Radiation dose response for supratentorial low-grade glioma--institutional experience and literature review

PURPOSE

To examine radiation dose response for low-grade glioma (LGG) based on our institutional experience and to review the literature on this topic.

METHODS AND MATERIALS

Sixty-seven patients with supratentorial low-grade nonpilocytic astrocytomas (n=36) or oligodendrogliomas (n=31) were treated with postoperative radiation therapy (RT). Twenty-seven patients (group A) received 5520 cGy; 24 patients (group B) received 5940 cGy; and 16 patients (group C) received 6375 cGy. The corresponding median follow-up was 60, 35 and 91 months, respectively.

RESULTS

The disease-specific survival (DSS) at 5 and 10 years were 90.2% and 56.2%, 67.6% and 47.3%, and 62.5% and 50% for groups A, B and C, respectively (P=0.40). Only a greater extent of surgical resection and absence of contrast enhancement predicted DSS on multivariate analyses. Patients receiving higher doses of RT had higher complication rates.

CONCLUSION

Our data confirmed the lack of radiation dose response for supratentorial LGG as demonstrated in the previous randomized trials. The radiation dose should not exceed 5520 cGy because dose escalation did not result in an improvement of DSS and it also increased the complication rates. Future research should focus on the eradication of radioresistant clones either by the improvement of surgical resection or the use of cytotoxic agents that can target on the radioresistant tumor cells.

Simultaneously presenting head and neck and lung cancer: a diagnostic and treatment dilemma

OBJECTIVES/HYPOTHESIS

Synchronous tumors are defined as malignancies presenting within 6 months of the index tumors. A significant subset of patients present at initial evaluation with malignant tumors of both the head and neck (head and neck squamous cell carcinoma) and the lung, which are termed simultaneous primaries. The management and treatment outcomes in this cohort of patients have not been clearly defined and are the subject of the present review.

STUDY DESIGN

Retrospective chart review of previously untreated patients.

METHODS

From January 1974 to December 1997, a total of 2964 patients were treated for mucosal squamous cell carcinoma of the head and neck. Forty-two patients fulfilled the criteria for synchronous head and neck and lung malignancy. Of these, 27 patients had simultaneous tumors of the head and neck and the lung. This cohort of patients (n = 27) was stratified into three treatment groups. Patients in group A (n = 10) had resectable head and neck and lung primaries treated with curative intent. Group B (n = 8) was composed of patients who could have been treated with curative intent but declined and were given only palliative therapy. Patients in group C (n = 9) were candidates for only palliative treatment.

RESULTS

The estimated 5-year disease-specific survival in group A was 47%, whereas patients in group B had a 5-year disease-specific survival of only 13% (P =.05). There were no survivors beyond 1 year in group C. The presence of mediastinal adenopathy in patients in group A portended poor clinical outcome. There was an estimated 5-year disease-specific survival of 51% in patients with no preoperative evidence of mediastinal adenopathy (n = 7), whereas 67% of patients with radiological evidence of mediastinal adenopathy died (two of three patients).

CONCLUSION

The presence of simultaneous head and neck squamous cell carcinoma and pulmonary malignancies should not be a deterrent to aggressive surgical therapy because a potentially satisfactory outcome can be expected in these patients.

Cancer of the buccal mucosa: are margins and T-stage accurate predictors of local control?

Cancer of the buccal mucosa is an uncommon and aggressive neoplasm of the oral cavity. Less than 2% of patients treated for cancer of the oral cavity at Roswell Park Cancer Institute (RPCI) from 1971 to 1997 had primary buccal cancers. Because the majority of these patients did not undergo any adjuvant treatment, this group provided us with the opportunity to assess the relationship between margin status and local recurrence for both small (T1-T2) and large (T3-T4) tumors treated with surgery alone.

MATERIALS AND METHODS

The RPCI tumor registry database reported 104 patients who were treated for buccal carcinoma. A retrospective chart review identified 27 patients who met our criteria for a buccal mucosal primary tumor (epicenter of the mass in the buccal mucosa). There were 13 men and 14 women, ranging in age from 34 to 94 years (mean, 75). Data were collected regarding patient demographics, presenting symptoms, stage, treatment received, and outcome.

RESULTS

All patients underwent surgical resection of their primary lesion; 21 (75%) had T1 or T2 tumors. The rate of local recurrence was 56% for the group as a whole. Patients with close or positive margins had a 66% local failure rate as compared with 52% when surgical margins were negative (greater than or equal to 5 mm from the resection margin after tissue fixation; P = ns). Among those in whom negative margins were achieved, patients with T1-T2 disease had a 40% local failure rate with surgical resection alone.

CONCLUSIONS

Local excision of T1 and T2 buccal mucosa cancers with pathologically negative margins had a high rate of local recurrence in our series. Low T-stage and negative margins are not adequate predictors of local control. Even early buccal tumors may benefit from adjuvant therapy to enhance local control.

Patterns of nodal metastasis and surgical management of the neck in supraglottic laryngeal carcinoma

BACKGROUND

Appropriate management of the clinically negative (N0) neck in supraglottic laryngeal cancer continues to be an area of controversy in head and neck surgery. Our treatment policy has been aggressive surgical management even in the clinically N0 neck.

METHODS

Between 1971 and 1991, 104 patients had the primary diagnosis of supraglottic laryngeal cancer. Ninety of these patients received their treatment at Roswell Park Cancer Institute and are the subject of this retrospective review.

RESULTS

All neoplasms included in this study were squamous cell cancers. The most common subsite involved with tumor in our series was the epiglottis, followed by the aryepiglottic folds and false cords. Supraglottic laryngectomy was performed of 29% of the cases; the remainder received total laryngectomy. Thirty-six percent of the patients had pathologic stage I/II disease, and 64% had stage III/IV. The 5-year survival rates were 100%, 81%, 73%, and 63% for stages I through IV, respectively. Fifty-seven patients had clinically N0 disease at presentation; of these 34 underwent elective neck dissection, and the remaining 23 patients were observed. Of those patients receiving neck dissection, 30% (n = 10) were found to have histologically positive disease, and of the 23 patients observed, 30% (n = 7) had histologically positive regional (neck) disease. Of the 17 clinically N0 and pathologically N+ patients, 82% (14 of 17) had involvement of level I (submandibular triangle), and 100% had involvement of level II. The incidence of bilateral disease in the clinically N0 patient was 44%. There were no local failures.

CONCLUSIONS

There is a high incidence of occult regional disease even in early-stage supraglottic squamous cell carcinoma of the larynx. In the surgical management the clinically N0 neck, we presently recommend bilateral neck dissection of levels I through IV to adequately address those regions at highest risk for occult disease.