IASLC 2011 Report – Management of pancoast tumours

by Dr Sunil Upadhyay – In 1838 E. S. Hare published work about tumours involving certain nerves.¹ However, Henry Pancoast, a radiologist from Philadelphia described the classical clinical presentation of pain of the eighth cervical or the first and second thoracic trunk associated with classical Horner syndrome, atrophy of the hand muscle and rib destruction. This he termed a superior pulmonary sulcus tumour at the American Medical Association meeting in 1932.²

Despite their peripheral position, the majority of these tumours are squamous cell carcinomas. Nearly 5% of all lung cancers are Pancoast tumours and chest CT scan is invariably indicated. The extent of the tumour, however, can be better delineated by MRI with or without a bone scan. In the current day and age PET scan should be desirable despite limited data. CT (or ultrasound) guided biopsy is commonly required to obtain the histological confirmation and molecular profiling.

Unfortunately, there is no standard treatment for Pancoast tumours. It remains one of the most challenging malignancies and is still considered fatal by many clinicians. According to the Japanese Association for Thoracic Surgery, only 139 cases (0.5%) were for Pancoast tumours among 27,387 cases surgically treated for primary lung cancer in 2008. Presence of mediastinal and/or supra-clavicular nodes, involvement of brachial plexus and distance metastasis at the time of initial presentation makes most of the tumours inoperable. The surgical treatment of Pancoast tumours continues to evolve and the choice of surgical approach is very important for en-bloc resection of Pancoast tumours.

Since successful curative resection is rare, a multi-modality approach is commonly employed. The results of the SWOG trial (9416) using induction concurrent chemo-radiotherapy (cisplatin, etoposide and 45 Gy of radiation) followed by surgery is the most preferred option with survival as high as 53% in completely resected patients.³ The Japan Clinical Oncology Group used mitomycin, vindesine, cisplatin and 45 Gy of radiotherapy in 76%. Complete resection was achieved in 68% and their 5-year survival was 56%. (Abstract GR02.4).

The majority of the inoperable Pancoast tumours are treated with radiotherapy with or without chemotherapy with palliative intent. However, CT and PET scan revolutionised the radiation oncologist’s ability to select patients and define targets. This then formed the foundation of 3D- and 4D treatment planning. IMRT, rapid arc therapy which requires good immobilisation and medical physicist’s collaboration has allowed dose escalation and normal tissue sparing, leading to better outcome and less toxicity. However, radiation dose escalation for Pancoast/apical non-small cell lung cancers may be limited by the proximity of tumours to the brachial plexus. The radiation tolerance of the brachial plexus and radiation induced brachial plexopathy (RIBP) are poorly understood. The results of a retrospective study from the USA, the incidence of RIBP and tumour related brachial plexopathy (TRBP) and associated dosimetric parameters in patients treated with curative intent was presented. The records of NSCLC patients with primary upper lobe, superior mediastinal nodal, or supraclavicular/cervical neck disease treated with definitive radiation or chemoradiotherapy between 2004 and 2010 was analysed. Brachial plexopathy was defined as the development of new neuropathic pain, motor weakness or sensory disturbances in the ipsilateral shoulder/arm after treatment. Ninety two patients were identified with a median follow-up of 16.5 months (range 1-70) and survival time of 12.5 months (range 1-38). The mean prescribed dose was 68.9 Gy ± 0.7 (range 57.4 – 84.0) and the mean maximal brachial plexus dose was 59.7 Gy (range 0.5 – 90.9). Seventy two patients received either concurrent or sequential chemotherapy. Twelve patients were found to have developed symptoms consistent with brachial plexopathy.

 

	No (%)	CTCAE V 4.0 grade	chemo- therapy	Mean brachial plexus Dose	Mean prescribed tumour dose	Median time to symptom (months)
Radiation induced	4 (4%)	II: 3 III: 1	Concurrent -2 Sequential -2	84.6 Gy	79.0 Gy	4.5
Tumour related	8 (8%)	II: 5 III: 3	Concurrent: 6 Sequential: 2	47.2 GY	67.0 Gy	6.0

The investigators concluded that the brachial plexus frequently receives radiation doses exceeding historically RTOG dose constraints (60-66 Gy) in patients with apical tumours treated with definitive radiation or chemo-radiotherapy. While a high percentage of patients are at risk of developing symptomatic tumour-related brachial plexopathy following recurrence, no patient who received a maximum dose of <79 Gy to the brachial plexus developed radiation induced plexopathy, The findings strongly suggest that primary tumour control with adequate doses of radiation outweighs the low risk of RIBP. (Abstract O02.02).

 

References:

1. Hare ES. Tumour involving certain nerves. Lond Med Gaz. 1838; 1: 16-18
2. Pancoast HK. Superior pulmonary sulcus tumor: Tumor characterized by pain, Horner’s syndrome, destruction of bone and atrophy of hand muscles. JAMA. 1932; 99: 1391-1396.
3. Rusch VW, Giroux DJ, Kraut MJ, Crowley J, Hazuka M et al JCO 2007; 25: 313-318