Author of

• 11946

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  P2.24 - Poster Session 2 - Supportive Care (ID 157)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Supportive Care
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 11950

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    P2.24-004 - Chest Wall toxicity following SABR for early lung cancer: A dosimetric analysis. (ID 652)

    09:30 - 09:30  |  Author(s): J. Littler
    • Abstract

    Background
    SABR is well established in medically inoperable patients with early lung cancer. These patients are usually elderly with multiple comorbidities. Chest wall toxicity is seen in 15% of cases, however in radiotherapy planning no chest wall constraints are used to minimise this risk. Some centres actively exclude the chestwall from PTV margin and some feel that the risk of sustaining a fracture is as high with 3 as with 5 fractions as rib is likely to behave similar to a serial structure.

    Methods
    Of the 85 patients treated with SABR from 2009 to 2013, cases with at least one year follow up were audited. Patients were treated with 18 Gy x 3# and 11 Gy x 5# on alternate days. Chest wall was defined as 3cm from the ipsilateral lung border excluding the skin. For the chest wall, the maximum dose and volume getting 30, 40 and 50 Gy was recorded. Patients were followed up three monthly for the first year with CT imaging and toxicity was scored using CTCAE v3.0. Dosimetric parameters were correlated against chest pain and rib fracture.

    Results
    50 patients with a median age of 70 (range 56-89) and follow up of 16.8 (range 1.2-44.9) months were audited. The majority (62%) of the patients had a PS of 2 and 66% had a T1 tumour. 6 patients developed a rib fracture and patients complained of dysaesthesia/chest pain. One patient sustained fractures in three adjacent ribs at two different time points. The rate of any grade rib fracture and chest pain was 12% and 16% respectively with median time to development of respective toxicities of 15.6 and 4.6 months. Grade 3 rib fracture was seen in one patient. All of the patients that sustained rib fracture/chest pain had SABR delivered over 5 fractions as the PTV overlapped the chest wall. Median survival is 34 months with a 1 year survival of 88%. No correlation was seen between rib fracture and chest wall dosimetric parameter. However chest pain correlated well to all dosimetric parameters.

    Conclusion
    Our series shows a similar rate of chest wall toxicity to that reported in the literature, which is largely less than grade 3 in severity. However it is important to minimize this side effect as much as possible as the patient population currently being treated with SABR is elderly with multiple comorbidities. As the incidence of this toxicity is low, large patient data is needed to identify useful dosimetric parameters to predict chest wall toxicity. Developing SABR in the UK within the consortium structure with national guidelines opens up the potential to obtain and analyse such data. However there are logistical challenges of pooling data across various hospitals.