Radiation therapy in early carcinoma of the glottic larynx T1N0M0

Comparison between 4-MV and 6-MV radiotherapy in T1N0 glottic cancer

OBJECTIVES/HYPOTHESIS

The purpose of this study was to report the outcomes of a retrospective consecutive cohort study of patients with T1N0M0 glottic carcinoma treated with 4-MV or 6-MV radiotherapy.

STUDY DESIGN

Retrospective case-control study.

METHODS

This was a retrospective review of all patients with T1N0M0 glottic carcinoma treated with radiotherapy between January 2000 and December 2012 in the Department of Radiation Oncology at National Cancer Center Singapore. A total of 124 patients were included. Clinical endpoints of interest were: local control (LC), overall survival (OS), and disease-specific survival (DSS). Other prognostic factors for LC were also analyzed: age, gender, smoking status, T substage, dose fraction, field size, anterior commissure involvement, total dose, and overall treatment time.

RESULTS

Six-megavolt photon radiotherapy was used in 73 patients and 4-MV photon radiotherapy in 51 patients. Median follow-up was 4.9 years. The 5-year LC and OS were as follows: 4 MV, 91.6% and 83.4%; 6 MV, 88.8% and 82.8%; and the 5-year LC, OS, and DSS for all patients were 90.4%, 83.3%, and 98.3%. There was no significant difference in LR and OS between 4-MV and 6-MV radiotherapy (P = .92, P = .16, respectively). In the univariate analysis of LC, none of the prognostic factors was statistically significant. Twenty patients (23%) developed second primary cancers, the majority in the lungs.

CONCLUSIONS

Six-megavolt photon radiotherapy yields comparable results to 4-MV photons. Bolus and computed tomographic simulation are useful to ensure adequate dose coverage of target volume. Follow-up postradiotherapy should incorporate chest imaging, smoking cessation advice, and thyroid function test.

LEVEL OF EVIDENCE

4 Laryngoscope, 127:1061-1067, 2017.

Radiotherapy for glottic T1N0 carcinoma with slight hypofractionation and standard overall treatment time: importance of overall treatment time

OBJECTIVE

We retrospectively investigated treatment outcomes in patients with glottic T1 carcinoma treated with 65 Gy in 26 fractions four times a week and discuss the importance of the overall treatment time.

METHODS

Two hundred one patients with glottic T1 carcinoma were evaluated. Sixty-five Gray in 26 fractions were delivered for 200 patients, whereas 1 patient received 62.5 Gy in 25 fractions. We delivered radiotherapy once daily four times a week in this period, for a weekly dose of 10 Gy. Weekdays except Wednesday were treatment days.

RESULTS

The overall survival rate was 96.8 ± 1.3% (standard error) at 3 years and 90.8 ± 2.2% at 5 years. The local control rate was 91.9 ± 2.0% at 3 years and 89.8 ± 2.3% at 5 years. In patients with an overall treatment time equal to or longer than 47 days, the local control rate was 82.6 ± 6.0% at both 3 and 5 years. In the patients with overall treatment time equal to or less than 46 days, the local control rate was 94.6 ± 1.9% at 3 years and 91.8 ± 2.4% at 5 years. There was a significant difference between these two groups (P = 0.0349). A severe late radiation reaction occurred in one patient. He experienced severe laryngeal edema that required tracheotomy at 6 months after the completion of radiotherapy. The tracheotomy was closed at 14 months after completion of radiotherapy.

CONCLUSIONS

Overall treatment time seems to be an important factor for a good local control rate for glottic T1N0 carcinoma even when treated with slight hypofractionation.

BCCIP as a prognostic marker for radiotherapy of laryngeal cancer

BACKGROUND

Recent studies have shown that BCCIP (BRCA2 and CDKN1A interacting protein) is essential for maintaining the transactivation activity of wild type p53. We analyzed the expression of BCCIP and p53 in a cohort of laryngeal cancer treated with radiotherapy and assessed whether BCCIP and p53, alone or in combination, would correlate with local control and overall survival.

