Long-term outcome and patterns of failure in patients with advanced head and neck cancer
© Hauswald et al; licensee BioMed Central Ltd. 2011
Received: 19 January 2011
Accepted: 10 June 2011
Published: 10 June 2011
To access the long-time outcome and patterns of failure in patients with advanced head and neck squamous cell carcinoma (HNSCC).
Methods and materials
Between 1992 and 2005 127 patients (median age 55 years, UICC stage III n = 6, stage IV n = 121) with primarily inoperable, advanced HNSCC were treated with definite platinum-based radiochemotherapy (median dose 66.4 Gy). Analysed end-points were overall survival (OS), disease-free survival (DFS), loco-regional progression-free survival (LPFS), development of distant metastases (DM), prognostic factors and causes of death.
The mean follow-up time was 34 months (range, 3-156 months), the 3-, 5- and 10-year OS rates were 39%, 28% and 14%, respectively. The median OS was 23 months. Forty-seven patients achieved a complete remission and 78 patients a partial remission. The median LPFS was 17 months, the 3-, 5- and 10-year LPFS rates were 41%, 33% and 30%, respectively. The LPFS was dependent on the nodal stage (p = 0.029). The median DFS was 11 months (range, 2-156 months), the 3-, 5- and 10-year DFS rates were 30%, 24% and 22%, respectively. Prognostic factors in univariate analyses were alcohol abuse (n = 102, p = 0.015), complete remission (n = 47, p < 0.001), local recurrence (n = 71, p < 0.001), development of DM (n = 45, p < 0.001; median OS 16 months) and borderline significance in nodal stage N2 versus N3 (p = 0.06). Median OS was 26 months with lung metastases (n = 17). Nodal stage was a predictive factor for the development of DM (p = 0.025). Cause of death was most commonly tumor progression.
In stage IV HNSCC long-term survival is rare and DM is a significant predictor for mortality. If patients developed DM, lung metastases had the most favourable prognosis, so intensified palliative treatment might be justified in DM limited to the lungs.
KeywordsHNSCC head and neck cancer radiotherapy radiochemotherapy irradiation long-term follow-up
The incidence of oropharyngeal cancer in German men in 2004 was 16.3 per 100.000 . Smoking and alcohol consumption were known risk factors for the development of head and neck squamous cell carcinoma (HNSCC)[2, 3]. New and optimized treatment methods increase loco-regional progression-free survival (LPFS) and disease-free survival (DFS) in patients with advanced head and neck carcinomas and thereby overall survival (OS) in the short-term follow-up [4–7]. Data on long-term follow-up and patterns of failure are rare . The published incidence of distant metastases (DM) in HNSCC is widespread and varies between 6% and 47%[9–14]. Spector et al published e. g. an incidence of 8.5% in 2550 patients treated for squamous cell carcinomas of the larynx and hypopharynx between 1971 and 1991 . The published incidence of DM in a subgroup of patients with stage IV disease was even as high as 55%. Reported factors influencing the incidence of DM were tumor stage, especially the extension of nodal disease, histological patterns and loco-regional tumor control [9, 16–18]. Lim et al reported that the presence of pathologic lymph nodes, especially bilateral neck metastases, was an independent risk factor for the development of DM in oral and oropharyngeal squamous cell carcinomas . The leading site for DM were the lungs, followed by the skeletal system [9, 14]. So DM might become a relevant problem and data on outcome is warranted to improve the adaption of the treatment. This retrospective study performs uni- and multivariate analyses on the outcome of patients treated with concurrent platinum-based, hyperfractionated-accelerated radiochemotherapy for primarily inoperable, advanced HNSCC according to the treatment protocol of Staar et al. . Furthermore factors possibly impacting on the development of DM in patients with advanced HNSCC were analyzed to identify subgroups, in which additional diagnostic and/or therapeutically options might improve prognosis, morbidity and mortality.
