Page 395 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

CHAPTER 20 Melanoma 373

TABLE 20.1 Published Studies on the Treatment of Oral Melanoma with Radiation Therapy—cont’d
Study, Study Type Source and Dose/Protocol of
VetBooks.ir (Year Published) Species (No.) Radiation Outcomes Chemotherapy

Cancedda et al, Prospec-
tive multicenter, non- Canine (27) Linear accelerator using Radiation therapy alone group: No chemotherapy given to
3/15 dogs had a complete
15. 12 received temozolomide
photons or electrons. Energy
2
randomized, two-arm not specified. 30 Gy in five response and 10/15 dogs had at 60 mg/m PO once daily for
clinical trial (2016) 136 fractions over 2.5 weeks. a partial response; PFS 110 5 days every 4 weeks.
days; MST: 192 days.
RT and temozolamide group:
2/15 dogs had a complete
response and 8/15 dogs had
a partial response. PFS of 205
days. MST: 401. Statistically
significant difference for PFS
but not MST.
Tollett et al, Retrospective Canine (11) 6 MV linear accelerator. 32 Gy in 0/11 dogs had a complete or par-
case series (2016) 141 four once-weekly 8-Gy frac- tial response. MST: 134 days.
tions (n = 9) or 36 Gy in six
once- or twice-weekly 6-Gy
fractions (n = 2).
IV, Intravenous; MST, median survival time; PFS, progression-free survival; PO, per os.

P P

L R L R

A A B A
• Fig. 20.8 Postcontrast axial computed tomography (CT) image of a dog with metastasis to the left man-
dibular lymph nodes (A, arrows) and the enlarged left medial retropharyngeal lymph node (B, arrow). Note
the heterogeneous contrast enhancement in both lymph nodes.

radiation protocol consisted of six once-weekly 6 Gy fractions. there may be a role for chemotherapy in the treatment of oral
Local recurrence was reported in 15% of dogs, the median time melanoma in combination with RT. In a multicenter retrospective
to metastasis was 10.2 months, and the MST was 11.9 months. study of 17 dogs with oral melanoma treated with surgery and
These results may have been favorably biased because the majority carboplatin, including 11 dogs also treated with RT, the overall
of dogs had either T1 (56.4%) or T2 (35.9%) stage melanomas. median PFS (259 days) and MST (440 days) for dogs did not
Several studies have looked at using adjuvant chemotherapy in significantly change when RT was added to the treatment pro-
addition to RT. Administered drugs included carboplatin, cispla- tocol. 135 The proportion of dogs with local recurrence, however,
tin, or melphalan. Adding chemotherapy to the radiation protocol was lower in the RT group (27%) compared with dogs not treated
did not improve outcomes. 107 However, two studies suggest that with RT (67%). The authors concluded that there may be a role