METHODS

One hundred twenty-three patients treated between 1975 and 2000 for early stage (stages I and II) squamous cell carcinoma of the larynx were included in the study. Treatment consisted of radiation therapy (RT) with standard fields and fractionation to a median dose of 66Gy. Tissue was collected from pre-RT biopsies and constructed in a tissue microarray, and BCCIP expression and p53 expression were determined using immunohistochemistry.

RESULTS

Loss of expression of BCCIP in combination with normal p53 (negative p53 staining) was associated with local recurrence (RR 2.04; 95% CI 0.99-4.56, p=0.05) and poor overall survival (RR 2.09; 95% CI 1.21-4.00, p=0.008) compared to patients who did express BCCIP. Expression of BCCIP or p53 alone was not found to be independently associated with benefits in local control or overall survival.

CONCLUSIONS

This study provides clinical evidence that BCCIP contributes to outcomes in patients with laryngeal cancer treated with RT. This benefit may be a result of increased radiosensitivity in patients who have functional BCCIP and p53. These data may be used to identify sub-groups of laryngeal cancer patients who are more likely to be cured with radiotherapy.

Prognostic significance of vascular endothelial growth factor protein levels in T1-2 N0 laryngeal cancer treated with primary radiation therapy

BACKGROUND

The purpose of this study was to assess the prognostic value of vascular endothelial growth factor protein levels in a large cohort of patients with T1-T2 N0 laryngeal cancer treated with primary radiation therapy (XRT).

METHODS

Primary tumor specimens from a cohort of 123 patients with T1-T2 N0 laryngeal cancer treated with XRT between 1975 and 2000 were constructed into a tissue microarray. Clinical prognostic factors included age, sex, T classification, and tumor subsite. Molecular prognostic factors included vascular endothelial growth factor, epidermal growth factor receptor, and p53 expression, determined by using immunohistochemistry on tissue microarrays. The association between vascular endothelial growth factor status, covariables, and outcome was assessed.

RESULTS

With a median follow-up of 9.9 years, 32 (26%) were diagnosed with local relapse (5-year local relapse-free rate, 70.4%). T2 tumor stage (31.7%) was a significant predictor of local relapse (relative risk [RR], 1.71; 95% confidence interval [CI], 1.21-2.43; P<.05). Positive expression of vascular endothelial growth factor, epidermal growth factor receptor, and p53 were: 8.5%, 58.7%, and 36.4%, respectively. In univariate analysis, vascular endothelial growth factor positivity was a significant predictor of overall survival (RR = 1.62; 95% CI, 0.99-2.42; P = .05). In multivariate analysis, positive vascular endothelial growth factor status maintained significant correlation with overall survival (RR, 2.79; 95% CI, 1.49-4.95; P = .002).

CONCLUSIONS

Vascular endothelial growth factor positivity appeared to be a significant predictor of overall survival in a multivariate model. Further evaluation of vascular endothelial growth factor-positive laryngeal cancers treated with primary XRT is warranted.

The treatment of early laryngeal cancers (T1-T2 N0): surgery or irradiation?

BACKGROUND

Carcinoma of the larynx is the most common cancer affecting the head and neck region. In Northern Europe, early laryngeal cancer is almost universally treated by irradiation, but elsewhere it is treated by surgery. The main aim of this study was to determine whether there was any difference in survival between the two main therapeutic options. The secondary aim was to assess speech and voice quality in a small, randomized sample of patients from each treatment group.

METHODS

The subjects investigated were 488 patients with T1-2, N0 squamous cell carcinoma of the larynx. The patients form an unselected sequential group of our institution's experience with treating this disease over three decades. Four hundred nineteen patients were treated by irradiation, and 69 were treated with surgery. Most surgical patients were treated earlier in the series, whereas radiotherapy later became the treatment of choice. The primary outcome measures were recurrence at the primary site, recurrence in the neck, and tumor-specific survival. The secondary outcome measure was speech and voice quality. Statistical analysis was by univariate and multivariate analysis of association and survival. Surgery included horizontal or vertical partial laryngectomy and various minor procedures on the glottis, including cordectomy. Over a 30-year period, radiotherapy was administered to a dose of 60-66 Gy given over 30-33 daily fractions.