Patients and methods
No. of patients
Tumor stage according to UICC classification 1997
Diagnostic work-up and Treatment
The initial workup included physical and laboratory examinations, imaging procedures, such as x-ray studies, ultrasound (US), magnetic resonance imaging (MRI) or computerized tomography scans (CT) as well as biopsies. Positron-emission tomography (PET) was not performed on a regular base. Data on HPV16/p16 was retrospectively accessible in 43 (34%) of the patients. Five of these patients were HPV16/p16 positive. The treatment consisted of a concurrent hyperfractionated-accelerated radiotherapy and platinum-based chemotherapy. Irradiation was planned using two- or three-dimensional-based techniques and controlled by simulator-based imaging. Patient immobilization was done by thermoplastic masks. Megavolt radiotherapy was administered by linear accelerators to a median dose of 66.4 Gy (range, 59.4-70.3 Gy). The median time interval between initial diagnosis and first irradiation was 25 days. Chemotherapy consisted of 5-FU (600 mg/m2 body surface) as a continuous infusion and carboplatinum (70 mg/m2 body surface) as short-term infusion day 1-5 and 29-33. Ten patients had to quit chemotherapy early due to toxicity (n = 2), personal wish (n = 2) or undocumented reasons (n = 6). Regular follow-up examinations included clinical examination, US, MRI or CT and were classified as complete remission (CR, requiring no detectable disease), partial remission (PR, tumor mass reduction of at least 50%), no response (NR, less than 50% tumor mass reduction) or as progressive disease (PD). The first follow-up examination was scheduled 6 to 8 weeks after radiotherapy was finished. Radiooncological treatment time ranged between 31 and 80 days (median 40 days).
The tumor was staged according to the TNM classification recommended by the International Union against Cancer (UICC) 1997. The latter was analysed regarding overall survival (OS), disease-free survival (DFS), loco-regional progression-free survival (LPFS), distant metastases-free survival (DMFS) and causes of death. Statistical analyses were carried out with SPSS statistical package (SPSS Inc., Chicago, IL, U.S.A.) using log-rank test (Mantel-Cox), Kaplan-Meier's estimation, multivariate Cox-regression analysis (backwards stepwise, p out >0.1, factors included: total dose of irradiation (>/= or < 66,4Gy); treatment time (>/= or <40 days); alcohol abuse; tobacco abuse; age (>/= or <55 years); Stage IVa versus IVb; stage N2 versus N3; localization oro- versus hypopharynx; CR versus PR; distant metastases; loco-regional recurrence) and Fisher's exact test. Significance was defined as p-value < 0.05. All time estimates began with the initiation of radiation treatment. Documented long-term side effects were classified according to the RTOG/EORTC Late Radiation Morbidity Scoring Scheme (Appendix IV, CTC Version 2.0).
Response to treatment and loco-regional control
The mean follow-up time was 34 months (range, 3-156 months). Forty-seven patients (37%; n = 29 hypopharyngeal- and n = 18 oropharyngeal carcinoma) achieved a complete remission, whereas 78 patients (61%; n = 55 hypopharyngeal- and n = 23 oropharyngeal carcinoma) showed a partial remission. One patient (1%) had progressive disease. No treatment response was available in one patient (1%). The median LPFS was 17 months, the 3-, 5- and 10-year LPFS rates were 41%, 33% and 30%, respectively. The median LPFS was significantly different (p = 0.029) in patients with N0 disease (20 months), N1 disease (43 months), N2 disease (18 months) and N3 disease (7 months).
Distant metastases and distant metastases-free survival
Results of the univariate analyses
Stage IVa versus IVb
Stage N2 versus N3
Total dose of irradiation (>/= or <66,4Gy)
Total radiooncological treatment time (>/= or <40 days)
Complete versus partial remission
Age (>/= or <55 years)
Secondary primary tumors
Results of the multivariate analyses on LPFS, DFS and OS
Stage IVa versus IVb
Stage N2 versus N3
CR versus PR
Age (>/= or <55 years)
Long-term side effects
Most common long-term side effects documented were xerostomia and alterations in taste. At last follow-up, 17 of the 33 patients who were still alive (51%) reported grade III to IV xerostomia.
Second primary carcinoma
Second primary carcinomas developed in 27 patients (21%). Their most common location was the head and neck region (n = 9), followed by the esophagus (n = 6), lungs (n = 5) and stomach (n = 2). One patient each developed a hepatocellular-, pancreatic-, penile-, prostatic- and renal cell carcinoma. Patients with secondary carcinomas did not have a significantly longer survival than those without secondary tumors (46 months versus 25 months, p = 0.26).
