients treated twice daily. The median overall treatment time was 55.5 days (range, 39 to 70 days) for once-daily irradiation and 46 days (range, 42 to 61 days) for twice-daily treatment. The treatment techniques have been described elsewhere.27-29 Patients with clinically negative neck nodes received elective irradiation to both sides of the entire neck.30 One hundred ten patients with clinically positive neck nodes received a unilateral (89 patients) or bilateral (21 patients) neck dissection.31 Three patients underwent a unilateral neck dissection before radiation therapy. Two patients underwent an ipsilateral neck dissection before radiation therapy and a contralateral neck dissection after irradiation. The remaining 105 patients underwent a planned neck dissection after radiation therapy. In recent years, 17 patients with advanced local-regional disease received adjuvant chemotherapy; 16 patients received induction chemotherapy, and one received concomitant chemotherapy. Induction chemotherapy usually consisted of two or three cycles of fluorouracil and cisplatin.32 Rates of local control, local-regional control, and survival were calculated using the product-limit method.33,34 Significance levels between curves were calculated using the log-rank test.34,35 Multivariate analyses of local control, local-regional control, and survival were performed using the forward stepwise log-rank tests of association of covariates.34,36 Parameters evaluated in the multivariate analysis included T stage, N stage, overall stage, histologic differentiation (well or moderately differentiated or not specified v poorly differentiated), overall treatment time (continuous variable), fractionation schedule (once v twice daily), adjuvant chemotherapy (yes v no), and planned neck dissection (yes v no). In addition, total irradiation dose (continuous variable) was evaluated in the multivariate analysis of local control, and continuous local control (yes v no) was included in the multivariate analysis of neck control.
Time to Recurrence Seventy-nine patients experienced recurrent disease after treatment; 77 (97%) did so within 5 years.
Local Control
Control of Neck Disease Figure 2 depicts the rates of control of neck disease at 5 years. Multivariate analysis of control of neck disease revealed that continuous local control (P = .0001), overall time (P = .0002), N stage (P = .0054), and addition of neck dissection (P = .0001) significantly affected this end point. Adjuvant chemotherapy (P = .2165), fractionation (P = .7459), histologic differentiation (P = .8417), and T stage (P = .8552) had no significant influence on control of neck disease in this analysis.
Local-Regional Control Figure 3 depicts the rates of local-regional control versus AJCC stage. The overall local-regional control rate at 5 years was 72%. Multivariate analysis of local-regional control revealed the following order of significance: T stage (P = .0001), overall time (P = .0001), overall stage (P = .0131), neck dissection (P = .0021), adjuvant chemotherapy (P = .1624), N stage (P = .5746), fractionation (P = .9530), and histologic differentiation (P = .9648).
Ten patients who had a local recurrence underwent salvage surgery, which was successful for two. Two of 10 patients died within 1 year of salvage surgery and were apparently disease-free; they were coded as dead with cancer present because there was insufficient follow-up to evaluate the success of the salvage operation. Seven patients with recurrent cancer in the neck underwent salvage treatment, which was successful for one. The rates of ultimate local-regional control (taking into account those patients who underwent salvage therapy successfully after a local-regional failure) are shown in Fig 4. The proportion of patients for whom salvage treatment was successful is quite small. Multivariate analysis of ultimate local-regional control revealed that the following parameters significantly influenced this end point: T stage (P = .0001), overall treatment time (P = .0008), overall stage (P = .0232), and addition of a neck dissection (P = .0053). Adjuvant chemotherapy (P = .3830), N stage (P = .5220), fractionation (P = .5688), and histologic differentiation (P = .7233) did not significantly affect ultimate local-regional control.
Distant Metastases The rates of distant metastases at 5 years versus AJCC stage were as follows: I, 0; II, 0; III, 8%; IVA, 21%; IVB, 35%; and overall, 17%.
Absolute Survival
Cause-Specific Survival The 5-year cause-specific survival rate for the overall group of 217 patients was 64%. Figure 6 shows cause-specific survival rates versus stage. The 5-year survival rates for patients with IVA and IVB disease were similar. Multivariate analysis of cause-specific survival revealed the following order of significance: T stage (P = .0001), N stage (P = .0003), overall treatment time (P = .0028), adjuvant chemotherapy (P = .0340), overall stage (P = .2829), neck dissection (P = .3526), histologic differentiation (P = .4939), and fractionation (P = .6339). Patients treated twice daily tended to be those with shorter overall treatment times.