RESULTS

Surgery tended to be performed early on in the series and radiotherapy thereafter. Surgery was more likely to be carried out for supraglottic disease. These differences apart, the radiotherapy and surgery groups of patients were well matched. The 5-year tumor-specific survival for those treated by irradiation was 87% and for surgery it was 77% (p=.1022). Glottic cancer and T1 disease were associated with high 5-year survivals: 90% and 91%, respectively. Supraglottic site and T2 disease both had a poorer prognoses: 79% and 69%, respectively. The differences for both sets of data were significant. There was no significant difference in primary site recurrence rates for the two treatment modalities, but regional recurrence was higher in the surgery group. Further analysis demonstrated that this was not a function of surgery per se but rather of the unit's policy toward the N0 neck at the time surgery was carried out. Regarding speech and voice quality, radiotherapy was far superior to surgery. All patients in the radiotherapy group but only 3 of 10 in the surgery group were judged to have a good or normal voice (p=.0017).

CONCLUSIONS

Both surgery and irradiation are equally effective at treating early laryngeal carcinoma. Speech and voice were highly significantly better in patients treated by irradiation than in those treated by surgery.

Radiotherapy for patients with early-stage glottic carcinoma: univariate and multivariate analyses in a group of consecutive, unselected patients

BACKGROUND

Radiotherapy (RT) has a remarkable success rate in the treatment of patients with glottic carcinoma. The objectives of the current study were to assess the results in a group of consecutive patients with comparable characteristics who were treated with RT (6-megavolt photon linear accelerator) and to determine the prognostic factors that may influence local control in patients with early-stage glottic carcinoma. The impact on local control of tobacco smoking and second primary malignancies also was investigated.

METHODS

Four hundred ten patients with T1-T2 squamous cell carcinoma of the glottis who were treated between 1986 and 2001 were analyzed retrospectively with regard to local control and overall survival. Potential prognostic factors for local control were evaluated with univariate and multivariate models. The impact of technologic advances also was evaluated.

RESULTS

The 5-year and 10-year overall survival rates were 83% and 63.5%, respectively. The overall 10-year local control rate for patients with T1-T2 glottic carcinoma was 89%. The median time to recurrence was 7 months. Univariate analysis showed that tumor category, tumor size, macroscopic appearance of the lesion, RT fraction size, persistent edema, year of RT treatment, unchanged dysphonia, and surgical option all had a significant influence on local control; whereas multivariate analysis showed that only persistent dysphonia and year of RT treatment were significantly associated with increased local control. A 22.2% rate of second primary malignancies was reported: second primary tumors were the major cause of death in the patients studied. Only 2 patients died of laryngeal carcinoma; 304 patients were alive with their disease in complete remission, 1 patient was alive with recurrent laryngeal carcinoma after undergoing salvage surgery, and 103 patients died of either intercurrent disease or a second primary tumor.

CONCLUSIONS

The use of a 6-megavolt photon linear accelerator achieved a high rate of local control in patients with T1-T2 glottic carcinoma. Dysphonia and the year of RT treatment were the most important prognostically significant factors for patient outcome. The occurrence of a second primary tumor was the most frequent cause of death, especially among patients who did not stop smoking after a diagnosis of glottic carcinoma.

Vocal outcome after endoscopic cordectomies for Tis and T1 glottic carcinomas

A cohort of 101 patients with previously untreated glottic cancer (15 Tis, 66 T1a, and 20 T1b) who underwent endoscopic CO2 laser excision between January 1995 and December 1997 was prospectively analyzed. The depth and extension of the excision were graded according to the European Laryngological Society Classification including 5 types of cordectomy. All patients were subsequently examined every 2 months for a period ranging from 30 to 66 months (mean, 48 months). The rates of 5-year overall survival, disease-free survival, ultimate local control with laser alone, and laryngeal preservation were 85%, 87%, 93%, and 95%, respectively. Sixty-nine patients underwent, at least 1 year after surgery, videolaryngostroboscopy combined with perceptual and objective evaluation of the voice, and spirometry. Acoustic parameters were compared with those obtained in a matched control group by Kruskal-Wallis test. No statistically significant difference was found (p > .05) between patients submitted to subepithelial (type I) and subligamental (type II) cordectomies and controls.