We report on a retrospective analysis of the treatment results in 127 patients treated with concurrent, platinum-based, hyperfractionated-accelerated radiochemotherapy between 1992 and 2005 for primarily inoperable advanced oro-and hypopharyngeal squamous cell carcinoma. A treatment regime for locally advanced oro- and hypopharyngeal squamous cell carcinoma is a definite concurrent platinum-based radiochemotherapy. In the daily routine, guidelines regarding the optimal treatment of the patients, including those with DM, are warranted. This study's aim was to evaluate the long-term treatment outcome at our institution as well as patterns of failure and help finding ways to improve prognosis, morbidity and mortality in patients with advanced HNSCC.
The treatment regime used in our patients was based on the prospective and multicentre trial on radiotherapy in advanced head and neck cancer initially published by Staar et al . After accelerated and hyperfractionated radiotherapy with concurrent 5-FU and carboplatinum chemotherapy the authors achieved a 1- and 2-year OS rate of 66% and 48%, respectively. The total response to treatment was above 90%. The rate of xerostomia 1 year after treatment was 66%. An update on the report was recently published by Semrau et al . The reported 5-year overall survival rate was 25.6% and the median survival 23 months. In a trial on concomitant radiochemotherapy in advanced oropharyngeal cancer Denis et al reported an median survival of 20 months and a 5-year overall survival rate of 22% for patients treated with concomitant radiochemotherapy . The 3-, 5- and 10-year OS rates of 39%, 28% and 14%, respectively as well as the median OS of 23 months in our cohort were comparable and in good agreement to the published data.
Adelstein et al reported on 222 patients with advanced head and neck squamous cell carcinoma treated with a multiagent concurrent radiochemotherapy with 5-FU and cisplatin during weeks 1 and 4 . The tumor was located in the oropharynx in 52%. The 5-year OS rate was 65%. This superiority of the results by Adelstein et al may be due to the selection, since preserving organ function was one mayor concern and patients with tumor-invasion into the bone or cartilage were not considered appropriate for this treatment approach. In their report on 81 patients treated with hypofractionated accelerated radiotherapy and concurrent chemotherapy for advanced HNSCC (including larynx, oral cavity, oro- and hypopharynx) Sanghera et al reported a 2-year OS rate of 67.8% in 68 patients with UICC stage III and IV . The superiority of these results may be due to the lower count of T4 tumors (25/81 patients) and lower count of N2c or N3 disease (14/81 patients) in the cohort of Sanghera et al. Improvements in survival with 1- and 2-year OS rates of up to 81.5% and 71.6% and loco-regional tumor relapse rates of 33-35% were found in studies on concomitant boost accelerated radiation regimes with concomitant cisplatin [4, 8].
As seen in our results as well as in earlier reports, there is a high incidence of persistent xerostomia which could negatively influence quality of life. An actual approach of reducing side effects of radiation therapy was published by Teguh et al. . The authors concluded that hyperbaric oxygen therapy shortly after finishing radiation therapy is an effective option for reducing radiation-induced side effects.
In the question of factors influencing the incidence of DM different variables as tumor stage, histological patterns and loco-regional tumor control were reported. Best predictor for overall survival and distant failure as reported by Brockstein et al was the stage of nodal disease . Leon et al analysed 1244 patients with loco-regionally controlled head and neck cancers. They found N-stage, T-stage and the localization of the tumor at hypopharynx or supraglottis to be variables increasing the incidence of DM on multivariate analysis . In the multivariate analysis of Lim et al the presence of pathologic positive lymph node, especially bilateral neck metastases, was an independent risk factor for the appearance of isolated distant metastases in oral and oropharyngeal squamous cell carcinoma . In our patient group, the stage of nodal disease was a significant predictor for survival (p = 0.025), but neither primary tumor localization (p = 0.89), nor treatment response (p = 0.23) or age (p = 0.85) were significantly related to the development of distant metastases. This finding might be due to the fact of a relatively small cohort. Extracapsular tumor spread and histological grading were retrospectively not accessible.
The most common site of distant metastases in previously published data as well as found in our cohort's findings were the lungs [9, 14, 27]. Furthermore, in the report by Alvi et al. DM developed after a mean time of 15 months and survival was 5 months after diagnosis of DM . Median time to distant failure (median 8 months) and median OS (median 16 months) in our cohort were comparable, keeping in mind that the time estimation in our analysis started at the initial diagnosis of the oro- or hypopharyngeal carcinoma. In general the salvage rates for distant failure were poor. Spector et al reported a curing rate of 16% in pyriform carcinoma with early solitary focal DM . A 5-year survival rate of 43% after surgical resection achieved Mazer et al on 44 patients with pulmonary metastases from upper aerodigestative tract cancer . Finley et al reported on their evaluation of surgical resection of pulmonary metastases of head and neck cancer that a resection of a solitary pulmonary metastasis resulted in long-term survival in selected patients . Since treatment after diagnosis of DM was palliative and individual in most cases in our cohort, it was not useful to analyze the different treatment approaches in the situation of DM.