Complications Eleven patients (5%) required a nasogastric feeding tube during radiation therapy, and 26 (10%) required a percutaneous gastrostomy tube. One patient (0.5%) required a treatment break. There were no planned treatment breaks. One additional patient required a 2-day hospitalization for dehydration. Four (3.7%) of 107 patients who underwent a planned postirradiation neck dissection sustained major complications, including postoperative wound breakdowns that necessitated a second operation (two patients), a chyle fistula that required surgical intervention (one patient), and a fatal cardiac arrest (one patient). Wound breakdowns after a postirradiation neck dissection often occurred in the portion of the neck that was included in the primary treatment portals so that the skin flaps received doses in the range of 70 Gy or more.31,37 Four (24%) of 17 patients who underwent salvage surgery experienced an orocutaneous fistula; all four had undergone resection of a local recurrence. Eight patients (3.7%) experienced severe late complications, including insufficient ability to swallow, necessitating a permanent gastrostomy (four patients); osteonecrosis, requiring hyperbaric oxygen and debridement (one patient); osteonecrosis, necessitating a segmental mandibulectomy (one patient); chondronecrosis, requiring a total laryngectomy (one patient); and a fatal radiation-induced sarcoma (one patient).
Comparing the results of nonrandomized data from surgical and radiation therapy series is difficult because of selection bias, differences in staging (clinical v pathologic), and differences in data analysis. Because there are no randomized data comparing the two therapeutic modalities, decisions must be based on nonrandomized data. The rates of local control after surgery, alone or with adjuvant irradiation, are compared with those obtained with external-beam irradiation, alone or followed by an interstitial implant (Table 1). Local control rates according to T stage is unavailable in some of the series. Surgery has no obvious advantage over radiation therapy.
According to Harrison et al,9 about 15% to 20% of patients treated with radiotherapy alone are unsuitable for an interstitial boost. With the exception of the series published by Puthawala et al,14 most authors reported few patients with T4 cancers undergoing a brachytherapy boost (Table 2). Puthawala et al reported that in eight of 12 patients with T4 cancers, local-regional control was obtained after treatment. A significant subset of patients with T4 cancers have lesions that are unsuitable for an interstitial boost because of disease extent that could bias a comparison with patients treated with external-beam irradiation alone. Therefore, with the possible exception of a subset of patients with T4 lesions, the local control rates after external-beam irradiation alone are similar to those obtained with external-beam radiotherapy and interstitial implant.
Table 2 lists the rates of disease control at the primary tumor site and in the neck. Although the radiation therapy series usually have a higher proportion of patients with stage IV disease, the local-regional control rates are at least as good as those observed after surgery, if not somewhat better. The likelihood of successful salvage treatment after recurrence in a previously positive neck node is remote both in our experience38 and in that of the Institut Curie (Paris).39 Table 3 lists the proportion of patients with advanced disease (T4 primary cancers and/or stage IV disease) and absolute and cause-specific survival rates after treatment. The radiation therapy series from the Institut Curie40 and the University of Florida are relatively unselected because they treated essentially all patients with squamous cell carcinoma of the base of tongue with primary radiation therapy. When patients who died of intercurrent disease are excluded, the cause-specific survival rates are approximately 60% to 65%, regardless of the treatment modality. Surgical management has no obvious advantage.
Some patients who experience complications may not do so immediately after treatment; indeed, some complications occur years after treatment. Therefore, patients require follow-up indefinitely. Table 4 lists the incidence of major complications. The likelihood of fatal complications is probably 1% to 2% after surgery and is remote after radiation therapy. The incidence of major nonfatal complications is higher after surgery, as is the likelihood of a permanent gastrostomy tube and/or tracheostomy.6,41 Nasri et al reported 31 patients treated surgically for squamous cell carcinoma of the base of tongue at the University of California, Los Angeles. Twenty-four patients (77%) had T1 or T2 cancers. After surgery, six patients (19%) were permanently dependent on a gastrostomy tube for nutrition. Similarly, Machtay et al reported 17 patients treated surgically followed by postoperative irradiation at the University of Pennsylvania. Five patients (29%) had a permanent gastrostomy (two patients), a permanent tracheostomy (two patients), or both (one patient).