[Treatment of T1N0 glottis carcinoma with radiotherapy. Results at our center and review of the literature]

OBJECTIVE

To evaluate the results of radiotherapy in the treatment of patients with T1N0 glottic squamous cell carcinoma.

MATERIAL AND METHODS

Retrospective study of a cohort of 338 patients with T1N0 glottic carcinoma treated with radiotherapy at our institution between 1985-1997. A review of the literature published during the last ten years was carried out.

RESULTS

Local control with radiotherapy in our patients was 82%, reaching 97% when salvage surgery was included. The local control with radiotherapy in most of the published series ranges between 81.90%.

CONCLUSIONS

Treatment with radiotherapy achieves local control in early glottic carcinomas (T1N0) in 80-90% of cases. In our centre such treatment achieved local control in 82% of cases.

Treatment of early and moderately advanced vocal cord carcinoma with 6-MV X-rays

PURPOSE

Whereas there are many reports regarding treatment of early vocal cord cancer with cobalt 60 or 2-4-MV X-rays, there are still few reports on the results of treatment with 6-MV X-rays. Theoretically, 6-MV X-rays result in greater underdosage of tumor at the air-tissue interface and at the anterior commissure. This paper analyzes the results of irradiation of early and moderately advanced squamous cell carcinoma of the true vocal cord treated exclusively with 6-MV X-rays in a community hospital. The literature pertinent to the issue is reviewed.

METHODS AND MATERIALS

Eighty-three patients with Tis, T1, T2, or T3 squamous cell carcinoma of the true vocal cord were treated with curative intent at Bethesda Memorial Hospital in Boynton Beach, Florida between April 1986 and April 1998. The dose schedules most commonly used were 63 Gy in 28 fractions (2.25 Gy per fraction once a day) for T1 tumors or 74.40 Gy in 62 fractions (1.2 Gy per fraction twice a day) for T2 and T3 tumors. All patients have minimum 2-year follow-up; 63 (76%) have 5-year minimum follow-up.

RESULTS

Local control was achieved in 6 of 6 Tis, 53 of 54 (98%) T1, 8 of 8 T2, and 6 of 6 T3 lesions. No complications were encountered.

CONCLUSIONS

A recent literature review indicates that the treatment of early vocal cord cancer with 6-MV X-rays remains controversial. The dose schedules used in the present paper produced a high rate of local control, a finding that is consistent with reports of other investigators who used dose schedules similar to those used in the present series. However, several other investigators have reported significantly lower rates of local control for T1 or T2 glottic cancer treated with 6-MV X-rays when compared to results obtained with cobalt 60 or 4 MV at their own institution. The latter institutions used lower total doses and/or lower dose per fraction than those institutions reporting high rates of local control with 6 MV. Data from the literature, as well as our own data, are consistent with the following hypotheses: (1) the lower rates of local control reported by several institutions when using 6 MV compared with cobalt or 2-4 MV, using the same radiation dose schedules for each beam energy, indicate that underdosage of mucosal surfaces in the laryngeal air cavity may be a clinically important phenomenon, and (2) time-dose factors, although certainly important for lower energy beams, may be even more important when using 6 MV.

Primary radiation therapy for early glottic cancer

OBJECTIVES/HYPOTHESIS

Early glottic squamous cell carcinoma can be effectively treated with either radiation or surgical intervention. We evaluated our experience treating early glottic cancer with primary radiation therapy and our vertical hemilaryngectomy (VHL) salvage experience.

STUDY DESIGN/METHODS

Retrospectively, patient records between January 1986 and December 1994 were reviewed and 45 patients with early glottic squamous cell carcinoma who received full-course radiation therapy at the Cleveland Clinic Foundation were identified.