Hyperfractionated-accelerated radiotherapy with concurrent platinum-based chemotherapy is an effective treatment option and offers a chance for long-term survival for patients with primarily inoperable, advanced HNSCC, which is still rare. New and optimized treatment methods increase loco-regional tumor control in patients with advanced head and neck carcinomas and thereby survival. So stage IV patients might be diagnosed with DM and this might become a relevant problem in achieving long-term control. Patients with DM restricted to the lungs had the most favourable prognosis compared to patients with other metastatic locations. Intensified palliative treatment might be justified especially in cases of DM limited to the lungs.
- Batzler W, Giersiepen K, Hentschel S: Krebs in Deutschland 2003 - 2004. Häufigkeiten und Trends2008. [http://www.rki.de/cln_151/nn_205770/DE/Content/GBE/Gesundheitsberichterstattung/GBEDownloadsB/KID2008,templateId=raw,property=publicationFile.pdf/KID2008.pdf]Google Scholar
- Mashberg A, Boffetta P, Winkelman R, Garfinkel L: Tobacco smoking, alcohol drinking, and cancer of the oral cavity and oropharynx among U.S. veterans. Cancer 1993, 72: 1369-1375. 10.1002/1097-0142(19930815)72:4<1369::AID-CNCR2820720436>3.0.CO;2-LView ArticlePubMedGoogle Scholar
- Lagiou P, Georgila C, Minaki P, Ahrens W, Pohlabeln H, Benhamou S, Bouchardy C, Slamova A, Schejbalova M, Merletti F, Richiardi L, Kjaerheim K, Agudo A, Castellsague X, Macfarlane TV, Macfarlane GJ, Talamini R, Barzan L, Canova C, Simonato L, Lowry R, Conway DI, McKinney PA, Znaor A, McCartan BE, Healy C, Nelis M, Metspalu A, Marron M, Hashibe M, Brennan PJ: Alcohol-related cancers and genetic susceptibility in Europe: the ARCAGE project: study samples and data collection. Eur J Cancer Prev 2009, 18: 76-84. 10.1097/CEJ.0b013e32830c8dcaView ArticlePubMedGoogle Scholar
- Ang KK, Harris J, Garden AS, Trotti A, Jones CU, Carrascosa L, Cheng JD, Spencer SS, Forastiere A, Weber RS: Concomitant boost radiation plus concurrent cisplatin for advanced head and neck carcinomas: radiation therapy oncology group phase II trial 99-14. J Clin Oncol 2005, 23: 3008-3015. 10.1200/JCO.2005.12.060View ArticlePubMedGoogle Scholar
- Bourhis J, Overgaard J, Audry H, Ang KK, Saunders M, Bernier J, Horiot JC, Le Maître A, Pajak TF, Poulsen MG, O'Sullivan B, Dobrowsky W, Hliniak A, Skladowski K, Hay JH, Pinto LHJ, Fallai C, Fu KK, Sylvester R, Pignon JP: Hyperfractionated or accelerated radiotherapy in head and neck cancer: a meta-analysis. Lancet 2006, 368: 843-854. 10.1016/S0140-6736(06)69121-6View ArticlePubMedGoogle Scholar
- Bernier J, Domenge C, Ozsahin M, Matuszewska K, Lefèbvre JL, Greiner RH, Giralt J, Maingon P, Rolland F, Bolla M, Cognetti F, Bourhis J, Kirkpatrick A, van Glabbeke M: Postoperative irradiation with or without concomitant chemotherapy for locally advanced head and neck cancer. N Engl J Med 2004, 350: 1945-1952. 10.1056/NEJMoa032641View ArticlePubMedGoogle Scholar
- Bonner JA, Harari PM, Giralt J, Azarnia N, Shin DM, Cohen RB, Jones CU, Sur R, Raben D, Jassem J, Ove R, Kies MS, Baselga J, Youssoufian H, Amellal N, Rowinsky EK, Ang KK: Radiotherapy plus cetuximab for squamous-cell carcinoma of the head and neck. N Engl J Med 2006, 354: 567-578. 10.1056/NEJMoa053422View ArticlePubMedGoogle Scholar