Data pertaining to the quality of life after treatment for squamous cell carcinoma of the base of tongue are limited. Functional outcomes after external-beam radiotherapy are similar to those reported after external-beam irradiation plus an 192Ir interstitial implant; both seem to be superior to the results obtained with surgery.42,43 In conclusion, patients treated with surgery (alone or combined with adjuvant radiation therapy) showed no significant difference in the likelihood of local control, local-regional control, or survival when they were compared with those who underwent radiation therapy alone. The risk of major complications and long-term morbidity (eg, permanent gastrostomy and/or tracheostomy) is higher after surgery. The functional results after radiotherapy are better than those obtained with surgery. Therefore, the treatment of choice at our institution is primary radiation therapy. External-beam radiation therapy may be given alone or combined with an interstitial boost. The likelihood of local-regional control, survival, and major complications is similar after either technique. If the patient is treated with external-beam irradiation alone, there is probably a higher likelihood of local-regional control after some altered fractionation schedules than is found with conventionally fractionated irradiation.19,44 Patients at the University of Florida are treated at 1.2 Gy per fraction to total doses ranging from 74.4 to 79.2 Gy in a continuous course. Radiation portals should be designed to minimize irradiation of uninvolved mucosa. Unnecessarily large fields are associated with a greater number of acute effects and late complications.28 Treatment splits should be avoided because of the increased risk of local-regional failure, particularly for advanced cancers.26 Induction chemotherapy is not associated with better local-regional control.23,45 We have observed improved survival rates in patients with T4 oropharyngeal cancers treated with induction chemotherapy.32 The reasons for this are unclear, and this effect has not been observed in randomized trials. In contrast, concomitant chemotherapy and radiation therapy (chemoradiation) may provide a higher cure rate than irradiation alone.22-24 At present, the optimal combination of radiation therapy (conventional or altered fractionation) and concomitant chemotherapy is unclear. Increased acute toxicity is the major disadvantage in chemoradiation, particularly if an aggressive regimen of altered radiotherapy fractionation is used. Observation may be the chosen approach for patients with N1 and early N2 neck disease located within the high-dose volume whose disease has totally regressed at completion of treatment. Otherwise, a planned neck dissection is performed 4 to 6 weeks after radiotherapy.46 Observation may also be the chosen approach for patients with more advanced neck disease that has responded completely after aggressive altered fractionation schedules.17,18 However, the likelihood of salvage of an isolated failure in the neck is remote. Therefore, when in doubt, we prefer to add the neck dissection.38 Patients with positive neck nodes who are treated with a lower dose of external-beam irradiation followed by an interstitial boost should also undergo a planned neck dissection to optimize the likelihood of local-regional control.9
Presented at the Forty-first Annual Meeting of the American Society for Therapeutic Radiology and Oncology, San Antonio, TX, October 31–November 4, 1999.
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Harari PM: Why has induction chemotherapy for advanced head and neck cancer become a United States community standard of practice? J Clin Oncol 15:2050-2055, 1997 46. Mendenhall WM, Parsons JT, Stringer SP, et al: Squamous cell carcinoma of the head and neck treated with irradiation: Management of the neck. Semin Radiat Oncol 2:163-170, 1992[Medline] 47. Nisi KW, Foote RL, Bonner JA, et al: Adjuvant radiotherapy for squamous cell carcinoma of the tongue base: Improved local-regional disease control compared with surgery alone. Int J Radiat Oncol Biol Phys 41:371-377, 1998[Medline] 48. Kraus DH, Vastola AP, Huvos AG, et al: Surgical management of squamous cell carcinoma of the base of the tongue. Am J Surg 166:384-388, 1993[Medline] 49. Thawley SE, Simpson JR, Marks JE, et al: Preoperative irradiation and surgery for carcinoma of the base of the tongue. Rhinol Laryngol 92:485-490, 1983 50. Spanos WJ Jr, Shukovsky LJ, Fletcher GH: Time, dose, and tumor volume relationships in irradiation of squamous cell carcinomas of the base of the tongue. Cancer 37:2591-2599, 1976[Medline] 51. Dupont JB, Guillamondegui OM, Jesse RH: Surgical treatment of advanced carcinomas of the base of the tongue. Am J Surg 136:501-503, 1978[Medline] Submitted April 2, 1999; accepted July 26, 1999.
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Copyright © 2000 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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ABSTRACT
INTRODUCTION