RESULTS

Local control after radiation therapy was 80% overall, 87.5% for T1 lesions, and 75% for T2 lesions. Four patients underwent VHL for salvage after local recurrence; 1 was successfully salvaged with VHL. Five patients underwent total laryngectomy salvage after radiation therapy; all were successful. Only 1 of the 6 patients who were originally candidates for VHL before radiation therapy was successfully salvaged with the larynx preserved.

CONCLUSIONS

Our local control rates using primary radiation therapy are consistent with prior published series, but voice sparing salvage is poor.

Local recurrences following transoral laser surgery for early glottic carcinoma: frequency, management, and outcome

Although transoral laser surgery (TLS) for the treatment of early stage glottic carcinoma is now widely used, the patterns of local recurrences, related re-treatment methods, and results have not been documented comprehensively. Two hundred fifty-two patients with glottic carcinoma stage I or II were treated for cure with TLS alone and followed up for 24 to 139 months (mean, 62 months). Their charts were retrospectively reviewed to identify local recurrence patterns. Thirty-five patients (13.9%) presented with local recurrences or second laryngeal primaries 4 to 84 months (mean, 23 months) after initial treatment. Of the 161 patients classified T1N0M0, 21 (13.0%) suffered local recurrences, and in the 91 classified T2N0M0, 14 (15.4%) tumors recurred. If tumors recurring more than 60 months after initial treatment are considered second primary tumors rather than recurrences, then only 18 (11.2%) of 161 patients classified T1N0M0 would have had a recurrence. However, the difference in local control between patients with stage I versus stage II disease would still not be significant (p = .41). Of the 35 patients with local recurrences, 16 (45%) were managed with total laryngectomy, 10 (28.6%) with further TLS, 4 (11.4%) with partial laryngectomy, and 2 (5.7%) with radiotherapy, and 3 (8.6%) had no curative treatment. Accordingly, 16 patients (45.7%) with local treatment failure could be treated with further organ-sparing treatment methods. The actuarial overall survival, disease-specific survival, and organ preservation rates 5 years after the diagnosis of recurrent disease were 43.6%, 74.6%, and 33.7%. Transoral laser surgery leads to local control rates that are comparable to those found after radiotherapy for lesions classified T1 and leads to slightly better control rates for lesions classified T2, but the results are inferior to those achieved with conventional partial laryngectomy. However, if local recurrence occurs, then more re-treatment options are available after TLS as compared to initial radiotherapy or open surgery.

Clinical radiobiology of glottic T1 squamous cell carcinoma

PURPOSE

Radiation therapy is the treatment of choice for early glottic squamous cell cancer in many institutions over the world. Despite a relatively homogenous clinical model of T1 glottic tumors for the fractionation studies, the relationships between dose-time parameters remain unclear. To analyze the influence of fractionation parameters and hemoglobin level on tumor cure, this study has been performed.

MATERIALS AND METHODS

This is a retrospective review of 235 patients with T1N0M0 glottic cancer treated by radiation therapy alone given in a conventional schedule with 5 fractions each week. The individual total dose, dose per fraction, and overall treatment time (OTT) ranged from 51-70 Gy, 1.5-3.0 Gy, and 24-79 days, respectively. The median follow-up was 48 months. Patient data--total dose, dose per fraction, OTT, and hemoglobin level (Hb) measured before the radiation treatment--were fitted by the mixed LQ/log-logistic model.

RESULTS

The 5-year local relapse-free survival rate was 84%. All parameters included in the mixed LQ/log-logistic model improved the fit significantly. The dose-response curve for 235 patients with T1 glottic cancer was well defined and steep, and showed significant decrease in tumor control probability (TCP) when total doses were below 61 Gy. The 10-day prolongation of OTT, from 45 to 55 days, decreased the TCP by 13%. The dose of 0.35 Gy/day, compensated repopulation during the 1 day of prolongation, which indicates a potential doubling time (Tpot) for glottic T1 tumor clonogens of 5.5 days. The drop of Hb level of 1 g/dl (from 13.8 g/dl to 12.8 g/dl) gave a 6% decrease of TCP, provided that OTT was 45 days.

CONCLUSION

The significant correlation between the total dose, overall treatment time, hemoglobin concentration, and tumor control probability has been found for T1 glottic cancer.