- Garden AS, Harris J, Trotti A, Jones CU, Carrascosa L, Cheng JD, Spencer SS, Forastiere A, Weber RS, Ang KK: Long-term results of concomitant boost radiation plus concurrent cisplatin for advanced head and neck carcinomas: a phase II trial of the radiation therapy oncology group (RTOG 99-14). Int J Radiat Oncol Biol Phys 2008, 71: 1351-1355. 10.1016/j.ijrobp.2008.04.006PubMed CentralView ArticlePubMedGoogle Scholar
- Garavello W, Ciardo A, Spreafico R, Gaini RM: Risk factors for distant metastases in head and neck squamous cell carcinoma. Arch Otolaryngol Head Neck Surg 2006, 132: 762-766. 10.1001/archotol.132.7.762View ArticlePubMedGoogle Scholar
- Jäckel MC, Reischl A, Huppert P: Efficacy of radiologic screening for distant metastases and second primaries in newly diagnosed patients with head and neck cancer. Laryngoscope 2007, 117: 242-247. 10.1097/01.mlg.0000248232.27668.57View ArticlePubMedGoogle Scholar
- Dietl B, Marienhagen J, Schaefer C, Pohl F, Kölbl O: [Frequency and distribution pattern of distant metastases in patients with ENT tumors and their consequences for pretherapeutic staging]. Strahlenther Onkol 2007, 183: 138-143. 10.1007/s00066-007-1611-7View ArticlePubMedGoogle Scholar
- Senft A, de Bree R, Hoekstra OS, Kuik DJ, Golding RP, Oyen WJG, Pruim J, van den Hoogen FJ, Roodenburg JLN, Leemans CR: Screening for distant metastases in head and neck cancer patients by chest CT or whole body FDG-PET: a prospective multicenter trial. Radiother Oncol 2008, 87: 221-229. 10.1016/j.radonc.2008.03.008View ArticlePubMedGoogle Scholar
- Merino OR, Lindberg RD, Fletcher GH: An analysis of distant metastases from squamous cell carcinoma of the upper respiratory and digestive tracts. Cancer 1977, 40: 145-151. 10.1002/1097-0142(197707)40:1<145::AID-CNCR2820400124>3.0.CO;2-9View ArticlePubMedGoogle Scholar
- Spector JG, Sessions DG, Haughey BH, Chao KS, Simpson J, El Mofty S, Perez CA: Delayed regional metastases, distant metastases, and second primary malignancies in squamous cell carcinomas of the larynx and hypopharynx. Laryngoscope 2001, 111: 1079-1087. 10.1097/00005537-200106000-00028View ArticlePubMedGoogle Scholar
- Kotwall C, Sako K, Razack MS, Rao U, Bakamjian V, Shedd DP: Metastatic patterns in squamous cell cancer of the head and neck. Am J Surg 1987, 154: 439-442. 10.1016/0002-9610(89)90020-2View ArticlePubMedGoogle Scholar
- Lim YC, Koo BS, Choi EC: Bilateral neck node metastasis: a predictor of isolated distant metastasis in patients with oral and oropharyngeal squamous cell carcinoma after primary curative surgery. Laryngoscope 2007, 117: 1576-1580. 10.1097/MLG.0b013e318093ee2bView ArticlePubMedGoogle Scholar
- Fakhry C, Westra WH, Li S, Cmelak A, Ridge JA, Pinto H, Forastiere A, Gillison ML: Improved survival of patients with human papillomavirus-positive head and neck squamous cell carcinoma in a prospective clinical trial. J Natl Cancer Inst 2008, 100: 261-269. 10.1093/jnci/djn011View ArticlePubMedGoogle Scholar
- Loh KS, Brown DH, Baker JT, Gilbert RW, Gullane PJ, Irish JC: A rational approach to pulmonary screening in newly diagnosed head and neck cancer. Head Neck 2005, 27: 990-994. 10.1002/hed.20261View ArticlePubMedGoogle Scholar
- Staar S, Rudat V, Stuetzer H, Dietz A, Volling P, Schroeder M, Flentje M, Eckel HE, Mueller RP: Intensified hyperfractionated accelerated radiotherapy limits the additional benefit of simultaneous chemotherapy--results of a multicentric randomized German trial in advanced head-and-neck cancer. Int J Radiat Oncol Biol Phys 2001, 50: 1161-1171. 10.1016/S0360-3016(01)01544-9View ArticlePubMedGoogle Scholar
- Semrau R, Mueller RP, Stuetzer H, Staar S, Schroeder U, Guntinas-Lichius O, Kocher M, Eich HT, Dietz A, Flentje M, Rudat V, Volling P, Schroeder M, Eckel HE: Efficacy of intensified hyperfractionated and accelerated radiotherapy and concurrent chemotherapy with carboplatin and 5-fluorouracil: updated results of a randomized multicentric trial in advanced head-and-neck cancer. Int J Radiat Oncol Biol Phys 2006, 64: 1308-1316. 10.1016/j.ijrobp.2005.10.039View ArticlePubMedGoogle Scholar
- Denis F, Garaud P, Bardet E, Alfonsi M, Sire C, Germain T, Bergerot P, Rhein B, Tortochaux J, Calais G: Final results of the 94-01 French Head and Neck Oncology and Radiotherapy Group randomized trial comparing radiotherapy alone with concomitant radiochemotherapy in advanced-stage oropharynx carcinoma. J Clin Oncol 2004, 22: 69-76.View ArticlePubMedGoogle Scholar
- Adelstein DJ, Saxton JP, Rybicki LA, Esclamado RM, Wood BG, Strome M, Lavertu P, Lorenz RR, Carroll MA: Multiagent concurrent chemoradiotherapy for locoregionally advanced squamous cell head and neck cancer: mature results from a single institution. J Clin Oncol 2006, 24: 1064-1071. 10.1200/JCO.2005.01.5867View ArticlePubMedGoogle Scholar
- Sanghera P, McConkey C, Ho KF, Glaholm J, Hartley A: Hypofractionated accelerated radiotherapy with concurrent chemotherapy for locally advanced squamous cell carcinoma of the head and neck. Int J Radiat Oncol Biol Phys 2007, 67: 1342-1351. 10.1016/j.ijrobp.2006.11.015View ArticlePubMedGoogle Scholar
- Teguh DN, Levendag PC, Noever I, Voet P, van der Est H, van Rooij P, Dumans AG, de Boer MF, van der Huls MPC, Sterk W, Schmitz PIM: Early hyperbaric oxygen therapy for reducing radiotherapy side effects: early results of a randomized trial in oropharyngeal and nasopharyngeal cancer. Int J Radiat Oncol Biol Phys 2009, 75: 711-716. 10.1016/j.ijrobp.2008.11.056View ArticlePubMedGoogle Scholar
- Brockstein B, Haraf DJ, Rademaker AW, Kies MS, Stenson KM, Rosen F, Mittal BB, Pelzer H, Fung BB, Witt ME, Wenig B, Portugal L, Weichselbaum RW, Vokes EE: Patterns of failure, prognostic factors and survival in locoregionally advanced head and neck cancer treated with concomitant chemoradiotherapy: a 9-year, 337-patient, multi-institutional experience. Ann Oncol 2004, 15: 1179-1186. 10.1093/annonc/mdh308View ArticlePubMedGoogle Scholar
- León X, Quer M, Orús C, del Prado Venegas M, López M: Distant metastases in head and neck cancer patients who achieved loco-regional control. Head Neck 2000, 22: 680-686. 10.1002/1097-0347(200010)22:7<680::AID-HED7>3.0.CO;2-JView ArticlePubMedGoogle Scholar
- Alvi A, Johnson JT: Development of distant metastasis after treatment of advanced-stage head and neck cancer. Head Neck 1997, 19: 500-505. 10.1002/(SICI)1097-0347(199709)19:6<500::AID-HED7>3.0.CO;2-2View ArticlePubMedGoogle Scholar
- Mazer TM, Robbins KT, McMurtrey MJ, Byers RM: Resection of pulmonary metastases from squamous carcinoma of the head and neck. Am J Surg 1988, 156: 238-242. 10.1016/S0002-9610(88)80282-4View ArticlePubMedGoogle Scholar
- Finley RK, Verazin GT, Driscoll DL, Blumenson LE, Takita H, Bakamjian V, Sako K, Hicks W, Petrelli NJ, Shedd DP: Results of surgical resection of pulmonary metastases of squamous cell carcinoma of the head and neck. Am J Surg 1992, 164: 594-598. 10.1016/S0002-9610(05)80714-7View ArticlePubMedGoogle Scholar
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